bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the Smart Diagnosis of Gas Turbine With Distributed Computing Technique
Authors: Wu Hang , Chen Jinwei , Zhang Huisheng
Published: November 2019

Monitoring and diagnosis of a gas turbine is a critical issue in equipment maintenance field. Traditional diagnosis methods are established on the basis of physical models. However, the complexity and degradation of gas turbine limit both comprehensiveness and accuracy of these physical models, making the diagnosis less effective. Therefore, data-driven models are introduced to supplement and revise previous models.

Benefitting from the prosperous development of machine learning, neural network has been greatly improved and widely used in various fields of data mining. Three neural networks, Multilayer Perceptron, Convolutional Neural Network and Long Short-term Memory Network are applied in data-driven model establishment. Their training time and prediction accuracy are the two most important factors in judging the effectiveness.

An active real time training which means training and predicting simultaneously is applied as the main modelling method for an on-line diagnosis system. Three periods are defined according to the time line: data preparation period, model establishing period and stable prediction period. From the three above neural networks, the most effective data-driven models that corresponding to the last two periods are tested and selected, the purpose is to ensure the high level of accuracy.

When high level of accuracy is demanded, neural network always need large computing time and memory space in data learning process. To avoid prediction delay and keep rapid response for the coming fault, distributed training on a 1-master 2-workers computer cluster is designed and applied in this system. Two types of data parallelism are realized on the cluster through Apache Spark and Shell Script for Linux. Comparing with each other and the local training mode, the results shows that dispensing data at first and averaging parameters at last reaches a better outcome both in high accuracy and low training time.
Accurate Field Compressor Inlet Flow Measurement System
Authors: McConkey Joshua , Bunce Richard H. , Claussen Heiko
Published: November 2019

Understanding the amount of air that enters a gas turbine is important for calculating their performance and efficiency. Flow meters are almost never used to measure that flow in production engines. Typical flow meters are impractical because the air flow into the compressor is very large, up to 1400 lbs/s (635 kg/s) or 1,000,000 ft3/min (28,300 m3/min), and typically an intentional pressure drop is involved in the measurement. This pressure drop negatively impacts the performance of the engine. If inlet air mass flow were known accurately without negatively impacting the engine performance, then engines could be run more efficiently. Currently, inlet mass flow is typically inferred, rather than measured. This leads to increased safety margins which require engines to be run more conservatively, i.e., at lower power. This paper describes a novel, inexpensive, and accurate air mass flow measurement system with negligible impact on engine performance.
AeroEngineS: Multi-Platform Application for Aero Engine Simulation and Compressor Map Operating Point Prediction
Authors: Pontika Evangelia C. , Kalfas Anestis I. , Aslanidou Ioanna
Published: November 2019

This paper presents the development of AeroEngineS (Aircraft Engine Simulation), a multi-platform app with graphical user interface for aero engine simulation and compressor map operating point prediction.

Gas turbine performance simulation is a crucial part of the design process. It provides information about the required operating conditions of all the components and the overall performance of the engine so that engineers can determine whether the current engine configuration meets the performance requirements. Some gas turbine simulation programs have been developed in the last decades, however, there was a lack of an open-source, lightweight, user-friendly, but still very accurate, application which would be easily accessible from all platforms.

AeroEngineS can be used as a user-friendly preliminary design tool, since, during this design phase, details about the geometry are not known yet. The main aim is to calculate simply and quickly the basic parameters of the thermodynamic cycle and the performance, in order to determine which design is able to meet the required specifications. AeroEngineS constitutes a free and simple app which can primarily serve educational purposes as it is easily accessible by students from any platform to assist them in aero engine technology courses. Secondarily, it has the potential to be used even by engineers as a quick tool accessible from all devices.

The app consists of two basic stand-alone functions. The first function is aero engine simulation at Design Point which solves thermodynamic calculations. The second function is compressor map operating point prediction using a novel method of combining scaling techniques and Artificial Neural Networks.
High Pressure Novel Single Hub Multi-Rotor Centrifugal Compressor: Performance Prediction and Loss Analysis
Authors: Muppana Sai , Siddappaji Kiran , Abdallah Shaaban
Published: November 2019

Blade loading on a single stage high pressure centrifugal compressor is limited due to separation that might occur on the suction side of the airfoil at mass flow rates lower than design point. A novel configuration of centrifugal compressor is designed and analyzed to overcome this issue by placing multiple rotors on the same hub with a stator vane in between similar to a multi-stage axial compressor blade arrangement. By having independent rotors, blade loading can be distributed more efficiently and higher pressure rise can be achieved through this design. As the blade chord length is reduced due to splitting of single impeller blade, the effective turning angle is divided through several stages thereby lowering the adverse pressure gradient reducing the chance of separation. Stator vanes are placed in between the rotors so that the successive rotor receives the flow at desired incidence angle. The attempt here is to apply the same principle of axial compressor multi-staging on a centrifugal compressor and compare the performance with single stage using low to high fidelity analysis framework developed in-house. A low fidelity 1D analysis tool CIMdes is used for evaluating blade angles and stage degree of reaction which are exported to T-blade3, in-house parametric geometry tool, for 3D blade generation. These blades are further analyzed using 3D CFD analysis using an in-house automated multifidelity framework. Loss quantification revealed that diffuser losses are higher in singlestage and the novel design increased the backsweep angle resulting in lower diffuser losses. Splitting the single rotor facilitated the increase in backsweep angle to a larger range as compared to single rotor impeller configurations. Two configurations with different shroud height for the single stage compressors are investigated and compared with the novel compressor with respective flowpaths at 100% speedline using a multi-fidelity design analysis suite. The flow capacity is extended near the stall with a penalty in efficiency for configuration-1. Configuration-2 showed an improvement in efficiency at design mass flow rate. The preliminary analysis demonstrates the advantages of the multi-staging on the same hub and extends the design space for performance range improvement with some trade-offs.
Combustion Characterization of a Fuel-Flexible Piloted Liquid-Spray Flame Apparatus Using Advanced Laser Diagnostics
Authors: Wang Yejun , Paschal Tyler , Kulatilaka Waruna D.
Published: November 2019

Primary energy sources for aviation gas turbines as well as direct-injection gasoline and diesel engines come in the form of liquid hydrocarbon fuels. These liquid fuels are atomized and mixed with air, prior to highly turbulent combustion and heat release processes inside engine hardware. Designing more efficient and cleaner gas turbine engines is hence dependent on the in-depth understanding of spray formation, mixing, heat release, combustion dynamics, and pollutant formation pathways in liquid-fuel spray flames. As compared to gaseous fuels, the additional steps of atomization, dispersion, and evaporation prior to turbulent mixing need to be considered for a variety of liquid fuels to enable fuel-flexible operation of these combustion hardware. Such studies can be largely facilitated by advanced laser diagnostics applied to simplified piloted liquid-spray flame configurations that can also be numerically modeled using well-defined boundary conditions. In this work, a modified configuration of a fuel-flexible piloted liquid-spray flame apparatus is used for detailed laser diagnostics studies using hydroxyl (OH) planar imaging. The configuration consists of a modified McKenna flat-flame burner fitted with a direct-injection high-efficiency nebulizer. OH radical is a primary marker of the reaction zone and a key indicator of the heat release process in flames. OH is abundant in the high-temperature combustion regions providing high signal-to-noise ratio single-laser-shot images revealing flame dynamics and instabilities. Therefore, OH planar laser-induced fluorescence (PLIF) is employed to characterize the dynamic structures of a range of piloted liquid-spray flames operated with methanol (CH3OH), n-Heptane (C7H16), iso-Octane (C8H18), dodecane (C12H26), gasoline (C4–C12), diesel (C12–C20), and kerosene (C6–C16). Single-shot and averaged OH-PLIF images show the presence of strong turbulence in the core region above the surface of the McKenna burner. The reaction zone mainly occurs around the periphery of this region, then it spreads more uniformly due to evaporation of liquid droplets downstream of the spray flame. Two-color OH PLIF thermometry in liquid spray flames operated with gasoline, diesel and kerosene, has been shown that the combustion temperature is in the range of 1200–2000 K. Overall, OH PLIF has been demonstrated to be an efficient approach for dynamic structures and temperature measurements in piloted liquid-spray flames operated with realistic fuels.
Response Surface Mapping and Multi-Objective Optimization of Crowning and Tapers in Water-Lubricated Thrust Bearings
Authors: Deng Xin , Watson Cori , He Minhui , Fittro Roger , Wood Houston
Published: November 2019

Fluid film bearings for turbomachinery are designed to support the loads applied by the rotor system. Oil-lubricated bearings are widely used in high speed rotating machines. However, environmental issues and risk-averse operations have made water lubricated bearings increasingly popular. Due to different viscosity properties between oil and water, the low viscosity of water decreases film thickness significantly. Crowning and tapers are two main ways to maintain the film thickness requirements in water lubrication, but no studies about the influence of these parameters on the film thickness in water-lubricated bearings have been reported. Therefore, further understanding of the performance associated with optimizing the bearing design with different weighted performance and their relationships to bearing design variables could be invaluable to bearing design engineers.

This study explores the impact of three crowning and taper design variables on the performance of one tilting pad thrust bearing using the design of experiments techniques applied to a thermoelastohydrodynamic (TEHD) bearing model. The bearing design variables analyzed in this study include the radius of the ground-in crown, taper circumferential angle offset, and the vertical taper distance at the inner and outer radii. Each of the design variables is first varied over five levels, each in central composite design. The outputs from the TEHD numerical simulations used as performance measures for each bearing design point were the minimum film thickness, the film thickness at the pivot location, maximum film pressure and power loss.

Multi-objective optimization was performed. A range of weighting parameters was selected for the optimization function to find a bearing design that maintains the minimum film thickness criterion while minimizing power loss. The resulting optimum design points allowed for a comparison between the design optimization at different weightings. This study demonstrates how designers can use these approaches to view the relationships between design variables and important performance metrics to design better bearing for a wide range of applications.
Numerical Investigation of Pin-Fin Influences on Cooling Air Flow Characteristics in Blade Trailing Edge Region
Authors: Wu Weilong , Xu Huazhao , Wang Jianhua , Wu Xiangyu , Wang Lei
Published: November 2019

This paper numerically investigated the influences of pin-fin size and layout on the flow characteristics of cooling air in the trailing edge of a real low pressure turbine blade. The discussion was given first for the baseline model without pin fins (denoted as M0) under a turbine design condition and two off design conditions. Then a comparison of the flow fields in the turbine blade especially in the trailing edge region was performed with three more trailing edge models, with the purpose of discovering the benefits of using pin fin configurations in a real low pressure turbine blade. The other three models (denoted as M1, M2, M3) have pin fins in different diameters and arrangements. The M1 model has a row of 13 pin fins with a diameter of 2mm, and the M2 and M3 models have two rows of pin fins arranged in a staggered pattern with a diameter of 1.2mm. Compared to the baseline model M0, it is shown that an addition of pin fin configurations helps greatly to improve cooling flow distributions and to mitigate the blockage of coolant in trailing slots. Meanwhile, the adoption of pin fins has not only affected significantly the flow field in the trailing passage but also has moderately affected flow fields in the middle and forward cooling passages. Increasing pressure ratio can increase total mass flow rate with no significant change in flow patterns. The baseline blade Model M0 shows a high value of 6 for a friction loss related performance function at the turbine design condition. However, only a moderate increase in the value of the performance function is discovered for all the three blades with pin fins.
Design and Maintenance Issues of Being Able to Repair Marine Gas Turbines Without Removal From the Ship
Authors: Thompson Bruce D. , Hartranft John J. , Groghan Dan
Published: November 2019

When the concept of aircraft derivative marine gas turbines were originally proposed, one of the selling points was the engine was going to be easy to remove and replace thereby minimizing the operational impact on the ship. Anticipated Mean Time Between Removal (MTBR) of these engines was expected to be approximately 3000 hours, due mostly to turbine corrosion damage. This drove the design and construction of elaborate removal routes into the engine intakes; the expected time to remove and replace the engine was expected to be less than five days. However, when the first USN gas turbine destroyers started operating, it was discovered that turbine corrosion damage was not the problem that drove engine maintenance. The issues that drove engine maintenance were the accessories, the compressor, combustors and engine vibration. Turbine corrosion was discovered to be a longer term affect. This was primarily due to the turbine blade and vane coatings used and intake air filtration. This paper discusses how engine design, tooling development, maintenance procedure development and engine design improvements all contributed to extending the MTBR of USN propulsion and electrical power generation gas turbines on the DD 963, CG 47, DDG 51 and FFG 7 classes to greater than 20,000 hours. The ability to remove the gas turbine rapidly or in most cases repair the engine in-place has given the USN great maintenance flexibility, been very cost effective and not impacted operational readiness.
Structural Optimization of Fir-Tree Root and Groove for Turbine Blade With Superellipse and P-Norm Aggregation Function
Authors: Yu Deqi , Zhang Xiaojuan , Yang Jiandao , Cheng Kai , Li Ming
Published: November 2019

Due to its finite size and the large centrifugal load, the fir-tree root is highly stressed, which leads to the possible early failure of the gas turbine and steam turbine. To find an optimized fir-tree root is an important issue for the design of the turbine structures. In this paper, a superellipse-based design optimization approach is proposed for the fir-tree root. Rather than the straight line and arc used in literature, the combination of the superellipse curve and line are employed to characterize the fir-tree root since the superellipse curve represents a large family of curves with limited parameters, which makes the design optimization easy and economic. For the design optimization, the objective function is to minimize the peak stress, which is a typical min-max problem with possible severe iterative oscillation and subsequent convergence difficulty. To avoid this problem, a P-norm aggregation function is proposed. The superellipse parameters are defined as design variables, while the stress concentration factor and the stress at root neck are specified as optimization constraints. With the P-series fir-tree root design as example, it is proved that our approach is effective to find the optimized configuration with better stress distribution and lower stress concentration.
The Influence of Geometric and Aerodynamic Boundary Conditions on Fuel Injector Feed and External Aerodynamics for Lean Burn Combustors
Authors: Li Y. , Denman P. A. , Walker A. D.
Published: November 2019

Lean burn combustion is currently a preferred technology to meet the future low emission requirements faced by aero gas turbines. Previous work has shown that the increased air mass flow and size of lean burn fuel injector alters the necessary redistribution of the airflow leaving the high-pressure compressor. This can lead to flow field non-uniformities in the feed to combustor annuli and the fuel injectors which have the potential to impact the overall performance of the combustion system. This paper presents a systematic assessment of the effect of several aerodynamic parameters on the air flow feed to the fuel injectors and the external combustion system aerodynamics for a generic lean burn system. This includes the effect of changes to the flow splits between various combustor cooling features and annulus flows and the effect of a biased compressor exit profile. Flow field data are generated using an isothermal RANS CFD model which is validated against test rig data. The data show that changes in the flow split between the annuli modified the flow uniformity and loss to both the combustor annuli and the fuel injector feed. Changes in the compressor exit profile have a larger effect introducing more notable variations in both flow uniformity and loss. Changes to the angle of the flame tube did not greatly affect the pre-diffuser but did modify annulus loss. Further analysis showed that changes to the combustor annulus flow split, compressor exit profile and flame tube angle modified the location, at compressor exit, of the flow captured by the annuli or each fuel injector passage. The loss to each of these depends on the flow quality (total pressure and uniformity) and from the source more than the flow uniformity delivered.
Vibration Analysis of a Mistuned Axial Turbine Blisk
Authors: Beirow Bernd , Kühhorn Arnold , Figaschewsky Felix , Bornhorn Alfons
Published: November 2019

An axial turbine blisk for turbocharger applications is analyzed with respect to the effect of intentional mistuning on the forced response. Originally, the intentional mistuning pattern has been designed by employing a genetic algorithm optimization in order to reduce the forced response caused by low engine order excitation (LEO) of the fundamental flap mode. The solution found has been implemented in a prototype of that blisk. For the purpose of comparison, a second reference blisk has been manufactured without intentional mistuning. The actual mistuning distributions of the blisks have been identified by employing blade-by-blade impact testing. Alternatively, a new inverse approach has been employed, which is based on a least squares formulation and benefits from less experimental effort. Based on the information gained by the aforementioned testing procedures, subset of nominal systems (SNM)-models have been updated, which allow for considering the aeroelastic coupling by means of aerodynamic influence coefficients (AIC). Despite of small but unavoidable deviations from the design intention it could be proved within numerical simulations that the intended 70 per cent reduction of the maximum forced response is nevertheless achieved.

In addition, the paper is addressing the effect of the aforementioned intentional mistuning pattern on a higher mode, which is relevant for the durability as well. Hence, new SNM-models have to be updated in order to calculate the forced response due to EO-excitation caused by the nozzle guide vane. Although the original mistuning pattern has been optimized solely for reducing the forced response of the fundamental flap mode, it hardly affects the higher mode forced response in a negative manner.
The Influence of Fan Root Flow on the Aerodynamics of a Low-Pressure Compressor Transition Duct
Authors: Walker A. D. , Mariah I. , Tsakmakidou D. , Vadhvana H. , Hall C.
Published: November 2019

To reduce fuel-burn and CO2 emissions from aero gas turbines there is a drive towards very-high bypass ratio and smaller ultra-high-pressure ratio core engine technologies. However, this makes the design of the ducts connecting various compressor spools more challenging as the higher required radius change increases their aerodynamic loading. This is exacerbated for the duct which feeds the engine core as it must accept the relatively low-quality flow produced by the fan root. This is characterised by a hub-low pressure profile and large secondary flow structures which will inevitably increase loss and the likelihood of flow separation. Additionally, the desire for shorter, lighter nacelles means that the engine intake may be unable provide a uniform inlet flow to the fan when the aircraft is at an angle of attack or subject to cross winds. Any inlet distortion this generates can also further degrade the quality of the flow entering the core of the engine. This paper uses a combination of experiments and CFD to examine the effects of the inlet flow on the aerodynamics of an engine section splitter and transition duct designed to feed the low-pressure spool of a high bypass ratio turbofan. A fully annular test facility incorporating a 1½ stage axial compressor was used to compare the system performance of a rotor that produced a nominally flat profile with one that had a notably hub deficient flow. A RANS CFD model, employing a mixing plane between the rotor and Engine Section Stator (ESS) and a Reynolds Stress turbulence model, was then validated and used to further investigate the effects of increased inlet boundary layer thickness and bulk swirl distortion at rotor inlet.

Overall, changes to the inlet condition were seen to have a surprisingly small effect on the flow at duct exit — i.e. the flow presented to the downstream compressor. Changes to the inlet did, however, generate increased secondary flows and degrade the performance of the ESS. This resulted in notably increased total pressure loss; in excess of 12% for the hub-low inlet and in excess of 30% at high inlet swirl where the flow in the ESS separated. However, the increased ESS wake structures, and the enhanced mixing, delayed separation in the duct suggesting that, overall the design was reasonably robust, albeit with a significant penalty in system loss.
Thermal Characterization of a Turbulent Free Jet With Planar Laser Induced Fluorescence (PLIF)
Authors: Seitz Sara , Wright Lesley M.
Published: November 2019

Two-color, toluene based, planar laser induced fluorescence (PLIF) is utilized to characterize the thermal structure of a turbulent, free jet. The PLIF technique has been used to measure concentration gradients for combustion applications, but its use to quantify thermal gradients is limited. To validate the method, compressed air is seeded with toluene particles. The seeded airflow is heated to temperatures varying from 300–375 K, and the heated jet exits a 1.27-cm diameter orifice into quiescent, room temperature air. The jet Reynolds number is varied from 5,000 to 15,000. As the jet exits the orifice, the toluene particles fluorescence across a 266 nm laser light sheet which ultimately provides a two-dimensional temperature distribution of the free jet. The rigorous calibration procedure for the PLIF technique is described along with the seeding nuisances needed to quantify the thermal structure of the jets. The PLIF technique has been demonstrated for this fundamental flow field, and it has proven to be applicable to more complex heat transfer and cooling applications. Furthermore, the time averaged temperature distributions obtained in this investigation can be used in the validation of turbulent CFD solvers.
On the Application of Particle Image Velocimetry for Turbofan Engine Flow Quantification
Authors: Sluss Dillon P. , George William M. , Lowe K. Todd
Published: November 2019

Given the robustness and maturity of contemporary particle image velocimetry (PIV) methods, detailed flow measurements are now possible in actual turbine engine environments. For instance, flow non-uniformity measurements are possible in fan outlet gas-paths by adapting PIV hardware to the restricted access afforded in such applications. In the present work, a framework is proposed and demonstrated for planning and executing stereoscopic PIV measurements in the fan outlet duct of a Pratt & Whitney Canada JT15D-1A research turbofan engine. Two case studies have been carried out by following this framework in order to demonstrate two different imaging methods — conventional lens/camera coupling and endoscopic imaging. A key step within the planning and execution framework is risk reduction, and this step resulted in considerable refinement of the methods in both cases. For instance, in endoscopic imaging, the risk reduction provided a new fluorescent paint application for obtaining near wall data not previously possible. The data obtained in the engine experiments have been used to quantify the uncertainty for both imaging methods, not surprisingly revealing 50% greater average uncertainties for endoscopic PIV versus conventional lens/camera imaging. The results from the case studies indicate that both imaging methods may be practically and economically implemented for detailed measurements in fan outlet ducts, and application demands may be carefully considered, and risks reduced, using the framework proposed.
Antipointing Reaches Do Not Adhere to Width-Based Manipulations of Fitts’ (1954) Equation
Authors: Pecora Marlowe , Tremblay Luc , Heath Matthew
Published: November 2019

Reaches with overlapping stimulus-response spatial relations (propointing) adhere to speed–accuracy relations as defined by Paul Fitts’ index of difficulty equation (IDFitts: in bits of information). This movement principle is attributed to response mediation via the “fast” visuomotor networks of the dorsal visual pathway. It is, however, unclear whether the executive demands of dissociating stimulus-response spatial relations by reaching mirror-symmetrical to a target (antipointing) elicits similar adherence to Fitts’ equation. Here, pro- and antipointing responses were directed to a constant target amplitude with varying target widths to provide IDFitts values of 3.0, 3.5, 4.3, and 6.3 bits. Propointing movement times linearly increased with IDFitts—a result attributed to visually based trajectory corrections. In contrast, antipointing movement times, deceleration times, and endpoint precision did not adhere to Fitts’ equation. These results indicate that antipointing renders a “slow” and offline mode of control mediated by the visuoperceptual networks of the ventral visual pathway.
Nucleotide exchange–dependent and nucleotide exchange–independent functions of plant heterotrimeric GTP-binding proteins
Authors: Maruta Natsumi , Trusov Yuri , Chakravorty David , Urano Daisuke , Assmann Sarah M. , Botella Jose R.
Published: November 2019

G protein α subunits in
Arabidopsis
can function independently of guanine nucleotide exchange.
Foot-and-Mouth Disease Virus Capsid Protein VP1 Interacts with Host Ribosomal Protein SA To Maintain Activation of the MAPK Signal Pathway and Promote Virus Replication
Authors: Zhu Zixiang , Li Weiwei , Zhang Xiangle , Wang Congcong , Gao Lili , Yang Fan , Cao Weijun , Li Kangli , Tian Hong , Liu Xiangtao , Zhang Keshan , Zheng Haixue
Published: November 2019

Identification of virus-cell interactions is essential for making strategies to limit virus replication and refine the models of virus replication. This study demonstrated that FMDV utilized the MAPK pathway for viral replication. The host RPSA protein inhibited FMDV replication by suppressing the activation of the MAPK pathway during FMDV infection. FMDV VP1 bound to RPSA to repress the RPSA-mediated regulatory effect on MAPK pathway activation. This study revealed an important implication of the MAPK pathway for FMDV infection and identified a novel mechanism by which FMDV VP1 has evolved to interact with RPSA and maintain the activation of the MAPK pathway, elucidating new information regarding the signal reprogramming of host cells by FMDV.
Genome Sequence of Arthrobacter sp. UKPF54-2, a Plant Growth-Promoting Rhizobacterial Strain Isolated from Paddy Soil
Authors: Shen Weishou , Yu Xinchun , Gao Nan , Ota Sayuri , Shiratori Yutaka , Nishizawa Tomoyasu , Isobe Kazuo , He Xinhua , Senoo Keishi
Published: November 2019

Arthrobacter
sp. strain UKPF54-2, a plant growth-promoting rhizobacterium having the potential ability to control fungal and bacterial pathogens, was isolated from paddy soil in Kumamoto, Japan. We report here the whole-genome sequence of this strain.
Draft Genome Sequence of Bacillus cereus ET31, Isolated from an Extreme Environment
Authors: Stathopoulou Panagiota , Nikolaki Sofia , Lanara Maria , Tsiamis George
Published: November 2019

Bacillus cereus
is a Gram‐positive, widely distributed bacterium that has a high level of metabolite production. Here, we report the draft genome sequence of a
B. cereus
strain exhibiting high and diverse hydrolytic potential that was isolated from glacial water samples from Svalbard, Norway.
Extraocular muscle positions in anterior plagiocephaly: V-pattern strabismus explained using geometric mophometrics
Authors: Touzé Romain , Heuzé Yann , Robert Matthieu P. , Brémond-Gignac Dominique , Roux Charles-Joris , James Syril , Paternoster Giovanna , Arnaud Eric , Khonsari Roman Hossein
Published: November 2019

Introduction

Ophthalmological involvement in anterior plagiocephaly (AP) due to unicoronal synostosis (UCS) raises management challenges. Two abnormalities of the extraocular muscles (EOM) are commonly reported in UCS without objective quantification: (1) excyclorotation of the eye and (2) malposition of the trochlea of the superior oblique muscle. Here we aimed to assess the positions of the EOM in AP, using geometric morphometrics based on MRI data.

Materials and methods

Patient files were listed using Dr WareHouse, a dedicated big data search engine. We included all patients with AP managed between 2013 and 2018, with an available digital preoperative MRI. MRIs from age-matched controls without craniofacial conditions were also included. We defined 13 orbital and skull base landmarks in order to model the 3D position of the EOM. Cephalometric analyses and geometric morphometrics with Procrustes superimposition and principal component analysis were used with the aim of defining specific EOM anomalies in UCS.

Results

We included 15 preoperative and 7 postoperative MRIs from patients with UCS and 24 MRIs from age-matched controls. Cephalometric analyses, Procrustes superimposition and distance computations showed a significant shape difference for the position of the trochlea of the superior oblique muscle and an excyclorotation of the EOM.

Conclusions

Our results confirm that UCS-associated anomalies of the superior oblique muscle function are associated with malposition of its trochlea in the roof of the orbit. This clinical anomaly supports the importance of MRI imaging in the surgical management of strabismus in patients with UCS.
Biomarker Research in ADHD: the Impact of Nutrition (BRAIN) - study protocol of an open-label trial to investigate the mechanisms underlying the effects of a few-foods diet on ADHD symptoms in children
Authors: Stobernack Tim , de Vries Stefan P W , Rodrigues Pereira Rob , Pelsser Lidy M , ter Braak Cajo J F , Aarts Esther , van Baarlen Peter , Kleerebezem Michiel , Frankena Klaas , Hontelez Saartje
Published: November 2019

Introduction

Attention deficit hyperactivity disorder (ADHD) is the most common childhood behavioural disorder, causing significant impediment to a child’s development. It is a complex disorder with numerous contributing (epi)genetic and environmental factors. Currently, treatment consists of behavioural and pharmacological therapy. However, ADHD medication is associated with several side effects, and concerns about long-term effects and efficacy exist. Therefore, there is considerable interest in the development of alternative treatment options. Double-blind research investigating the effects of a few-foods diet (FFD) has demonstrated a significant decrease in ADHD symptoms following an FFD. However, an FFD requires a considerable effort of both child and parents, limiting its applicability as a general ADHD treatment. To make FFD intervention less challenging or potentially obsolete, we need to understand how, and in which children, an FFD affects ADHD behaviour and, consequently, the child’s well-being. We hypothesise that an FFD affects brain function, and that the nutritional impact on ADHD is effectuated by a complex interplay between the microbiota, gut and brain, that is, the microbiota–gut–brain axis.

Methods and analysis

The Biomarker Research in ADHD: the Impact of Nutrition (BRAIN) study is an open-label trial with researchers blinded to changes in ADHD symptoms during sample processing and initial data analyses.

Ethics and dissemination

The Medical Research and Ethics Committee of Wageningen University has approved this study (NL63851.081.17, application 17/24). Results will be disseminated through peer-reviewed journal publications, conference presentations, (social) media and the BRAIN study website. A summary of the findings will be provided to the participants.

Trial registration number

NCT03440346.

Study dates

Collection of primary outcome data started in March 2018 and will be ongoing until 100 children have participated in the study. Sample data analysis will start after all samples have been collected.
Effect of mobile phone text message reminders on improving completeness and timeliness of routine childhood vaccinations in North-West, Ethiopia: a study protocol for randomised controlled trial
Authors: Mekonnen Zeleke Abebaw , Tilahun Binyam , Alemu Kassahun , Were Martin
Published: November 2019

Introduction

Non-attendance and delay in vaccination schedules remain a big challenge to healthcare workers. With the continuous growth of mobile network coverage and exponential penetration of mobile devices in the developing world, adoption of short message service has been shown to increase attendance for health services by targeting participant characteristics such as forgetfulness. Therefore, the aim of this trial is to determine the effect of mobile text message reminders on completeness and timeliness of childhood vaccination in North-West, Ethiopia.

Methods and analysis

A two-arm, parallel, superiority, randomised controlled trial study will be employed. The study arms are the intervention group (text message reminders plus routine care) and the control group (routine care only). Mother–infant pairs will be randomised to one of the groups during enrolment. The trial will consider a sample size of 434 mother–infant pairs with 1:1 allocation ratio. Mothers assigned to the intervention group will receive text message reminder 1 day before the scheduled vaccination visit at 6 weeks, 10 weeks, 14 weeks and at 9 months. Initially, descriptive statistics will be computed. For the primary outcome log-binomial regression model will be used to identify associated factors, and relative risk with 95% CI will be reported. Primarily, iIntention-to-treat analysis principle will be applied. STATA V.14 software will be used for the analysis.

Ethics and dissemination

This study obtained ethical approval from the University of Gondar Institutional Ethical Review Board. The trial findings on the effectiveness of mobile text message reminders in improving vaccination uptake will help to inform decision makers on the use of mobile health interventions in developing countries like Ethiopia. The scientific findings of the trial will also be published in reputable journals.

Trial registration number

PACTR201901533237287.
‘Serious’ factor—a relevant starting point for further debate: a response
Authors: Kleiderman Erika , Ravitsky Vardit , Knoppers Bartha Maria
Published: November 2019

In this reply, we wish to defend our original position and address several of the points raised by two excellent responses. The first response (De Miguel Beriain) questions the relevance of the notion of ‘serious’ within the context of human germline genome modification (HGGM). We argue that the ‘serious’ factor is relevant and that there is a need for medical and social lenses to delineate the limits of acceptability and initial permissible applications of HGGM. In this way, ‘serious’ acts as a starting point for further discussions and debates on the acceptability of the potential clinical translation of HGGM. Therefore, there is a pressing need to clarify its scope, from a regulatory perspective, so as to prevent individuals from using HGGM for non-therapeutic or enhancement purposes. The second response (Kalsi) criticizes the narrow interpretation of the objectivist approach and the apparent bias towards material innovations when discussing the right to benefit from scientific advancements. As an in-depth discussion of the objectivist and constructivist approaches was beyond the scope of our original paper, we chose to focus on one specific objectivist account, one which focuses on biological and scientific facts. We agree, however, with the critique that material innovations should not be the sole focus of the right to benefit from scientific advancements, which also incorporates freedom of scientific research and access to scientific knowledge scientific freedom and knowledge, including the influence of these on ethical thinking and cultures.
The source of performance and excretion data affects the environmental impact of pig rearing estimated by life cycle assessment
Authors: Monteiro A.N.T.R. , Dourmad J.-Y. , Moreira C.A. , Rossi R.M. , Ferreira L.F.M. , Costa A.E.R. , Pozza P.C.
Published: November 2019

The objective of this study was to calculate the environmental impact of raising pigs fed diets with 192, 182, 172, or 162 g kg−1crude protein (CP) from 15 to 30 kg live weight, using a life cycle assessment (LCA) based on either predicted or observed performance and excretion data. The predicted data were calculated for two animal profiles: one with feed intake and weight gain data being representative of the national Brazilian average (yp-AVG), and the other being representative of the specific experimental farm conditions (yp-SPC). Performance and excretion of pigs were either measured (yobs) or predicted (yp) for each CP scenario by using InraPorc®model and LCA impacts were calculated from these data. The ypand yobsdata of performance, nutrient excretion, and LCA were then compared using a Bayesian paired approach. Whatever the calculation methods, the decrease in dietary CP reduced the environmental impacts per kilogram of weight gain on acidification potential (AP), eutrophication potential (EP), and land occupation. Predicted data from yp-SPCdid not differ from yobsdata except for nitrogen excretion and AP and EP impacts. Predicted data from yp-AVGdiffered from yobsfor all criteria except for body weight gain, phosphorus excreted, and cumulative energy demand, mainly because of the lower feed conversion ratio for average data. It was concluded that the use of predicted data calculated from specific farm indicators could better explain the environmental impact of pig farming in Brazil compared with the use of national average indicators.
Fostering a cast-in-place steel–UHPFRC connector for ductile timber–concrete composite structures: parametric study of the shear behaviour and design considerations
Authors: Naud Nicolas , Sorelli Luca , Salenikovich Alexander , Cuerrier-Auclair Samuel
Published: November 2019

Timber–concrete composite (TCC) structures provide a breakthrough solution for multi-storey buildings. Besides the importance of the connection stiffness, recent research has focused on ductile connectors. This work aims at developing an economic new cast-in-place connector to guarantee the suitable stiffness and structural ductility. A new composite connector has been developed by combining an ultra-high performance fiber reinforced concrete (UHPFRC) shell with an embedded inner steel rod. The former governs the connection stiffness, while the latter governs the connection strength and ductility. To realize a cast-in-place construction method, firstly a wide experimental investigation on the connection shear behaviour with different geometry was carried out. Secondly, the results were analyzed using Winkler’s model, which allowed to define a simplified formula. Finally, a design example of the ductile connectors is presented with emphasis on the importance of a smart design of the connection system for avoiding a brittle structural failure.
Bootstrapped Newtonian stars and black holes
Authors: Casadio Roberto , Lenzi Michele , Micu Octavian
Published: November 2019

We study equilibrium configurations of a homogenous ball of matter in a bootstrapped description of gravity which includes a gravitational self-interaction term beyond the Newtonian coupling. Both matter density and pressure are accounted for as sources of the gravitational potential for test particles. Unlike the general relativistic case, no Buchdahl limit is found and the pressure can in principle support a star of arbitrarily large compactness. By defining the horizon as the location where the escape velocity of test particles equals the speed of light, like in Newtonian gravity, we find a minimum value of the compactness for which this occurs. The solutions for the gravitational potential here found could effectively describe the interior of macroscopic black holes in the quantum theory, as well as predict consequent deviations from general relativity in the strong field regime of very compact objects.
Mapping the physics research space: a machine learning approach
Authors: Chinazzi Matteo , Gonçalves Bruno , Zhang Qian , Vespignani Alessandro
Published: November 2019

Scientific discoveries do not occur in vacuum but rather by connecting existing pieces of knowledge in new and creative ways. Mapping the relation and structure of scientific knowledge is therefore central to our understanding of the dynamics of scientific production. Here we introduce a new approach to generate scientific knowledge maps based on a machine learning approach that, starting from the observed publication patterns of authors, generates an N-dimensional space where it is possible to measure the similarity or distance between different research topics and knowledge domains. We provide an implementation of the proposed approach that considers the American Physical Society publications database and generates a map of the research space in Physics that characterizes the relation among research topics over time. We use this map to measure two indicators, the research capacity fingerprint and the knowledge density, to profile the research activity in physical sciences of more than 400 urban areas across the world. We show that these indicators can be used to analyze and predict the evolution over time of the research capacity and specialization of specific geographical areas. Furthermore we provide an extensive analysis of the relation between socio-economic development indicators and the ability to produce new knowledge for 67 countries, as measured by our approach, highlighting some key correlates of scientific production capacity. The proposed approach is scalable to very large datasets and can be extended to study other disciplines and research areas without having to rely on ad-hoc science classification schemes.
Temperature-dependent structure, dielectric properties of Bi0.95Ba0.05Fe0.95Ti0.05O1.3
Authors: Cheng G. F. , Yin H. D. , Ruan Y. J. , Xie Q. Y. , Wu X. S.
Published: November 2019

The temperature-dependent structure and dielectric properties of Bi[Formula: see text]Ba[Formula: see text]Fe[Formula: see text] Ti[Formula: see text]O3 ceramic are studied systematically. At the temperature range of 25–800[Formula: see text]C, the cell parameters are increasing, this indicates its distorted rhombohedral [Formula: see text]3[Formula: see text] structure. A structural phase transformation from rhombohedral [Formula: see text]3[Formula: see text] to cubic Pm3[Formula: see text] is observed at 850[Formula: see text]C. The thermal expansion coefficients in the temperature range 25–700[Formula: see text]C are calculated. Meanwhile, the temperature-dependent dielectric constant ([Formula: see text]) and dielectric loss ([Formula: see text][Formula: see text]) at different frequencies are measured. This work attempts to show the thermodynamic stability and the effect of charge defects on the electric properties for doped BiFeO3 ceramics.
The effect of temperature, hydrostatic pressure and magnetic field on the nonlinear optical properties of AlGaAs/GaAs semi-parabolic quantum well
Authors: You Jin-Feng , Zhao Qiang , Zhang Zhi-Hai , Yuan Jian-Hui , Guo Kang-Xian , Feddi Elmustapha
Published: November 2019

In this paper, we explore the optical properties of AlGaAs/GaAs semi-parabolic quantum well (QW) under different temperature, hydrostatic pressure and applied magnetic field. We calculate the nonlinear optical absorption coefficients and the refractive index changes (RICs) with the compact density-matrix approach and iterative method. Then, within the framework of the effective mass and parabolic-band approximations, the energy eigenvalues and the corresponding wave functions for semi-parabolic QW have been obtained by the finite difference method. The theoretical findings show that (1) the energy spectrum depends strongly on temperature, hydrostatic pressure and applied magnetic field; (2) the linear and third-order nonlinear optical absorption coefficients and the RICs are quite sensitive to temperature, hydrostatic pressure and applied magnetic field. Our study provides a theoretical basis for the fabrication of QW structure.