bluuebunny/crossref_metadata_2025 huggingface dataset:
Feasibility investigation of a smart thermoacoustic configuration for general aviation aircrafts
Authors: Viscardi Massimo , Arena Maurizio , Porpora Valerio , Di Paola Giuliano , Aubry Edoardo
Published: November 2018

One of the most disturbing noise for passengers is related to the engine fan. This noise is mainly tonal and in the low-frequency range. Reducing its impact for the comfort of passengers is an important and challenging issue in aeronautics. One suitable way to reduce cabin noise is to use efficient thermal acoustic insulation blankets between the interior trim panel and the exterior shell. General Aviation Aircrafts, are generally equipped with a cabin poorly efficient both in terms of thermal and acoustic insulation; this due mainly to the not availability of the most innovative solutions or materials like those used on Large Passenger Aircraft. In this context the authors have faced this crucial issue within SPAIN Project “Smart Panels for SAT Aircrafts Cabin Insulation” which makes part of the Systems Integrated Technology Demonstrator (ITD) Program in EU Clean Sky 2. This project aims scientific and technological breakthroughs in the development and validation of new insulation treatments used in aircraft developing a thermo-acoustic insulation system with materials and innovative solutions highly efficient at an affordable cost for this class of aircrafts. According to the available materials on the market with high thermal and acoustic individual performance, SPAIN goal is to design, develop and test an efficient insulation panel suitable for the General Aviation Aircraft compliant with the technical specification in terms of and weight to performance, and cost to performance aspects. Another item that has been strongly worked on, is the integration technology of this solution with the actual interiors configuration with specific focus to maintenance aspects. A set of sandwich configurations have been designed for each specific area of the fuselage to fulfil the overall noise level target; preliminary test have been performed at coupon level and sub-assembly level to confirm the expected outcomes.
Integrated collaboration capabilities for competitive aircraft design
Authors: Baalbergen Erik , Lammen Wim , Noskov Nikita , Ciampa Pier-Davide , Moerland Erwin
Published: November 2018

Airlines need to continuously extend and modernise their fleets, to keep up with the challenges of air-travel growth, competition, green, safe and secure operations, and growing passenger demands. As a result, the aircraft industry and its supply chain have to manage the growing needs for cost-efficient and complex aircraft in increasingly shorter time. Meanwhile they face their own challenges, such as certification and global competition. Quick evaluation of promising new technologies and concepts facilitates a short time to market. However, the required innovations are costly and risky, and require involvement of many experts from different disciplines and partners. Increasing the level of collaboration within the aircraft industry and its supply chain will be an essential step forward to deal with the challenges. Developing modern aircraft in an increasingly cost and time efficient manner in a collaborative set-up however requires step changes. The EU-funded Horizon2020 project AGILE has developed methods and tools for efficient and cross-organisation collaborative aircraft design, facilitating the rapid evaluation of new technologies and concepts at the early stages of aircraft development. This paper describes the capabilities and illustrates the successful integrated application of the capabilities by means of a collaborative aircraft rudder design evaluation.
Challenges of fully-coupled high-fidelity ditching simulations
Authors: Müller Maximilian , Woidt Malte , Haupt Matthias , Horst Peter
Published: November 2018

An important element of the process of aircraft certification is the demonstration of the crashworthiness of the structure in the event of an emergency landing on water, also referred to as ditching. Novel numerical simulation methods that incorporate the interaction between fluid and structure open up a promising way to model ditching in full scale. This study presents a numerical framework for the simulation of ditching on a high–fidelity level. A partitioned approach that combines a finite volume hydrodynamic fluid solver as well as an finite element structural solver is implemented using a Python-based distributed coupling environment [1]. High demands are placed both on the fluid and the structural solver. The fluid solver needs to account for hydrodynamic effects such as cavitation in order to correctly compute the ditching loads acting on the aircraft structure. In the structural model, the highly localized damage induces nonlinearities and large differences in model scale. In order to reduce the computational effort a reduced order model is used to model the failure of fuselage frames. The fluid-structure coupling requires an explicit coupling scheme. It is shown that the standard Dirichlet-Neumann approach exhibits unstable behaviour if a strong added-mass effect is present, as is the case in aircraft ditching. This indicates a need for methods other than the standard Dirichlet-Neumann approach [2].
Development of aeronautical epoxy nanocomposites having an integrated selfhealing ability
Authors: Guadagno Liberata , Vertuccio Luigi , Naddeo Carlo , Calabrese Elisa , Barra Giuseppina , Raimondo Marialuigia , Sorrentino Andrea , Binder Wolfgang H. , Michael Philipp , Rana Sravendra
Published: November 2018

Functionalized multi-wall carbon nanotubes (MWCNTs) have been embedded in a rubber-toughened epoxy formulation in order to explore the possibility to impart an auto-repair function to the epoxy matrix. The nanofiller has been covalently functionalized with hydrogen bonding moieties able to act as donor and acceptor of hydrogen bondings. Healing efficiencies have been evaluated for nano charged epoxy formulations at a loading of 0.5% wt/wt of functionalized MWCNTs bearing barbituric acid and thymine-based ligands. For both the performed functionalizations, a self-healing efficiency higher than 50% has been found. Dynamic Mechanical Analysis (DMA) highlights that the inclusion of nanofiller increases the storage moduli. Furthermore, DMA analysis evidences the presence of a phase characterized by a greater mobility of the epoxy chains, which promotes the activation of self-healing mechanisms.
Optimal Sizing of Electric Multirotor Configurations
Authors: Avanzini Giulio , de Angelis Emanuele L. , Giulietti Fabrizio , Minisci Edmondo
Published: November 2018

A sizing tool for the definition of the configuration of electrically powered multirotor platforms is developed, which accounts for a realistic battery discharge model. The tool is developed to provide the community with the possibility of deriving the best configuration for performing a given task, while accounting for specific constraints and performance requirements. An evolutionary algorithm is used for searching the design space and to identify feasible designs with optimal performance in terms of maximum hovering time on the target and payload weight fraction.
Prediction of mechanical properties of nanocrystalline materials using Voronoi FE models of representative volume elements
Authors: Bazios Panagiotis , Tserpes Konstantinos , Pantelakis Spiros
Published: November 2018

In the present work, a numerical model is developed to predict the mechanical properties of nanocrystalline materials using a Finite Element Analysis. The model is based on Representative Volume Elements (RVE) in which the microstructure of the material is described using the Voronoi tessellation algorithm. The use of the Voronoi particles was based on the observation of the morphology of nanocrystalline materials by Scanning Electron and Transmission Electron Microscopy. In each RVE, three-dimensional modelling of the grain and grain boundaries as randomlyshaped sub-volumes is performed. The developed model has been applied to pure nanocrystallline copper taking into account the parameters of grain size and grain boundary thickness. The mechanical properties of nanocrystalline copper have been computed by loading the RVE in tension. The numerical results gave a clear evidence of grain size effect and the Hall-Petch relationship, which is a consequence of macroscopic strain being preferentially accumulated at grain boundaries. On the other hand, for a given grain volume fraction, the results for elastic moduli showed no effect of the grain size. The model predictions have been validated successfully against numerical results from the literature and predictions of the Rule of Mixtures and the Mori-Tanaka analytical model.
Innovative passive multifrequency propeller device for noise and vibration reduction in turboprop fuselage
Authors: De Fenza Angelo , Arena Maurizio , Lecce Leonardo
Published: November 2018

One of the main comfort issue affecting the passenger comfort into a turboprop aircraft fuselage is the propeller tonal noise and the related vibrations. It is well known that propeller rotation during flight generates the main noise sources, depending upon its rotational angular velocity, number of blades, power at shaft generating aircraft thrust and blades geometry. Thanks to the progress behind the control systems of the blades rotations, an innovative highly selective DVA has been conceived. The purpose of the research activity has been improving the performances of the standard passive tonal noise control system used for the BPF tuned noise and vibration attenuation in turboprop aircraft. Due to specific commercial need, the use of bi-tuned frequency can lead at a passive noise reduction at two RPM regimes. Generally, the turboprop aircrafts use only two RPM regimes: 100% at take-off, climb and approach, 86% during cruise, climb and descent. An innovative passive bi-tonal device capable to be tuned at two different frequencies in order to optimize the fuselage noise reduction at two different flight regimes (100% and 86%), has been designed and numerically verified. The functional effectiveness of the bi-frequential tuned device has been analysed by finite elements simulations on a linear beam, representative of the turboprop fuselage frame. The outcomes achieved within this activity encourage the advancement of this research sector, as a support to the needs of the turboprop aeronautical industry. According to the long experience gained by the research group, the proposed multifunctional concept can be a valid technology solution ready to be manufactured as well as validated in flight.
Experimental study of a helicopter rotor model in hover
Authors: Panayotov Filip , Dobrev Ivan , Massouh Fawaz , Todorov Michael
Published: November 2018

This paper presents the results from an experimental study of the aerodynamic performance and efficiency of a model helicopter rotor in steady hover at Reynolds numbers below 70000. Results are shown for a two-, three- and four-bladed rotor configuration for various pitch angles and speeds of rotation. The influence of the rotor solidity on the aerodynamic efficiency in terms of the Figure of Merit is highlighted. The profile drag component is evaluated as a function of the Reynolds number. The internal friction losses of the test stand are estimated and taken into account in all measurements. A brief description of the designed test stand is provided. The experimental setup allows for the measurement of thrust and torque of helicopter rotors with diameters of up to 1 meter, for pitch angles varying from -12° to +24° and for rotational speeds of up to 3000 RPM. Conclusions are drawn about the aerodynamic performance and efficiency of the studied rotor configurations. This experimental study provided a significant database, which will serve for validation purposes.
General approach to optimize settings of ship radars repair procedures
Authors: Guglev Evgeni , Alexandrov Chavdar
Published: November 2018

A number of possible formal methods for constructing an approach to solve the problem of global optimization of the setting process of ship radars repair procedure are introduced in this paper. The basis of the formalized task assignment is the selection of a sequence of operations related to determining the corresponding values of the electronic (electrical) components of radars, providing the global optimum of the created imitation model of the whole task with the corresponding subtasks. The algorithm of the global optimization task is built in the form of imitation experimental procedures with a multi-alternative optimization model. The multi-plan character (taking into account the different ranges) and the multi-criteria of such an experiment require an automatic search for optimizing the scanning at different ranges. The alternative for inclusion in the relevant group, with good result achieved is set in accordance with expert estimations (for the time of the scanning), Boolean variables (alternative for the inclusion of different ranges) or stochastic variables – by nomograms. The six-steps method (for six different ranges) is presented as a sequence of achieved optimums for the different ranges. The optimal set of functions determined by the task solution method is a solution of a stochastic problem including scanning time, pulse duration and ranges.
Experimental study of electric vehicle gearbox efficiency
Authors: Břoušek Josef , Zvolský Tomáš
Published: November 2018

This paper presents an experimental analysis of the overall efficiency of the gearbox for an electric vehicle with a Dual Motor Drive System (DMDS) propulsion system. The efficiency was measured in the powertrain testbed where the gearbox was placed between two dynamometers. The main aim of the experiment was to get relevant values of an overall efficiency as a function of input speed and torque. All these measured values of the gearbox efficiency are included in graphs and efficiency maps. Tests were run with two different amounts of oil charge. The experiment confirmed the expected high values of the overall mechanical gearbox efficiency. The results can be used further for advanced simulations and other electric vehicle experiments.
Study of the vibrational behaviour of the components of a car suspension
Authors: Georgiev Zlatin , Kunchev Lilo
Published: November 2018

The paper presents a study of the vibrational behaviour of a car suspension in the frequency range from 50 to 200 Hz. The vehicle has a torsion spring suspension. The aim of the study is to provide a numerical approach, which evaluates the impact of the tyre vibration characteristics and the elastic properties of suspension elements on the vibrational behaviour of the “tyre-suspension-body” system. The object of the study are the elements of the suspension – stub-axle, upper and lower suspension arms, strut rod, torsion bar and others. The suspension is equipped with pneumatic tyres with different vibration characteristics. Laboratory experiments are done. The tyre contact patch is disturbed by harmonic force. The accelerations of the wheel axle and specific points of the suspension are obtained. A numerical model of the system is created by using the Finite Element Method available in SolidWorks Simulation software. The model allows to determinate the accelerations at different points of the suspension. The results of the experimental and theoretical studies are compared. The values obtained in the two studies are similar.
Dynamic loading of the tank container on a flat wagon considering fittings displacement relating to the stops
Authors: Fomin Oleksij , Gerlici Juraj , Lovskaya Alyona , Gorbunov Mykola , Kravchenko Kateryna , Prokopenko Pavlo , Lack Tomas
Published: November 2018

The mathematical modelling of the dynamic loading of the container-tank during maneuvering collision of the flat wagon has made it possible to obtain an accurate value of the accelerations acting on its supporting structure. At the same time, possible movements of the tank-container relative to the frame of the flat wagons due to the presence of a technological gap in the pair “fitting stop-fitting” are taken into account. It is established that this acceleration, which is a component of the dynamic load, exceeds the one permitted by the regulatory documents. A computer simulation of the dynamic loading of the tank container in the CosmosWorks software environment was also carried out. The calculation was carried out using the finite element method. The results of the simulation made it possible to determine the distribution fields of the accelerations acting on the supporting structure of the tank-container during the shunting of the flat wagon, as well as their numerical values. Checking the adequacy of the mathematical and computer models using the Fisher criterion allowed us to conclude that the hypothesis of adequacy is not rejected.
Analysis of the effectiveness of noise abatement measures in relation to the type of train
Authors: Hranický Michal Petr , Štefancová Vladimíra , Kendra Martin
Published: November 2018

The paper is focused on the comprehensive analysis of the railway noise issues. Not only does it deal with the influence on the environment, but also with the Czech laws in this field. Moreover, it presents all the options how the noise from the railway transport might be reduced and several proposals how to increase effectiveness of noise protection. In conclusion, the theoretical part is complemented by a practical one in the form of measuring and subsequent analysis.
Cancellation of delayed trains: passengers’ and capacity points of view
Authors: Bulíček Josef
Published: November 2018

The paper is focused on interface between passenger transport demand after utilization of individual trains influenced by current operational situation (delays, overtaking of trains etc.) and on aspects of capacity utilization of railway line. The research is inspired by an idea (based on UIC 406) to operate rush lines on higher level of capacity utilization due to possibility to cancel delayed trains and make the time schedule more stable in this way. Simulation model of distribution of passengers between trains according to current operational situation is modified and applied for this assessment. The main result is that the effectiveness of this measure (especially in passengers’ point of view) is depended not only on high capacity utilization of railway line, but also on time schedule and a complex of other operational conditions.
Draft of strategy of the European rail freight corridor Amber
Authors: Kanis Juraj , Dolinayova Anna , Kmetik Matej
Published: November 2018

An increase in rail freight transport performances is affected by the quality of transport services, which is influenced to the great extent by the transport infrastructure and infrastructure manager services. An increase in the quality of services provided by railway infrastructure has also been achieved through the establishment of the European rail freight corridors. At the same time, the trends in routing of goods flows and demand for transport services have contributed to the establishment of the new European rail freight corridor “Amber”. For this reason, an implementation strategy of the Amber corridor is proposed using the SWOT method and Balanced Score Card method. The draft of strategy is based on the findings contained in the study of transport and market environment of the Amber corridor.
Brake actuator optimization of the brake test stand as a tool for improvement railway safety
Authors: Harušinec Jozef , Suchánek Andrej , Šťastniak Pavol , Strážovec Peter
Published: November 2018

In recent years have been the speed, comfort and safety of rail transport significantly increased. This asks for higher demands on reliability and safety of rail vehicles parts meeting. The important is research the properties of brake pair, therefore build specialized test equipment, where it is possible to programmatically load wheels, wheelset, bogie or complete vehicles. Tests on the friction test stand brake represent a special group, which replace the expensive tests of complete vehicles, that are more costly. The test stand brake allows the implementation of experimental tests of the actual brake units and components under simulated conditions.
Design of a new railway wagon for intermodal transport with the adaptable loading platform
Authors: Šťastniak Pavol , Kurčík Pavol , Pavlík Alfréd
Published: November 2018

The aim of the article is to present the structural design of freight railway wagon with variable use of loading space with regard to the safe operation and assessment of the properties by the calculation methods of simulation analysis. Virtual model of wagon was created in a computer program PTC/Creo. After creating the construction, the calculation model of the wagon frame was subjected to the static and dynamic analysis in programs ANSYS and ADAMS/Rail. On the basis of computer aided simulation analysis was optimized the chassis frame of the wagon. This wagon will be able to offer even more capacity and utilize less resources and energy than current wagons for intermodal transport.
Proposal of stiffness of triple spring of a passenger railway vehicle
Authors: Suchánek Andrej , Harušinec Jozef , Loulová Mária , Kurčík Pavol
Published: November 2018

The article deals with the calculation of stiffness of a secondary suspension spring built in a bogie of a rail vehicle with a tilting car body. The vertical stiffness of the springs was calculated using the ANSYS program. The results were compared with calculated values afterwards. The lateral stiffness was evaluated in a similar manner. Analyt-ical method by Gross, Wahl, Budrick, Timoshenko and Ponomarieva was used for comparison with numerical values. The ANSYS simulation was performed for calculating the vertical stiffness of the triple springs. The most suitable analytical method is a method by Timoshenko and Ponomarieva, where the percentage difference was the smallest. The obtained data will be used as an input for the design of coil springs which will be implemented in a model of a vehicle with a tilting car body, for which the comfort values during transition in curve will eventually be determined.
Modelling fuel consumption and refuelling of autonomous vehicles
Authors: Zöldy Máté , Zsombók Imre
Published: November 2018

In our research we highlighted the problematic of the refuelling of autonomous vehicles. During the way to be full autonomous, the vehicles take over more and more driving function from the driver. It is lot of focus on automotive cyber security or trajectory following, but refuelling is not in the main researches. After reviewing the vehicle drivetrains, it was specified which to focus for further testing. In the second part of the article the main influencers of fuel consumption was listed based on a literature overview. Main aspects of the carried out test is listed and results helped us to refine the research direction. For modelling the refuelling of the vehicle it is an enabler to set realistic models for fuel consumption. Relevant researches were studied and these was extended with overview of refuelling studies. Based on these the main direction of our research was set.
The Role of Slovak Airports in Tourism Development
Authors: Gúčik Marian , Vetráková Milota , Marciš Matúš
Published: November 2018

Tourism is in a close connection with the transport operations and as such develop thanks to various forms of transport. A large role in the effects on the growth potential of international tourism play the individual countries, whose task is to promote the development of air transport, and hence boosting the national economy and many of its areas. The article presents the evaluation of the air transport infrastructure in Slovakia, which is a prerequisite for the development of tourism. It contains theoretical backroad of air transport service and analyses of the role of Slovak airports in tourism development. The article deals with the assumption that the transport accessibility of a country with a regular air service is the basis for international transport. The aim of the article is to evaluate the role of Slovak airports in terms of passenger transport and tourism development. Its emphasizes the development of air transport in Slovakia, analyses airports performances and investments in the air transport infrastructure. Secondary sources were used and processed by selected mathematical and statistical methods of descriptive statistics.
Forces prediction in micro-grinding single-crystal copper considering the crystallographic orientation
Authors: Zhao Man , Ji Xia , Li Beizhi , Liang Steven Y.
Published: November 2018

In the micro-grinding of single-crystal copper, the effect of crystallography becomes significant as the wheel works intra-crystalline. To quantify the effect of crystallographic orientation (CO) related to the cutting direction on the micro-grinding process, this article presents a Taylor factor model by examining the number and style of activated slip systems. Then, the flow stress model of monocrystalline material is developed considering the variation of the Taylor factor. Furthermore, the models of chip formation and rubbing forces are derived from the flow stress model, while the plowing force is predicted by the Vickers hardness. Then, the overall grinding force model of the whole wheel is developed by incorporating the process parameters and the wheel properties. Finally, micro-grinding experiments are conducted to verify the model, using only the Taylor factor as the variable. The proposed analysis is also compared with the previously reported model, which considers the Taylor factor as a constant of 3.06. The comparison between the two predictions and experimental data shows that the consideration of Taylor factor variability improves the accuracy of prediction.
A tale of two LAMS: a report of benign tissue ingrowth resulting in recurrent gastric outlet obstruction
Authors: Parekh Parth , Shakhatreh Mohammad , Yeaton Paul
Published: November 2018

Background and study aims Endoscopic ultrasound (EUS)-guided gastroenterostomy is a novel, off-label, procedure that has been facilitated by availability of a novel lumen apposing metal stent (LAMS) (Axios, Boston Scientific, Marlbourough Massachusetts, United States). The literature suggests its efficacy to be comparable to surgical gastrojejunostomy. In theory, this procedure overcomes the issues associated with woven enteral stents, which are subject to continuous, straightening, axial forces. We report the adverse event of tissue ingrowth in an Axios stent placed as an EUS-guided gastroduodenostomy, resulting in recurrence of gastric outlet obstruction, treated by a stent-inside-stent technique.
Bewährte Indikationen von Natrium muriaticum in der Veterinärmedizin
Authors: Danowski Klaus
Published: November 2018

Es werden 4 häufige Indikationen vorgestellt. Zuerst ein Fall von Depression bei einem Wellensittich mit begleitender Nierenerkrankung. Nach einer Gabe C1000 war innerhalb von 4 Wochen wieder ein normales Verhalten zu beobachten. Der 2. Fall berichtet von einem Terrier mit Nüchternerbrechen. Als Ursache wurde eine Hyperchlorämie festgestellt. Nat-m. in C200 beendete das Erbrechen nach 8 Wochen und steigerte die Fitness deutlich. Das 3. Beispiel handelt von unkontrolliertem Harnabsatz. Der Irish Setter litt unter einer Nierenentzündung mit Überlaufblase. Grundproblematik war eine ausgeprägte Futterallergie. Begleitend bestand ein juckender Hautausschlag. Mit Tuberculinum Koch C1000 und Nat-m. C1000 heilten die Beschwerden innerhalb von 11 Wochen. Der letzte Fall schildert einen typischen Hautausschlag, ein sog. miliares Ekzem bei einer Stubenkatze. Nat-m. in C200 mehrmals pro Woche führte über einen interkurrenten Zahnwurzelabszess nach 3 Monaten zur Beschwerdefreiheit. Zuletzt wird von seit 1 Jahr bestehenden starken konkurrenzbedingten Spannungen mit der 2. Katze im Haus berichtet.
Pro und Kontra: „Bewährte Indikation“
Authors: Bleul Gerhard , Drexler Leopold , Sparenborg-Nolte Anne
Published: November 2018

Der Artikel diskutiert aus den Perspektiven „Pro“ und „Kontra“ die Einsatzmöglichkeiten sowie die Vor- und Nachteile der „Bewährten Indikation“ in der Homöopathie.
Effect of Flying at High Altitude on Early Exposure of Paracetamol in Humans
Authors: Idkaidek Nasir , Al-Ghazawi Ahmad
Published: November 2018

Pharmacokinetics of paracetamol (APAP) was studied on-board during an air flight and compared to those on ground after 500 mg oral dose in 20 healthy human volunteer in parallel design study. Saliva samples were obtained every 15 min up to 2 h after dosing. Pharmacokinetic parameters were calculated by non compartmental analysis and one compartment models using Winnonlin program V5.2. Results have showed that on-board to ground ratios for area under curves AUC0→1, AUC0→2, time to reach maximum saliva concentration Tmax, absorption rate constant Ka and maximum saliva concentration Cmax were 0.62, 0.38, 1.01, 0.81 and 0.79 respectively. Effective membrane permeability coefficients were optimized by Nelder-Mead algorithm using Simcyp program V13. This showed similar rate of absorption and early exposure up to one hour, and lower bioavailability after 1 h on-board. This can be explained by the increased liver blood flow at high altitude that led to increased liver metabolism on-board. However, APAP elimination parameters were not calculated due to short sampling time. This suggests a need for dose adjustment on-board during long air flights, especially for narrow therapeutic index drugs with flow limited metabolism.
Head Biometry in Fetuses with Isolated Congenital Heart Disease
Authors: Graupner Oliver , Koch Jessica , Enzensberger Christian , Götte Malena , Wolter Aline , Müller Vera , Kawecki Andreea , Herrmann Johannes , Axt-Fliedner Roland
Published: November 2018

Purpose Altered cerebral hemodynamics are involved in changes in head biometry in fetuses with congenital heart disease (CHD). We compared head growth in different CHD groups with published normative values and investigated whether CHD groups differ from each other in terms of head circumference (HC) development over gestational age (GA).

Materials and Methods Retrospective cohort study consisting of 248 CHD fetuses. Subgroups were generated according to the expected ascending aorta oxygen saturation: Low placental blood content (BC) and therefore low oxygen delivery to the brain (group 1: n = 108), intermediate placental and systemic BC due to intracardiac mixing of blood (group 2: n = 103), high placental BC (group 3: n = 13) and low placental BC and low oxygen delivery to the brain without mixing of blood (group 4: n = 24). Furthermore, group 1 was divided into antegrade (n = 34) and retrograde (n = 74) flow through the aortic arch. Comparisons were made at a GA of 22, 30 and 38 weeks.

Results Estimated values of zHC (z-score transformed) were not significantly different between the four CHD groups at the three time points in gestation (all p > 0.05). Within group 1 fetuses with retrograde aortic arch flow showed a significant negative association between HC and GA compared to reference values (b = –0.054, p < 0.001) and had significantly lower zHC values at 38 weeks (–0.836) compared to fetuses with antegrade flow (0.366, p = 0.009).

Conclusion Our data do not confirm that CHD fetuses in general have a significantly smaller HC. HC becomes smaller throughout gestation depending on the direction of aortic arch flow.
Novel Synthesis of 1,2-Substituted 4-Quinolones
Authors: Bandatmakuru Sreenivasulareddy , Arava Veerareddy
Published: November 2018

An efficient method for the straightforward synthesis of N-functionalized 4-quinolones and 1,2-substituted 4-quinolones from simple 2-aminoacetophenones has been developed.
Cluster Preface: Synthesis of Materials
Authors: Swager Timothy
Published: November 2018

Timothy M. Swager is the John D. MacArthur Professor of Chemistry and the Director, Deshpande Center for Technological Innovation at the Massachusetts Institute of Technology. A native of Montana, he received a BS from Montana State University in 1983 and a Ph.D. from the California Institute of Technology in 1988. After a postdoctoral appointment at MIT he was on the chemistry faculty at the University of ­Pennsylvania and returned to MIT in 1996 as a Professor of Chemistry and served as the Head of Chemistry from 2005 to 2010. He has published more than 450+ peer-reviewed papers and more than 90+ ­issued/pending patents. Swager’s honors include: Election to the ­National Academy of Sciences, an Honorary Doctorate from Montana State University, the ­Linus Pauling Medal, the Lemelson-MIT Award for Invention and Innovation, Election to the American Academy of Arts and Sciences, The American Chemical Society Award for Creative Invention, and The Carl S. Marvel Creative Polymer Chemistry Award (ACS). Swager’s research interests are in design, synthesis, and study of organic-based electronic, sensory, high-strength, liquid crystalline, and colloid materials. His inventions have had wide-ranging commercial impact, including the ­FidoTM sensors, which are the world’s most sensitive explosives detectors. He is the scientific founder of five companies (­DyNuPol, Iptyx, PolyJoule, C2 Sense, and Xibus Systems) and has served on ­numerous corporate and government boards.
The Easy Approach to N-Hydroxy-N-cycloalkenylamides through Nitrosocarbonyl Ene Reactions to Cycloalkenes: Valuable Compounds for Antiviral Syntheses
Authors: Quadrelli Paolo , Hameed Karzan , Amin Ahmed , Hussain Faiq , Memeo Misal , Moiola Mattia
Published: November 2018

An easy approach to N-hydroxy-N-cycloalkenylamides, ene adducts of cyclic alkenes of different sizes, is presented. The products can be obtained both through the thermal generation of the nitrosocarbonyl intermediates and via the photochemical fragmentation of the Wieland heterocycle, this being the mildest way to generate these fleeting species, also affording the best results so far in terms of chemical yields. The use of the ene reaction for the synthesis of biologically active molecules represents an interesting and valuable aspect of modern organic synthesis, and this is the strategy proposed as a remarkable alternative to current methods.
Comparison between Rescue Flap and Double Flap Technique
Authors: Benzer Murat , Biceroglu Huseyin , Ates Murat Samet , Kaya Isa , Ozgiray Erkin , Midilli Rasit , Karcı Bulent , Gode Sercan
Published: November 2018

Objectives Endoscopic techniques in pituitary surgery lead to inevitable mucosal loss of the sphenoethmoidal recess and posterior nasal septum in the nasal cavity. There is no other comparative study between primary reconstruction of septal perforation and secondary healing in the literature. The aim of this study is to evaluate postoperative patient morbidity with or without posterior septal perforation in endonasal pituitary surgery by comparing two commonly used techniques: rescue and double nasoseptal flaps.

Design Prospectively randomized study.

Setting Tertiary academic center.

Participants Sixty patients underwent endoscopic endonasal pituitary surgery.

Main Outcomes and Measures Functional results (breathing) using visual analog scale (VAS), sphenoid sinusitis, presence of synechia, perforation in the posterior septum, and crusting in the sphenoethmoidal recess were assessed.

Results Pre- and postoperative mean VAS scores were 71.67 ± 11.47 and 67.67 ± 9.71 mm in the intact septum group and 77.67 ± 14.06 and 62.67 ± 10.48 mm in the posterior septal perforation group. There was a significant difference between pre- and postoperative VAS values in all groups. There was significant worsening in both groups; worsening in VAS values was much higher in the posterior septal perforation group. In the posterior septal perforation group, much more crusting was seen.

Conclusions This is the first study to compare the postoperative patient morbidity in endoscopic endonasal pituitary surgery with and without a posterior septal perforation. Reconstruction of the posterior septum along with less mucosal loss yields better postoperative nasal symptom score.
The Impact of a Location-Sensing Electronic Health Record on Clinician Efficiency and Accuracy: A Pilot Simulation Study
Authors: King Kevin , Quarles John , Ravi Vaishnavi , Chowdhury Tanvir , Friday Donia , Sisson Craig , Feng Yusheng
Published: November 2018

Background Through the Health Information Technology for Economic and Clinical Health Act of 2009, the federal government invested $26 billion in electronic health records (EHRs) to improve physician performance and patient safety; however, these systems have not met expectations. One of the cited issues with EHRs is the human–computer interaction, as exhibited by the excessive number of interactions with the interface, which reduces clinician efficiency. In contrast, real-time location systems (RTLS)—technologies that can track the location of people and objects—have been shown to increase clinician efficiency. RTLS can improve patient flow in part through the optimization of patient verification activities. However, the data collected by RTLS have not been effectively applied to optimize interaction with EHR systems.

Objectives We conducted a pilot study with the intention of improving the human–computer interaction of EHR systems by incorporating a RTLS. The aim of this study is to determine the impact of RTLS on process metrics (i.e., provider time, number of rooms searched to find a patient, and the number of interactions with the computer interface), and the outcome metric of patient identification accuracy

Methods A pilot study was conducted in a simulated emergency department using a locally developed camera-based RTLS-equipped EHR that detected the proximity of subjects to simulated patients and displayed patient information when subjects entered the exam rooms. Ten volunteers participated in 10 patient encounters with the RTLS activated (RTLS-A) and then deactivated (RTLS-D). Each volunteer was monitored and actions recorded by trained observers. We sought a 50% improvement in time to locate patients, number of rooms searched to locate patients, and the number of mouse clicks necessary to perform those tasks.

Results The time required to locate patients (RTLS-A = 11.9 ± 2.0 seconds vs. RTLS-D = 36.0 ± 5.7 seconds, p < 0.001), rooms searched to find patient (RTLS-A = 1.0 ± 1.06 vs. RTLS-D = 3.8 ± 0.5, p < 0.001), and number of clicks to access patient data (RTLS-A = 1.0 ± 0.06 vs. RTLS-D = 4.1 ± 0.13, p < 0.001) were significantly reduced with RTLS-A relative to RTLS-D. There was no significant difference between RTLS-A and RTLS-D for patient identification accuracy.

Conclusion This pilot demonstrated in simulation that an EHR equipped with real-time location services improved performance in locating patients and reduced error compared with an EHR without RTLS. Furthermore, RTLS decreased the number of mouse clicks required to access information. This study suggests EHRs equipped with real-time location services that automates patient location and other repetitive tasks may improve physician efficiency, and ultimately, patient safety.
Not a Cheap Investment: Estimating the Cost of the 2017 to 2018 Ophthalmology Residency Match to the Applicant and Program
Authors: Moore Daniel
Published: November 2018

Purpose To estimate the cost of the match process for all ophthalmology applicants and the departmental costs at the University of Kentucky during the 2017 to 2018 match cycle.

Design Financial analysis.

Methods Using the available national match statistics for the 2017 to 2018 ophthalmology residency match and the mean of all residency interview costs available in the literature, the estimated mean and total match costs were calculated for all applicants, including application fees and interviews. Program costs were estimated based on direct interview costs, lost productivity, and fixed costs.

Results Of 625 applicants, 475 matched into an ophthalmology residency position in 2017 to 2018. The mean estimated cost was US$6,613 for matched applicants, and all applicants spent US$4,646,950 on the match in aggregate. Our department spent an estimated US$179,327 over four interview days with 12 faculty volunteers, or an average of US$3,736 per each of 48 interviewed applicants.

Conclusions and Relevance Matching into an ophthalmology residency position is expensive not only for the applicant but also the program. Reforms to the process would likely be beneficial to both parties.
Tentorial Incision vs. Retraction of the Tentorial Edge during the Subtemporal Approach: Anatomical Comparison in Cadaveric Dissections and Retrospective Clinical Case Series
Authors: Archavlis E. , Serrano L. , Ringel F. , Kantelhardt S. R.
Published: November 2018

Objective The aim of this study was to compare tentorial incision (group A) versus retraction and tack up suture (group B) of the tentorial edge during the subtemporal approach for surgery in the high basilar region.

Design 24 cadaveric dissections and 4 clinical cases of aneurysms of the high basilar region are presented. Assessment included visibility and operability afforded by either tentorial incision creating a dural flap (group A) or retraction of the tentorial edge and tethering with a suture (group B). Four patients, two with superior cerebellar artery aneurysms and two with proximal posterior cerebral artery aneurysms were treated with each approach.

Results In the quantitative evaluations, we found no significant difference in the exposure of the posterior cerebral, superior cerebellar, and perforant arteries as well as surgical working area provided by either approach. However, tentorial incision allowed a significantly greater exposure of the basilar artery and the fourth cranial nerve (both p < 0.001). Concerning operability, tentorial incision provided no objective advantage for direct clipping of the high basilar region (groups A vs. B, p > 0.05). Subjectively, clipping of the high basilar segment was feasible using tentorial tethering only.

Conclusion Retraction of the free edge of the tentorium downward by tethering with a suture is simple and fast method for exposure of aneurysms in the high basilar region when the pathology does not require a proximal control. In our data the rather more invasive and time consuming tentorial incision provided an additional objectified advantage only for placement of a proximal temporary clip.
Energy response characterization of InGaP X-ray detectors
Authors: Lioliou G. , Krysa A. B. , Barnett A. M.
Published: November 2018

Two custom-made In0.5Ga0.5P p+-i-n+ circular mesa spectroscopic X-ray photodiodes with different diameters (200 μm and 400 μm) and a 5 μm i layer have been characterized for their response to X-ray photons within the energy range 4.95 keV to 21.17 keV. The photodiodes, operating uncooled at 30 °C, were coupled, in turn, to the same custom-made charge-sensitive preamplifier. X-ray fluorescence spectra of high-purity calibration foils excited by a Mo target X-ray tube were accumulated. The energy resolution (Full Width at Half Maximum) increased from 0.79 ± 0.02 keV at 4.95 keV to 0.83 ± 0.02 keV at 21.17 keV, and from 1.12 ± 0.02 keV at 4.95 keV to 1.15 ± 0.02 keV at 21.17 keV, when using the 200 μm and 400 μm diameter devices, respectively. Energy resolution broadening with increasing energy was attributed to increasing Fano noise (negligible incomplete charge collection noise was suggested); for the first time, the Fano factor for In0.5Ga0.5P was experimentally determined to be 0.13, suggesting a Fano limited energy resolution of 145 eV at 5.9 keV. The charge output of each system had a linear relationship with photon energy, across the investigated energy range. The count rate of both spectroscopic systems increased linearly with varying X-ray tube current up to ∼105 photons s−1 cm−2 incident photon fluences. The development of In0.5Ga0.5P based spectrometers is particularly important for hard X/γ-ray astronomy, due to the material’s large linear X-ray and γ-ray absorption coefficients and the ability to operate uncooled at high temperatures.
Poor Early Growth of Wheat Under Direct Drilling
Authors: Chan KY , Mead JA , Roberts WP
Published: November 2018

Poor early growth of wheat under direct drilling on a hardsetting duplex soil was studied in the
light of a range of soil physical and biological properties. Two systems of direct drilling were included
in the study: one with a short fallow maintained by herbicide (chemical fallow), and another in
which a fallow period was absent and herbicide was applied 1 week before sowing (nil fallow).
Plant measurements indicated that the poor early growth observed under both direct drilled systems,
as compared to that under conventional cultivation, was not due to poor germination or poor emergence.
Rather, it was shown to be a consequence of reduced growth after establishment. Weight per plant
measured 64 days after sowing for the conventional, chemical and nil fallow treatments was found to
be in the ratio of 3.2: 1.8 : 1.0, respectively. Soil physical measurements during the 9 weeks from
sowing indicated that moisture availability was unlikely to be an important factor affecting the observed
growth difference for the particular season. Much higher bulk density (1.66 versus 1.35 Mg/m3 at
50-100 mm) and vane shear strength values were found in the undisturbed soil between the drill rows
in the top 100 mm of the two direct drilled treatments. Vane shear strength measured in the top 50 mm
layer of the direct drilled plots was up to 2.9 times higher between the drill rows than in the drill rows.
The poor vegetative growth on the chemical fallow plots was probably caused by restricted root growth
in the denser and stronger 0-100 mm depth of undisturbed soil. The poor early vegetative and root
growth of wheat in the nil fallow could not be fully explained by the soil physical properties, but
indicated the presence of other root inhibitory factors. Our results suggest that one such factor is the
presence of inhibitory Eacteria on the roots.
Arithmetic Device Based on Multiple Schottky-like Junctions
Authors: Mech Justyna , Kowalik Remigiusz , Podborska Agnieszka , Kwolek Przemysław , Szaciłowski Konrad
Published: November 2018

Photoelectrodes containing cadmium sulfide deposited as powders and crystalline thin layers combined with semi-solid ionic liquid electrolyte behave like Schottky photodiodes. Appropriate connection of these devices results in simple optoelectronic logic gates (AND, XOR) and enables construction of an optoelectronic binary half-adder.
The Nucleophilic Addition of β-Lactam Carbenes to Alkylphenylketenes for a Ready Approach to Spiro[β-lactam-2,1′-indene] Derivatives
Authors: Li Yong-Jia , Yan Cai-Xia , Sun Zhong-Xin , Cheng Ying
Published: November 2018

The nucleophilic reaction of ambident β-lactam carbenes with alkylphenylketenes is studied, which produces two types of spiro[β-lactam-2,1′-indene] derivatives in total yields of 55–89 %. This work not only provides the first example that ambident carbenes behave with high activity towards ketenes, but also developes the application of β-lactam carbenes in the construction of spiro-β-lactam compounds.
Aromatic Schiff Bases Multiply Substituted with Terminal Ethynyl Groups: Potential Building Blocks for Conjugated Polymers and Oligomers
Authors: Stahlová Sabina , Sedlácek Jan , Svoboda Jan , Polášek Miroslav , Zedník Jirí
Published: November 2018

Nine mostly novel aromatic Schiff bases containing from two-to-four terminal ethynyl groups and one or two methanimine groups per one molecule are reported. The spectral and density functional theory characteristics and the extent of conjugation are discussed in connection with the structure and architecture of the prepared compounds. The applicability of compounds as building blocks for conjugated polymers is shown in TaCl5-catalyzed polycyclotrimerization (proceeding in ethynyl groups) yielding either soluble luminescent or insoluble microporous polymers.