bluuebunny/crossref_metadata_2025 huggingface dataset:
Method of railway line audit in terms of the condition of railway infrastructure
Authors: Bartoś Magdalena , Gołębiowski Piotr
Published: October 2019

The most important problems concerning the organization of railway traffic is continuous provision and systematic improvement the level of safety of services provided by railway transport enterprises. This safety results from many factors – including condition of the infrastructure, state of superstructure or the way of conducting railway traffic. This article covers railway infrastructure within its scope. In this regard include, among others take appropriate actions to monitor its condition. One of the methods may be the audit of the railway line in terms of infrastructure condition. The purpose of the article is to present the method of railway line audit in the area of infrastructure. The concept of railway line audit from the point of view of infrastructure status was defined in the paper. The audit method was presented along with the identification of problems that may occur as a result of the audit and suggestions for solutions to these problems. The presented method was verified for a selected railway line in Poland railway line No. 12 Skierniewice – Łuków. The possibilities of improving the condition of this line were proposed together with the estimation of the amount of expenditures necessary to make therefore and time gains achieved through improvement.
Methodology of risk assessment and forms of environmental safety management for the transport of dangerous goods by railway transport
Authors: Zelenko Yuliia , Dzhus Oleh , Dzhus Volodymyr , Yanchenko Dmytro
Published: October 2019

The authors examined the scientific basis for managing environmental and economic risks in the transport of dangerous goods by rail. The importance of optimizing the monitoring of environmental safety and the organization of environmental risk management was noted. The paper presents the interrelation of the functional strategy of ensuring the reliability of the transportation process with other strategies. A new functional strategy and a schematic diagram of the environmental management system for making management decisions to optimize environmental management in railway transport have been proposed. A conceptual apparatus has been developed to identify and determine environmental risks and the principle of their management during the transport of dangerous goods by railway transport.
Reducing noise influence on an audio frequency track circuit
Authors: Saiapina Inna , Babaiev Mykhailo , Аnanіevа Olha
Published: October 2019

In connection with electromagnetic interference influence on the track circuits, the purpose of the research is finding the means to increase the noise immunity of an audio frequency track circuit. The authors propose a new engineering solution, which enables reducing the effect of noises on the input of the track receiver in the intervals between signal current pulses. The proposed noise-immune audio frequency track circuit is based on inserting a delay line, an adjustable single-pulse generator and a controlled electronic switch into the existing audio frequency track circuit equipment. To analyze its efficiency, the operation of the audio frequency track circuit was simulated under conditions of traction current disturbances, impulse and fluctuation interferences with the known parameters. The results show that proposed device for railway transport allows to increase a signal-to-noise ratio on the track receiver input from 8% to 30%, depending on the interference parameters and the level of the useful signal.
Stress-strain state analysis of the leading car body of DPKr-2 diesel train under action of design and operational loads
Authors: Kostritsa Sergei , Pshinko Alexander , Ursulyak Lyudmila , Kuzyshyn Andriy , Kramarenko Maxim , Grechkin Alex
Published: October 2019

Purpose.Provision of strength and durability of the main structural element of DPKr-2 diesel train -the leading car body. Methodology. A spatial solid-state 3-D model of the body is built and durability calculations are carried out concerning action of loads stipulated by regulatory documents operating in Ukraine. In particular, the following main estimated modes are considered: mode 1 – a notional safety mode which takes into account the possibility of considerable longitudinal forces arising during shunting movements, transportation and accidental collision; mode 2 – an operational mode which takes into account forces acting on a train during acceleration to constructional speed, coasting or braking from this speed while passing a curve. Results. Based on the results of theoretical and experimental studies a conclusion has been made that the leading car body construction of DPKr-2 diesel train meets the requirements of regulatory documents regarding strength and durability. Practical relevance. A complex of calculation and experimental work concerning assessment of stress-strain state of the leading car body of DPKr-2 diesel train under action of design and operational loads allowed the creation of construction which meets not only operational requirements but also strength and durability ones.
Distribution of information flows in the advanced network of MPLS of railway transport by means of a neural model
Authors: Zhukovyts’kyy Ihor , Pakhomova Victoria , Domanskay Halyna , Nechaiev Andrew
Published: October 2019

Ensuring interoperability of railway transport is possible only due to the developed information structure. Today, Ukraine uses the information-telecommunication system (ITS) of railway transport, which is based on a data communication network. The effectiveness of its work is largely determined by the routing system. The current algorithm for choosing the shortest route, which is used in the existing routing protocol (OSPF), does not always lead to an effective result. However, there is MPLS technology, which could improve the quality of the ITS network by creating virtual channels between its nodes. The authors proposed a scheme for selecting tunnels for the flows in the MPLS network, which is based on the neural model of a multilayer perceptron of configuration 18–3–3–10 with the activation function Softmax in hidden layers and a linear activation function in the input layer. To simulate the network operation, flow data is needed: class of service (CoS), sender and recipient identifiers, average flow rate vector and tunnel data (their initial load). The final load of the tunnels is taken as the resulting output of the neural network, on the basis of which the tunnel is selected for the flow of the k-th class of service.
Intellectualization of logistic supply chains on the basis of forecasting volumes of cargo transportation
Authors: Gurnak Vitalii , Volynets Lyudmila , Khalatska Ilona
Published: October 2019

Research shows that the accelerated economic movement towards a more intelligent model of development and rapid dissemination of knowledge contributes to the emergence of new modern logistics technologies and approaches to managing global supply chains. The dominant feature of the sustainable development of transport services is the invariant concept of management, the basis of which is the socioecological and economic model. Indicators of the transport sector show a decline in volumes of transportation, but the positive dynamics of growth is demonstrated by the agrarian sector, which produces half of all export volumes and provides one third of the currency revenues of the state.Factors that inhibit the effective functioning of the logistics chain are revealed. In particular, the technological orientation of railways, mainly on route transportation, highlighted the problem of uneven development of ports at ports and railway ports, as well as inconsistencies in grain volumes in Stevedoring companies’ deals with real port facilities. In fact, there is a schedule of seasonal fluctuations in the transportation of cereals, in particular, their absence for 3-4 months per year.The rational model of management and intellectualization of grain supply logistic chain, which takes into account the indicators of artificial neural network forecasting and seasonal grain transportation parameter, is proposed.
Methodical foundations of cargo owners’ transport services logistics management
Authors: Yanovsky Petro , Yanovska Viktoriia , Lytvynenko Sergiy , Lytvynenko Larysa , Vodchic Oleksandr
Published: October 2019

In the article methodical foundations of transport services logistics management of cargo owners were realized, on the basis of integrated estimation of economic efficiency of holistic progressive logistic chain operation of cargo delivery. In the making of the study, the authors have identified the provision of logistic management conditions by production and mainline rail transport in carrying out transportations. In the successful implementation of finished product loading and arriving cargo processing plans, clear interaction of all logistics chain elements is an important factor, achieved on the basis of introduction of a stable cargo train schedule at sections and the submission of local operation organization in nodes, at sections and stations. On the basis of modelling possible variants of different parameters ratios of the logistic interaction process of production with mainline rail transport, it was determined that at different parameters ratios results can be obtained that will vary by waiting time of carrying out loading in railway cars and waiting time of removal of finished products from manufacturer’s warehouse, required car fleet and loading of material handling vehicles. In this case, the most economical option should be taken as the main condition for ensuring a rational interaction of industrial and mainline rail transport.
Modelling of the electric locomotion DS3 working
Authors: Bannikov Dmytro , Radkevich Anatoliy , Muntian Antonina
Published: October 2019

The purpose of the work is to evaluate the spatial distribution of the rigidity of the carrier frame and the body of the Ukrainian electric locomotive DC3 as a single system during operation and repair. The research was carried out on the basis of the finite element method with the application of design and computing complex SCAD for Windows. The numerical model of the electric locomotive was built, tested and then used to identify the causes and providing guidance on solving some specific operational questions. They are included, for example, the possibility of eliminating the body skew when jacking up on jacks and jamming the door as a result. The researches showed that the structure of the electric locomotive DS3 in general has a rather high spatial rigidity, both in transverse and longitudinal directions, and on torsion. However, for some practical repair tasks there is not enough for that rigidity. It was recommended to increase the thickness of the shell of its body up to 4 mm or the roof up to 8 mm, which leads to an increasing in the total mass of the machine by about 2,5 and 3,5 tons, respectively.
Systems mutual loadings of traction asynchronous cars
Authors: Afanasov Andriy , Shapovalov Oleksandr , Voitenko Maryna
Published: October 2019

The review of methods of post-repair tests of traction asynchronous motors under conditions of locomotive depot is carried out.The necessity of introducing special stands for post-repair tests is shown in order to improve their quality, reduce the number of failures of service equipment, improve safety of the railway transport. Let’s consider a question of power supply of the research asynchronous engine in wide frequency range and also a possibility of creation of the universal stand for testing important asynchronous engines of the electrorolling stock. Survey of possible versions of the scheme mutual loadings of asynchronous electrical machines which can be used for testing traction asynchronous engines of the rolling stock is executed. Such systems can be constructed both with use of the static converter of frequency, and without it. The given short characteristic of each alternative, certain advantages and shortcomings of each of system options. It is shown that systems with use of static converters of frequency differ in high power efficiency, allow to carry out tests in the wide frequency range of power supply, however have higher prime cost. Schemes without converters of frequency differ in smaller power efficiency, impossibility to carry out tests in the wide range of frequency of power supply, high level of consumption of reactive power . The results of the carried-out analysis can be used when choosing rational option of a system mutual loadings of asynchronous electric motors which will differ in higher functionality and power efficiency. Use of such systems will allow to lower capital expenditure for creation new and modernization of traction electrical machines that exist at the station for test.
Full-thickness resection of neuroendocrine tumors in the rectum
Authors: Meier Benjamin , Albrecht Heinz , Wiedbrauck Thomas , Schmidt Arthur , Caca Karel
Published: October 2019

Background Rectal neuroendocrine tumors (NETs) are subepithelial tumors with potential for malignancy. Depending on tumor characteristics, endoscopic or surgical resection is recommended. However, the optimal endoscopic approach is not defined. This is the first larger study evaluating endoscopic full-thickness resection (EFTR) of rectal NETs.

Methods For resection, the full-thickness resection device (FTRD) was used. A registry was created as part of post-market clinical follow-up. All cases of rectal NETs in the registry were analyzed retrospectively.

Results 31 German centers entered data of 501 FTRD procedures and 40 cases of rectal NETs were identified. The median lesion size was 8 mm. All lesions could be resected using FTRD. The median procedure time was 18.5 minutes. Resection was macroscopically and histologically complete in all cases. Full-thickness resection was achieved in 95 %. No major adverse events occurred. Endoscopic follow-up showed no evidence of residual or recurrent tumor.

Conclusion EFTR is safe and effective for resection of smaller rectal NETs. Prospective comparative trials are needed to define the role of EFTR of rectal NETs.
Experience with Fully Covered Self-Expandable Metal Stents for Esophageal Leakage in Children
Authors: Lange Bettina , Demirakca Süha , Kähler Georg , Weiß Christel , Wessel Lucas , Kubiak Rainer
Published: October 2019

Background There is a lack of experience with fully covered self-expandable metal stents (SEMSs) for the treatment of esophageal leakage particularly in infants and neonates.

Methods Eight patients (5M, 3F) with a median age of 17 months (range, 1–135 months) who underwent treatment with SEMSs for an anastomotic leakage or perforation of the esophagus were recruited to this retrospective study. Four children were born premature. In six patients the stents were placed primarily as an emergency procedure.

Results Median duration of individual stent placement was 42 days (range, 13–72 days). Six out of eight patients (75%) were treated with one stent only. In three preterm infants who had their stents inserted within the first month relative weight gain was 17% compared with 2% in five patients who were treated later in life (p=0.0986). In four cases (50%) distal migration of the stent was observed. Seven out of eight patients (88%) had their leakage resolved after stent therapy.

Conclusions Insertion of fully covered SEMSs is an alternative tool for the treatment of esophageal leakage in children and preterm infants, and successful with only one single application in selected cases. It can be used either following previous therapy or as part of an emergency procedure. Because of the absence of manufactured, age-related devices SEMSs that are originally designed for other organs can be applied.
Zusammenfassung, Replizierbarkeit und methodologische Qualität von Frühmobilisation im Akutkrankenhaus bei Patienten mit Schädel-Hirn-Trauma – Systematische Literaturübersicht
Authors: Knols Ruud H. , Hellweg Stephanie , Häni Nathalie , Manettas Anastasios , Brugger Peter , de Bruin Eling D.
Published: October 2019

Hintergrund Die Implementierung von Frühmobilisation in der Akutversorgung bei Patienten mit Schädel-Hirn-Trauma (SHT) könnte sowohl in Bezug auf die funktionelle Erholung als auch auf die Hospitalisationsdauer von großer Bedeutung sein. Derzeit fehlen hierzu jedoch detaillierte, replizierbare Interventionsbeschreibungen.

Ziel Der Beitrag bietet eine Zusammenfassung der aktuellen Literatur zu Therapieinterventionen der Frühmobilisation einschließlich detaillierter Interventionsbeschreibung mit einer Bewertung der berichteten Interventionsparameter und der methodologischen Qualität der randomisierten klinischen Studien (RCT).

Methode In 5 Datenbanken (Medline-Ovid, Embase, CINAHL, PsychINFO, Cochrane Library) erfolgte eine systematische Literatursuche. Unabhängig voneinander bewerteten 2 Autoren die berichteten Interventionsparameter mittels Template for Intervention Description and Replication (TIDieR) Checkliste und überprüften die methodologische Qualität der RCT anhand der Downs-and-Black-Checkliste 1.

Ergebnisse In den Review wurden 2 RCT eingeschlossen 2
3. Die Überprüfung anhand der TIDieR-Checkliste zeigte, dass diese jeweils 6 bzw. 8 von 12 TIDieR-Items beschrieben. Die Informationssammlung bezog sich auf die verwendeten Materialien (Item 3), die Fachexpertise der Behandler (Item 5), den Zeitpunkt und die Häufigkeit der Frühmobilisation (Item 8), den Zeitpunkt einer eventuellen Anpassung (Item 9), die mögliche Modifikation der Intervention (Item 10), die Art der Überprüfung der Adhärenz (Item 11) und die Adhärenz (Item 12). Beide RCT erhielten 20 bzw. 22 von 28 möglichen Punkten der Down-and-Black-Checkliste 1. Die Items 8 (Beschreibung von Nebenwirkungen), 12 (Repräsentativität der eingeschlossenen Patienten), 14 (Verblindung der eingeschlossenen Patienten) und 25 (statistische Korrektur einer Verzerrung) waren in beiden Studien nicht erwähnt.

Schlussfolgerungen Die Replizierbarkeit der Frühmobilisation bei Patienten mit SHT im Akutkrankenhaus ist derzeit nicht gegeben. Um die Qualität der Interventionsbeschreibungen zu verbessern und somit die Replizierbarkeit der Interventionen für Folgestudien und den Transfer in den klinischen Alltag zu gewährleisten, wird eine konsequente Verwendung der TIDieR-Checkliste in klinischen Studien empfohlen.
Stereoselective Synthesis of syn-γ-Hydroxynorvaline and Related α-Amino Acids
Authors: Valachová Dominika , Ferko Branislav , Puchľová Eva , Caletková Oľga , Berkeš Dušan , Kolarovič Andrej , Jakubec Pavol
Published: October 2019

The total syntheses of three enantiomerically pure non-proteinogenic amino acids, l-norvaline, γ-oxonorvaline, and syn-γ-hydroxynorvaline, are reported. The chromatography-free route pivoted on the construction of highly enantiomerically enriched substituted α-amino-γ-oxopentanoic acid, from which all three members were accessed divergently via chemoselective and stereoselective reductions. The rapid synthesis of this key α-amino-γ-oxopentanoic acid was achieved by a highly diastereoselective crystallisation-driven three-component Mannich reaction from the readily available building blocks acetone, glyoxylic acid monohydrate, and (S)-(4-methoxyphenyl)ethylamine. The enantiomeric purity of all target molecules was confirmed by HPLC analysis, either of the amino acids or their derivatives.
Copper(II)-Catalyzed C–N Coupling of Aryl Halides and N-Nucleophiles Promoted by Quebrachitol or Diethylene Glycol
Authors: Du Fangyu , Zhou Qifan , Fu Yang , Chen Yuanguang , Wu Ying , Chen Guoliang
Published: October 2019

Herein, we report the natural ligand quebrachitol (QCT) as a promoter for a Cu(II) catalyst, which is highly effective for N-arylation of various amines and related aryl halides. A series of diarylamine derivatives were obtained in high yields by using diethylene glycol (DEG) as both ligand and solvent. The C–N coupling reactions proceed under mild conditions and exhibit good functional group tolerance.
Quadricuspid Aortic Valvulopathy and Acute Type A Aortic Dissection
Authors: Klassen Sheila L. , Hutchison Stuart J.
Published: October 2019

This case report describes a 55-year-old male who presented with acute Type A aortic dissection. He underwent emergent surgical repair, and his intraoperative transesophageal echocardiography revealed a quadricuspid aortic valve. His aortic root measured 45 mm. Quadricuspid aortic valves have previously been associated with aortic root dilation. This case illustrates the possible association of quadricuspid aortic valves with aortic dissection, similar to what is described with bicuspid valves.
Tailored Surgical Approaches for Foramem Magnum Tumors
Authors: Lynch Jose Carlos , Pereira Celestino Esteves , Weling Leonardo C. , Gonçalves Mariangela
Published: October 2019

Objective To describe our surgical techniques, analyze their safety and their postoperative outcomes for foramen magnum tumors (FMTs).

Methods From 1986 to 2014, 34 patients with FMTs underwent surgeries using either the lateral suboccipital approach, standard midline suboccipital craniotomy, or the far lateral approach, depending on the anatomic location of the lesions.

Results In the present series, there were 22 (64.7%) female and 12 (35.2%) male patients. The age of the patients ranged from 12 to 63 years old. We observed 1 operative mortality (2.9%). A total of 28 patients (82.3%) achieved a score of 4 or 5 in the Glasgow Outcome Scale (GOS). Gross total resection (GTR) was obtained in 22 (64.7%) patients. After the surgery, 9 (26%) patients developed lower cranial nerve dysfunction (LCNd) weakness. The follow-up varied from 1 to 24 years (mean: 13.2 years).

Conclusion The majority of tumors located in the FM can be safely and efficiently removed using either the lateral sub occipital approach, standard middle line sub occipital craniotomy, or the far lateral approach, depending on the anatomic location of the lesions.
Influence of Thymoquinone Exposure on the Micro-Hardness of Dental Enamel: An In Vitro Study
Authors: Farooq Imran , Ali Saqib , Siddiqui Intisar Ahmad , Al-Khalifa Khalifa S. , Al-Hariri Mohammed
Published: October 2019

Objective The aim of this study was to assess changes in micro-hardness level of enamel after it was exposed to thymoquinone (TQ).

Materials and Methods Sixteen enamel blocks were prepared and divided into two groups (each group received eight blocks, n = 8); Gp 1 (control): enamel blocks kept in 100 mL artificial saliva (AS) for 24 hours and Gp 2: enamel blocks kept in a mixture of TQ powder (1 g) and AS (100 mL) for 24 hours. Post-immersion they were subjected to simulated brushing with each sample receiving 8,000 linear strokes. For brushing, 3 mL of AS and TQ oil was used for groups 1 and 2, respectively. Enamel surfaces were analyzed for changes in values of surface micro-hardness (pre-immersion, post-immersion, and post-brushing) by obtaining Vickers hardness number (VHN).

Results The present study indicated improvement in micro-hardness levels for both groups although experimental group showed more enhancement. The mean baseline VHN for control group was 498.6, 500.4 for post-immersion, and 503.5 for post-brushing. The mean baseline VHN for experimental group was 448.7, 531 for post-immersion, and 610.3 for post-brushing. Statistically significant differences (p < 0.05) were observed when post-brushing VHN values of both groups were compared and also within the experimental group when post-brushing values were compared with baseline values.

Statistical Analysis Wilcoxon signed-rank test was applied for the evaluation of pre- and post-exposure hardness values. Level of significance was ≤0.05.

Conclusion The exposure of enamel to TQ led to an improvement in its micro-hardness levels. Further studies are required to understand the mechanism of action of TQ on human tissues.
Differences, Opportunities, and Strategies in Drug Alert Optimization—Experiences of Two Different Integrated Health Care Systems
Authors: Saiyed Salim M. , Davis Katherine R. , Kaelber David C.
Published: October 2019

Background Concerns about the number of automated medication alerts issued within the electronic health record (EHR), and the subsequent potential for alarm fatigue, led us to examine strategies and methods to optimize the configuration of our drug alerts.

Objectives This article reports on comprehensive drug alerting rates and develops strategies across two different health care systems to reduce the number of drug alerts.

Methods Standardized reports compared drug alert rates between the two systems, among 13 categories of drug alerts. Both health care systems made modifications to the out-of-box alerts available from their EHR and drug information vendors, focusing on system-wide approaches, when relevant, while performing more drug-specific changes when necessary.

Results Drug alerting rates even after initial optimization were 38 alerts and 51 alerts per 100 drug orders, respectively. Eight principles were identified and developed to reflect the themes in the implementation and optimization of drug alerting.

Conclusion A team-based, systematic approach to optimizing drug-alerting strategies can reduce the number of drug alerts, but alert rates still remain high. In addition to strategic principles, additional tactical guidelines and recommendations need to be developed to enhance out-of-the-box clinical decision support for drug alerts.
Relationship between General Health Behaviors and Oral Health Behaviors in 2015–2016 NHANES Adult Population
Authors: Saadeh Rami , Bober-Moken Irene , Challa Suman
Published: October 2019

Objectives The aim of this study was to examine the relationship between general health behaviors and oral health behaviors in adults who participated in the interview component of the National Health and Nutrition Examination Survey (NHANES) of 2015 to 2016.

Materials and Methods This was a cross-sectional study design of a national data set that included 5,992 adults who represented a sample of civilian, noninstitutionalized US population.

Statistical Analysis Chi-squared test of independence was used to describe the relationship of demographic information with oral health behaviors of participants. Multivariate logistic regression was used to determine the association between general and oral health behaviors.

Results More than half (53.6%) of the participants had seen a dentist in the past 12 months and the main reason for that visit was for a regular checkup, cleaning, or examination. More than one-quarter (28.7%) reported visiting a dentist because something was hurting or bothering them. Most respondents (63.4%) reported being hardly ever or never having been embarrassed by their mouth condition. Age at one’s first sexual encounter, having a new sexual partner, mental health counseling, moderate- intensity sports, and computer use were significantly associated with positive oral health behaviors.

Conclusions For maximum effectiveness, health promotion efforts should target risk behaviors common to both oral and general health.
Novel COL11A2 Pathogenic Variants in a Child with Autosomal Recessive Otospondylomegaepiphyseal Dysplasia: A Review of the Literature
Authors: Selvam Pavalan , Singh Shekhar , Jain Angita , Atwal Herjot , Atwal Paldeep S.
Published: October 2019

Otospondylomegaepiphyseal dysplasia (OSMED) is an inherited autosomal dominant and recessive skeletal dysplasia caused by both heterozygous and homozygous pathogenic variants in COL11A2 encoding the α2(XI) collagen chains, a part of type XI collagen. Here, we describe a 2-year-old girl presenting from birth with a phenotype suggestive of OSMED. On whole exome sequence analysis of the family via commercially available methods, we detected two novel heterozygous pathogenic variants in the proband. In addition, we reviewed the phenotype of autosomal recessive OSMED cases with COL11A2 pathogenic variants reported to date and quantitatively highlighted the phenotypic spectrum.
Antegrade Versus Retrograde Technique for Fixation of Scaphoid Waist Fractures: A Comparison of Screw Placement
Authors: Lucenti Ludovico , Lutsky Kevin F. , Jones Christopher , Kazarian Erick , Fletcher Daniel , Beredjiklian Pedro K.
Published: October 2019

Background Scaphoid waist fractures are often treated using headless compression screws using dorsal or volar approaches.

Objectives The purpose of this study is to compare differences in screw position using a volar (retrograde) or dorsal (antegrade) approach.

Patients and Methods A total of 82 patients were retrospectively evaluated: 41 treated with a volar and 41 with a dorsal approach were selected. Postoperative radiographs were reviewed by three observers who rated screw location in the proximal pole, waist, and distal pole.

Results Thirty-four patients (83%) in the antegrade group had central screw placement in the waist of the scaphoid in posteroanterior and lateral planes compared with 14 (34.9%) in the retrograde group (p < 0.05). For the antegrade group, the screw was central in 217 of 246 zones (88.2%) compared with 127 of 246 (51.6%) in the retrograde group (p < 0.05).

Conclusions The dorsal antegrade approach appears to allow the surgeon to achieve central screw placement along all three scaphoid regions.

Level of Evidence This is Level III study.
Numerical investigation of toroidal bubble dynamics in a compressible fluid based on boundary integral method
Authors: Xiao W. , Zhang A.-M. , Ye X. , Sun L. Q.
Published: October 2019

The external liquid compressibility cannot be ignored because the speed of the bubble jet emerging at the end of bubble collapse reaches hundreds of meters per second. Additionally, when the bubble jet penetrates the surface of a bubble, a toroidal bubble forms and the singly connected flow domain changes to a doubly connected topology. As the Biot–Savart law is based on the assumption of incompressibility, the vortex ring model is very difficult to extend to compressible fluids. This paper describes the use of the boundary integral method to establish a numerical model of a toroidal bubble, considering the external liquid compressibility and the internal gas wave effect. A cut is introduced into the fluid domain so that it can be considered as singly connected, with the discontinuity of velocity across this cut equal to the circulation of the flow. Furthermore, the initial bubble condition is calculated by the volume acceleration model. The numerical model is validated through comparisons with experimental data from underwater explosions. The numerical results are found to correlate well with the experimental results. Then, the influence of buoyancy parameters and the internal gas wave effect on toroidal bubble dynamics in a gravitational field is investigated.
Impact of the scattering physics on the power factor of complex thermoelectric materials
Authors: Graziosi Patrizio , Kumarasinghe Chathurangi , Neophytou Neophytos
Published: October 2019

We assess the impact of the scattering physics assumptions on the thermoelectric properties of five Co-based p-type half-Heusler alloys by considering full energy-dependent scattering times vs the commonly employed constant scattering time. For this, we employ density functional theory band structures and a full numerical scheme that uses Fermi's golden rule to extract the momentum relaxation times of each state at every energy, momentum, and band. We consider electron-phonon scattering (acoustic and optical), as well as ionized impurity scattering, and evaluate the qualitative and quantitative differences in the power factors of the materials compared to the case where the constant scattering time is employed. We show that the thermoelectric power factors extracted from the two different methods differ in terms of (i) their ranking between materials, (ii) the carrier density where the peak power factor appears, and (iii) their trends with temperature. We further show that the constant relaxation time approximation smoothens out the richness in the band structure features, thus limiting the possibilities of exploring this richness for material design and optimization. These details are more properly captured under full energy/momentum-dependent scattering time considerations. Finally, by mapping the conductivities extracted within the two schemes, we provide appropriate density-dependent constant relaxation times that could be employed as a fast first-order approximation for extracting charge transport properties in the half-Heuslers we consider.
Road traffic state prediction based on a graph embedding recurrent neural network under the SCATS
Authors: Xu Dongwei , Dai Hongwei , Wang Yongdong , Peng Peng , Xuan Qi , Guo Haifeng
Published: October 2019

Road traffic state prediction is one of the essential and vital issues in intelligence transportation system, but it is difficult to get high accuracy due to the complicated spatiotemporal characteristics of traffic flow data, especially under the Sydney coordinated adaptive traffic system. In this work, we represent the traffic road network as a graph and propose a novel traffic flow prediction framework named the graph embedding recurrent neural network (GERNN). It could tackle the difficulty in the road traffic state prediction. We conduct numerical tests to compare GERNN with other existing methods using a real-world dataset.
Simulation of perovskite solar cell temperature under reverse and forward bias conditions
Authors: Mehdizadeh-Rad Hooman , Singh Jai
Published: October 2019

We have developed a model to calculate the temperature of an illuminated perovskite solar cell (PSC) under the forward bias and that of a shaded one under the reverse bias at different ambient conditions. The results show that the dissipated power due to the reverse bias (PRB) should be more than around 6 W to have a higher temperature in the shaded solar cell than that in the illuminated solar cell at the solar irradiance of 1000W/m2, and this result is almost ambient temperature and wind velocity independent. It is also found that the generated thermal power due to the nonradiative recombination (PRec) becomes significant at the open circuit voltage (Voc) condition, leading to illuminated solar cell temperature (Tcr) higher than that at the short circuit current (Jsc) condition by about 12.7 K, 13.3 K, and 13.9 K at the ambient temperatures of 270 K, 300 K, and 330 K, respectively. In addition, the influence of the thickness of the illuminated solar cell on its temperature at the Voc condition is investigated, which reveals that, by increasing the thickness from 100 nm to 300 nm, the solar cell temperature can increase by 20 K.
Collective dynamics of rate neurons for supervised learning in a reservoir computing system
Authors: Maslennikov Oleg V. , Nekorkin Vladimir I.
Published: October 2019

In this paper, we study collective dynamics of the network of rate neurons which constitute a central element of a reservoir computing system. The main objective of the paper is to identify the dynamic behaviors inside the reservoir underlying the performance of basic machine learning tasks, such as generating patterns with specified characteristics. We build a reservoir computing system which includes a reservoir—a network of interacting rate neurons—and an output element that generates a target signal. We study individual activities of interacting rate neurons, while implementing the task and analyze the impact of the dynamic parameter—a time constant—on the quality of implementation.
Fermi-Löwdin orbital self-interaction correction using the strongly constrained and appropriately normed meta-GGA functional
Authors: Yamamoto Yoh , Diaz Carlos M. , Basurto Luis , Jackson Koblar A. , Baruah Tunna , Zope Rajendra R.
Published: October 2019

Despite the success of density functional approximations (DFAs) in describing the electronic properties of many-electron systems, the most widely used approximations suffer from self-interaction errors (SIEs) that limit their predictive power. Here, we describe the effects of removing SIE from the strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation using the Fermi-Löwdin Orbital Self-Interaction Correction (FLOSIC) method. FLOSIC is a size-extensive implementation of the Perdew-Zunger self-interaction correction (PZ-SIC) formalism. We find that FLOSIC-SCAN calculations require careful treatment of numerical details and an integration grid that yields reliable accuracy with this approach. We investigate the performance of FLOSIC-SCAN for predicting a wide array of properties and find that it provides better results than FLOSIC-LDA and FLOSIC-PBE in nearly all cases. It also gives better predictions than SCAN for orbital energies and dissociation energies where self-interaction effects are known to be important, but total energies and atomization energies are made worse. For these properties, we also investigate the use of the self-consistent FLOSIC-SCAN density in the SCAN functional and find that this DFA@FLOSIC-DFA approach yields improved results compared to pure, self-consistent SCAN calculations. Thus, FLOSIC-SCAN provides improved results over the parent SCAN functional in cases where SIEs are dominant, and even when they are not, if the SCAN@FLOSIC-SCAN method is used.
Time-resolved dynamics in iodide-uracil-water clusters upon excitation of the nucleobase
Authors: Kunin Alice , McGraw Valerie S. , Lunny Katharine G. , Neumark Daniel M.
Published: October 2019

The dynamics of iodide-uracil-water (I−·U·H2O) clusters following π-π* excitation of the nucleobase are probed using time-resolved photoelectron spectroscopy. Photoexcitation of this cluster at 4.77 eV results in electron transfer from the iodide moiety to the uracil, creating a valence-bound anion within the cross correlation of the pump and probe laser pulses. This species can decay by a number of channels, including autodetachment and dissociation to I− or larger anion fragments. Comparison of the energetics of the photoexcited cluster and its decay dynamics with those of the bare iodide-uracil (I−·U) complex provides a sensitive probe of the effects of microhydration on these species.
Machine-learning-assisted thin-film growth: Bayesian optimization in molecular beam epitaxy of SrRuO3 thin films
Authors: Wakabayashi Yuki K. , Otsuka Takuma , Krockenberger Yoshiharu , Sawada Hiroshi , Taniyasu Yoshitaka , Yamamoto Hideki
Published: October 2019

Materials informatics exploiting machine learning techniques, e.g., Bayesian optimization (BO), have the potential to reduce the number of thin-film growth runs for optimization of thin-film growth conditions through incremental updates of machine learning models in accordance with newly measured data. Here, we demonstrated BO-based molecular beam epitaxy (MBE) of SrRuO3, one of the most intensively studied materials in the research field of oxide electronics, mainly owing to its unique nature as a ferromagnetic metal. To simplify the intricate search space of entangled growth conditions, we ran the BO for a single condition while keeping the other conditions fixed. As a result, high-crystalline-quality SrRuO3 film exhibiting a high residual resistivity ratio of over 50 as well as strong perpendicular magnetic anisotropy was developed in only 24 MBE growth runs in which the Ru flux rate, growth temperature, and O3-nozzle-to-substrate distance were optimized. Our BO-based search method provides an efficient experimental design that is not as dependent on the experience and skills of individual researchers, and it reduces experimental time and cost, which will accelerate materials research.
Rusting at the atomic level
Authors: Kish Stacy W.
Published: October 2019

Researchers identified the structures that form along the surface of the mineral magnetite when submerged in water.
Divergent responses of above- and below-ground chemical defence to nitrogen and phosphorus supply in waratahs (Telopea speciosissima)
Authors: Ritmejerytė Edita , Boughton Berin A. , Bayly Michael J. , Miller Rebecca E.
Published: October 2019

Plant nutrition can affect the allocation of resources to plant chemical defences, yet little is known about how phosphorus (P) supply, and relative nitrogen (N) and P supply, affect chemical defences, especially in species with intrinsically conservative nutrient use adapted to P-impoverished soils. Waratah (Telopea speciosissima (Sm.) R.Br.), like other Proteaceae, is adapted nutrient-poor soils. It was identified as having cyanogenic glycosides (CNglycs) throughout the plant. T. speciosissima seedlings were grown for 15 weeks under two N and P concentrations. CNglycs (N-based defence) and nutrients were quantified in above- and below-ground organs; foliar carbon (C)-based phenolics and tannins were also quantified. CNglyc concentrations in roots were on average 51-fold higher than in above-ground tissues and were affected by both N and P supply, whereas foliar CNglyc concentrations only responded to N supply. Leaves had high concentrations of C-based defences, which increased under low N, and were not correlated with N-based defences. Greater root chemical defence against herbivores and pathogens may be important in a non-mycorrhizal species that relies on basal resprouting following disturbance. The differing responses of secondary chemistry in above- and below-ground organs to P and N demonstrate the importance of broadening the predominantly foliar focus of plant defence studies.
The paradox of imagining the post-human world
Authors: Laakso Maria
Published: October 2019

Since the beginning of the twenty-first century, works depicting a post-human world have become a popular non-fiction genre. This kind ofdisanthropyis an extreme form of apocalyptic thinking. In this article, I examine one such disanthropic narrative, Alan Weisman’s bestselling non-fiction bookThe World Without Us(2007), using the theoretical framework of narrative fictionality studies.The World Without Usfalls between the conventional oppositional pairing of factual and fictional narratives. The book bases its rhetoric heavily on scientific facts – or at least on scientific expectations – especially in its use of interviews with scientists. Nevertheless, the core idea of a world without humans is inevitably fictional since the presence of readers makes the book’s premise manifestly counterfactual and paradoxical. In my analysis, I adopt a rhetorical approach to fictionality and factuality to ask how particular techniques and strategies connected to fictionality and factuality are employed in Weisman’s text in order to discuss the anxieties, desires, hopes, and fears of the possibility of human extinction.
Making fiction out of fact
Authors: Mason Jessica
Published: October 2019

This article explores fictionality within the context of the discourse of conspiracy. In particular it examines the phenomenon of ‘false flag’ narratives: alternative versions of an event constructed by individuals who have become convinced that a news story has in fact been staged for malfeasant purposes. The article uses figure-ground analysis, which facilitates examination of how attention is distributed within a text. Specifically, it enables an examination of the prominence and salience that is afforded to particular elements within a text, and how this can be used to construct a fiction out of facts. The article problematises the notion of using a pragmatic assessment of authorial intention to establish the fictive or nonfictive status of a text. Finally, it proposes that more work needs to be undertaken in considering instances where authors either do not know or are conflicted about what they believe.
Unique structural features in an Nramp metal transporter impart substrate-specific proton cotransport and a kinetic bias to favor import
Authors: Bozzi Aaron T. , Bane Lukas B. , Zimanyi Christina M. , Gaudet Rachelle
Published: October 2019

Natural resistance-associated macrophage protein (Nramp) transporters enable uptake of essential transition metal micronutrients in numerous biological contexts. These proteins are believed to function as secondary transporters that harness the electrochemical energy of proton gradients by “coupling” proton and metal transport. Here we use the Deinococcus radiodurans (Dra) Nramp homologue, for which we have determined crystal structures in multiple conformations, to investigate mechanistic details of metal and proton transport. We untangle the proton-metal coupling behavior of DraNramp into two distinct phenomena: ΔpH stimulation of metal transport rates and metal stimulation of proton transport. Surprisingly, metal type influences substrate stoichiometry, leading to manganese-proton cotransport but cadmium uniport, while proton uniport also occurs. Additionally, a physiological negative membrane potential is required for high-affinity metal uptake. To begin to understand how Nramp’s structure imparts these properties, we target a conserved salt-bridge network that forms a proton-transport pathway from the metal-binding site to the cytosol. Mutations to this network diminish voltage and ΔpH dependence of metal transport rates, alter substrate selectivity, perturb or eliminate metal-stimulated proton transport, and erode the directional bias favoring outward-to-inward metal transport under physiological-like conditions. Thus, this unique salt-bridge network may help Nramp-family transporters maximize metal uptake and reduce deleterious back-transport of acquired metals. We provide a new mechanistic model for Nramp proton-metal cotransport and propose that functional advantages may arise from deviations from the traditional model of symport.
Experimental study of the triboelectric charging of a glass bead impacting against a polymer plate
Authors: Lesprit Ugo , Paillat Thierry , Zouzou Noureddine , Paquier Anna , Yonger Marc
Published: October 2019

The charging properties of a particle during a single impact have been studied before in research. Despite these contributions, there remains incomprehension on the very mechanisms responsible for the charge transfer and predictions regarding the tribocharging of a dielectric particle against another dielectric material are still rather unreliable. Glass, found with various different chemical compositions, is a good example of a material that defies the expectations of triboelectric series. This article reports the development of a setup measuring the charge generated by a single impact between a glass bead and a dielectric. The setup is designed to control most relevant parameters to achieve the highest level of reproducibility possible, and to perform series of tests to maximize statistical relevance. Preliminary results on parameters such as the normal velocity at impact, the relative humidity and the impact angle are described.
Contact Electrification of Adhesion Films on Flat Panel Displays
Authors: Viheriäkoski T , Hillberg J , Smallwood J , Holdstock P
Published: October 2019

Contact electrification of a protective adhesion film on a flat panel display may result in high charge accumulation on an electrically insulating surface affecting production yield and field failures. Tendency for triboelectric charging on planar surfaces was evaluated with the different film structures and different plane materials. Manual separation and constant speed separation techniques were adopted in the experiments. Triboelectrification had random effects that may be difficult to control without electrical conductivity. Electrostatic dissipative properties on the adhesion surface may increase charging of the insulating display. An inherently dissipative layer of the adhesion film significantly mitigated charge accumulation of the film itself.