bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of reduced pressure on carbon dioxide flow boiling heat transfer in minichannels
Authors: Mikielewicz Dariusz , Jakubowska Blanka
Published: December 2018

In the paper presented are the results of the study on the effect of reduced pressure on flow boiling heat transfer data in minichannels as well as conventional ones. That effect renders that most of heat transfer correlations fail to return appropriate results of predictions. Mostly they have been developed for the reduced pressures from the range 0.1-0.3. The special correction has been postulated to the in-house model of flow boiling and condensation which modifies the two-phase flow multiplier as well as the temperature gradient in pool boiling. Four two-phase flow multiplier models were tested for this purpose, i.e. due to Friedel, Tran, Müller-Steinhagen and Heck and finally its in-house modification for applicability to minichannels. The model has been tested against a large selection of experimental data collected from various researchers to investigate the sensitivity of the in-house developed model. The collected experimental data came from various studies from literature and were conducted for the full range of quality variation and a wide range of mass velocity and saturation temperatures. In the work are presented the results of calculations obtained using the in-house developed semi empirical model on selected experimental flow boiling data related to carbon dioxide.
Numerical modelling of air-cooler using simplified methods
Authors: Śmierciew Kamil , Gagan Jerzy , Butrymowicz Dariusz
Published: December 2018

The fin-and-tube air coolers have been extensively used in refrigeration systems applied to cold storage chambers. The performance of the heat exchanger affects the efficiency of the systems and makes the study of heat exchanger becomes important. Prediction of the temperature, humidity, as well as velocity distribution in cold storage chamber requires accurate prediction of operation of the finned air cooler. The presence of the air cooler unit is usually taken into account by the investigators, but with very simplified geometry and physics. Results of numerical modelling using the computational fluid dynamics (CFD) software ANSYS FLUENT of fin-and-tube air cooler is presented in the paper. Two different approaches were used: the Dual Cell Model and porous media model.
The study on the heat recovery from air compressors
Authors: Broniszewski Mariusz , Werle Sebastian
Published: December 2018

Effective use of utilities in production plants is an issue that is becoming increasingly significant in energy policy of Europe. Production of compressed air consumes 3% of the total electricity consumption in Europe. In order to produce compressed air, approximately 10-20% of electricity transferred to compressor is used, the rest is lost due to lack of tightness and heat losses. The aim of this work is to evaluate the possibility to install recovery systems on air compressors to recover the lost waste heat and its management for the needs of heating office buildings/production halls and analysis of investment profitability. The investment will be supported by co-financing in the form of energy efficiency certificates (so-called white certificates), which the production plant will be able to sell after receiving them from Polish Energy Regulatory Office in return for completing an investment that consists recovering waste heat from air compressors.
Development of the experimental stand for investigation of heating and drying phenomena in the porous building materials with one surface of the sample exposed to the flowing air
Authors: Cieślikiewicz Łukasz , Łapka Piotr , Wasik Michał , Kubiś Michał , Pietrak Karol , Wiśniewski Tomasz S. , Furmański Piotr , Seredyński Mirosław
Published: December 2018

The paper presents development of the experimental stand for investigation of heating and drying phenomena in the porous building materials with one surface of the sample exposed to the flowing air. Moreover, results of preliminary measurements which verify the range of operating conditions achieved by the stand are shown. These conditions were assumed in the following range: 15℃-60℃, 10-90% and 0.1-10 m/s for temperature, relative humidity and velocity of the flowing air, respectively. In order to control the parameters of air used for heating and drying of porous materials, a closed-loop concept of the stand was proposed and equipped with several elements, i.e., the cooler (vapour condenser), fan with variable rotational speed, humidifier and heater. Furthermore, two parallel measurement ducts which allow to obtain two air streams with identical parameters were proposed. This enables two measurements at one time as well as faster verification of the repeatability of the performed measurements. The temperature measurements at the top surface and inside the sample are carried out applying the IR thermography and several K-type thermocouples, respectively, while overall moisture amount and the moisture content distribution in the specimen are found using tensometric force and electrical resistance meters, respectively.
Ampacity of power cables exposed to solar radiation – recommendations of standards vs. CFD simulations
Authors: Czapp Stanislaw , Czapp Marian , Szultka Seweryn , Tomaszewski Adam
Published: December 2018

Ampacity of power cables strictly depends on the ambient conditions. It is very important whether a cable is buried in soil, installed in the air or placed in ducts. When a cable is installed in free air, potential solar radiation has the dominant impact on the prospective ampacity. International standards indicate how to calculate ampacity of power cables exposed to solar radiation, however the standards’ recommendations are characterised by some simplifications. In order to consider many complex factors influencing ampacity of power cables, and modelling advanced heat transfer phenomena, a Computational Fluid Dynamics (CFD) can be used. This paper presents a comparison of ampacity calculation of an example power cable for two approaches – first: according to international standards; second: with a CFD employed. Differences in results obtained for these two approaches are commented.
Prechamber selection for a two stage turbulent jet ignition of lean air-gas mixtures for better economy and emission
Authors: Pielecha Ireneusz , Wislocki Krzysztof , Cieslik Wojciech , Fiedkiewicz Lukasz
Published: December 2018

The paper presents the results of thermodynamic and exhaust emission analyses of the combustion process using three combustion chambers. The combustion process research was performed on a single-cylinder AVL 5804 engine equipped with a dual-band compressed natural gas system supplied at different fuel pressures to the inlet channel and to the pre-chamber. Based on the performed analyses, the thermodynamic indicators of the combustion process and the emission factors were determined. Having the thermodynamic and emission analyses of the Turbulent Jet Ignition (TJI) combustion system, the pre-chamber was selected with the best collective features. The selection of the best chamber was made using the weighted-purpose method for average indicated pressure, CO and NOx emissions as well as the indicated engine efficiency, taking into account the impact factors.
Increasing electrical power output and fuel efficiency of gas engines in integrated energy system by absorption chiller scavenge air cooling on the base of monitoring data treatment
Authors: Radchenko Andrii , Radchenko Mykola , Konovalov Andrii , Zubarev Anatolii
Published: December 2018

An advanced scavenge air cooling system for reciprocating gas engines of integrated energy system for combined electricity, heat and refrigeration generation has been developed. New method of deep scavenge air cooling and stabilizing its temperature at increased ambient air temperatures and three-circuit scavenge air cooling system with absorption lithium-bromide chiller and wet-type cooling tower was proposed. Such cooling method does not require essential constructive changes in the existing scavenge air cooling system but only an addition heat exchanger for chilling scavenge air cooling water of scavenge air low-temperature intercooler closed contour by absorption chiller. A chilled water from absorption chiller is used as a coolant. To evaluate the effect of gas engine scavenge air deeper cooling compared with its typical radiator cooling, data on the dependence of fuel consumption and power output of gas engine on ambient air temperature at the inlet of the radiator are analized. The efficiency of engine scavenge air deep cooling at increased ambient air temperatures was estimated by reducing the gas fuel consumption compared with radiator cooling.
Does an increase in water color intensity affect the lake trophic status and phytoplankton metrics?
Authors: Lenard Tomasz , Ejankowski Wojciech , Poniewozik Małgorzata
Published: December 2018

During the 11-year period covered by this study (2003–2013), high precipitation events increased the water level in the deep hardwater of Lake Rogóźno (Eastern Poland), causing its water to become browner. We investigated the effect of a change in water color on the physical, chemical, and biological parameters of the lake. The concentration of total phosphorus and nitrogen decreased, whereas the total phytoplankton biomass, coupled with a high biomass of flagellate species, increased, with the increase in water color intensity. Such changes had an effect on the determination of ecological status, based on selected phytoplankton metrics (i.e., Polish, German, and Estonian) as well as the trophic status of Lake Rogóźno. The decrease of phosphorus concentration associated with an increase in water color intensity improved the trophic status of the lake based on Carlson's Trophic State Index. The changes in the phytoplankton community caused the deterioration of the ecological status of the lake when using the Polish and German indices adopted for clear water lakes. The use of the Estonian index, which is adapted to colored lakes, suggested that, despite the increase in water color intensity, the good ecological status of the lake was maintained or even improved. Our findings suggest that, in the event of a transformation like the one that occurred in the lake studied here, the use of only one index, adapted by state environmental monitoring programs in individual European countries, may be insufficient for the appropriate assessment of the ecological status of European lakes.
Discrete hysteretic sine-Gordon model: soliton versus hysteresis
Authors: Meleshenko Peter A. , Tolkachev Akim V. , Semenov Mikhail E. , Perova Alla V. , Barsukov Andrey I. , Klinskikh Alexander F.
Published: December 2018

In this work we consider a nonlinear dynamical system which is a set of nonlinear oscillators coupled by springs with hysteretic blocks (hysteretic sine-Gordon model). The hysteretic nonlinearity is modeled using the phenomenological Bouc-Wen model). The wave processes (solitonic solutions) in such a system are investigated taking into account the hysteretic nature of the coupling.
Legal approach to marine accidents: a comparative research between Turkish and international perspectives
Authors: Degirmenci Nil Kula
Published: December 2018

The importance of prevention of marine accidents increases parallel to the technological improvements in maritime transportation and the rise of sensitiveness to environmental protection. Legal approach to marine accidents can be gathered under three important topics as follows: legal approach to general average, legal approach to collision and legal approach to salvage. The international perspective on the issue has been shaped through international conventions and advisory rules, as applied in the field of general average, and some of their modernized amendments. Turkey which is one of the most important countries in maritime transportation especially as a result of its geographical position, on the one hand aims to protect its existing legal regime to prevent the occurrence of marine accidents and on the other hand follows the updated legal developments on the issue. In the study, it is aimed to point the important facts of general average, salvage and collision and analyze the Turkish and international perspectives comparatively. Thus the success in ensuring uniformity which is targeted through the international studies on these issues is tried to be measured for the Turkey example.
Research of the changeability of the vessels traffic intensity of inland waterways – case study for Lower Vistula
Authors: Jerzyło Patrycja , Wawrzyńska Aleksandra
Published: December 2018

The article presents an analysis of the changeability of traffic intensity of inland waterway vessels in the Vistula Delta. The concept of traffic intensity was defined, traffic flows and disturbances were identified in the studied area. The characteristics of the inland waterway traffic model are presented. The results of the analysis indicate the need to carry out modernization of inland waterways for the needs of inland waterway transport: introduction of a traffic control system, unification of the navigational marking system and strict correlation of renovation/modernization works of hydrotechnical structures with a navigation period.
How to measure the economic value of ecosystem functions and processes and link such value to the MSP?
Authors: Kamińska Ilona , Zarzycki Tomasz , Zaucha Jacek , Ciołek Dorota
Published: December 2018

The paper aims at answering questions on implications of the economic valuation of regulatory ecosystem service in maritime spatial planning. The biogeochemical processes that occur in marine sediments such as denitrification, contribute indirectly, though significantly, benefits to human wellbeing. Such direct and indirect benefits are called ecosystem services. According to the Common International Classification of Ecosystem Services (CICES V5.1) for the Integrated Environmental and Economic Accounting, the case study: ecosystem service lies within the: Section - Regulation & Maintenance (Biotic); Division - Transformation of biochemical or physical inputs to ecosystems; Group - Mediation of wastes or toxic substances of anthropogenic origin by living processes and Class - Bio-remediation by micro-organisms, algae, plants, and animals (Code 2.1.1.1). Marine sediments are economically evaluated mainly as sources of providing services (sand and gravel extraction or space for potential industrial use). Their regulatory function is often neglected in such studies. Therefore, we employed the methodology from the field of ecological economics and assessed the economic value of denitrification of the Gulf of Gdansk. This paper suggests the possible implications of using such data in MSP and discusses the competition sea uses in order to determine the final benefits for society.
Spatial Evolution of the European Container Ports’ System in Perspective of the Location Theory
Authors: Krośnicka Karolina A.
Published: December 2018

The maritime container terminal is no longer a spatially coherent object. Functionally it ends, where their most external components are located. The process of location splitting of container terminals (ger. Standortspaltung) can be treated as next stage of their discrete growth. The new container facilities are being built to improve the containers’ flow, passing from port terminals to cities situated in their hinterland and vice versa. The external components of container terminals have a very diverse program, are functionally complex, and due to advanced technologies of information and logistics they are interconnected into one system. The structure of the functional bindings of a maritime container terminal could be compared to the dendritic shape of a neuron, the kernel of which is a terminal, and the arms are transportation corridors ended with distant land intermodal terminals. The physical feature of this system is the logistics landscape with vast areas and large cubature. The aim of the paper is to present the graphical model explaining the changes in distribution and hierarchy of container terminals’ external elements in relation to the network of cities and transportation.
Sea port as an element of a city sustainability based on city-port of Gdańsk
Authors: Oniszczuk-Jastrząbek Aneta , Pawłowska Barbara , Czermański Ernest
Published: December 2018

Cities and ports are elements of the socio-economic space of coastal regions and they are integrally interrelated with each other while their development is mutually conditioned. Cooperation of the port and the city usually would bring development of both these elements in the historical perspective. The seaport has always grown and developed along with the city and the region. On the one hand, a port-city performs functions related to maritime economy in the broad sense of the word, i.e. maritime functions, and on the other hand - land functions that result from the city's location in relation to its land base. When the maritime function is overwhelming, the port has a powerful impact on the city, its spatial and economic layout. The very nature of the port has a significant impact on shaping the face of the city and the region. Contemporary cities are currently facing many various problems resulting from their rapid development: debt, commercialization of the public space, degradation of the infrastructure, deteriorating quality of public services, or excessive and inefficient consumption. Since the time concept of sustainable development came into being, it has been adopted as the basis for all activities at various levels of territorial organization, including at the city level. Nonetheless, each tier of development planning has its own specificity, similarly to individual territorial units within a specific tier. This is related but not limited to cities, particularly port-cities, in respect of which sustainable development should be understood a little differently than in other cities, due to the complexity of their relationships and the special role that they play in the economic system. The aim of this article is to indicate such a way of understanding the sustainable development that refers to the specificity of a port-city. Ports and cities interact across many dimensions, however, a more detailed insight how port-cities integrate the port and urban functions is still lacking. The survey conducted among city representatives, businesses and port authorities is to help identify the directions of activities for sustainable development and indicate the common grounds of these activities, where both parties could support each other.
Sustainability issues in ports: content analysis and review of the literature (1987- 2017)
Authors: Özispa Nergis , Arabelen Gamze
Published: December 2018

Sustainability, which has environmental, social and economic dimensions, is a phenomenon that has been used extensively in recent times. As decided in Brundtland Conference in 1987, it basically aims to meet the needs of the present without compromising the ability of future generations to meet their own needs. When it is taken into consideration in terms of sustainability, it is known that ports are one of the most polluting sectors due to their nature. However, in recent years many ports have started to different sustainability programs and invested in large amounts over the years to reduce emissions and to gain a competitive advantage. When examined the past studies, it is determined that the sustainability concept is a relatively recent approach in the maritime literature and still a gap exist in this field. It is thought that the analysis of these studies in a systematic way will contribute to the port sustainability literature. Therefore, in this study, it is aimed to review port sustainability concept with the help of existing literature. For the methodology, studies obtained from different databases were evaluated systematically by using content analysis. The study has been concluded with the findings for the related literature, recommendations for the sector and guidelines for future researches.
Main Drivers for Maritime Cluster and Shipping in the Baltic Sea
Authors: Pöntynen Riitta , Erkkilä-Välimäki Anne , Nieminen Hanna
Published: December 2018

One of the main aims of Maritime Spatial Planning (MSP) is to observe and determine factors affecting the development of various future sea uses. As a part of the transboundary MSP research done in the Maritime Spatial Planning for Sustainable Blue Economies (Plan4Blue) project, drivers for the creation of alternative scenarios for Blue Economy in the Gulf of Finland and the Archipelago Sea have been defined. The Blue Economic sectors analysed were energy, the maritime cluster, maritime and coastal tourism, the blue bioeconomy and subsea resources. The drivers affecting the development of blue economy sectors by the year 2050 were identified by experts through Delphi-surveys and workshops. First, the drivers were explored using the PESTEL-classification: political, economic, social, technological, environmental and legal drivers. The main drivers were then analysed and presented in futures tables. The results of this analysis are discussed from the viewpoint of the maritime cluster and shipping. The most important shipping drivers identified are transnational in nature: global economic trends and environmental policies, which connect national and regional MSP with the global scale. Driver analysis supports the identification of the sector’s needs in the context of MSP. Challenges encountered in the process are highlighted in this text.
ECA compliance and enforcement – legal regime for ships
Authors: Pyć Dorota
Published: December 2018

This paper addresses the importance of the prevention air pollution from ships in terms of international legal compliance and enforcement. In addition to effectively enforcing international norms, standards and procedures, flag States have an obligation to prevent polluting ships from sailing. The International Convention for the Prevention of Pollution from Ships (MARPOL) has been described by the International Maritime Organization as “the most ambitious international treaty covering maritime pollution ever adopted”. Annex VI of the MARPOL allows for the establishment of Emission Control Areas (ECAs). ECAs have been implemented to reduce the amount of air pollution from ships. The new ECA regulations entered into force on the 1st of January 2015. First and foremost, this paper examines some aspects of the implementation of the new ECA regulations on shipping industry and control air emissions in the Baltic Sea ECA. Moreover, it outlines that Port State Control and Flag State Control are commitment to monitor and enforce compliance through inspections and penalties.
Future CO2 emissions from shipping: four-scenarios using a multi-level perspective – a proposed methodology
Authors: Wells Peter , Pettit Stephen , Abouarghoub Wessam , Haider Jane , Beresford Anthony
Published: December 2018

Previous work by Pettit et al (2017) drew on Socio-technical Transitions Theory (STT) to contextualise recent developments in the technological and operational eco-efficiency of ships which may ameliorate sustainability issues in shipping. Within STT the Multi-Level Perspective (MLP) is a framework used to explain the permeation of innovations into society (Geels, 2014). The framework has three levels: Landscape; Regime and Niche. In order to develop a better understanding of changes that may take place in the future, this paper uses the MLP to assess the broad range of challenges facing the shipping industry with respect to future CO2 emissions at each of the three levels. The framework is applied to four scenarios for global shipping in order to understand the potential range of outcomes for CO2 emissions. The four scenarios are: ‘Business as Usual’; ‘Managed Transition’; ‘Chaotic Transition’; and ‘Managed Degrowth’. It is contended that changes in the shipping industry alone are unlikely to lead to large-scale changes in its CO2 emissions. Under ‘Business as Usual’ conditions, CO2 emissions will continue to rise as the changes required at all three levels, but primarily at the regime level, will have limited impact. Under the other three scenarios, it is suggested that there is room for optimism that CO2 emissions will decline over time.
Role of maritime ports and shipping in the creation of the economic value of the sea areas
Authors: Zaucha Jacek , Matczak Maciej
Published: December 2018

The sea coast location of a country has been regarded as a critical value for its development and prosperity for years. It relates to economic, military, and environmental issues. A wide scope of economic activities, like shipping and maritime ports, fishing and aquaculture, underwater mining (e.g., oil, gas, sand) and sea coast tourist activities all require access to the sea. The sea area should also be regarded as a limited resource thus the activities need to compete for maritime space. Today, comprehensive economic valuation of selected activities, both from the private and public point of view, became significantly important. The aim of this article is an attempt to evaluate the economic value of maritime space, which is generated by ports and shipping. Initially, review of the literature regarding the valuation of economic effects of maritime port and shipping was carried out. The analysis has been based on a model of the interrelation between ports and shipping and its socio-economic environment. Then, redefinition and extension of identified values to the sea areas were provided. Finally, a calculation of the unit value of sea space [PLN per sq. km] as well as identification of most valuable spatial parts of the sea was completed. The application part of the study was based on the example of Polish seaports as well as Polish maritime areas on the Baltic Sea.
Herzklappenerkrankungen – Update ESC-Leitlinie 2017
Authors: Ince Hüseyn , Zeus Tobias
Published: December 2018

Was ist neu?

Aortenklappenstenose mit intermediärem OP-Risiko Die Therapie der Aortenklappenstenose (AS) erfolgt aktuell nicht mehr ausschließlich chirurgisch, sondern zunehmend interventionell durch die kathetergestützte Aortenklappenimplantation (Transkatheter-Aortenklappenimplantation, TAVI). Erstmalig werden in der Leitlinie die Daten randomisierter Studien zu Patienten mit intermediärem OP-Risiko berücksichtigt. Hier ist die TAVI gleichwertig zum chirurgischen Klappenersatz zu bewerten.

Therapie der Mitralklappeninsuffizienz Die Mitralklappeninsuffizienz (MI) ist ein komplexes Vitium mit guten OP-Resultaten bei primärer Genese und mäßigen Ergebnissen bei sekundärer Genese. Die sekundäre MI beruht in der Regel auf einer zugrundeliegenden linksventrikulären Erkrankung mit Dilatation der Anatomie. Die interventionelle Therapie durch das edge-to-edge-Verfahren (Mitraclip) stellt eine Alternative bei Patienten mit hohem Operationsrisiko dar.

Komorbiditäten Die Empfehlungen zur Behandlung einer begleitenden koronaren Herzerkrankung (KHK) bei Herzklappenfehlern wurden durch aktuelle Daten angepasst. Grundsätzlich gilt, dass eine proximale Stenose ≥ 70 % entweder durch einen Bypass bei chirurgischem Vorgehen oder durch eine perkutane koronare Intervention (PCI) bei interventionellem Vorgehen versorgt werden soll.

Herzteam und Herzklappenzentren Durch das erweiterte interventionelle und chirurgische Therapiespektrum bei allen vier Klappen rückt das Herzteam in den Mittelpunkt. Eine gemeinsame Sichtung der Befunde und der Patienten soll durch Kardiologen und Kardiochirurgen erfolgen. Weitere Fachdisziplinen sind bei Bedarf hinzuzuziehen. Die Behandlungseinheiten sollen klar vorgegebene Strukturvoraussetzungen erfüllen, um qualitativ hochwertige Ergebnisse zu erzielen.
Depressionsbehandlung aus Betroffenensicht – Eine qualitative Analyse der subjektiven Behandlungsvorstellungen über Psychotherapie und hausärztliche Versorgung von Menschen mit Depressionen
Authors: Magaard Julia Luise , Seeralan Tharanya , De Anjuli , Schulz Holger , Brütt Anna Levke
Published: December 2018

Ziel Identifikation subjektiver Vorstellungen von Betroffenen über Psychotherapie und hausärztliche Versorgung von depressiven Störungen.

Methodik 21 leitfadengestützte Interviews mit Betroffenen, ausgewertet anhand der qualitativen Inhaltsanalyse nach Mayring.

Ergebnisse Ergebnis- und Prozesserwartungen sowie Vorstellungen über strukturelle Aspekte und Auswirkungen wurden identifiziert.

Schlussfolgerung Befürchtungen über unerwünschte Ergebnisse, hausärztliche Kompetenz, mangelnde Kapazitäten sowie Unklarheiten über Psychotherapie sollten adressiert werden.
Cu(III)-Mediated Aerobic Oxidations
Authors: Lumb Jean-Philip , Esguerra Kenneth
Published: December 2018

CuIII species have been invoked in many copper-catalyzed transformations including cross-coupling reactions and oxidation reactions. In this review, we will discuss seminal discoveries that have advanced our understanding of the CuI/CuIII redox cycle in the context of C–C and C–heteroatom aerobic cross-coupling reactions, as well as C–H oxidation reactions mediated by CuIII–dioxygen adducts.

1 General Introduction

2 Early Examples of CuIII Complexes

3 Aerobic CuIII-Mediated Carbon–Heteroatom Bond-Forming Reactions

4 Aerobic CuIII-Mediated Carbon–Carbon Bond-Forming Reactions

5 Bioinorganic Studies of CuIII Complexes from CuI and O2

5.1 O2 Activation

5.2 Biomimetic CuIII Complexes from CuI and Dioxygen

5.2.1 Type-3 Copper Enzymes and Dinuclear Cu Model Complexes

5.2.2 Particulate Methane Monooxygenase and Di- and Trinuclear Cu Model Complexes

5.2.3 Dopamine–β-Monooxygenase and Mononuclear Cu Model Complexes

6 Conclusion
Recent Advances in Enantioselective C–C Bond Formation via Organocobalt Species
Authors: Yoshikai Naohiko
Published: December 2018

This Short Review describes recent developments in cobalt-catalyzed enantioselective C–C bond-forming reactions. The article focuses on reactions that most likely involve chiral organocobalt species as crucial catalytic intermediates and their mechanistic aspects.

1 Introduction

2 Hydrovinylation

3 C–H Functionalization

4 Cycloaddition and Cyclization

5 Addition of Carbon Nucleophiles

6 Cross-Coupling

7 Conclusion
Bony Tunnel Formation Associated with the Distal Segment of the Frontal Branch of the Middle Meningeal Artery
Authors: de Campos Deivis , da Silveira Caroline Haubert , Jotz Geraldo Pereira , Malysz Tais
Published: December 2018

The knowledge of certain anatomical variations is fundamental and any surgeon who operates without that knowledge may encounter difficulty during surgery. In this context, there is the middle meningeal artery (MMA) which also engenders considerable clinical interest due to its location. The MMA is predominantly periosteal, irrigating the bone and dura mater. It enters the floor of the middle cranial fossa through the foramen spinosum, travels laterally through a middle fossa bony ridge, and curves anteriorly over the upper-greater wing of the sphenoid where it divides into parietal and frontal branches at a variable point. Occasionally, the distal segment of the frontal branch may pass through a bony tunnel of variable size. To the best of our knowledge, there is no evidence in the current literature on the incidence of this rare bony tunnel. Therefore, we decided to investigate the incidence of this bony tunnel in 85 dry skulls of adults (both genders) belonging to the didactic collection of the Human Anatomy Laboratory of the Universidade de Santa Cruz do Sul, Brazil. All the skulls were examined bilaterally for the presence or absence of the bony tunnel associated with the distal segment of the frontal branch of the MMA. Of the 85 skulls analyzed, the bony tunnel was present on the right side in 1.18% and on the left side in 5.88% (p = 0.045). Thus, in the studied sample, there was a significant tendency for this bony tunnel to be formed on the left side.
The conditional entropy power inequality for quantum additive noise channels
Authors: De Palma Giacomo , Huber Stefan
Published: December 2018

We prove the quantum conditional entropy power inequality for quantum additive noise channels. This inequality lower bounds the quantum conditional entropy of the output of an additive noise channel in terms of the quantum conditional entropies of the input state and the noise when they are conditionally independent given the memory. We also show that this conditional entropy power inequality is optimal in the sense that we can achieve equality asymptotically by choosing a suitable sequence of Gaussian input states. We apply the conditional entropy power inequality to find an array of information-theoretic inequalities for conditional entropies which are the analogs of inequalities which have already been established in the unconditioned setting. Furthermore, we give a simple proof of the convergence rate of the quantum Ornstein-Uhlenbeck semigroup based on entropy power inequalities.
Computational screening of methylammonium based halide perovskites with bandgaps suitable for perovskite-perovskite tandem solar cells
Authors: Kar M. , Körzdörfer T.
Published: December 2018

We aim to find homovalent alternatives for lead and iodine in CH3NH3PbI3 perovskites that show bandgaps suitable for building novel perovskite-perovskite tandem solar cells. To this end, we employ a computational screening for materials with a bandgap between 1.0 eV and 1.9 eV, using density functional theory calculations at the Perdew-Burke-Ernzerhof and Heyd-Scuseria-Ernzerhof levels of theory. The room-temperature stability of the materials and their phases that satisfy the bandgap criteria is evaluated based on the empirical Goldschmidt tolerance factor. In total, our screening procedure covers 30 different perovskite structures in three phases (orthorhombic, cubic, tetragonal) each. We find 9 materials that are predicted to be stable at room temperature and to have bandgaps in an energy range suitable for application in tandem solar cells.
Isotropic phase transition of single-crystal iron (Fe) under shock compression
Authors: Liu Xun , Mashimo Tsutomu , Kawai Nobuaki , Sano Tomokazu , Zhou Xianming
Published: December 2018

The α−ɛ phase transition stresses of single-crystal iron under shock compression along the [100], [110], and [111] crystal orientations were measured to be ∼13.3 ± 0.5, 13.5 ± 0.4, and 12.8 ± 0.4 GPa, respectively. Within the uncertainty of the measurement, the phase transition stresses of single crystal iron do not show obvious orientational dependence. These results differ from the simulation studies of the nonequilibrium molecular dynamics. We suggest that single crystal iron loses most shear stress beyond the Hugoniot-elastic-limit and the phase transition happens under a nearly hydrostatic state.
Transient electrical behavior of an electrode/electrolyte interface based on a surface micro-structured with gold mushroom shapes
Authors: Reis João A. , Medeiros Maria C. R. , Inácio Pedro M. , Cerquido Mónica , Ventura João , Gomes Henrique L.
Published: December 2018

The transient electrical behavior of an electrode/electrolyte interface based on an electrode micro-structured with gold protruding mushroom shapes is measured and modeled. The application of a voltage pulse train with changing frequency generates a corresponding train of current pulses with an offset current that approaches a saturation limit exponentially. The transient behavior of the electrical current was accurately reproduced using the Nernst-Planck-Poisson model and the geometric parameters of the mushroom shape. Spatiotemporal patterns of the electric field demonstrate that the current transient is caused by a slow kinetics of charges accumulating at the gold/electrolyte interface and under the micro-mushroom cap. The accumulation of charges establishes an internal electrical potential that drives a Faradic current through the mushroom/electrolyte interface. The aim of this work is to understand how this charge dynamics in the vicinity of the three-dimensional electrode surfaces is established and how it can be minimized to prevent damage to cells and tissues under electrical stimulation.
Influence of trace water on decomposition mechanism of c-C4F8 as environmental friendly insulating gas at high temperature
Authors: Xiao Song , Li Yi , Zhang Xiaoxing , Zhuo Ran , Wang Dibo , Tang Ju , Zhang Ji , Chen Qi
Published: December 2018

Fluorocarbon gas has excellent environmental characteristics and insulation properties and has the potential of replacing SF6 for medium-voltage electrical equipment. While c-C4F8 will decompose under discharge or overheating faults conditions. At present, studies on the decomposition characteristics of c-C4F8 have made some achievements, but little attention has been paid to the influence of temperature and trace water. In this paper, the interaction between OH· and H· produced by H2O and c-C4F8 is analyzed based on the density functional theory (DFT) and plasma discharge decomposition experiment. The decomposition path, reaction enthalpy and activation energy, and the impact of temperature on the reaction path is discussed. It is found that the decomposition of c-C4F8 requires an endothermic heat of about 420 kJ/mol, and the decomposition of c-C4F8 to C2F4 is more likely to occur at high temperature. The H· and OH· generated by trace water will promote the decomposition of c-C4F8, which produces HF and low fluoride particles. The main decomposition products of c-C4F8 in the trace water environment are C2F4, CF4, CF3OH, CF3H, C2F6, CF2O and HF. Among them, CF2O and HF are toxic and corrosive substances, which pose a threat to the safety of operation and maintenance personnel. Relevant research results not only reveal the decomposition mechanism of c-C4F8, but also provide guidance for the application of c-C4F8 gas mixture.
Multiple-band enhanced light absorption of monolayer graphene with critical coupling to guided mode resonance
Authors: Zou Xiu-juan , Zheng Gai-ge , Chen Yun-yun , Xian Feng-lin , Xu Lin-hua , Lai Min
Published: December 2018

We investigate subwavelength grating-coupled distributed Bragg reflector (DBR) in order to achieve total absorption at preselected wavelengths in a graphene monolayer. Multispectral and near-unity absorption (approximately 99.44% of the incident light at normal incidence) can be achieved in the proposed photonic structure at near-infrared (NIR) regimes. When the system meets the condition of critical coupling, the excited guided mode resonance (GMR) occurs at the resonance wavelength, and the corresponding electric field intensity around the graphene sheet can be greatly enhanced due to the reinforced light-graphene interaction. Multiple absorption peaks can be tuned within the wavelength region of 1.3 μm to 1.6 μm by varying the structural parameters. Our findings also indicate that the near-total-absorption peaks are highly dependent on the number and thickness of unit cells in DBR. These features make the proposed structure have great potential in applications of scalable perfect absorbers (PAs).
Imaging and visualization of the polarization state of the probing beam in polarization-sensitive optical coherence tomography
Authors: Tang Peijun , Xu Jingjiang , Wang Ruikang K.
Published: December 2018

We propose a simple and efficient method of color-encoded Stokes parameters to visualize the polarization states for polarization-sensitive optical coherence tomography (PS-OCT) of biological tissue. In this method, polarization states of the probing light are detected and described in the Stokes domain. Three primary colors of red, green, and blue are used to code Stokes parameters of Q, U, and V, respectively, which can be used to represent and visualize each unique polarization state. A strategy that uses the polarization state as the PS-OCT imaging parameter is first introduced to obtain high contrast images of the birefringent samples. Then, color-based automatic segmentation of birefringent components from 3D scanned tissue volume is proposed to isolate the network of the 3D nerve bundles in a mouse brain without cutting the brain into slices. Experimental validation and demonstrations are given by imaging ex vivo mouse tail and brain tissues to show the usefulness of proposed polarization state imaging and segmentation methods.
A comparison of two classifications of solvable Lie algebras
Authors: Bryenton Nicolas , Davies Cameron , Douglas Andrew , Haque Saminul , Hauser Kieran , Janisse Thaddeus , Koster Matthew , Liu Jessica (Chengjin) , Ma Thomas , Mooroogen Yuveshen , Rabinovich Arthur , Repka Joe , Sorkhou Saied , Wu Matt
Published: December 2018

The literature contains two different classifications of solvable Lie algebras of dimensions up to and including 4. This paper is devoted to comparing the two classifications and translating each into the other. In particular, we exhibit an isomorphism between each solvable Lie algebra of one classification and the corresponding algebra of the second. The first classification is provided by de Graaf, and the second classification is from a recent book by Šnobl and Winternitz.
Investigation of GaN-on-GaN vertical p-n diode with regrown p-GaN by metalorganic chemical vapor deposition
Authors: Fu Kai , Fu Houqiang , Liu Hanxiao , Alugubelli Shanthan Reddy , Yang Tsung-Han , Huang Xuanqi , Chen Hong , Baranowski Izak , Montes Jossue , Ponce Fernando A. , Zhao Yuji
Published: December 2018

To mimic selective-area doping, p-GaN was regrown on an etched GaN surface on GaN substrates by metalorganic chemical vapor deposition. Vertical GaN-on-GaN p-n diodes were fabricated to investigate the effects of the etch-then-regrowth process on device performance. The crystal quality of the sample after each epitaxial step was characterized by X-ray diffraction, where the etch-then-regrowth process led to a very slight increase in edge dislocations. A regrowth interfacial layer was clearly shown by transmission electron microscopy. Strong electroluminescence was observed with three emission peaks at 2.2 eV, 2.8 eV, and 3.0 eV. The forward current density increased slightly with increasing temperature, while the reverse current density was almost temperature independent indicating tunneling as the reverse transport mechanism. This result is very similar to the reported Zener tunnel diode comprising a high doping profile at the junction interface. High levels of silicon and oxygen concentrations were observed at the regrowth interface with a distribution width of ∼100 nm. This work provides valuable information on p-GaN regrowth and regrown GaN p-n diodes, which can serve as an important reference for developing selective doping for advanced GaN power electronics for high voltage and high power applications.
Photoluminescence properties of N and B codoped fluorescent 4H-SiC and 6H-SiC single crystals
Authors: Zhuo Shi-Yi , Liu Xue-Chao , Huang Wei , Xu Ting-Xiang , Han Wei-Wei , Yan Cheng-Feng , Shi Er-Wei
Published: December 2018

In this paper, N and B codoped 4H-SiC and 6H-SiC single crystals were prepared by physical vapour transport method and their photoluminescence properties were studied. The photoluminescence spectra, dopant concentrations, Raman spectra, and transmission spectra of these obtained crystals were characterized. It is observed that the fluorescent crystals radiate a warm white light that covers a wide band spectrum from 450 nm to 750 nm when they are excited by a 325 nm laser. The doped 4H-SiC single crystal presents a higher photoluminescence intensity and larger spectral band compared to that of doped 6H-SiC single crystal under the similar growth and measurement conditions. Further analyze by doping concentration and transmission spectra indicate that the photoluminescence property is strongly influenced by the N donor and B acceptor impurity level.
Analysis of equivalent circuit models in lithium-ion batteries
Authors: You Hyun Woo , Bae Jun Ik , Cho So Jeong , Lee Jong Moon , Kim Se-Hun
Published: December 2018

This study investigates lithium-ion (Li-ion) battery discharge at a constant current by comparing equivalent circuit simulation data with experimental data. The simulations employ Thévenin equivalent circuit models consisting of a resistance, capacitance, and power source. Voltage and resistance are measured during battery discharge at a constant 2 A direct current (DC). The experimental output results of the resistor-capacitor (RC) circuit are calculated and compared to the simulation results over the time of discharge. Both single and triple RC circuits are utilized in the experiment, with the triple RC circuit model demonstrating less error than the single RC circuit when compared to the simulated data. This study suggests that the output voltage of a Li-ion battery generally obeys a simulated Thévenin equivalent circuit model composed of the multiple RC elements under constant current discharge.
Single-axis control of manganite films by helium doping via He-co-sputtering
Authors: Wang Haoru , Xie Xiangnan , Lin Guankai , Wang Yongqiang , Tong Wei , Zhu Hong
Published: December 2018

We have studied the effect of the out-of-plane lattice on tensile strained (001) La0.7Ca0.3MnO3 thin films. The films were deposited on SrTiO3 substrates through magnetron sputtering technique under different Ar/O2/He gas flow ratios, varying the out-of-plane lattice from 3.823 Å to 3.845Å, which corresponds to an increase in the metal-insulator transition temperature. These changes are reversible after high-temperature anneal due to a massive helium release from the films occurring at temperatures around 540°C. The dependence of the transition temperature on lattice distortion is in good agreement with the prediction proposed by Millis et al. [J. Appl. Phys. 83, 1588 (1998)]. Considering the Jahn-Teller distortion enhanced by the in-plane biaxial strain in the films, we attribute the elevated transition temperature to the distortion relaxation due to He doping in the tensile strained films. The effective He doping by magnetron sputtering technique provides a simple strategy for manipulating functionality of oxide films.
New radio-frequency setup for studying large 2D complex plasma crystals
Authors: Nosenko V. , Meyer J. , Zhdanov S. K. , Thomas H. M.
Published: December 2018

Complex plasma crystals are popular model systems where various plasma-specific or generic phenomena can be studied at the level of individual particles. Addressing the growing need for larger two-dimensional (2D) plasma crystals, a new plasma setup was built at the DLR Institute of Materials Physics in Space. The setup allows obtaining larger than before, highly ordered 2D plasma crystals and exploring new parameter ranges. It is based on a relatively large (90 cm in diameter) vacuum chamber where a capacitively coupled radio-frequency discharge is used to levitate polymer microparticles. The discharge is created between the lower rf electrode and the grounded chamber walls, the particles levitate in the plasma (pre)sheath above the electrode and are observed by video microscopy through the large top glass window and through the side windows. The first observations of plasma crystals in the new setup are reported.
New equation of state as international standard to describe thermodynamics of heavy water
Authors: DeJarnette Drew
Published: December 2018

New standard reference equation of state describes the thermodynamic behavior of heavy water to enable greater accuracy and lower uncertainties over a wider range of conditions.