bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of a Realistic O+ Source on Modeling the Ring Current
Authors: Menz A. M. , Kistler L. M. , Mouikis C. G. , Spence H. E. , Henderson M. G.
Published: November 2019

We use the UNH‐IMEF electric field model to simulate the convection of O+ from the near‐earth plasma sheet into the ring current during the 17 March 2015 storm. Using Van Allen Probes data from the night side apogee, we reconstruct a realistic O+ source. Modeling this storm using the UNH‐IMEF electric field and a dipole magnetic field has previously been found to have good agreement. Using the realistic source along with drift times and charge exchange loss from these results, we model an inbound pass near the peak of the storm where O+ is increasingly dominant over H+. We find that the time‐varying realistic O+ source is necessary to reproduce the observed spectral features and the O+ pressure enhancements at low L‐shells, while our previous results showed that the H+ was able to be modeled sufficiently with a simple, unchanging boundary condition. Further, our results show that adiabatic convective transport of O+ from the near‐earth plasma sheet (L ~ 6) can explain the observed ring current enhancements.
Systematic Uncertainties in Plasma Parameters Reported by the Fast Plasma Investigation on NASA's Magnetospheric Multiscale Mission
Authors: Gershman Daniel J. , Dorelli John C. , Avanov Levon A. , Gliese Ulrik , Barrie Alexander , Schiff Conrad , Da Silva Daniel E. , Paterson William R. , Giles Barbara L. , Pollock Craig J.
Published: November 2019

Systematic uncertainties in the conversion of measured counts to phase space density by charged particle instrumentation result in errors in reported plasma moments (e.g., density, velocity, and temperature). Unlike previous particle instrumentation that relied on a spacecraft spin to sample all look‐directions, the Fast Plasma Investigation (FPI) suite on NASA's Magnetospheric Multiscale mission nearly simultaneously images the full sky. This configuration results in unprecedented time resolution but also introduces the possibility of spin tones in plasma moments, in particular electron bulk velocity. Here we characterize the effect of systematic linear errors of corrected FPI phase space densities on its reported plasma moments. We find that the flat‐fielding correction factors (i.e., scale factor errors) of FPI are typically accurate to within a few percent but can nonetheless result in significant spin tones in magnetospheric plasmas.
A Statistical Study of Pi2 Pulsations Observed in the Upper Ionosphere Using Swarm Magnetic Field Data
Authors: Park Jae‐Hee , Kim Khan‐Hyuk , Kwon Hyuck‐Jin , Jee Geonhwa , Hwang Junga
Published: November 2019

The properties of Pi2 pulsations observed in the upper ionosphere are studied using magnetic field data acquired by the Swarm A spacecraft in low Earth orbit and at the low‐latitude Bohyun ground station (BOH, L=1.3) for January 2014 to June 2015. From time intervals when Swarm A was on the nightside (magnetic local time (MLT) = 1800–0600 hr) and the BOH station was near midnight (MLT = 2100–0300 hr), we identified 621 Pi2 events in the horizontal H component of the BOH data. For each event we examined the coherence between the horizontal H component on the ground and the Bx (radial), By (azimuthal), or Bz (compressional) components at Swarm A. Out of 621 events, the Bx−H high‐coherence (> 0.7) events are ∼6%, the By−H high‐coherence events are ∼2%, and the Bz−H high‐coherence events are ∼25%. The ground satellite high‐coherence events occurred when the spacecraft was located at magnetic latitudes between −50° and 50°. Using the ground satellite high‐coherence events, we statistically examined the latitudinal structure of the relative amplitude and phase of the ionospheric Pi2 pulsations and found that their latitudinal variations is consistent with the north‐south mode structure expected from the plasmaspheric resonance model. Our statistical results indicate that the source of ionospheric Pi2 pulsations is the plasmaspheric resonance.
Late Paleozoic Exhumation of the West Junggar Mountains, NW China
Authors: Gillespie Jack , Glorie Stijn , Jepson Gilby , Xiao Wenjiao , Collins Alan S.
Published: November 2019

The Tianshan and Altai mountain belts dominate the present‐day topography of central Asia and are major constituents of the Central Asian Orogenic Belt. These mountain belts have been extensively studied using low‐temperature thermochronology to understand their uplift and exhumation history. In comparison, few studies have focused on the spatial extent and timing of intracontinental deformation in the intervening ranges, such as the West Junggar Mountains. Apatite fission track (AFT) and apatite U‐Pb dating of igneous samples from the West Junggar Mountains reveals AFT central ages ranging from latest Carboniferous to Middle Jurassic and mean confined track lengths between 14.1 and 12.0 µm, which are negatively correlating to AFT central ages. Apatite U‐Pb dating produced mid‐Carboniferous‐early Permian ages within uncertainty of zircon U‐Pb crystallization ages, indicating cooling to below ∼450–550 °C immediately following emplacement. Thermal history modeling of our AFT data combined with published (U‐Th)/He data predicts rapid cooling to <60 °C during the early‐middle Permian (285–260 Ma), followed by slower cooling rates during the Mesozoic‐Cenozoic. The rapid cooling event coincides with (1) the timing of major basinward thrusting in the Junggar Basin adjacent to the study area and (2) exhumation in the Chinese Altai to the north. In contrast to previous studies, our results imply that the West Junggar Mountains do not record significant exhumation during the Mesozoic‐Cenozoic. This suggests that Mesozoic deformation of the Central Asian Orogenic Belt was less pervasive and widespread than previously assumed.
Modeling the Seismic Response of Unstable Rock Mass With Deep Compliant Fractures
Authors: Burjánek Jan , Kleinbrod Ulrike , Fäh Donat
Published: November 2019

An experimental quantification of the strength and volume of real, heterogeneous, fractured rock masses is crucial when assessing rock slope stability. In order to quantitatively characterize the internal structure of fractured rock slopes, we present three‐dimensional numerical simulations of seismic wave propagation and compare with observations. We introduce a simple, effective model for fractured rock mass, which can easily be applied to simulate weak‐motion seismic wave propagation. The macroscopic compliant fractures cutting the rock mass are modeled as finite‐width zones of reduced elastic parameters characterized by shear and normal stiffness. The widths of such zones are not fixed and can be adjusted to fit the grid step in the numerical method. The proposed rock mass model is applied and tested for the Walkerschmatt site in southwest Switzerland. Synthetic ambient vibrations are generated using a finite‐difference method for the fractured rock mass, shaped by the real terrain geometry, and compared with the measurements. The observed seismic response is satisfactorily reproduced in a broad frequency range (0.5–10 Hz). The synthetized response is primarily controlled by the stiffness, depth, number of fractures, and inertial mass of the fractured rock. The simulated amplification and ground‐motion directionality correspond with the observed levels, unless (1) the simplified cracks reach depths of 200–300 m; and (2) the fracture network is larger with respect to the mapped network. This illustrates the potential of ambient vibration methods in combination with numerical simulations to infer depth, volume, and mechanical characteristics of slope instability.
Can Convection‐Permitting Modeling Provide Decent Precipitation for Offline High‐Resolution Snowpack Simulations Over Mountains?
Authors: He Cenlin , Chen Fei , Barlage Michael , Liu Changhai , Newman Andrew , Tang Wenfu , Ikeda Kyoko , Rasmussen Roy
Published: November 2019

Accurate precipitation estimates are critical to simulating seasonal snowpack evolution. We conduct and evaluate high‐resolution (4‐km) snowpack simulations over the western United States (WUS) mountains in Water Year 2013 using the Noah with multi‐parameterization (Noah‐MP) land surface model driven by precipitation forcing from convection‐permitting (4‐km) Weather Research and Forecasting (WRF) modeling and four widely used high‐resolution datasets that are derived from statistical interpolation based on in situ measurements. Substantial differences in the precipitation amount among these five datasets, particularly over the western and northern portions of WUS mountains, significantly affect simulated snow water equivalent (SWE) and snow depth (SD) but have relatively limited effects on snow cover fraction (SCF) and surface albedo. WRF generally captures observed precipitation patterns and results in an overall best‐performed SWE and SD in the western and northern portions of WUS mountains, where the statistically interpolated datasets lead to underpredicted precipitation, SWE, and SD. Over the interior WUS mountains, all the datasets consistently underestimate precipitation, causing significant negative biases in SWE and SD, among which the results driven by the WRF precipitation show an average performance. Further analysis reveals systematic positive biases in SCF and surface albedo across the WUS mountains, with similar bias patterns and magnitudes for simulations driven by different precipitation datasets, suggesting an urgent need to improve the Noah‐MP snowpack physics. This study highlights that convection‐permitting modeling with proper configurations can have added values in providing decent precipitation for high‐resolution snowpack simulations over the WUS mountains in a typical ENSO‐neutral year, particularly over observation‐scarce regions.
The Primary Convective Pathway for Observed Wildfire Emissions in the Upper Troposphere and Lower Stratosphere: A Targeted Reinterpretation
Authors: Fromm Michael , Peterson David , Di Girolamo Larry
Published: November 2019

The literature—spanning several recent decades—describes numerous attempts to characterize the efficacy of cumulonimbus “Cb” convection as a pollutant pathway connecting the planetary BL to the upper troposphere and lower stratosphere (UTLS). The relatively new discovery of wildfires triggering deep convection and Cb formation, referred to as pyrocumulonimbus “pyroCb,” has provided a new convective candidate for examination. Previous studies have shown that the pyroCb pathway offers a reinterpretation of supposed volcanic aerosol layers observed in the stratosphere. The community now questions whether this relatively unappreciated phenomenon has been overlooked or imprecisely characterized in published analyses of observed UTLS biomass burning constituents attributed to traditional convection, such as individual Cbs or larger mesoscale convective systems. Here we show that on at least two occasions, a reinterpretation of the literature is required. Both are in the context of coordinated measurement campaigns in summertime Central and North American domains. We provide a strategic review of prior studies and explore three selected works, wherein the pyroCb naturally explains observations of dramatically strong, remote, and high‐altitude biomass burning pollution. We complete our discussion with the implications for including the pyroCb phenomenon in case studies and assessments of the primary convective pathway for smoke particles to enter the UTLS.
Intraseasonal to Interannual Modulation of Diurnal Precipitation Distribution Over Eastern Africa
Authors: Camberlin Pierre , Gitau Wilson , Kiladis George , Bosire Emily , Pohl Benjamin
Published: November 2019

The modulation of the rainfall diurnal cycle at intraseasonal and interannual time scales is examined using gridded rainfall data over Eastern Africa and the nearby Indian Ocean for the period 1998–2014. Our focus is on the October‐December season which is strongly impacted by both the Madden‐Julian Oscillation (MJO) and the Indian Ocean Dipole Mode (IODM). The effect of the MJO, which is not synchronized across the whole region, is mainly through changes in the amplitude of the diurnal cycle, especially an enhancement of the late afternoon peak in active phases of the MJO. The rainfall phase only shows minor variations between the active and quiescent phases of the MJO, except over the drier regions and the Indian Ocean where the overall diurnal rainfall signal is more uneven. The effect of the positive phase of the IODM (warm western Indian Ocean) on Eastern Africa rainfall is found at any time of the day, but the enhancement is more prominent during the wettest part of the day (generally the afternoon). Substantial changes in the diurnal phase of the rains are found in some land areas away from the coast or from mountain ranges, where the dominant afternoon peak during the negative IODM phase is replaced by a nighttime maximum during the positive phase. Cross‐sections and a cluster analysis of diurnal rainfall patterns over Kenya and southern Somalia suggest that this feature may be associated with the development of longer‐lived rainfall systems propagating inland from the coast during the IODM positive phase.
Understanding the Moisture Variance in Precipitating Shallow Cumulus Convection
Authors: Anurose T. J. , Bašták Ďurán Ivan , Schmidli Juerg , Seifert Axel
Published: November 2019

The impact of precipitation in shallow cumulus convection on the moisture variance and third‐order moments of moisture is investigated with the help of large‐eddy simulations. Three idealized simulations based on the Rain in Cumulus over the Ocean field experiment are analyzed: one nonprecipitating, on a smaller domain, and two precipitating cases, on a larger domain with different initial profiles of moisture. Results show that precipitation and the associated cloud organization lead to increased generation of higher‐order moments (HOM) of moisture compared to the nonprecipitating case. To understand the physical mechanism and the role of individual processes in this increase, budgets of HOM of moisture are studied. Microphysics directly decreases the generation of HOM of moisture, but this effect is not dominant. The gradient production term is identified as the main source term in the HOM budgets. The influence of the gradient production term on moisture variance is further examined separately in cloud active and nonactive regions. The main contribution to the gradient production term comes from the smaller cloud active region because of the stronger moisture flux. Further analyses of the horizontal and vertical cross sections of moisture fluctuations show that the precipitation‐induced downdrafts and updrafts are the main mechanism for the generation of moisture variance. The variance increase is linked to shallow dry downdraft regions with horizontal divergence in the subcloud layer, moist updrafts with horizontal convergence in the bulk cloud layer, and finally wider areas of horizontal divergence in the cloud inversion layer.
Salt Marsh Establishment and Eco‐Engineering Effects in Dynamic Estuaries Determined by Species Growth and Mortality
Authors: Brückner Muriel Z. M. , Schwarz Christian , van Dijk Wout M. , van Oorschot Mijke , Douma Harke , Kleinhans Maarten G.
Published: November 2019

Growth conditions and eco‐engineering effects of vegetation on local conditions in coastal environments have been extensively studied. However, interactions between salt marsh settling, growth, and mortality as a function of hydromorphology and eco‐engineering lack sufficient understanding to forecast morphological development of dynamic systems. We predict salt marsh establishment with an ecomorphodynamic model that accounts for literature‐based seasonal settling and life‐stage‐dependent growth and mortality of a generic salt marsh species. The model was coupled to a calibrated hydromorphodynamic model of an intertidal bar and, on a coarser grid, to the entire Western Scheldt estuary. To quantify the importance of eco‐engineering effects we compared the dynamic model results to a static model approach. The ecomorphodynamic model reproduces spatial pattern, cover, and growth trends over 15 years. The modeled vegetation cover emerges from the combination of a positive and a new negative eco‐engineering effect: vegetation reduces tidal flow strength facilitating plant survival while the developing salt marsh increases the hydroperiod, which limits large‐scale marsh expansion. The reproduced spatial gradient in vegetation density by our model is strongly correlated to their life‐stages, which underlines the importance of age‐dependence when modeling vegetation and for predictions of the stability of the marsh. Upscaling of the model to the entire estuary on a coarser grid gives implications for grid size‐dependent modeling of hydrodynamics and vegetation. In comparison with static model results, the eco‐engineering effects reduce vegetation cover, showing the importance of vegetation dynamics for predictions of salt marsh growth.
Mechanistic Modeling of Microtopographic Impacts on CO2 and CH4 Fluxes in an Alaskan Tundra Ecosystem Using the CLM‐Microbe Model
Authors: Wang Yihui , Yuan Fengming , Yuan Fenghui , Gu Baohua , Hahn Melanie S. , Torn Margaret S. , Ricciuto Daniel M. , Kumar Jitendra , He Liyuan , Zona Donatella , Lipson David A. , Wagner Robert , Oechel Walter C. , Wullschleger Stan D. , Thornton Peter E. , Xu Xiaofeng
Published: November 2019

Spatial heterogeneities in soil hydrology have been confirmed as a key control on CO2 and CH4 fluxes in the Arctic tundra ecosystem. In this study, we applied a mechanistic ecosystem model, CLM‐Microbe, to examine the microtopographic impacts on CO2 and CH4 fluxes across seven landscape types in Utqiaġvik, Alaska: trough, low‐centered polygon (LCP) center, LCP transition, LCP rim, high‐centered polygon (HCP) center, HCP transition, and HCP rim. We first validated the CLM‐Microbe model against static‐chamber measured CO2 and CH4 fluxes in 2013 for three landscape types: trough, LCP center, and LCP rim. Model application showed that low‐elevation and thus wetter landscape types (i.e., trough, transitions, and LCP center) had larger CH4 emissions rates with greater seasonal variations than high‐elevation and drier landscape types (rims and HCP center). Sensitivity analysis indicated that substrate availability for methanogenesis (acetate, CO2 + H2) is the most important factor determining CH4 emission, and vegetation physiological properties largely affect the net ecosystem carbon exchange and ecosystem respiration in Arctic tundra ecosystems. Modeled CH4 emissions for different microtopographic features were upscaled to the eddy covariance (EC) domain with an area‐weighted approach before validation against EC‐measured CH4 fluxes. The model underestimated the EC‐measured CH4 flux by 20% and 25% at daily and hourly time steps, suggesting the importance of the time step in reporting CH4 flux. The strong microtopographic impacts on CO2 and CH4 fluxes call for a model‐data integration framework for better understanding and predicting carbon flux in the highly heterogeneous Arctic landscape.
Understanding Hail in the Earth System
Authors: Allen John T. , Giammanco Ian M. , Kumjian Matthew R. , Jurgen Punge Heinz , Zhang Qinghong , Groenemeijer Pieter , Kunz Michael , Ortega Kiel
Published: November 2019

The processes leading to the development of hail and the distribution of these events worldwide are reviewed. Microphysical and physical characteristics of hail development are described to provide context of the notable gaps in our understanding of what drives hail to grow large, or what determines how it falls to the ground. Distributional characteristics of hail are explored, utilizing both surface observations of hailstones and remotely sensed observational data sets to identify opportunities and needs for new observations. These observational deficiencies contribute to our limited capacity to both forecast hail or its expected size and reduce the effectiveness of using favorable conditions for hail development as a proxy to frequency where observations are unavailable. Given the substantive influences of both climate variability and the changing Earth system on hail, the latest understanding of their contributions to risk are addressed. Applying this understanding of the distribution and physical characteristics of hail, the damage by hail to agriculture and insured property is assessed. Much remains unknown about the processes leading to hail growth and environmental controls on hail occurrence, size, and magnitude, particularly outside of the United States and Europe. A better understanding of the global occurrence of hail is also needed to better anticipate the hazard and associated impacts.
CeO2−x quantum dots with massive oxygen vacancies as efficient catalysts for the synthesis of dimethyl carbonate
Authors: Wang Zhi-Qiao , Zhang Ming-Jian , Hu Xiao-Bing , Dravid Vinayak P. , Xu Zhong-Ning , Guo Guo-Cong
Published: November 2019

CeO2–x quantum dots with massive oxygen vacancies are obtained by a one-step single molecular synthesis strategy. The yield of dimethyl carbonate from CO2 and methanol is more than 5 times that for commercial CeO2 nanoparticles.
Aggregation-induced emission-active Au nanoclusters for ratiometric sensing and bioimaging of highly reactive oxygen species
Authors: Ran Xiang , Wang Zhenzhen , Pu Fang , Liu Zhen , Ren Jinsong , Qu Xiaogang
Published: November 2019

A nanoprobe based on aggregation-induced emission-active Au nanoclusters for ratiometric sensing and bioimaging of highly reactive oxygen species is constructed.
Highly efficient H2 production from H2S via a robust graphene-encapsulated metal catalyst
Authors: Zhang Mo , Guan Jing , Tu Yunchuan , Chen Shiming , Wang Yong , Wang Suheng , Yu Liang , Ma Chao , Deng Dehui , Bao Xinhe
Published: November 2019

The electrocatalytic decomposition of the abundant and toxic H2S from industrial by-products is a promising energy conversion technology for H2 production and simultaneously removing this environmental pollutant.
Spherical triboelectric nanogenerator integrated with power management module for harvesting multidirectional water wave energy
Authors: Liang Xi , Jiang Tao , Liu Guoxu , Feng Yawei , Zhang Chi , Wang Zhong Lin
Published: November 2019

A spherical TENG with a spring-assisted multilayered structure was power-managed to effectively harvest multidirectional water wave energy.
Scalable production of high-quality boron nitride nanosheets via a recyclable salt-templating method
Authors: Xu Yancui , Li Taotao , Xu Weiwei , Li Chaowei , E Songfeng , Wang Liangjie , Long Xiaoyang , Bai Yu , Xu Lai , Yao Yagang
Published: November 2019

Hollow-structured boron nitride nanosheet cubes were produced via a recyclable salt-templating method, which leads to a high efficiency up to 88.4% on a gram scale.
A ‘Trojan horse strategy’ for the development of a renewable leather tanning agent produced via an AlCl3-catalyzed cellulose depolymerization
Authors: Jiang Zhicheng , Ding Wei , Xu Shuguang , Remón Javier , Shi Bi , Hu Changwei , Clark James H.
Published: November 2019

The oligosaccharides from AlCl3-catalyzed cellulose depolymerization improve penetration of Al ion into the skin matrix for further crosslinking reaction.
A novel lead-free and high-performance barium strontium titanate-based thin film capacitor with ultrahigh energy storage density and giant power density
Authors: Fan Yuzhu , Zhou Zhiyong , Chen Ying , Huang Wei , Dong Xianlin
Published: November 2019

High-quality epitaxial barium strontium titanate-based thin film capacitor was successfully fabricated with simultaneously ultrahigh energy storage density and power density.
Neural network‐based non‐linear adaptive controller design for a class of bilinear system
Authors: Bamgbose Samuel Oludare , Li Xiangfang , Qian Lijun
Published: November 2019

This study presents a novel neural network (NN)‐based non‐linear adaptive control strategy for the global stability of multi‐input–multi‐output state‐control homogeneous bilinear system (BLS) at the equilibrium position. Although this class of non‐linear system is neither piecewise nor feedback linearisable, conditionally stabilisable control system design can be utilised to generate multiple state transitions and corresponding control gains. The collected data was used to train a NN to obtain an optimal gain estimator. Then the optimal gain estimator was integrated into real‐time control system operation to adaptively compute control gains, ensuring that the controller is continuously adjustable to changing behaviour of the system. The proposed design was shown, through an illustrative example, to overcome the stability limitations of traditional controllers for the investigated class of BLS. Furthermore, discussions about the utility of the traditional control and learning system integration, as well as stability analysis of the proposed scheme were presented.
Current pulse shaping technique for low spur fractional‐N phase‐locked loop
Authors: He Dan , Lu Fujian , Wang Dezhi
Published: November 2019

Current pulse shaping technique is proposed for low spur fractional‐N phase‐locked loop, which is realised by a variable amplitude charge pump (VA‐CP) and a fixed‐position, fixed‐width and variable‐period pulse generator (FFVPG). The current pulse of VA‐CP driven by the FFVPG is shaped to fixed position, fixed width, variable amplitude and variable period for eradicating both reference spurs and fractional spurs. The period of VA‐CP's current pulse is TREF during transient and N1 × TREF during locking status, in which the N1 should be properly set in order to reduce fractional spurs as far as possible and accelerate locking time. The spur performance of the proposed fractional phase‐locked loop is evaluated by analysing the spectrum of tuning voltage when reference frequency is 20 MHz and division ratio is 120.13. Spectre based simulation results show the reference spurs at integer multiplies of 20 MHz is eradicated, and the fractional spurs at 10 MHz and the other fractional frequencies are 19.67 dB and much less than that with the existing technique, which verify the feasibility of this study.
Semantic analysis framework for protecting the power grid against monitoring‐control attacks
Authors: Wang Jiankang , Constante Gonzalo , Moya Christian , Hong Junho
Published: November 2019

The pervasive use of heterogeneous and non‐proprietary information and communication technology exposes the power grid to cyber‐attacks. In particular, monitoring‐control attacks (MCA), which manipulate control decisions by fabricating measurements, are highly threatening, because MCA are difficult to detect and can coordinately inflict severe consequences at a large scale. To defend against MCA, a semantic analysis framework is proposed in complement to direct‐setting intrusion detection. The proposed framework has the advantages of promising runtime and detection performance. The performance of the proposed framework is evaluated under different attack scenarios and compared with a direct‐settings intrusion detection systems using a 6‐bus test system and the New‐England 39‐bus test system.
Reliable mixed H∞ /passive control for T–S fuzzy semi‐Markovian jump systems under different event‐triggered schemes
Authors: Xu Yihao , Wang Yanqian , Zhuang Guangming , Lu Junwei
Published: November 2019

This study investigates the problem of reliable mixed /passive control for Takagi–Sugeno (T–S) fuzzy semi‐Markovian jump systems under different event‐triggered schemes. An asynchronous fuzzy fault‐tolerant controller is designed to deal with the actuator failures, which results in the closed‐loop system is stochastically stable with a prescribed mixed /passive performance level even if the actuator failures appear. In order to relieve the transmission pressure over the network, the authors utilise different event‐triggered schemes and compare their ability of network resource saving. In addition, there is a difference between the system modes and the controller modes to formulate the asynchronisation phenomena. By implementing the delay system method, in combination with the free‐weighting matrix and Lyapunov–Krasovskii functional, some conditions on the performance analysis are established to ensure the stochastic stability of the system. Then, controller gain matrices and event‐triggered matrices can be obtained simultaneously based on a group of feasible linear matrix inequalities. Finally, simulations are given to show the availability of the proposed method.
Enhanced leader adaptive velocity particle swarm optimisation based global maximum power point tracking technique for a PV string under partially shaded conditions
Authors: Mathi Dileep Krishna , Chinthamalla Ramulu
Published: November 2019

Under partially shaded conditions (PSC), obtaining the global maximum on the multi‐peak power‐voltage (P–V) curve by particle swarm optimisation (PSO) method requires proper tuning of parameters to avoid premature convergence problems. In this study, a new fast tracking global maximum power point tracking (GMPPT) technique for a photovoltaic (PV) string under PSC is proposed. The proposed GMPPT technique has the advantages of two PSO techniques: leader PSO (LPSO) and adaptive velocity PSO (AVPSO). The proposed enhanced leader adaptive velocity PSO (ELAVPSO) GMPPT technique overcomes the limitations of conventional PSO such as premature convergence and difficulty in parameter tuning. Furthermore, a new shading detection scheme is proposed, which accurately finds the type of shading from P–V curve scanning. With the proposed scheme, ELAVPSO GMPPT method is used only to find the global maximum power point during PSC and perturb & observe algorithm is used for maximum power point tracking during uniform irradiance. Under PSC, the limits of the search space of the proposed GMPPT technique can be identified at the time of curve scanning. The proposed algorithm is simulated and experimentally validated by using a boost direct current–direct current (DC–DC) converter prototype.
Multi‐objective optimisation method for coordinating battery storage systems, photovoltaic inverters and tap changers
Authors: Hashemipour N. , Aghaei Jamshid , Lotfi Mohamed , Niknam Taher , Askarpour Mohammad , Shafie‐khah Miadreza , Catalão Joao P.S.
Published: November 2019

The many well‐established advantages of distributed generation (DG) make their usage in active distribution networks prevalent. However, uncontrolled operation of DG units can negatively interfere with the performance of other equipment, such as tap‐changers, in addition to resulting in sub‐optimal usage of their potential. Thus, adequate scheduling/control of DG units is critical for operators of the distribution system to avoid those adverse effects. A linearised model of a multi‐objective method for coordinating the operation of photovoltaics, battery storage systems, and tap‐changers is proposed. Three objective functions are defined for simultaneously enhancing voltage profile, minimising power losses, and reducing peak load power. The formulated multi‐objective problem is solved by means of the epsilon‐constraint technique. A novel decision‐making methodology is offered to find the Pareto optimality and select the preferred solution. To assess to proposed model's performance, it is tested using 33‐bus IEEE test system. Consequently, tap‐changers suffer lessened stress, the batteries state‐of‐charge is kept within adequate limits, and the DG units operation is at higher efficiency. The obtained results verify the effectiveness of this approach.
Enhancement of wind speed using converging duct for cooling off‐grid mast‐mounted flat solar PV panels to improve its power generation
Authors: Subramanian Rajkumar , Murugesan Chandrasekar , Tamilkolundu Senthilkumar , Jaganath Dhobarathy
Published: November 2019

The potential of wind speed for cooling a mast‐mounted solar photovoltaic (PV) panel is tapped by placing a converging duct in the windward direction of the PV panel mounting. Owing to this arrangement, the wind speed beneath the PV panel is increased, which resulted in decrease of the operating temperature of PV panel and increase in PV electrical power generation. The wind speed is increased by a factor of 1.5, which reduced the temperature of PV panel by 2–3°C and increased the electrical output power by 0.7 W. Correlations in terms of ambient temperature, solar irradiation and wind velocity were developed for predicting the PV panel temperature and were validated with the experimental values.
Two‐dimensional composite (BiOCl/GO/MOF‐5) by ultrasonic‐assisted solvothermal synthesis with enhanced photocatalytic activity
Authors: Zhai Boyin , Chen Ying , Li Jing , Liang Yuning
Published: November 2019

In this work, a novel two‐dimensional photocatalyst (BiOCl/GO/MOF‐5) was successfully developed by ultrasonic‐assisted solvothermal method. X‐ray diffraction, scanning electron microscope, Brunauer–Emmett–Teller, UV–visible diffuse reflectance spectrum, photoluminescence and NH3‐TPD were employed to characterise its unique structure and property. The results show that the specific surface area of the two‐dimensional composite (205.1 mg2 ·g−1) is significantly higher than single BiOCl (3.14 mg2 ·g−1), which provide much more active site for the photocatalystic process. Also the photocatalytic efficiency could reach to 90.6% that is much higher than pure BiOCl. This could be attributed to the effective electrons‐holes separations and proper bandgap to enhance photocatalytic performance. At the same time, the formation mechanism and the possible photocatalytic mechanism of photocatalyst were proposed.
The young stellar content of the giant H II regions M 8, G333.6−0.2, and NGC 6357 with VLT/KMOS
Authors: Ramírez-Tannus M. C. , Poorta J. , Bik A. , Kaper L. , de Koter A. , De Ridder J. , Beuther H. , Brandner W. , Davies B. , Gennaro M. , Guo D. , Henning T. , Linz H. , Naylor T. , Pasquali A. , Ramírez-Agudelo O. H. , Sana H.
Published: November 2019

Context.The identification and characterisation of populations of young massive stars in (giant) H IIregions provides important constraints on (i) the formation process of massive stars and their early feedback on the environment, and (ii) the initial conditions for population synthesis models predicting the evolution of ensembles of stars.

Aims.We identify and characterise the stellar populations of the following young giant H IIregions: M 8, G333.6−0.2, and NGC 6357.

Methods.We have acquiredH- andK-band spectra of around 200 stars using theK-band Multi Object Spectrograph on the ESO Very Large Telescope. The targets for M 8 and NGC 6357 were selected from the Massive Young Star-Forming Complex Study in Infrared and X-ray (MYStIX), which combines X-ray observations with near-infrared (NIR) and mid-infrared data. For G333.6−0.2, the sample selection is based on the NIR colours combined with X-ray data. We introduce an automatic spectral classification method in order to obtain temperatures and luminosities for the observed stars. We analysed the stellar populations using their photometric, astrometric, and spectroscopic properties and compared the position of the stars in the Hertzprung-Russell diagram with stellar evolution models to constrain their ages and mass ranges.

Results.We confirm the presence of candidate ionising sources in the three regions and report new ones, including the first spectroscopically identified O stars in G333.6−0.2. In M 8 and NGC 6357, two populations are identified: (i) OB main-sequence stars (M >  5M⊙) and (ii) pre-main sequence stars (M ≈ 0.5 − 5 M⊙). The ages of the clusters are ∼1−3 Myr, < 3 Myr, and ∼0.5−3 Myr for M 8, G333.6−0.2, and NGC 6357, respectively. We show that MYStIX selected targets have > 90% probability of being members of the H IIregion, whereas a selection based on NIR colours leads to a membership probability of only ∼70%.
Radiation output system for planar gyrotron
Authors: Sobolev Dmitry , Zaslavsky Vladislav , Ginzburg Naum , Kuftin Andrey
Published: November 2019

Gyrotrons with planar resonator cavity offer some advantages over conventional cylindrical ones for submillimetre wavelengths. The radiation in the planar gyrotron should be converted from the mixture of several high modes of the rectangular waveguide into the Gaussian beam with high efficiency. For the experimental 145 GHz gyrotron, a two- channel output is considered. Both channels consist of waveguide converter and two convex mirrors and direct the radiation through the single output window. Calculated total efficiency of the system exceeds 98%.
Development of components of electro-optic modulators on a semiconductor substrate for microwave photonics
Authors: Ishutkin S.V. , Kulinich I.V. , Shageev R.
Published: November 2019

The results of research and development of components of Mach-Zehnder electro-optic modulator, in particular, the Y-divider and MMI divider are presented. Technological studies were carried out and an optical divider on an InP semiconductor substrate was obtained.
Polygon “Simeiz-Katsively” - changes in the average pole of the Earth and the geomagnetic field over the last century
Authors: Volvach Larisa , Kurbasova Galina , Dmytrotsa Andrej , Neyachenko Dmitry
Published: November 2019

The character of changing the trajectory of the middle of the North geographical pole of the Earth's surface over the last century is studied. The peculiarities in the changes of its coordinates are established. The epochs of the appearance of especial points are compared with the epochs of jumps in the data on the parameters of the geomagnetic field. A model of secular variations of geomagnetic declination at a point with geodetic coordinates of 90° north latitude, 0° west longitude is obtained. Coherent relationships have been established between changes in the parameters of the Earth’s middle pole and the geomagnetic field over the past century.
The 400-m Front Crawl Test: Energetic and 3D Kinematical Analyses
Authors: Correia Ricardo de Assis , Feitosa Wellington Gomes , Figueiredo Pedro , Papoti Marcelo , Castro Flávio Antonio de Souza
Published: November 2019

The aim of the study was to verify the relative contributions of energetic and kinematic parameters to the performance in 400-m front crawl test. Fourteen middle-distance swimmers participated in the study. Oxygen consumption was measured directly and blood samples were collected to assay lactate concentration. Both oxygen consumption and lactate concentration were used to calculate the: (i) overall energy expenditure, (ii) anaerobic (alactic and lactic) and (iii) aerobic contributions. The mean centre of mass speed and intracycle velocity variation were determined through three-dimensional kinematic analysis. Mean completion time was 315.64±26.91s. Energetic contributions were as follows: 6.1±0.28% from alactic anaerobic metabolism, 5.9±0.63% from anaerobic lactic and 87.8±0.88% from aerobic. Mean intracycle velocity variation was 0.14±0.03. The results indicated that performance of 400-m test relies predominantly on aerobic power. Parameters such as lactate, mean speed, anaerobic lactic and alactic (kW) correlated with performance of 400-m test (p <0.05). Multiple linear regressions indicated that mean centre of mass speed and anaerobic alactic (kW) determined the 400-m test performance (R2=0.92). Even though the T400 is characterized by aerobic metabolism, the anaerobic alactic component cannot be negligible at this competition level.
E-Zigarettenkonsum und späterer Konsum konventioneller Zigaretten
Authors: Hansen J. , Janssen J. , Morgenstern M. , Hanewinkel R.
Published: November 2019

Ziel Es sollte untersucht werden, ob der vorherige E-Zigarettenkonsum das spätere Probieren konventioneller Zigaretten vorhersagt.

Methode Im Schuljahr 2016/2017 nahmen in den Bundesländern Baden-Württemberg, Mecklenburg-Vorpommern, Nordrhein-Westfalen, Rheinland-Pfalz, Schleswig-Holstein und Sachsen 2388 Kinder und Jugendliche, die nie zuvor konventionelle Zigaretten geraucht haben, über 2 Jahre an einer Fragebogenstudie teil (mittleres Alter = 11,8 Jahre, SD = 1,21; 49,6 % weiblich).

Ergebnisse Zur Eingangserhebung gaben 85 Schülerinnen und Schüler (3,6 %) an, schon einmal E-Zigaretten probiert zu haben. Im Beobachtungszeitraum begannen 430 der ehemals nie rauchenden Jugendlichen (18,0 %) mit konventionellen Zigaretten zu experimentieren. Auch nach statistischer Kontrolle von Alter, Geschlecht, Migrationshintergrund, „Sensation Seeking“, subjektiver Schulleistung, Alkoholkonsum, sozioökonomischem Status und Schulart war das relative Risiko für das Experimentieren bei Nutzern von E-Zigaretten um 85 % erhöht (adjustiertes relatives Risiko = 1,85, 95 % KI [1, 34 – 2,56]). Weiterführende Analysen zeigten, dass das Risiko insbesondere für Jugendliche mit niedrigem „Sensation Seeking“ erhöht war.

Schlussfolgerungen Jugendliche experimentierten häufiger mit konventionellen Zigaretten, wenn sie zuvor E-Zigaretten konsumiert hatten. Diese Assoziation scheint stärker für Jugendliche zu sein, die ein generell niedrigeres Risiko haben, mit dem Rauchen zu beginnen.
Idiopathic Hypertrophic Pyloric Stenosis with Complete Ladd's Band: A Rare Association
Authors: Abo Elyazeed Ahmed M. , Shalaby Mohamed M. , Awad Mohamed M. , Effat AbdelMotaleb M. , Abdella Ahmed E. , Shehata Sherif Mohamed
Published: November 2019

A male infant aged 45 days presented with projectile nonbilious vomiting for 2 weeks. Ultrasound showed picture of idiopathic hypertrophic pyloric stenosis. Laparoscopic pyloromyotomy was done, but postoperative vomiting that was mainly nonbilious continued without improvement. After 4 days of persistent vomiting, laparoscopic exploration was done and complete pyloromyotomy was confirmed and malrotation with complete Ladd's band was found, then case converted to open laparotomy and Ladd's procedure was done. Postoperatively, vomiting stopped completely and baby began gradual feeding till reaching full feed. Despite that the presentation of concurrent Idiopathic Hypertrophic Pyloric Stenosis with malrotation is extremely rare; a formal laparoscopic abdominal exploration should be done as the first step before proceeding to pyloromyotomy.
The Irreducible Knee Dislocation
Authors: Malik Shahbaz S. , MacDonald Peter B.
Published: November 2019

Irreducible knee dislocations are a small subset of acute knee dislocations and are extremely rare. The most common type of irreducible knee dislocation is posterolateral, which can be challenging to diagnose both clinically and on plain radiographs. Vascular injury is uncommon and closed reduction is seldom possible due to medial femoral condyle buttonholing through soft tissues requiring open or arthroscopic reduction. Ligament injuries mostly include medial collateral ligament, anterior cruciate ligament, and posterior cruciate ligament. Literature has numerous case reports with a couple of small series giving short- to mid-term outcomes of posterolateral knee dislocations. There is, however, no consensus on management of ligament injuries with case reports showing good outcomes in early or delayed ligament reconstruction. This article sheds light on previous case reports and describes how to identify irreducible knee dislocations and provides an algorithm on how to manage ligament injuries in posterolateral dislocations.
Fetus in Fetu: Lessons Learned from a Large Multicenter Cohort Study
Authors: Taher Heba M. A. , Abdellatif Mostafa , Wishahy Ahmed Mohamed Kadry , Waheeb Saber , Saadeldin Yasser , Kaddah Sherif , Abdulsattar Ayman Hussein , Osman Mohamed Abdulkader , El Tagy Gamal Hassan , Elbarbary Mohamed M. , Khairi Ahmad , Tawfik Sherifa , Anis Shady , Anis Elia , Farouk Moemn , Abdelfattah Ahmed Hamdy , Muensterer Oliver J.
Published: November 2019

Introduction Fetus in fetu (FIF) is an extremely rare condition of abnormal twinning during embryogenesis. Most publications are single case reports. We describe the combined experience of four large tertiary referral centers with FIF which were not previously reported or published, and thereby draw conclusions to establish criteria for the workup, diagnosis, and management including intraoperative risk.

Materials and Methods A survey was forwarded to a national pediatric surgery group which includes members from all pediatric surgery centers in the country enquiring about unpublished cases of FIF encountered over a 20-year interval. The cohort was analyzed for age of presentation, type of presentation, diagnostic workup, surgical management, and outcome.

Results From 1998 to 2018, a total of 10 FIF cases were included in the study. Mean age of presentation was 4 months. Computed tomography and ultrasound were the main preoperative diagnostic modality in our cohort. Resection of the mass was curative in nine cases. Two cases in which the FIF was in direct topographic proximity to the biliary tree suffered severe intraoperative or lethal postoperative complications.

Conclusion Complete excision of FIF is the treatment of choice and generally results in excellent long-term quality of life. Mortality is rare and may be associated with biliary involvement and retroperitoneal right upper quadrant location of the FIF tends to be associated with increased risk in excision, and there is also a possible association with the presence of immature elements in the pathology report.
Intrauterine Pressure Catheter Use Is Associated with an Increased Risk of Postcesarean Surgical Site Infections
Authors: Gee Stephen E. , Ma'ayeh Marwan , Ward Calvin , Buhimschi Catalin , Klebanoff Mark , Rood Kara
Published: November 2019

Objective This study aimed to determine if intrapartum placement of an intrauterine pressure catheter (IUPC) is associated with an increased rate of surgical site infections in women undergoing a cesarean delivery.

Study Design This was a secondary analysis of the prospective observational Maternal–Fetal Medicine Units Network Vaginal Birth after Cesarean Registry. We compared patients with and without IUPC use. A multivariable logistic regression was performed to evaluate for an association between IUPC use and postcesarean surgical site infections.

Results The study included 16,887 women: 7,441 with IUPC use and 9,446 without IUPC use. After adjustment for potential cofounders, IUPC use was associated with an increased risk of postcesarean infections compared with those without IUPC use (adjusted odds ratio: 1.28; 95% confidence interval: 1.10–1.50; p = 0.002).

Conclusion IUPC use is associated with an increased risk of postcesarean surgical site infections. This supports the judicious use of IUPC for limited clinical indications and provides a potential area of focus for reduction in postcesarean infections.
The Way to Man's Heart Is through the Stomach
Authors: Grossman Rebecca , Francis Rohin
Published: November 2019

Organ systems do not exist in a vacuum. However, in an era of increasingly specialized medicine, the focus is often on the organ system alone. Many symptoms are associated with differential diagnoses from upper gastrointestinal (GI) and cardiovascular medical and surgical specialties. Furthermore, a large number of rare but deadly conditions cross paths between the upper GI tract and cardiovascular system; a significant proportion of these are iatrogenic injuries from a parallel specialty. These include unusual fistulae, herniae, and embolisms that transcend specialties. This review highlights these conditions and the shared anatomy and embryology of the two organ systems.