bluuebunny/crossref_metadata_2025 huggingface dataset:
Operating a cesium sputter source in a pulsed mode
Authors: Blahins J. , Leopold T. , Apsitis A. , Berzins U. , Ubelis A. , Rohlén J. , Lu D. , Hanstorp D.
Published: February 2020

A scheme is presented for pulsing of a cesium sputter negative ion source by periodically switching on and off the high voltage driving the sputtering process. We demonstrate how the pulsed ion beam can be used in combination with a pulsed laser (6 ns pulse length) that has a 10 Hz repetition rate to study the photodetachment process, where a negative ion is neutralized due to the absorption of a photon. In such experiments, where the ion beam is used only for a small fraction of the time, we show that the pulsed mode operation can increase the lifetime of a cathode by two orders of magnitude as compared with DC operation. We also investigate how the peak ion current compares with the ion current obtained when the source is run in a DC mode. We find that the peak current in the pulsed mode is strongly dependent on the ion species. In some cases, we observed a strong enhancement, whereas others showed only a moderate enhancement, or even a decrease, in the peak current. We conclude that the pulsed mode operation can be of great value when the negative ion to be investigated requires cathodes that have short lifetimes, expensive materials, or those with relatively small ion beam yields, in the latter case limited to elements with large enhancement factors.
Laser-free GHz stroboscopic transmission electron microscope: Components, system integration, and practical considerations for pump–probe measurements
Authors: Lau June W. , Schliep Karl B. , Katz Michael B. , Gokhale Vikrant J. , Gorman Jason J. , Jing Chunguang , Liu Ao , Zhao Yubin , Montgomery Eric , Choe Hyeokmin , Rush Wade , Kanareykin Alexei , Fu Xuewen , Zhu Yimei
Published: February 2020

A 300 keV transmission electron microscope was modified to produce broadband pulsed beams that can be, in principle, between 40 MHz and 12 GHz, corresponding to temporal resolution in the nanosecond to picosecond range without an excitation laser. The key enabling technology is a pair of phase-matched modulating and de-modulating traveling wave metallic comb striplines (pulsers). An initial temporal resolution of 30 ps was achieved with a strobe frequency of 6.0 GHz. The placement of the pulsers, mounted immediately below the gun, allows for preservation of all optical configurations, otherwise available to the unmodified instrument, and therefore makes such a post-modified instrument for dual-use, i.e., both pulsed-beam mode (i.e., stroboscopic time-resolved) and conventional continuous waveform mode. In this article, we describe the elements inserted into the beam path, challenges encountered during integration with an in-service microscope, and early results from an electric-field-driven pump–probe experiment. We conclude with ideas for making this class of instruments broadly applicable for examining cyclical and repeatable phenomena.
Predicting NMR relaxation of proteins from molecular dynamics simulations with accurate methyl rotation barriers
Authors: Hoffmann Falk , Mulder Frans A. A. , Schäfer Lars V.
Published: February 2020

The internal dynamics of proteins occurring on time scales from picoseconds to nanoseconds can be sensitively probed by nuclear magnetic resonance (NMR) spin relaxation experiments, as well as by molecular dynamics (MD) simulations. This complementarity offers unique opportunities, provided that the two methods are compared at a suitable level. Recently, several groups have used MD simulations to compute the spectral density of backbone and side chain molecular motions and to predict NMR relaxation rates from these. Unfortunately, in the case of methyl groups in protein side chains, inaccurate energy barriers to methyl rotation were responsible for a systematic discrepancy in the computed relaxation rates, as demonstrated for the AMBER ff99SB*-ILDN force field (and related parameter sets), impairing quantitative agreement between simulations and experiments. However, correspondence could be regained by emending the MD force field with accurate coupled cluster quantum chemical calculations. Spurred by this positive result, we tested whether this approach could be generally applicable, in spite of the fact that different MD force fields employ different water models. Improved methyl group rotation barriers for the CHARMM36 and AMBER ff15ipq protein force fields were derived, such that the NMR relaxation data obtained from the MD simulations even now display very good agreement with the experiment. Results herein showcase the performance of present-day MD force fields and manifest their refined ability to accurately describe internal protein dynamics.
Simulation of Alfvénic avalanche onset in NSTX
Authors: White R. B. , Duarte V. N. , Gorelenkov N. N. , Fredrickson E. D. , Podesta M.
Published: February 2020

In some tokamak discharges, a number of Alfvén eigenmodes (AEs) have been observed to cause a large-scale collapse of the high energy particle distribution, a phenomenon referred to as an avalanche. We examine the necessary conditions for an avalanche using the available experimental information from NSTX on the equilibrium and mode properties for two cases, one with a measurable but benign AE activity and one with an AE activity leading up to an avalanche. To produce an avalanche, the modes present in the discharge must possess resonances that can overlap with a modest increase in instability magnitude, providing a path to global particle stochastic motion. We find that the modes present in the avalanche-free discharge do not provide such a path even at a very large amplitude. During the discharge which subsequently produces an avalanche, the high energy population is growing and the Alfvén frequency is dropping due to increasing density, and we find that both these changes, producing a small increased drive or an increased resonance width for the Alfvén modes, can lead in this case to uncontrolled mode growth and large-scale beam particle loss.
Reconversion of the CdHgTe conductivity type after plasma etching process at low temperature
Authors: Gorshkov D. V. , Sidorov G. Yu. , Varavin V. S. , Sabinina I. V. , Yakushev M. V.
Published: February 2020

We report on the relaxation of Hall coefficient RH (77 K) depending on the magnetic field in p-CdxHg1−xT (x = 0.222) to the initial values, which were before the plasma etching process in argon and methane plasma. The time required to change the conductivity type from the n-type, which was created on the sample surface at a depth of around a micrometer, to the p-type is less than 165 min. We show that the electron concentration in the thin layer near the sample surface decreases to an insignificant value with the increasing storage time at room temperature.
Solvent effects on the π* shape resonances of uracil
Authors: Cornetta L. M. , Coutinho K. , Varella M. T. do N.
Published: February 2020

We have investigated the effect of microsolvation on the π* shape resonances of uracil, referred to as π1* and π2* in the order of increasing energy. Our study considered uracil–water aggregates with six solvent molecules obtained from Monte Carlo simulations in the liquid phase. To explore the ensemble statistics, we combined scattering calculations, performed in the static exchange and static exchange plus polarization approximations, with linear regressions of virtual orbital energies to the scattering results. In general, the solvent molecules stabilize the anion states, and the lower lying π1* resonance becomes a bound state in most of the solute–water clusters. We also discuss how the strength of the H bonds can affect the energies of the anion states, in addition to the number and donor/acceptor characters of those bonds. The thermal distributions for the vertical attachment energies, obtained from 133 statistically uncorrelated solute–solvent clusters, are significantly broad in the energy scale of the autoionization widths. The distributions for the π1* and π2* anion states slightly overlap, thus giving rise to a quasi-continuum of attachment energies below ≲2.5 eV, in contrast to the gas phase picture of electron attachment to well separated resonances below the electronic excitation threshold. Both the stabilization of the anion states and the spread of attachment energies could be expected to favor the dissociative electron attachment processes believed to underlie the electron-induced damage to biomolecules.
Initial steps toward Auad island nucleation on a c(2 × 2)-Cl Au(001) surface investigated by DFT
Authors: Dávila López Alexandra Celinda , Pehlke Eckhard
Published: February 2020

Density functional theory calculations are reported that elucidate the initial steps toward Au ad-island nucleation on c(2 × 2)-Cl covered Au(001) surfaces, which is relevant for Au electrodeposition in Cl− containing electrolytes. The atomic geometry of (Auad)n adatom structures for n ≤ 4, as well as their stability as a function of Cl chemical potential, has been determined. The electrolyte, however, has not been accounted for in the computation. We find a weakly bonded (AuadCl2)-chain as the most stable structure in the case of Cl chemical potentials such that Cl vacancies are suppressed. In the range of Cl chemical potential, where Cl vacancies occur in equilibrium and bind to an (modified) Auad induced ad-structure, the formation of a dimer from two monomers is accompanied by an energy gain between 0.06 and 0.23 eV. For Auad trimer and tetramer formation, the calculations suggest a similar tendency. This suggests that on c(2 × 2)-Cl covered Au(001) surfaces, the Au ad-island nucleation is supported by the presence of vacancies in the Cl adlayer.
Influence of hydrogen implantation on emission from the silicon vacancy in 4H-SiC
Authors: Bathen M. E. , Galeckas A. , Coutinho J. , Vines L.
Published: February 2020

The silicon vacancy (VSi) in 4H-SiC is a room temperature single-photon emitter with a controllable high-spin ground state and is a promising candidate for future quantum technologies. However, controlled defect formation remains a challenge, and, recently, it was shown that common formation methods such as proton irradiation may, in fact, lower the intensity of photoluminescence (PL) emission from VSi as compared to other ion species. Herein, we combine hybrid density functional calculations and PL studies of the proton-irradiated n-type 4H-SiC material to explore the energetics and stability of hydrogen-related defects, situated both interstitially and in defect complexes with VSi, and confirm the stability of hydrogen in different interstitial and substitutional configurations. Indeed, VSi-H is energetically favorable if VSi is already present in the material, e.g., following irradiation or ion implantation. We demonstrate that hydrogen has a significant impact on electrical and optical properties of VSi, by altering the charge states suitable for quantum technology applications, and provide an estimate for the shift in thermodynamic transition levels. Furthermore, by correlating the theoretical predictions with PL measurements of 4H-SiC samples irradiated by protons at high (400°C) and room temperatures, we associate the observed quenching of VSi emission in the case of high-temperature and high-fluence proton irradiation with the increased mobility of Hi, which may initiate VSi-H complex formation at temperatures above 400°C. The important implication of hydrogen being present is that it obstructs the formation of reliable and efficient single-photon emitters based on silicon vacancy defects in 4H-SiC.
First-principles study of electronic and diffusion properties of intrinsic defects in 4H-SiC
Authors: Yan Xiaolan , Li Pei , Kang Lei , Wei Su-Huai , Huang Bing
Published: February 2020

As a wide bandgap semiconductor, SiC holds great importance for high temperature and high power devices. It is known that the intrinsic defects play key roles in determining the overall electronic properties of semiconductors; however, a comprehensive understanding of the intrinsic defect properties in the prototype 4H-SiC is still lacking. In this study, we have systematically investigated the electronic properties and kinetic behaviors of intrinsic point defects and defect complexes in 4H-SiC using advanced hybrid functional calculations. Our results show that all the point defects in 4H-SiC have relatively high formation energies, i.e., low defect concentrations even at high growth temperatures. Interestingly, it is found that the migration barriers are very high for vacancies (>3 eV) but relatively low for interstitial defects (∼1 eV) in SiC. Meanwhile, the diffusion energy barriers of defects strongly depend on their charge states due to the charge-state-dependent local environments. Furthermore, we find that VSi in SiC, a key defect for quantum spin manipulation, is unstable compared to the spin-unpolarized VC–CSi complex in terms of the total energy (under p-type conditions). Fortunately, the transformation barrier from VSi to VC–CSi is as high as 4 eV, which indicates that VSi could be stable at room (or not very high) temperature.
Thermodynamics and structural properties of CaO: A molecular dynamics simulation study
Authors: Alvares Cecilia M. S. , Deffrennes Guillaume , Pisch Alexander , Jakse Noël
Published: February 2020

A detailed theoretical study of CaO in the solid and liquid states by means of combined classical and ab initio molecular dynamics simulations is presented. Evolution of the specific heat capacity at constant pressure as a function of temperature is studied, and the melting temperature and enthalpy of fusion are determined. It is shown that an empirical Born–Mayer–Huggins potential gives a good representation of pure CaO in the liquid and solid states as compared to available experimental data and density functional theory calculations. Consistency of the predicted results obtained for CaO with the data available in commercial thermodynamic databases and experimental values in the literature is discussed. The present methodology and theoretical results provide a new accurate basis for calculations of thermodynamic properties in a temperature range that is hardly accessible by experiments.
Correlation between exciton polarized lifetime and fine structure splitting in InAs/GaAs quantum dots
Authors: Chen Hao , Zhuo Zhiyao , Huang Junhui , Dou Xiuming , He Xiaowu , Ding Kun , Ni Haiqiao , Niu Zhichuan , Jiang Desheng , Sun Baoquan
Published: February 2020

Semiconductor self-assembled single quantum dots (QDs) provide a promising solid-state light source for single photons and entangled photons. The structural asymmetry in QDs results in fine structure splitting (FSS) of exciton and biexciton emission lines. Here, we propose a method to study QD symmetry by measuring the difference in two different polarized lifetimes of QD excitonic emission lines under applied stress. The method can be reasonably correlated with the direct FSS measurement. Actually, due to the limitation of the resolution of the spectrometer, the zero value of FSS is difficult to measure. Instead, the lifetime measurement is an effective method to judge the symmetry condition of single QDs.
Density-functional theory prediction of the elastic constants of ice Ih
Authors: Santos Rego Jéssica , de Koning Maurice
Published: February 2020

We assess the elastic stiffness constants of hexagonal proton-disordered ice Ih as described by density-functional theory calculations. Specifically, we compare the results for a set of nine exchange-correlation functionals, including standard generalized-gradient approximations (GGAs), the strongly constrained and appropriately normed (SCAN) metaGGA functional, and a number of dispersion-corrected versions based on the van der Waals (vdW) and VV10 schemes. Compared to the experimental data, all functionals predict an excessively stiff response to tensile and compressive distortions, as well as shear deformations along the basal plane, with the SCAN metaGGA functional displaying the largest deviations as compared to the experimental values. These discrepancies are found to correlate with underestimates of inter-molecular distances, on the one hand, and overestimates of intra-molecular separations, on the other. The inclusion of non-local vdW corrections according to the vdW approach generally improves these structural parameters and softens the elastic response functions compared to their parent GGA functionals. The dispersion-corrected SCAN-rVV10 functional, however, acts in the opposite direction, further worsening the comparison to experiment. In this view, it appears useful that the database employed to gauge the quality of exchange-correlation functionals for water includes an assessment of their elastic response of ice Ih and possibly other crystalline phases.
Constructing the digital self in the Global South
Authors: Campbell Baird , Haynes Nell
Published: February 2020

The papers in this special section examine how people in various contexts of the Global South “construct the self” in
online spaces. With examples from Chile, Senegal, and Trinidad, the papers show the wide range of discursive practices, encompassing the
textual and the aesthetic, which individuals use to enact gendered and sexual selves online. By privileging gender and sexuality as central
components of selfhood, we draw from the longstanding attention paid to gender and sexuality in linguistic studies of identification (see
Bucholtz & Hall 2004). In placing this concept within digital worlds, we pay attention to
the ways in which daily life is now lived and experienced online. Authors in this issue think critically about practices of self-formation
and the performance of gender and sexuality that differ from those that have normalized in the Global North, considering both revolutionary
possibility, and re-entrenchment of constraint.
Supporting Erasmus students through integrating reflective practicesin the curriculum
Authors: Holfter Gisela , Rieder Maria
Published: February 2020

There is considerable evidence that suitable preparation for the Erasmus experience can make a significant difference to students. Often, however, institutions have to battle to provide in-depth pre-departure training, and re-entry events or training are too seldom available. Following Erasmus there is rarely space in the curriculum of the home university for reflection, assessment and the integration of the experiences and multi-faceted learning that took place abroad. This article argues that the challenge is therefore to integrate meaningful reflections and assessment into more traditional modules, such as literature-based ones. Accordingly, this article presents some options of how to integrate re-entry reflections in the form of a module on travel literature as well as a voluntary re-entry module that can be offered to returning students irrespective of their course of study. Components of the Erasmus+ CONNECT training programme serve as an example of training material.
The role of social networks and intense friendships in study abroad students’ L2 use and speaking
development
Authors: Baten Kristof
Published: February 2020

This article examines the connections among self-reported social network development, L2 use, and self-perceived
speaking proficiency development in a group of Belgian ERASMUS students (n = 59) who studied abroad in different
European countries (Austria, France, Germany, Ireland, Italy, Spain, Sweden, and the UK). The results suggest a number of
differences between the participants in this study and the US cohorts who have been traditionally the focus of previous SA
research. For example, the Belgian students report high levels of proficiency in the target language before going abroad and high
levels of target language use while abroad. Furthermore, a number of social network variables point to differences between the
ERASMUS students in the present study and the US students featuring in previous research. Nevertheless, the results also reveal
some similarities, especially with regard to the social network variables ‘size’ and ‘intensity of friendship’ which were
predictors of language gains for the group of students under analysis in this study and, consequently, corroborated findings of
previous studies conducted with US cohorts.
Identification of SFL1 as a positive regulator for flor formation in Zygosaccharomyces rouxii
Authors: Mogi Ryosuke , Watanabe Jun
Published: February 2020

Some wild Zygosaccharomyces rouxii impair the quality of soy sauce through the generation of unpleasant odors induced by the formation of flor. Flor formation in Z. rouxii depends on the expression of the FLO11D gene, which is a homolog of the FLO11 gene that encodes a cell surface protein in Saccharomyces cerevisiae. FLO11 expression in S. cerevisiae is regulated by multiple pathways. To investigate the regulation of FLO11D expression in Z. rouxii, we created 13 gene knockout mutants (STE12, TEC1, HOG1, MSS11, FLO8, MSN1, MSN2/4, SKO1, TUP1, CYC8, YAK1, MIG1, and SFL1) related to those pathways and examined whether these mutants form flor. Unexpectedly, SFL1 knockout mutant could only form a very weak flor due to decreased FLO11D expression, suggesting that SFL1 acts as a potential activator of flor formation through FLO11D expression. This result is in contrast to S. cerevisiae SFL1, which acts as a repressor of FLO11 expression.
Differential turnover of Nup188 controls its levels at centrosomes and role in centriole duplication
Authors: Vishnoi Nidhi , Dhanasekeran Karthigeyan , Chalfant Madeleine , Surovstev Ivan , Khokha Mustafa K. , Lusk C. Patrick
Published: February 2020

NUP188 encodes a scaffold component of the nuclear pore complex (NPC) and has been implicated as a congenital heart disease gene through an ill-defined function at centrioles. Here, we explore the mechanisms that physically and functionally segregate Nup188 between the pericentriolar material (PCM) and NPCs. Pulse-chase fluorescent labeling indicates that Nup188 populates centrosomes with newly synthesized protein that does not exchange with NPCs even after mitotic NPC breakdown. In addition, the steady-state levels of Nup188 are controlled by the sensitivity of the PCM pool, but not the NPC pool, to proteasomal degradation. Proximity-labeling and super-resolution microscopy show that Nup188 is vicinal to the inner core of the interphase centrosome. Consistent with this, we demonstrate direct binding between Nup188 and Cep152. We further show that Nup188 functions in centriole duplication at or upstream of Sas6 loading. Together, our data establish Nup188 as a component of PCM needed to duplicate the centriole with implications for congenital heart disease mechanisms.
An optimized toolbox for the optogenetic control of intracellular transport
Authors: Nijenhuis Wilco , van Grinsven Mariëlle M.P. , Kapitein Lukas C.
Published: February 2020

Cellular functioning relies on active transport of organelles by molecular motors. To explore how intracellular organelle distributions affect cellular functions, several optogenetic approaches enable organelle repositioning through light-inducible recruitment of motors to specific organelles. Nonetheless, robust application of these methods in cellular populations without side effects has remained challenging. Here, we introduce an improved toolbox for optogenetic control of intracellular transport that optimizes cellular responsiveness and limits adverse effects. To improve dynamic range, we employed improved optogenetic heterodimerization modules and engineered a photosensitive kinesin-3, which is activated upon blue light–sensitive homodimerization. This opto-kinesin prevented motor activation before experimental onset, limited dark-state activation, and improved responsiveness. In addition, we adopted moss kinesin-14 for efficient retrograde transport with minimal adverse effects on endogenous transport. Using this optimized toolbox, we demonstrate robust reversible repositioning of (endogenously tagged) organelles within cellular populations. More robust control over organelle motility will aid in dissecting spatial cell biology and transport-related diseases.
JEM women in STEM: Unique journeys with a common purpose
Authors: O’Garra Anne , Belkaid Yasmine , Sharpe Arlene , Kaech Susan , Cherry Sara , Passegué Emmanuelle
Published: February 2020

Before one can think of the challenges that face women in science and the hurdles that impair their development into leadership positions, it is worth considering the diversity within the collective of women scientists at the level of culture and past experience and life events.
Effect of external axial magnetic field on a helium atmospheric pressure plasma jet and plasma-treated water
Authors: Tschang Chen-Yon Tobias , Bergert Roman , Mitic Slobodan , Thoma Markus
Published: February 2020

Potential in biomedical-related applications by atmospheric pressure plasma-treated water gradually increased recently. In order to enhance the generation of reactive species in atmospheric pressure plasma in regards to liquid treatment, this study aims to investigate the effect of external axial magnetic field on a helium atmospheric pressure plasma jet (APPJ) and plasma-irradiated water. Magnetic field strength up to 2.0 T was generated by an electromagnet in Helmholtz configuration. The dielectric barrier discharge-based APPJ is driven by 4.4 slm helium and sinusoidal 30 kHz, 10 k

V

p
p

signals. Plasma was mainly characterized by optical emission where vibrational and rotational temperature was estimated by nitrogen second positive system, and electron temperature and density by emission intensity line ratio method. Representative reactive species of nitrite, nitrate, and hydrogen peroxide concentration in the plasma-treated water were also quantified. Results of vibrational temperature and electron density showed a first drop then rise trend which partially corresponds to the reactive species in the plasma-treated water. No significant changes were found in rotational temperature, while electron temperature monotonically increased with the magnetic field.
Feasibility and limitations of quantitative SPECT for 223Ra
Authors: Gustafsson Johan , Rodeño Emilia , Mínguez Pablo
Published: February 2020

The aim of this paper is to investigate the feasibility and limitations of activity-concentration estimation for 223Ra using SPECT. Phantom measurements are performed using spheres (volumes 5.5 mL to 26.4 mL, concentrations 1.6 kBq mL−1 to 4.5 kBq mL−1). Furthermore, SPECT projections are simulated using the SIMIND Monte Carlo program for two geometries, one similar to the physical phantom and the other being an anthropomorphic phantom with added lesions (volumes 34 mL to 100 mL, concentrations 0.5 kBq mL−1 to 4 kBq mL−1). Medium-energy and high-energy collimators, 60 projections with 55 s per projection and a 20% energy window at 82 keV are employed. For the Monte Carlo simulated images, Poisson-distributed noise is added in ten noise realizations. Reconstruction is performed (OS-EM, 40 iterations, 6 subsets) employing compensation for attenuation, scatter, and collimator-detector response. The estimated concentrations in the anthropomorphic phantom are also corrected using recovery coefficients. Errors for the largest sphere in the physical phantom range from −25% to −34% for the medium-energy collimator and larger deviations for smaller spheres. Corresponding results for the high-energy collimator are −15% to −31%. The corresponding Monte Carlo simulations show standard deviations of a few percentage points. For the anthropomorphic phantom, before application of recovery coefficients the bias ranges from −16% to −46% (medium-energy collimator) and −10% to −28% (high-energy collimator), with standard deviations of 2% to 14% and 1% to 16%. After the application of recovery coefficients, the biases range from −3% to −35% (medium energy collimator) and from 0% to −18%. The errors decrease with increasing concentrations. Activity-concentration estimation of 223Ra with SPECT is feasible, but problems with repeatability need to be further studied.
Performance Evaluation of Power Swing Blocking in Compensated Transmission Lines
Authors: Çapar A , Ünverdi E , Basa Arsoy A
Published: February 2020

Traditional and modern compensation devices can increase power flow limit and enhance voltage drop in transmission lines. However, these systems can cause to malfunction of distance relays utilized to protect transmission lines. While compensation devices can effect distance relay operation, some disturbances like power swings are significant risk to ability of distance relays to distinguish faults. Power swing blocking (PSB) methods are used to discriminate faults from power swings. This study focuses on efficiency of conventional PSB methods when transmission lines are compensated with various compensation devices such as series capacitor (SC), thyristor-controlled series capacitor (TCSC) and static VAR compensator (SVC). A test system is simulated on PSCAD under various operating conditions. Conventional PSB methods (swing center voltage, reactive power change and change rate of impedance) are tested under these scenarios. The study revealed that compensation devices significantly affect the accuracy of PSB algorithms, therefore it is recommended to develop an adaptive PSB method to block power swing in the case of various operating conditions.
Performance Assessment of the RTDS/RSCAD VSC Model
Authors: Tinajero G D A , Guerrero J. M. , Segundo J. , Esparza A.
Published: February 2020

This document presents a performance assessment of the three-phase two-level voltage source converter (VSC) model of the real-time digital simulator RTDS/RSCAD. This evaluation is conducted through two case studies. One case is a simple two-bus power electronic-based system, and the second case is a three-bus system with a frequency-dependent transmission line model and a closed-loop controlled VSC with communication delay. The results obtained reveal that the RTDS/RSCAD VSC model presents some issues on stability, harmonic spectrum, ripple, and power quality in general, as compared with the PSCAD VSC solutions. These results also suggest the need for better power electronic components models.
Renewable Energy Generation and Impacts on E-Mobility
Authors: Sree Lakshmi G , Rubanenko O , Hunko I
Published: February 2020

This paper gives information about Renewable Energy Generation and its impacts on E-Mobility. By 2050, the two pillars of modern transformation are E-Mobility and Renewable Energy. This transformation requires adaptation to meet demographic and economic growth without increasing pollution and congestion. The modern world needs affordable, secure and inclusive, sustainable and integrated with customer-centric infrastructure and services. There is a great fundamental change needed in road transportation sector, which is to achieve its objective of a long term transition to a low-carbon economy. Electric Vehicles when charged with the electricity generated from Renewable Energy Sources can reduce future emissions of greenhouse gases and air pollutants from road transport. Electric Vehicles combined with renewable energy paint a different picture from the oversimplification of gas miles versus electric miles.Smart Mobility and Smart Grid technologies make people live more sustainable and efficiently.
The research to reduce the transient grounding resistance of communication protection system with resistance matching method
Authors: Wan Zheng , Tian Dongliang , Li Lei , Chen Jianping , Wang Wangrong , Qu Xinbo , Hu Bin
Published: February 2020

In this paper, we study reducing the transient grounding resistance (TGR) of communication protection system with resistance matching method. We set single or double matching layers surround the grounding rod and change their sizes and conductivity to get the laws about reducing the TGR peak and stable value. The finite-difference time-domain (FDTD) method is adopted for calculating. For the single matching layer, both of the peak and stable value of the vertical grounding rod TGR reduce, compared with normal case, as matching layer exists when the conductivity of matching layer is larger than that of ground. For the double matching layers, the TGR value will reduce even more than single matching layer case when the conductivity of outer matching layer is larger than that of ground.
Load restoration strategy considering the recovery state of power plants in system restoration stage
Authors: Wu Shengjun , Feng Xinzhen , Zhou Qian , Cui Hongfen , Li Hongyi
Published: February 2020

Load restoration is important for reducing outage time and loss of smart grid after a blackout. Load recovery strategy of network reconfiguration is maximizing load amount during system restoration without considering the startup characteristic of thermal plants, which may result in the time-delay of hot-start generators and decrease the efficiency of power system restoration. In order to increase the restoration efficient of network reconfiguration stage, this paper proposes a load restoration strategy considering the recovery state of power plants based on logical preference description language (LPDL). Firstly, the load selection constraint determined by the recovery state of power plants in each time step is formulated by LPDL. Then, a non-linear optimization model for load restoration during network reconfiguration is established with the load selection constraint. Artificial Bee Colony algorithm (ABC) is employed to obtain the optimal load restoration scheme. Finally, the New England power system is employed to demonstrate the validation of the proposed method.
Comparison of optimal reactive power flow model in the polar form and the mixed polar form
Authors: Wang Aifeng , Wei Hua , Huang Guohui
Published: February 2020

This paper establishes the optimal reactive power flow (ORPF) model in the polar form and the mixed polar form. The analysis shows that the ORPF model in the polar form not only has less calculation amount of equality constraints than the ORPF model in the mixed polar form, but also has more concise expressions, which makes it easier to understand, analyze, and remember. The test results of IEEE30, 118, 300, 1047 bus systems show that the ORPF model in the polar form obtains the same optimal value and iteration number as the ORPF model in the mixed polar form, but its calculation time is shorter, and the solving efficiency is higher. With the increasing scale of modern power system, the calculation time of ORPF problem rises, so it is necessary to improve its solving efficiency. The ORPF model in the polar form is more suitable for power system analysis and calculation because of its high solving efficiency.
Unit commitment of wind integrated power system considering optimal scheduling of reserve capacity
Authors: Wenxue Liu , Liang Wang , Bing Zhang , Changhui Ma , Zhengtang Liang
Published: February 2020

There are multiple uncertainties in the power system with wind farms, such as wind power output, load and forced outage of units, which lead to consider the spinning reserve capacity in unit commitment, which undoubtedly increases the difficulty of problem solving. In order to solve this problem, the fuzzy parameters of wind power output and load are obtained by using the error’s fuzzy characteristics, and the mathematical model of generating unit combination is established to optimize the generator output and spinning reserve simultaneously by using the chance constraint, and the model is solved by using intelligent algorithm. The model fully analyses the cost difference of different units providing spinning reserve and the economic benefit of spinning reserve, aiming at minimizing the difference between the cost of generating reserve and the economic benefit of reserve, so as to maximize the overall economic benefit of the system. The feasibility and validity of the proposed model are verified by a 10-unit system with wind farms. The analysis shows that the model can reasonably consider reserve decision-making in unit commitment to deal with uncertainties in power system.
Day-ahead optimal scheduling of integrated energy system with electric heat pump
Authors: Zhang Nianchu , Wang Qi , Ni Ming , Li Manli , Zhang Zheng
Published: February 2020

The regional integrated energy system is an effective way to realize energy cascade utilization and improve the flexibility and economy of the load side operation. Combine cooling heating and power (CCHP) system is a typical form of integrated energy systems. However, due to heat-load-based operation mode, the peak modulation capacity of CCHP units and the accommodation of renewable energy are limited. This paper explores methods of increasing the flexibility and economy of the system. An optimal scheduling model is proposed for integrated energy systems containing an electric heat pump, considering heating network characteristics. Simulation results show that the electric heat pump can help the system realize heat-and-power decoupling, improve the flexibility of the system and reduce the operating cost of the system.
The differences of depth on the species composition of spiny lobster puerulus on south Pacitan Regency East Java
Authors: Saputra W A , Pambudi K A , Setyanto A , Tumulyadi A
Published: February 2020

Lobster resources are one of renewable resources but if catches are increasing without any control will cause a depleted resource. Catching lobsters is not only in the adult phase but all phases are captured. The purpose of this study to determine the composition of lobster seeds between depths that have a high value of lobster seeds collection so that it can be used as a reference for lobster protection in nature. This research was conducted in January – February 2019, located in Pacitan district with the operational area in Wawaran beach waters. The statistical method used in this research was Chi-Square analysis and Kruskall-Wallis. Based on the results of the operation atracror puerulus lobster in two different depths (14 and 20 meters) in Wawaran beach waters found that there are four species puerulus, i.e., Panulirus homarus, Panulirus penicillatus, Panulirus ornatus and Panulirus versicolor. Its found that different depths did not affect the composition of the collected puerulus species. Then the Kruskal-Wallis test at 14 meters and 20 meters depth found a significant difference in the value of each type of lobster. The type of puerulus from Panulirus homarus has the dominant results compared than the other three species.
Nursery method of Jatimbulan Tilapia (Oreochromis niloticus) in Pasuruan, East Java
Authors: Anggraeni I , Sari P D W
Published: February 2020

Jatimbulan Tilapia (Oreochromis niloticus) is the third generation of the crossover six parental strain of tilapia. The nursery method for Jatimbulan Tilapia (Oreochromis niloticus) fry is carried out in soil and concrete-walled pond, as well as seeds having an average length of 2.3 cm and an average weight of 0.181 grams. The treatment used is feeding pellets by feeding frequency two times a day with a 30% feeding rate of the biomass. Treatment significantly generating good growth and survival; SGR (1.12%) and SR (97%). Water quality in the maintenance media contained in a reasonable range for raising Jatimbulan Tilapia.
Identification and prevalence infection of helminth in the gastrointestinal tract swamp eel (Synbranchus bengalensis) which marketed in Surabaya, East Java
Authors: Subekti S , Kurniawan M R , Sudjarwo S A
Published: February 2020

Disease is one of the obstacles in cultivation are caused by an imbalance of the interaction between environmental factors, host, and disease agents. This study aimed to determine the prevalence of helminth species and endoparasites which infect the gastrointestinal tract swamp eel (Synbranchus bengalensis) is marketed in the city of Surabaya, East Java. Samples was taken 75 swamp eel of (10%) from total population 750. The research method used is a survey method. The collected data were analyzed descriptively. Based on the results of checks are performed on 75 samples of eel swamp tail result 22 positive swamp eels infected with helminth endoparasit Pingus sinensis and Eustrongylides Ignotus. Based on these results the prevalence values obtained for an average of 29.3%. In this study, found a single L3 Pingus sinensis infection with a prevalence rate of 4% and a single infection L4 Eustrongylides Ignotus infection rate of 8%. While the prevalence of infection mixture L3 Pingus sinensis and L4 Eustrongylides Ignotus by 16%. These results indicate that the helminth Pingus sinensis and Eustrongylides Ignotus often infects the eel.
The effect of hydrochloric acid concentration and temperature demineralization on characteristics of chitin from penshell (Atrina pectinata)
Authors: Nugroho I L , Masithah E D , Pursetyo K T
Published: February 2020

This study aims to determine the effect of HCl concentration and temperature affect chitin characteristics as the result of demineralization process from penshells. This study uses Completely Randomized Design (CRD) factorial consisting. The method based on two steps, there are demineralization and deproteination. This study aims to determine the effect of HCl concentration and temperature on chitin characteristics as the result of demineralization process for penshells. This study used Completely Randomized Design (CRD) with two factors, including HCl concentration (2N, 4N, and 6N) and temperature (33°C and 60°C) which consists six combination treatments and three replications. Data was analyzed by analysis of variance (ANOVA) and followed by Duncan’s Multiple Range Test to determine differences between treatments. The results showed that interaction of HCl concentration and temperature has significant effect (p⌄0.05) to ash content of chitin. The use concentration of 6N and 33°C produces low ash content. Characteristics chitin resulted from the treatment of 6N and 33°C produces ash content 25.33%±6.82, moisture content 3.67%±1.10, yield 0.72%±0.12 and protein content 5.86 %.
Difference in the Level of p-Selectin Blood Edge between Uni-Valvular and Multivalvular in Rheumatic Heart Disease
Authors: Filianovika F , Lefi A , Romdoni R , Ramadhan M F
Published: February 2020

Rheumatic heart disease remains a major medical problem of children and young adults. Rheumatic heart disease is sequelae of acute rheumatic fever, a bacterial infection Group A beta Hemolitiycus streptococci (GAS) in the pharynx. It is based on genetic predisposition and an autoimmune process causing defect of heart valves, hemodynamic changes, endothelial damage. Further, it is usually illustrated by elevated levels of P selectin. This study was conducted to prove the difference between peripheral P selectin level in multivalve and univalve (mitral stenosis) in rheumatic heart disease. This cross sectional study involving 37 RHD patients consists of 18 univalve (mitral stenosis), 19 multivalve, and 22 healthy controls. P selectin levels were collected through peripheral vein and echocardiography was performed. Peripheral P selectin was significantly higher in univalve and multivalve rheumatic heart disease than normal. Peripheral P selectin in multivalve group was higher than univalve group (2,384ng/mL vs 2,028ng/mL; ρ < 0.05). There was significant difference of peripheral P selectin between multivalve and univalve (mitral stenosis). P selectin potentially has an important role as an indicator of inflammation and progression of valve damage in mitral stenosis, rheumatic heart disease.
Association between White Blood Cell to Mean Platelet Volume Ratio (WMR) with Troponin for Refractory Angina Prediction in NSTE-ACS patients
Authors: Hermawati I E , Assegaf M Y
Published: February 2020

Hematological parameters provide independent information as well as troponin in non-ST-Elevation-Acute-Coronary-Syndrome (NSTE-ACS) patient. Refractory angina in NSTE-ACS patients significantly transforms this optimal management due to risk enhancement. This study aims to prove the association of white blood cell (WBC) to mean platelet volume ratio (WMR) with troponin and authenticate the best parameter for refractory angina prediction in NSTE-ACS patients. This observational study was conducted in ICCU Dr. Soetomo General Hospital, Surabaya. There were 49 NSTE-ACS patients recruited as the study subject. Complete Blood Count (CBC), High Sensitivity Cardiac Troponin I (hs-cTnI) and CKMB examinations were conducted at the time of admission. We observed angina symptom for three months. The mean age of the patients was 60.8±8.67 years, and 75.5% of them were male. Elevated hs-cTnI level was found in 83.7% of study subjects. WMR significantly correlated with hs-cTnI (r=0.434 p=0.002). Refractory angina was found in 14.3% of study subjects. There was a positive moderate correlation of WMR and refractory angina (r=0.534 p=0.000), a positive moderate significant correlation of hs-cTnI and refractory angina (r=0.470 p=0.001). No significant correlation of other parameters. This study proved that WMR was an independent hematological predictor for refractory angina event in NSTE-ACS patients with higher significance level than hs-cTnI.
Correlation between Left Ventricular Function with Functional Capacity in Post Infarct Myocard Patients with Heart Failure
Authors: Sudirman I , Pikir B S , Rinjani L G P
Published: February 2020

In myocardial infarct patient with heart failure, left ventricular (LV) function evaluation after myocardial infarction provides prognostic information. However, the relationship between exercise capacity and LV function has not been fully explored. This study aims to analyze the correlation of LV function with functional capacity in acute myocardial infarct patient with heart failure. From 33 patients who fulfilled the inclusion and exclusion criteria, treadmill and echocardiography were examined (LVEDd, myocardial performance index (MPI), E/E’ diastolic function, LV Stiffness). The results are then statistically analyzed using SPSS. The mean LV ejection fraction is 44.27 ± 9.0% by Teich, and 40.55 ± 8.3% by Biplane. The value of the global MPI function is (0.60-0.90). The average E/A ratio is 1.0 ± 0.5, deceleration time (DT) is > 220m / sec, and E / E ratio is 11.46 ± 5.82ms. The functional capacity value is 3.4 (1.1-8.4) METS. There is a significant positive correlation of LV systolic function and functional capacity and significant negative correlation between MPI and functional capacity in myocardial infarct patients with heart failure. Furthermore, there is a non-significant correlation between diastolic function and functional capacity.
Levofloxacin and Drug-Induced Long QT Syndrome (diLQTS): The Incidence and How to Prevent It
Authors: Catelya L G , Tjahjono C T , Hanafi A
Published: February 2020

Levofloxacin is a fluoroquinolone antibiotic which is used widely in treating various infections. Despite this benefit, Levofloxacin has a cardiac side effect called drug-induced long QT syndrome (diLQTS), which is associated with Torsades de Pointes (TdP). In this study, our objective was to analyze the incidence of diLQTS associated with Levofloxacin use in Ahmad Dahlan Hospital Kediri. This study included patients who were admitted to Ahmad Dahlan Hospital Kediri from March-May 2019 and received Levofloxacin 500mg therapy once daily. An electrocardiogram was performed before and after initiation of therapy. Prolonged QTc was defined by heart rate-corrected QT ≥450ms for male and ≥470ms for female, calculated using Bazett formula; or if the prolongation of QT interval is >60ms from baseline. Acquired data were analyzed using Paired T-test. Of all 24 patients who received Levofloxacin, six patients developed long QTc. Two of which had >60ms difference from base ECG (p-value >0.05). No symptom of TdP was reported. The incidence of diLQTS associated with Levofloxacin use was 25%. Risk factor stratification and ECG monitoring should be done from the beginning of the therapy.