bluuebunny/crossref_metadata_2025 huggingface dataset:
N-Heterocyclic Carbene Catalyzed Stereoselective Synthesis of 2-Nitro-thiogalactosides
Authors: Hu Yu-Long , Gou Bo-Bo , Wang Jiao , Zhao Ming , Liu Jia-Lin , Chen Jie , Zhou Ling
Published: June 2019

A highly selective NHC-catalyzed Michael addition of alkanethiols or thiophenol to 2-nitro-d-galactal compounds for the synthesis of 2-nitro-thiogalactoside derivatives has been developed for the first time. A wide variety of 1,2-cis-2-nitro-thiogalactosides can be prepared in good to excellent yields and high to excellent α-selectivities.
1-Nicotinoylbenzotriazole: A Convenient Tool for Site-Selective Protection of 5,7-Dihydroxycoumarins
Authors: Fatykhov Ramil F. , Khalymbadzha Igor A. , Chupakhin Oleg N. , Charushin Valery N. , Inyutina Anna K. , Slepukhin Pavel A. , Kartsev Victor G.
Published: June 2019

1-Nicotinoylbenzotriazole (NicBt) was uncovered as an efficient protecting agent for the site-selective acylation of resorcinol-type phenolic groups with almost equal reactivity. The use of NicBt allows selective protection of the 7-OH group in 5,7-dihydroxycoumarins in one simple scalable step, while combination of the nicotinoylation with tosylation–denicotinoylation or silylation–denicotinoylation yields 5-OH-protected 5,7-dihydroxycoumarins. Furthermore, nicotinoylated 5,7-dihydroxycoumarins proved useful in a gram-scale three-step preparation of a 2,2-dimethylpyrano[2,3-f]coumarin, a key intermediate for the synthesis of calanolide A, an HIV reverse transcriptase and Mycobacterium tuberculosis inhibitor, and its active analogues.
Introduction of Group Discussion as a Teaching—Learning Method in Dissection Hall for the First MBBS Students
Authors: Tandel Mehul , Kanjiya Daxa , Vedi Neeraj , Sharma Deepak , Singh Praveen ,   Sumati
Published: June 2019

Background Human cadaveric dissection is considered as a core teaching tool and plays a major role in active learning process of students. However, students’ active participation and self-directed learning in dissection hall has declined over the period of time. Group discussion in dissection hall allows students to participate actively, engage in cooperative interaction, communicate effectively, and utilize self-directed learning. Therefore, group discussion has been introduced and assessed as a teaching-learning method in dissection with the aim of improving participation, learning, and communication skill of students in dissection hall.

Methods This study was conducted on 100 students of Pramukhswami Medical College, Karamsad, Anand, Gujarat, India, during the 2018–2019 academic year. Students were divided in 10 groups for dissection. Group discussion was introduced as a teaching-learning method and assessed during dissection. Data were collected through anonymous feedback and then statistically analyzed.

Result There was significant increase in active participation of most students during dissection: 79% students rated this method as good or excellent; 51 to 74% students agreed that this method helped them in better understanding of subject, improving dissection skills and communication; and 68% students agreed that working in group is better as compared with traditional method of dissection. The Cronbach's alpha of feedback questionnaire was 0.816.

Conclusion Students perceived that the group discussion during dissection not only helped in creating active participation and better understanding of subject but also helped improve learning, communication, and dissection skills.
Minithoracotomy and Beating Heart Strategy for Mitral Surgery in Secondary Mitral Regurgitation
Authors: Grinberg Daniel , Pozzi Matteo , Bordet Marine , Nouhou Kaled Adamou , Kwon Young Joon , Obadia Jean-François , Vola Marco
Published: June 2019

Background In patients with secondary mitral regurgitation (MR) associated with low ejection fraction or previous heart surgery, minimally invasive mitral valve surgery without aortic cross-clamp (MIMVS-WAC) has shown promising results. We report our experience for this strategy in our centers.

Methods Between August 2011 and April 2017, 46 patients (mean age 69 ± 11 years, 76% males) received MIMVS-WAC. Indications for this technique were prior coronary bypass surgery (26%), severe or recent left ventricular (LV) dysfunction (30%), or both (39%). The mean EuroSCORE II was 12 ± 10.

Results For each procedure, we conducted right minithoracotomy and hypothermic cardiopulmonary bypass (CPB) after peripheral cannulation. Mean CPB time was 159 ± 39 minutes. A mitral valve replacement (MVR) was performed in 23 cases (50%), an annuloplasty in 22 cases (48%), and a prosthesis pannus removal in 1 case (2%). Mean hospital length of stay was 12 ± 5.4 days. We report no sternotomy conversions, six reoperations for bleeding, and three deaths at 30 days. Transfusion was requested in 62% (mean infusion 2 ± 2.4 packed red blood cells). The postoperative echocardiography showed an LV function preservation in 69% of cases and a reduction of pulmonary arterial pressure in 73% of cases. Four additional deaths occurred in the long-term follow-up (mean 637 ± 381 days, median 593 days). No mitral reoperation was required, with a MR ≤ 2 in 90% of patients.

Conclusion In high-risk patients, the MIMVS-WAC is a safe technique. It avoids hard dissections while ensuring excellent preservation of cardiac function.
Clinical Findings, Treatments and Outcomes in Farm Animals with Vertebral Fractures or Luxations: 22 Cases (2006–2017)
Authors: Boorman Sophie , Johnson Amy L. , Schaer Thomas P. , Fecteau Marie-Eve
Published: June 2019

Objective The aim of this study was to describe the signalment, clinical presentation, diagnostic findings, medical and surgical treatment and outcome of 22 farm animals diagnosed with a vertebral fracture or luxation.

Study design Medical records of 22 farm animals (7 goats, 6 alpacas, 5 cattle, 3 sheep and 1 deer) were reviewed for signalment, history, presenting clinical signs and neurological examination findings, clinicopathological results, diagnostic imaging, final diagnosis, medical and surgical management, clinical progression and outcome.

Results Animals' age ranged from 1 day to 15 years. Neurological examination findings included decreased motor function (20/22), recumbency (14/22), altered mentation (13/22), cranial nerve deficits (4/22) and lack of nociception (3/22). Lesions were localized to the atlanto-occipital region (2/22), C1 to C5 (7/22), C6 to T2 (4/22), T3 to L3 (3/22), and L4 to S1 (6/22). Diagnoses included vertebral fracture only (4/22), luxation only (5/22) or both vertebral fracture and luxation (13/22). In five cases, no therapy was attempted, while 12 cases were treated medically and five cases were treated surgically. Surgical interventions included manual reduction (n = 1); arthrodesis (n = 2); laminectomy (n = 1); and laminectomy with pin fixation, cerclage wire and polymethylmethacrylate bridging (n = 1). Five of the 22 cases survived to hospital discharge; two of these were treated surgically.

Conclusion The cervical region was most commonly affected. Prognosis for these injuries in farm animals is guarded.
A High Prevalence Rate of Tibia Hemimelia in a Subregion of West Azarbaijan, Iran
Authors: Taleb Hasan , Afshar Ahmadreza , Abdi rad Isa , Tabrizi Ali , Ghazani Reza Babaei , Bateni Amin
Published: June 2019

From 1995 to 2017 an abnormally high number of tibia hemimelia (TH) patients from the Maku subregion in the West Azarbaijan province of Iran were referred to our orthopedic department for treatment. Regarding the occurrence of TH in many families in a restricted region and negative results of available genetic tests, we hypothesized that a founder mutation etiology that is different from previous known genetic disorders might produce the trait of TH in our patients. Through a retrospective study, we collected demographic data including date of birth, patients and parents place of birth, sex, type of TH, presence of other musculoskeletal anomalies, and treatment from the patients who were referred to our department. We obtained a blood sample for genetic studies. We carried out genetic studies in cytogenetics and molecular levels on a patient with familial TH. The prevalence of TH in the Maku subregion of West Azarbaijan was 149.5 (95% confidence interval [CI]: 68.4–283.8) per 1 million live birth. The patients did not fit with any known syndromes with TH. Genetic evaluations of a patient with familial history of TH in this case series exhibited no detectable change in both cytogenetic and molecular levels. There was an obvious increased prevalence rate of TH in this province and particularly in the Maku subregion. The cytogenetic locations for known syndromic TH are not responsible for the observed anomalies in our patients. Our next step for detecting possible genetic mutations in our patients would be mutation analysis via very high-resolution whole genomic sequencing in more patients or genetic linkage study.
Measurement of yield and spectrum of secondary electron emission and their characteristics under modification of conductive materials
Authors: He Jialong , Yang Jie , Peng Yufei , Long Jidong , Yang Zhen , Wang Tao , Liu Ping , Li Jie , Zheng Le , Dong Pan , Li Xi , Lan Chaohui , Zhao Wei , Liu Erxiang , Shi Jinshui
Published: June 2019

Surface modification technique of secondary electron emission (SEE) characteristics of materials, which is utilized to suppress or promote the SEE from material surface under electron bombardment, has extensive applications in a variety of fields. Measurement of the secondary electron yield (SEY) and the secondary electron spectrum (SES) before and after surface modification is essential for the evaluation of effectiveness and the investigation of mechanism of material modification. A SEY and SES measurement system is reported in this article. The comparative measurements of the total SEY, the true SEY, the backscattered electron yield, and the SES of nickel and free-standing vertical graphene, which was grown in situ on the surface of nickel substrate by plasma enhanced chemical vapor deposition, were performed using this system. The measurement results demonstrate that this system could facilitate the study of surface modification on the SEE characteristics of conductive materials.
Explosive death in complex network
Authors: Verma Umesh Kumar , Sharma Amit , Kamal Neeraj Kumar , Shrimali Manish Dev
Published: June 2019

We report the emergence of an explosive death transition in a network of identical oscillators interacting to other oscillators through nonlocal coupling in the presence of a common environment. This transition has an abrupt and irreversible characteristic in parameter space which has been a common signature of first order phase transition. For the similar coupling scheme, both ensemble of chaotic and periodic oscillators showed qualitatively similar kind of transition, hence making it a universal transition. The details of which along with dependence of environmental and nonlocal coupling on this first-order like phase transition is also discussed.
A data-driven approach to model calibration for nonlinear dynamical systems
Authors: Greve C. M. , Hara K. , Martin R. S. , Eckhardt D. Q. , Koo J. W.
Published: June 2019

A data-driven approach to model calibration is developed to accurately obtain the input parameters for nonlinear dynamical systems. The paper focuses on the convergence properties of the proposed method, which play a significant role in understanding the validity and usefulness of any data-driven model. The input parameters of nonlinear dynamical systems are optimized to a reference solution, which can be experimental data or results from a high-fidelity computer simulation, using the Wasserstein metric and a phase-space representation of a set of time-dependent signals. Test cases shown in this paper include the Lorenz system and the discharge plasma of a Hall effect thruster to characterize the numerical uncertainties of the proposed data-driven approach, given a constructed reference solution. Distinct wells in the cost function, the Wasserstein metric, are obtained relative to the reference solution, illustrating the applicability of the proposed method to dynamical problems. The numerical uncertainties associated with the phase-space portrait and sampling time are discussed.
Infrared optical anisotropic properties and photocarriers lifetime in 2D black phosphorus by angle-resolved absorption and reflectometry
Authors: Penillard A. , Beccacce L. , Billot L. , de Rossi A. , Combrié S. , Holé S. , Géron E.
Published: June 2019

In this article, angle and polarization-resolved absorption and time-resolved pump-probe measurements have been carried out on multilayer black phosphorus (BP) at infrared wavelength (around 1550 nm), which is an extension of the previous studies of the BP behavior done at higher frequency [Lazar et al., Nanoscale 10(19), 8979–8988 (2018)]. Exfoliated down to a few layers, BP reveals the properties of a 2D material with anisotropic response, high mobility (up to 10 000 cm2/V/s), and absorption, which are very relevant to optoelectronics. BP bandgap is tunable according to the number of layers, allowing applications from UV to IR. The bandgap height of the single and thicker layers has been measured through absorption and reflection spectra. We report the measurement of the ambipolar carrier lifetime, which has been determined to be about 15 ps. The structure-induced anisotropy is studied. The results confirm BP as a suitable material for ultrafast devices such as microwave photoswitches, samplers, terahertz antenna, for instance.
Small-angle neutron polarimetry apparatus (SANPA): Development at the NIST Center for Neutron Research
Authors: Tosado J. , Chen W. C. , Gnewuch S. , Hasaan T. , Dax T. , Rodriguez E. E.
Published: June 2019

Spherical neutron polarimetry directly measures the rotation of the neutron polarization after scattering from materials with magnetic structure. It is an under utilized measurement technique that is capable of measuring all nine elements of the polarization tensor of a material. In this article, we describe our new cryogen-free small-angle neutron polarimetry apparatus and infrastructure at the NIST Center for Neutron Research. The resulting apparatus is capable of continuous operation and is designed for measurements at low temperatures (4–8 K) using niobium Meissner shielding and mu-metal shielding to produce a zero-field (≤1 μT) cooling sample environment.
B-site disorder driven multiple-magnetic phases: Griffiths phase, re-entrant cluster glass, and exchange bias in Pr2CoFeO6
Authors: Pal Arkadeb , Singh Prajyoti , Gangwar V. K. , Ghosh Surajit , Prakash P. , Saha S. K. , Das Amitabh , Kumar Manoranjan , Ghosh A. K. , Chatterjee Sandip
Published: June 2019

The magnetic spin ordering and the magnetization dynamics of a double perovskite Pr2CoFeO6 have been investigated by employing the (dc and ac) magnetization and neutron powder diffraction techniques. The study revealed that Pr2CoFeO6 adopted a B-site disordered orthorhombic structure (Pnma). Furthermore, ab initio band structure calculations suggested an insulating antiferromagnetic ground state. Magnetization measurements revealed that the system possesses a spectrum of competing magnetic phases, viz., long range canted antiferromagnetic (AFM) spin ordering (TN ∼ 269 K), Griffiths-like phase, re-entrant cluster glass (TG ∼ 34 K), and exchange bias effects. The neutron diffraction study divulged the exhibition of a long range G-type of canted AFM spin ordering. The random nonmagnetic dilution of magnetic Fe3+ (high spin) ions by Co3+ (low spin) ions due to B-site disorder essentially played a crucial role in manifesting such magnetic properties of the system.
Strain-modulated early stage oxidation of Fe films
Authors: Wu Yihan , Yu Wenshan , Shen Shengping
Published: June 2019

The way in which external loading influences the oxidation kinetics and oxide structure evolution is important for understanding the initial oxidation of metal surface. Here, we demonstrate that prestrain is capable of modulating the oxidation of Fe (100), (110), and (111) surfaces using molecular dynamics simulations. It is found that oxygen preferentially occupies tetrahedral sites of the Fe lattice during oxidation, leading to a unique BCC-to-FCC transformation of Fe, particularly for the (100) surface. Moreover, whether the ordered-to-disordered oxide structure transformation occurs or not depends on prestrain and surface indices. The prestrain changes the order of oxidation rates among three surfaces. We establish correlations between structure, internal stress, and oxidation kinetics and further validate them by our proposed theoretical models. Finally, the diffusivities of Fe and O in FexOy are found to be extremely low at y:x = 1:1. This suggests that the formation of FeO may prevent more oxygen from reaching the unoxidized Fe side, and thus may impede further oxidation of Fe. The findings presented in this work may provide new insights into the nanoscale strain-modulated oxidation of iron.
An objective version of the Rortex vector for vortex identification
Authors: Liu Jianming , Gao Yisheng , Liu Chaoqun
Published: June 2019

Vortices are a ubiquitous natural phenomenon, and their structure, shape, and characteristics should be independent of the observer, which implies that the vortex identification method or vortex definition should maintain its objectivity. Currently, most of the vortex identification methods rely on velocity gradient tensors. The calculation of the velocity gradient tensor is based on the reference frame of the observer, and the velocity gradient tensor will vary with the observer’s motion. By these vortex identification methods, very different vortex structures could be visualized and described in a moving reference frame. Recently, a mathematical definition of the Rortex vortex vector was proposed to represent the local fluid rotation. The definition used velocity gradient tensor to derive the local rigid rotation axis and strength. However, the original definition of the Rortex vector is nonobjective. In order to obtain the objectivity, in this paper, by a definition of a net velocity gradient tensor, an objective Rortex vortex vector is defined which uses a spatially averaged vorticity to offset the impact of the motion frame. Some typical numerical examples, such as an implicit large-eddy simulation result for shock and boundary layer interaction and a direct numerical simulation for boundary layer transition, are provided to show the objectivity of the developed method.
Kinetics model of femtosecond laser ionization in nitrogen and comparison to experiment
Authors: Peters Christopher J. , Shneider Mikhail N. , Miles Richard B.
Published: June 2019

A zero-dimensional kinetics simulation of femtosecond laser ionization in nitrogen is proposed that includes fast gas heating effects, electron scattering (elastic and inelastic) rate coefficients from BOLSIG+, and photoionization based on filamentation theory. Key rate coefficients possessing significant uncertainty are tuned (within the range of variation found in the literature) to reproduce the time-varying signal acquired by a bandpass-filtered photomultiplier tube with good agreement up to several hundred nanoseconds. Separate spectral measurements calibrate the relative strength of signal components. Derived equations relate the model to experimental measurements in absolute units. Reactions contributing to the rate of change of important species are displayed in terms of absolute rate and relative fraction. In general, decreasing the gas density lengthens the duration of early reactions and delays the start of later reactions. The model agrees with data taken in a variable temperature and pressure free jet by an intensified camera. Results demonstrate that initial signal depends primarily on gas density and secondarily on gas temperature. The initial signal is optimized (maximized) at subatmospheric conditions. Decreases in gas density alter the evolution of excited-state populations, postponing the peak (while reducing its value) and slowing the rate of decay. For the optimal case, populations are favorably shifted in time with respect to the gate delay (and width) to boost the signal. Reductions in gas temperature generally enhance initial signal due to elevated dissociative recombination of cluster ions (along with excited-state coupling from quenching and energy pooling).
Deep-ocean inertial subrange small bandwidth coherence and Ozmidov-frequency separation
Authors: van Haren Hans
Published: June 2019

The inertial subrange of turbulence in a density stratified environment is the transition from internal waves to isotropic turbulence, but it is unclear how to interpret its extension to anisotropic “stratified” turbulence. Knowledge about stratified turbulence is relevant for the dispersal of suspended matter in geophysical flows, such as in most of the ocean. For studying internal-wave-induced ocean-turbulence, moored high-resolution temperature (T-)sensors are used. Spectra from observations on episodic quasiconvective internal wave breaking above a steep slope of large seamount Josephine in the Northeast-Atlantic demonstrate an inertial subrange that can be separated in two parts: A large-scale part with relatively coherent portions adjacent to less coherent portions and a small-scale part that is smoothly continuous (to within standard error). The separation is close to the Ozmidov frequency and coincides with the transition from anisotropic/quasideterministic stratified turbulence to isotropic/stochastic inertial convective motions as inferred from a comparison of vertical and horizontal cospectra. These observations contrast with T-sensor observations of shear-dominated internal wave breaking in an equally turbulent environment above the slope of a small Mid-Atlantic ridge-crest, which demonstrate a stochastic inertial subrange throughout.
Propagation of surface plasmons on plasmonic Bragg gratings
Authors: Chaves A. J. , Peres N. M. R.
Published: June 2019

We use coupled-mode theory to describe the scattering of a surface-plasmon polariton (SPP) from a square-wave grating (Bragg grating) of finite extension written on the surface of either a metal-dielectric interface or a dielectric-dielectric interface covered with a patterned graphene sheet. We find analytical solutions for the reflectance and transmittance of SPPs when only two modes (forward- and back-scattered) are considered. We show that in both cases, the reflectance spectrum presents stop-bands where the SPP is completely back-scattered, if the grating is not too shallow. In addition, the reflectance coefficient shows Fabry-Pérot oscillations when the frequency of the SPP is out of the stop-band region. For a single dielectric well, we show that there are frequencies of transmission equal to 1. We also provide a simple analytical expression for the different quantities in the electrostatic limit.
Exact and asymptotic solutions to magnetohydrodynamic flow over a nonlinear stretching sheet with a power-law velocity by the homotopy renormalization method
Authors: Kai Yue , Zheng Bailin , Zhang Kai , Xu Wenlong , Yang Nan
Published: June 2019

We apply an asymptotic analysis to a nonlinear magnetohydrodynamic boundary-layer flow over a nonlinear stretching sheet with two types of boundary conditions: slip and no-slip. The original partial differential equations governing the flow regime are first transformed into a nonlinear ordinary equation by using a special type of similarity transformation. Asymptotic solutions are then obtained in simple explicit form via the homotopy renormalization method. These solutions satisfy the boundary conditions, and, for special values of the parameters, the asymptotic solutions are just the exact solutions. In addition, the impacts of the magnetic energy effect, the electrical conductivity, and the slip boundary are shown graphically. The validity of the asymptotic solutions is evaluated by comparison with numerical solutions. The results show that the explicit solutions, with finite numbers of terms, perform very well over the whole domain, indicating that our solutions are almost exact.
In situ TEM study of the transitions between crystalline Si and nonstoichiometric amorphous oxide under bipolar voltage bias
Authors: Tian Xinchun , Ma Tao , Zhou Lin , Brennecka Geoff , Tan Xiaoli
Published: June 2019

The electrical responses, either structurally or chemically, at the interface between a SiO2 thin film and a single crystalline Si substrate are an important research subject in Si-based devices. Dielectric breakdown-induced epitaxial migration of Si into SiO2 has been reported as a degradation mechanism in field effect transistors. Here, we show a direct observation of electric field induced conversion of single crystalline Si to nonstoichiometric amorphous oxide starting from the Si/native oxide interface using in situ transmission electron microscopy. We further show that nanocrystalline Si can form in the amorphous oxide under a voltage bias of reversed polarity. Electron energy loss spectroscopy and energy dispersive X-ray spectroscopy analyses indicate that the observed amorphization process was caused by the oxidation of Si and the recrystallization process was caused by the reduction of nonstoichiometric amorphous silicon oxide. Both transitions are a result of field-driven directional migration of oxygen which originally comes from its native oxide layer.
Double- and multi-slit interference in photodetachment from nanometer organic molecular anions
Authors: Liu Yuan , Ning Chuan-Gang , Wang Lai-Sheng
Published: June 2019

We present the predictions of double-slit and multislit interference of photoelectrons from a nanometer-size molecular negative ion. The interference clearly appears in both photoelectron angular distributions and photodetachment cross sections. In contrast to the diatomic photoelectron interference via the X-ray photon, the interference in the nanometer-size negative ions can be readily observed via a visible or extreme ultraviolet laser. Therefore, the phenomenon can be realized on a table-top setup, instead of a large accelerator.
Plastic-crystalline solid-state electrolytes: Ionic conductivity and orientational dynamics in nitrile mixtures
Authors: Reuter D. , Lunkenheimer P. , Loidl A.
Published: June 2019

Many plastic crystals, molecular solids with long-range, center-of-mass crystalline order but dynamic disorder of the molecular orientations, are known to exhibit exceptionally high ionic conductivity. This makes them promising candidates for applications as solid-state electrolytes, e.g., in batteries. Interestingly, it was found that the mixing of two different plastic-crystalline materials can considerably enhance the ionic dc conductivity, an important benchmark quantity for electrochemical applications. An example is the admixture of different nitriles to succinonitrile, the latter being one of the most prominent plastic-crystalline ionic conductors. However, until now, only few such mixtures were studied. In the present work, we investigate succinonitrile mixed with malononitrile, adiponitrile, and pimelonitrile to which 1 mol. % of Li ions was added. Using differential scanning calorimetry and dielectric spectroscopy, we examine the phase behavior and the dipolar and ionic dynamics of these systems. We especially address the mixing-induced enhancement of the ionic conductivity and the coupling of the translational ionic mobility to the molecular reorientational dynamics, probably arising via a “revolving-door” mechanism.
Alkali-Metal Modification of Li(Ni0.33Mn0.33Co0.33)O2
Authors: Wu Jimmy , Sharma Neeraj
Published: June 2019

Layered lithium transition metal oxides are widely used as cathodes in lithium-ion batteries and are continuously being developed to provide more energy. Here, the synthesis and structure of Li(Ni0.33Mn0.33Co0.33)O2, ‘Li0.9K0.1(Ni0.33Mn0.33Co0.33)O2’, and ‘Li0.9Cs0.1(Ni0.33Mn0.33Co0.33)O2’ are characterised in detail and compared with similar studies in the literature. Structural models are evaluated based on the statistical quality of fitting via the Rietveld method with X-ray diffraction data and the use of a range of starting structural models. Critically, this work highlights that the larger alkali atoms do not dope on to the Li sites but rather are likely to be distributed on the surface of the particles which is also evidenced with electron microscopy. This work showcases that care must be taken by researchers when using such doping regimes and the concentration of the dopants.
Multilayered surface for the interactive separation of perchlorate from aqueous medium
Authors: Shalumon C. S. , Aravindakumar Charuvila T. , Aravind Usha K.
Published: June 2019

Environmental contextPerchlorate from rocket fuel plants or firework manufacturing units can seriously contaminate drinking water. We developed a separation skin on a microfiltration membrane and on sand that can remove perchlorate from water in the presence of competing ions. This method is suitable for a domestic water purification unit selective for perchlorate removal.
AbstractThis study reports an interactive separation of perchlorate (ClO4−) by polyethyleneimine (PEI) and poly (styrene sulfonate) (PSS) deposited on a microfiltration membrane and on sand surfaces. The variation of the interaction with respect to deposition and feed variables was assessed. The 9 bilayered ((PEI/PSS) 0.15M NaCl, pH 6)) membranes showed a ClO4− rejection of ~80%. An increase in the feed concentration to 25mgL−1 reduced the rejection to 58%. With a feed pH from 4 to 10, the rejection varied between almost 100% and 16%. The presence of ions reduced the rejection percentage of ClO4− with the interference by the ions in the order of SO42−>HCO3−>NO3−>Cl−. The interference is attributed to the characteristics of the competing ions and the nature of the multilayers. A positive impact of post-treatment (98%) and capping layers on rejection percentage (80% to nearly complete) for synthetic and ClO4− contaminated field water samples is clearly established. The presence of competing ions is also accounted for by a capped membrane system. The selectivity of the competing ions increases with capping layers of 1M NaCl in the order of HCO3−>NO3−>SO42−. In the field water samples up to a SO42− concentration of 3.0mgL−1, the capping layers with 0.4M NaCl result in a near complete rejection of ClO4−, whereas further enhancement requires a capping layer of 1M NaCl. A sand filtration system was developed by incorporating the pre-optimised polyelectrolyte multilayer on sand. Deposition of a single bilayered PEI/PSS multilayer on sand effectively (nearly completely) removes ClO4−.
An environmentally friendly method for the determination of polycyclic aromatic hydrocarbons in different soil typologies
Authors: De Nicola Flavia , Concha-Graña Estefanía , Picariello Enrica , Memoli Valeria , Maisto Giulia , López-Mahía Purificación , Muniategui-Lorenzo Soledad
Published: June 2019

Environmental contextPolycyclic aromatic hydrocarbons (PAHs) are widespread organic pollutants that tend to accumulate in soil. We developed an environmentally friendly analytical method for PAHs to evaluate human health risks associated with their presence in soils. The method is feasible for the analysis of soils with widely varying PAH contamination levels, and is well suited to environmental monitoring studies of relevance to human health.
AbstractA microwave-assisted extraction, with a dispersive solid-phase purification step followed by programmed temperature vaporisation–gas chromatography–tandem mass spectrometry, is proposed as an environmentally friendly, simple and cheap analytical method for polycyclic aromatic hydrocarbons (PAHs) in soil. Different extraction and clean-up operating variables were tested to achieve satisfactory analytical performances: trueness from 92 to 114%, limit of quantification (LOQ) from 0.4 to 2µgkg−1 for most PAHs and intermediate precision, calculated as relative standard deviation (RSD), below 10%. The method was validated using both Certified Reference Material and real soil samples collected at sites subjected to different human activities. PAH contents ranged from 0.11 (in holm oak forest soil) to 1mgkg−1 d.w. (in an industrial soil) according to the anthropic gradient. The soil PAH contents measured were used to estimate the risk to human health, which suggested the exposure to the PAHs in soil as a potential risk for human health, especially at the industrial site. The feasibility of the method for soils with different PAH contamination degrees makes it relevant in monitoring programs.
Cognitive and speech perception outcomes after cochlear implantation in Fabry disease
Authors: Aslan Filiz , Yıldırım Mehtap , Sennaroğlu Gonca
Published: June 2019

Purpose:

To study the audiological, rehabilitative and cognitive outcomes of cochlear implantation in patients with Fabry disease (FD).

Method:

This is a retrospective case study. Two adults with progressive hearing loss were followed up for over 3 years.

Results:

The patients had progressive hearing loss from the first decade of life. Preoperative evaluations indicated delays in speech perception and cognitive skills due to hearing loss. There was a significant increase in hearing thresholds and speech perception in both patients after the cochlear implantation. The cognitive skills and memory skills of the patient who started using the cochlear implant later in life continued to lag.

Conclusion:

In FD, hearing loss should be closely monitored and appropriate interventions should be selected early. Two patients from the same family showed the strong impact of early intervention on speech perception and cognitive skills. The study aimed to emphasize the necessity of speech perception and cognitive skills assessment during the follow-up of patients with FD.
Increasing N content in GaNAsP nanowires suppresses the impact of polytypism on luminescence
Authors: Jansson Mattias , Francaviglia Luca , La Rui , Balagula Roman , Stehr Jan E , Tu Charles W , Fontcuberta I Morral Anna , Chen Weimin M , Buyanova Irina A
Published: June 2019

Cathodoluminescence (CL) and micro-photoluminescence spectroscopies are employed to investigate effects of structural defects on carrier recombination in GaNAsP nanowires (NWs) grown by molecular beam epitaxy on Si substrates. In the NWs with a low N content of 0.08%, these defects are found to promote non-radiative (NR) recombination, which causes spatial variation of the CL peak position and its intensity. Unexpectedly, these detrimental effects can be suppressed even by a small increase in the nitrogen composition from 0.08% to 0.12%. This is attributed to more efficient trapping of excited carriers/excitons to the localized states promoted by N-induced localization and also the presence of other NR channels. At room temperature, the structural defects no longer dominate in carrier recombination even in the NWs with the lower nitrogen content, likely due to increasing importance of other recombination channels. Our work underlines the need in eliminating important thermally activated NR defects, other than the structural defects, for future optoelectronic applications of these NWs.
Impact of a REBCO coated conductor stabilization layer on the fault current limiting functionality
Authors: Búran Marek , Vojenčiak Michal , Mošať Marek , Ghabeli Asef , Solovyov Mykola , Pekarčíková Marcela , Kopera Ľubomír , Gömöry Fedor
Published: June 2019

Reliability is one of the crucial requirements of conductors used in resistive superconducting fault current limiters. Possible critical current degradation of a REBCO coated conductor during the limiter operation restrains broader application of devices based on these conductors. In this article the impact of an electrical stabilization layer on the conductor protection against overheating as well as its effect on electrical current evolution during the limitation period are investigated. For the experimental part of the study, a commercial copper stabilized REBCO coated conductor and a modified conductor without copper stabilization are compared. Extensive experimental work complemented by electro-thermal numerical modeling paved the way for studying the electrical and thermal effects separately. The numerical model assuming adiabatic conditions is sufficient to reproduce experimental results and predict the peak temperature for conductors with various stabilization layers in realistic conditions. Reduction of the conductor critical current caused by multiple current limitation pulses was studied using pulses with various durations. It was observed that the degradation due to temperature rise is gradual with the rate depending solely on the peak temperature. It is this quantity through which other parameters like the pulse duration, the thickness of stabilization and the peak current cause the tape damaging.
Long-length YBCO coated conductors for ultra-high field applications: gaining engineering current density via pulsed laser deposition/alternating beam-assisted deposition route
Authors: Usoskin Alexander , Betz Ulrich , Gnilsen Johannes , Noll-Baumann Sonja , Schlenga Klaus
Published: June 2019

Gaining engineering critical current density (J

e
) in high-temperature superconducting (HTS) coated conductors based on double-disordered YBCO for operation at high fields is one of the key requirements in upcoming magnet/accelerator projects. Currently, the development of a tape with advanced J

e
-s is performed based on an alternating beam-assisted deposition–pulsed laser deposition (ABAD–PLD) manufacturing route. An obvious way to improve J

e
-s is to reduce substrate thickness. A 40% J

e
increase is expected owing to the thickness reduction from 100 to 50 μm. Nevertheless, the reduction of substrate thickness in case of the applied processing technology that employs relatively thick (2–3 μm) yttria-stabilized zirconia buffer layers leads to the manifestation of considerable strain in the tape resulting in strong tape bowing. Advanced processing routes have been developed to suppress this effect. The highest engineering current density was recorded at well above 1000 A mm−2 under an ultra-high field of 18 T at 4.2 K, B//c. Influence of tape bowing and the impact of longitudinal defects are studied via V–I measurements at 77 K and a moderate magnetic field with intrinsic edge gradients. Potential for further gaining of J

e
was found employing mechanisms of (i) film nucleation from lateral flows that provide material transfer during the PLD process. Further steps include suppressing the instability of instantaneous temperature via quasi-adiabatic pulsed heating of the growing HTS film via (ii) control of laser plume energy, and (iii) energy release during film condensation (condensation enthalpy). These effects disturb the instantaneous temperature of the growing HTS layer, which exhibits very limited capability of heat transfer. Temperature pulses reaching 30–40 K were evaluated via heat transfer modeling. Stabilization of the level of pulsed temperature during layer growth is anticipated to result in a further increase in J

e
.
Interpreting observations of ion cyclotron emission from large helical device plasmas with beam-injected ion populations
Authors: Reman B.C.G. , Dendy R.O. , Akiyama T. , Chapman S.C. , Cook J.W.S. , Igami H. , Inagaki S. , Saito K. , Yun G.S.
Published: June 2019

Ion cyclotron emission (ICE) is detected from all large toroidal magnetically confined fusion (MCF) plasmas. It is a form of spontaneous suprathermal radiation, whose spectral peak frequencies correspond to sequential cyclotron harmonics of energetic ion species, evaluated at the emission location. In ICE phenomenology, an important parameter is the value of the ratio of energetic ion velocity

to the local Alfvén speed

. Here we focus on ICE measurements from heliotron-stellarator hydrogen plasmas, heated by energetic proton neutral beam injection (NBI) in the large helical device, for which

takes values both larger (super-Alfvénic) and smaller (sub-Alfvénic) than unity. The collective relaxation of the NBI proton population, together with the thermal plasma, is studied using a particle-in-cell (PIC) code. This evolves the Maxwell–Lorentz system of equations for hundreds of millions of kinetic gyro-orbit-resolved ions and fluid electrons, self-consistently with the electric and magnetic fields. For LHD-relevant parameter sets, the spatiotemporal Fourier transforms of the fields yield, in the nonlinear saturated regime, good computational proxies for the observed ICE spectra in both the super-Alfvénic and sub-Alfvénic regimes for NBI protons. At early times in the PIC treatment, the computed growth rates correspond to analytical linear growth rates of the magnetoacoustic cyclotron instability (MCI), which was previously identified to underlie ICE from tokamak plasmas. The spatially localised PIC treatment does not include toroidal magnetic field geometry, nor background gradients in plasma parameters. Its success in simulating ICE spectra from both tokamak and, here, heliotron-stellarator plasmas suggests that the plasma parameters and ion energetic distribution at the emission location largely determine the ICE phenomenology. This is important for the future exploitation of ICE as a diagnostic for energetic ion populations in MCF plasmas. The capability to span the super-Alfvénic and sub-Alfvénic energetic ion regimes is a generic challenge in interpreting MCF plasma physics, and it is encouraging that this first principles computational treatment of ICE has now achieved this.
Two 0.5-m robotic telescopes for Timau National Observatory in eastern Indonesia
Authors: Bumbungan M T , Priyatikanto R P , Danarianto M D , Saputra M B , Rohmah F , Murti M D , Mumtahana F , Nurzaman M Z , Legita N D
Published: June 2019

Timau National Observatory will be the new Indonesia’s astronomical observatory in East Nusa Tenggara, planned for 2020. Besides the main 3.8-m optical telescope, it will host two 0.5-m “off-the-shelf” f/3.8 and f/8.0 telescopes, equipped with two CCD cameras and two filter wheels. The system will be controlled with a robotic system for autonomous operation. In this paper, we present the system description and current development progress, as well as the future plan for the facility, including its two potential scientific studies: near-Earth objects and exoplanetary transits.
Diffuse Interstellar Bands (DIBs) as a tracer of warp in the Third Galactic Quadrant: Preliminary Results
Authors: Istiqomah A N , Puspitarini L , Arifyanto M I
Published: June 2019

We measured 6613.6 Å diffuse interstellar band (DIB) recorded in the 318 stellar spectra of stars located in the Third Galactic Quadrant. In agreement with previous studies, we found that the DIB strength has a positive correlation with the interstellar extinction, even though significant deviations were found. The correlation study between the DIB strength and the extinction is limited by the fact that the 3D extinction survey in the Galaxy is incomplete. The DIB spatial distribution toward the South Galactic Pole indicates that the DIB carrier(s) are distributed similarly as other Galactic warp tracer. More data, especially DIB measurements from target stars above Galactic principal plane, are needed to demonstrate that DIB can be used as a tracer of Galactic warp.
Photospheric Vector Magnetic Field Parameters as A Predictor of Major Solar Flares
Authors: Nurzaman M Z , Dani T
Published: June 2019

Photospheric vector magnetic field data which have several Space-weather HMI Active Region Patches (SHARP) parameters are used to study active regions that produced major solar flares. SHARP parameter data obtained from the Helioseismic Magnetic Imager (HMI) instruments onboard Solar Dynamics Observatory (SDO) have a good spatial and temporal sampling. We consider three SHARP parameters with high F-scores, namely total unsigned vertical current, total photospheric magnetic free energy, and total unsigned current helicity as a useful predictor for major solar flares. In this paper, we present the data analysis procedure and sample results focusing only on major solar flares (M and X class flares). The preliminary results showed in some cases, one of SHARP parameters for the M-class flare almost has the same value as X-class flare in which ideally should be higher.
Zenithal sky glow measurement in Bandar Lampung as consideration in drafting the regulation of light pollution-free areas around the Lampung Astronomical Observatory (LAO)
Authors: Muztaba R , Saryantono B , Putri A N I , Pratiwi T D
Published: June 2019

Urban development to big cities generally will be accompanied by excessive use of artificial light, such as street lamps, billboards, and building lighting systems. Ineffective and incorrect lighting installation design causes environmental degradation, i.e light pollution. Today, light pollution is one indicator of environmental degradation and energy waste behavior. Study on light pollution has progressed in many fields of science, extending from traditional fields of astronomy to atmospheric physics, environmental science, natural science, and social life. Measurement of sky brightness is also an indicator of the feasibility of an observatory development plan. The location of the observatory is located at coordinates latitude -05° 27′ 71″ and longitude 105° 09′ 39″ with a height of 1030 above mean sea level. The construction of an observatory requires a study of the sky’s brightness conditions as a matter of consideration to obtain the best observation result. Therefore, to support the Lampung Provincial Government, Institut Teknologi Sumatera (ITERA) and Institut Teknologi Bandung (ITB) in carrying out the construction of observatories in TAHURA WAR, Gunung Betung, Lampung. We did the sky brightness measurements as far as 15 km from the location point of the observatory. We use SQM to measure the brightness of the sky towards the zenith in every crowded area in the city of Bandar Lampung. Then, from the measurement results, we make a map of light pollution. From the mapping results, there are four locations that are indicated to be contaminated by light pollution, namely Tanjung Senang, Teluk Betung, Kemiling, and Gedong Tataan with respective values of 15.8 mpas, 16.6 mpas, 16.8 mpas, and 17.00 mpas.
Internet of Things (IoT) For Galactic Cosmic Ray Application Over Astronomical Observatory in Near Future: A Review Study
Authors: Putro W. S. , Muztaba R. , Pratiwi N. , Putri A. N. I. , Birastri W.
Published: June 2019

Galactic Cosmic Ray (GCR) it’s very harmful for human life. The Ultra high Neutrino radiation GCR energy from outside galaxy were intimidated Earth and Environmental. The measurement GCR energy using neuron monitor is successful to capture Ultra-high Neutron and Gamma ray, respectively. During Fourth Industrial Revolution (4IR), the current neutron monitor was expanded into Internet of Things (IoT) system to obtain Ultra-high Neutron and Gamma ray in near future. Thus, in this study aimed to develop conceptual study of Neutron Monitor with IoT system over Astronomical Observatory. The result shows Neutron Monitor with IoT system need to deploy in Equator and Antarctic region due to Gamma ray distribution. Here, Neutron Monitor data with IoT system were applied to analyse Natural Hazard potential with predictor from GCR flux parameter. By using auto send status from IoT system, Natural Hazard potential will be updated per-hour into stakeholder (e.g. hospital, Astronautics, and meteorology service). Thus, a disaster victim from Natural Hazard potential caused by Ultra-high Neutron and Gamma ray will be minimized using IoT system during evacuation process in near future.