bluuebunny/crossref_metadata_2025 huggingface dataset:
September epsilon Perseids observed by the Czech Fireball Network
Authors: Shrbený Lukáš , Spurný Pavel
Published: August 2019

We present 25 photographic fireballs belonging to the September epsilon Perseid (SPE, IAU #208) meteor shower observed by the Czech part of the European Fireball Network in 2013–2017. Exceptional high activity of bright photographic fireballs was observed in 2013, while a lower activity, but still higher than in other years, was observed in the period of 2015–2017. Physical properties of these SPE fireballs were studied and compared to other meteor showers. Perseids are found to be the closest analog to SPE. Corrected geocentric radiant of the 2013 outburst fireballs was determined for solar longitude 167.20° and has right ascension 47.67 ± 0.04° and declination 39.493 ± 0.013° (J2000.0). On the basis of determined heliocentric orbits the parent body of the shower is an unknown long-period comet on retrograde orbit with an orbital period of the order of a thousand years.
Discovery of weak magnetic fields in four DZ white dwarfs in the local 20 pc volume
Authors: Bagnulo S. , Landstreet J. D.
Published: August 2019

We report the discovery of weak magnetic fields in three white dwarfs within the local 20 pc volume (WD 0816−310, WD 1009−184, and WD 1532+129), and we confirm the magnetic nature of a fourth star (WD 2138−332) in which we had previously detected a field at a 3σ level. The spectra of all these white dwarfs are characterised by the presence of metal lines and lack of H and He lines, that is, they belong to the spectral class DZ. The polarisation signal of the Ca II H+K lines of WD 1009−184 is particularly spectacular, with an amplitude of 20% that is due to the presence of a magnetic field with an average line-of-sight component of 40 kG. We have thus established that at least 40% of the known DZ white dwarfs with an He-rich atmosphere contained in the 20 pc volume have a magnetic field, while further observations are needed to establish whether the remaining DZ white dwarfs in the same volume are magnetic or not. Metal lines in the spectra of DZ white dwarfs are thought to have originated by accretion from rocky debris, and it might be argued that a link exists between metal accretion and higher occurrence of magnetism. However, we are not able to distinguish whether the magnetic field and the presence of a polluted atmosphere have a common origin, or if it is the presence of metal lines that allows us to detect a higher frequency of magnetic fields in cool white dwarfs, which would otherwise have featureless spectra. We argue that the new highly sensitive longitudinal field measurements that we have made in recent years are consistent with the idea that the magnetic field appears more frequently in older than in younger white dwarfs.
Performance of seven commercial automated assays for the detection of low levels of anti-Toxoplasma IgG in French immunocompromised patients
Authors: Douet Tiphaine , Armengol Catherine , Charpentier Elena , Chauvin Pamela , Cassaing Sophie , Iriart Xavier , Berry Antoine , Fillaux Judith
Published: August 2019

Background: Immunocompromised patients are at high risk for the development of severe toxoplasmosis from tissue cyst reactivation, the most frequently, or from recently acquired acute infections. Knowledge of serologic status is therefore crucial. Screening for toxoplasmosis is sometimes performed while patients are already immunocompromised and have a low or even undetectable IgG titer by routine automated enzyme immunoassays. The aim of this study was to assess the sensitivity and specificity of seven reagents for the detection of low levels of IgG. Sera from 354 patients were collected and analysed. Results: Elecsys® offered the best analytic performances, superior to those of Architect® and Platelia®, which were superior to those of Access II® and TGS TA®. Vidas II® and Liaison II® reagents exhibited poor analytical performances in this cohort. For Elecsys®, Platelia® and Architect®, new thresholds for the grey zone and positive zone have been defined to improve the sensitivity of these reagents while maintaining excellent specificity. Conclusions: Commercialized assays for toxoplasmosis screening are not suitable for IgG low-level detection in patients without adapting the supplier thresholds to avoid false negative results and risk generalized toxoplasmosis.
Gene expression profiles of antigenic proteins of third stage larvae of the zoonotic nematode Anisakis pegreffii in response to temperature conditions
Authors: Palomba Marialetizia , Paoletti Michela , Colantoni Alessandra , Rughetti Aurelia , Nascetti Giuseppe , Mattiucci Simonetta
Published: August 2019

Anisakis pegreffii, a recognised etiological agent of human anisakiasis, is a parasite of homeothermic hosts at the adult stage and of ectothermic hosts at the third larval stage. Among distinct factors, temperature appears to be crucial in affecting parasite hatching, moulting and to modulate parasite-host interaction. In the present study, we investigated the gene transcripts of proteins having an antigenic role among excretory secretory products (ESPs) (i.e., a Kunitz-type trypsin inhibitor, A.peg-1; a glycoprotein, A.peg-7; and the myoglobin, A.peg-13) after 24 h, in A. pegreffii larvae maintained in vitro, under controlled temperature conditions. Temperatures were 37 °C and 20 °C, resembling respectively homeothermic and ectothermic hosts conditions, and 7 °C, the cold stress condition post mortem of the fish host. Primers of genes coding for these ESPs to be used in quantitative real-time PCR were newly designed, and qRT-PCR conditions developed. Expression profiles of the genes A.peg-1 and A.peg-13 were significantly up-regulated at 20 °C and 37 °C, with respect to the control (larvae kept at 2 °C for 24 h). Conversely, transcript profiles of A.peg-7 did not significantly change among the chosen temperature conditions. In accordance with the observed transcript profiles, sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) revealed the presence of the three target ESPs at 37 °C, while only A.peg-13 was observed at 7 °C. The results suggest that temperature conditions do regulate the gene expression profiles of A.peg-1 and A.peg-13 in A. pegreffii larvae. However, regulation of the glycoprotein A.peg-7 is likely to be related to other factors such as the host’s immune response.
Geografische Cluster der Unterimmunisierung gegen Influenza
bei über 60-Jährigen am Beispiel Westfalen-Lippe
Authors: Völker Sebastian
Published: August 2019

Hintergrund Die Unterimmunisierung gegen Influenza steigt in den
vergangenen Jahren an. Es wird eine räumliche Clusterung der
Unterimmunisierung vermutet. Diese Cluster können Risiken
für die Gesundheitsvorsorge bedeuten und das Erreichen von
Qualitätsstandards der Immunisierung erschweren. Ziele des
vorliegenden Papers sind (a) räumliche Cluster auf PLZ-Ebene mit
hohen Quoten der Unterimmunisierung gegen Influenza zu identifizieren und zu
beschreiben, (b) die Cluster mit weiteren Vorsorgeleistungen zu vergleichen
und (c) mögliche Einflussfaktoren der Unterimmunisierung zu
modellieren.

Material und Methoden Aus den kassenärztlichen
Abrechnungsdaten der Kassenärztlichen Vereinigung Westfalen-Lippe
wurden Patienten ≥ 60 Jahren und Impfleistungen von
2012–2017 extrahiert. Als Methodik wurde die räumliche
Scanstatistik gewählt, die hohe relative Risiken einer
Unterimmunisierung in Clustern ausweist.

Ergebnisse und Diskussion Es konnten 4 statistisch signifikante
Cluster der Unterimmunisierung gegen Influenza identifiziert werden, die
sich auch nach Abgleich mit dem zeitlichen Trend lokaler
Unterimmunisierungsraten als stabil erwiesen. Die Quote der
Unterimmunisierung betrug in der Grippesaison 2016/2017 in den
Clustern mit höherem Risiko (RR>1)
71,9%-74,7%, die Quote außerhalb dieser Cluster
67,0%. Als Einflussfaktoren auf die Unterimmunisierung wurden u.a.
sozio-ökonomische Faktoren und das Impfverhalten in der Vorsaison
identifiziert. Unterimmunisierungsquoten sind geographisch geclustert. Die
räumliche Scanstatistik kann für die Identifikation von
persistenten Clustern genutzt werden, um gezielte raum- und
adressatenspezifische Maßnahmen zur Verringerung der
Unterimmunisierungsraten durchzuführen.
Sepsis-Induced Coagulopathy and Disseminated Intravascular Coagulation
Authors: Iba Toshiaki , Levi Marcel , Levy Jerrold H.
Published: August 2019

Disseminated intravascular coagulation (DIC) has been recognized as a deadly complication in sepsis, and its early recognition followed by appropriate management of the underlying infection are the current management strategies. The activation of coagulation, inflammation, and other pathways are fundamental host responses against infection but also produce injury to the host. Recent advances have helped define the critical roles of thrombus formation in overcoming infection. In addition to activation of coagulation induced by pathogens, other important pathways including damage-associated molecular patterns, neutrophil extracellular traps, extracellular vesicles, and glycocalyx damage are involved in the pathogenesis of sepsis-induced DIC. The hallmark of DIC is thrombosis in the microvasculature; however, sepsis-induced DIC is a laboratory diagnosis based on coagulation test results and clinical setting. Although simplified criteria were recently introduced, DIC should be distinguished from other similar conditions such as thrombotic microangiopathy and heparin-induced thrombocytopenia. In DIC, treating the underlying cause is crucial, and additional adjunct therapies including antithrombin, thrombomodulin, and heparins may have potential benefit, but evidence supporting their use in terms of improvement of clinically relevant outcomes continues to be debated. In this review, we introduce recent findings regarding the pathophysiology, diagnosis, and treatment of sepsis-induced DIC. In addition, we also discuss future potential therapeutic approaches regarding this complex, life-threatening complication.
Integrable nonlocal Hirota equations
Authors: Cen Julia , Correa Francisco , Fring Andreas
Published: August 2019

We construct several new integrable systems corresponding to nonlocal versions of the Hirota equation, which is a particular example of higher order nonlinear Schrödinger equations. The integrability of the new models is established by providing their explicit forms of Lax pairs or zero curvature conditions. The two compatibility equations arising in this construction are found to be related to each other either by a parity transformation P, by a time reversal T or a P T-transformation possibly combined with a conjugation. We construct explicit multisoliton solutions for these models by employing Hirota’s direct method as well as Darboux-Crum transformations. The nonlocal nature of these models allows for a modification of these solution procedures as the new systems also possess new types of solutions with different parameter dependence and different qualitative behavior. The multisoliton solutions are of varied type, being, for instance, nonlocal in space, nonlocal in time of time-crystal type, regular with local structures either in time/space or of rogue wave type.
SpraySyn—A standardized burner configuration for nanoparticle synthesis in spray flames
Authors: Schneider F. , Suleiman S. , Menser J. , Borukhovich E. , Wlokas I. , Kempf A. , Wiggers H. , Schulz C.
Published: August 2019

In many scientific communities, the definition of standardized experiments has enabled major progress in process understanding. The investigation of the spray-flame synthesis of nanoparticles at a well-defined standard burner by experiment and simulation makes it possible to produce a comprehensive data set with various established and novel measuring methods. In this work, we introduce the design of the SpraySyn burner as a new standard for a free-jet type burner that offers well-defined and simulation-friendly boundary conditions and geometries as well as accessibility for optical diagnostics. A combustible precursor solution is fed through a centrally located capillary and aerosolized with an oxygen dispersion gas flow. The spray flame is stabilized by a premixed flat methane/oxygen pilot flame fed via a porous bronze matrix surrounded by a stabilizing nitrogen coflow emanating through the same porous matrix, providing easy-to-calculate boundary conditions for simulations. This burner design enables the use of a wide choice of solvents, precursors, and precursor combinations. Best-practice operating instructions and parameters are given, and large-eddy simulations are performed demonstrating the suitability of the SpraySyn burner for computational fluid dynamics simulations. For ensuring reproducible operation across labs, we define a consumer-camera-based flame characterization scheme for the quantitative assessment of the flame geometry such as flame length, diameter, tilt angle, and photometric distribution of visible chemiluminescence along the center axis. These parameters can be used for benchmarking the pilot and spray flame by each user of the SpraySyn burner with the reference flames.
Mixed moments of characteristic polynomials of random unitary matrices
Authors: Bailey E. C. , Bettin S. , Blower G. , Conrey J. B. , Prokhorov A. , Rubinstein M. O. , Snaith N. C.
Published: August 2019

Following the work of Conrey, Rubinstein, and Snaith [Commun. Math. Phys. 267, 611 (2006)] and Forrester and Witte [J. Phys. A: Math. Gen. 39, 8983 (2006)], we examine a mixed moment of the characteristic polynomial and its derivative for matrices from the unitary group U(N) (also known as the CUE) and relate the moment to the solution of a Painlevé differential equation. We also calculate a simple form for the asymptotic behavior of moments of logarithmic derivatives of these characteristic polynomials evaluated near the unit circle.
Zernike functions, rigged Hilbert spaces, and potential applications
Authors: Celeghini E. , Gadella M. , del Olmo M. A.
Published: August 2019

We revise the symmetries of the Zernike polynomials that determine the Lie algebra su(1, 1) ⊕ su(1, 1). We show how they induce discrete as well as continuous bases that coexist in the framework of rigged Hilbert spaces. We also discuss some other interesting properties of Zernike polynomials and Zernike functions. One of the areas of interest of Zernike functions has been their applications in optics. Here, we suggest that operators on the spaces of Zernike functions may play a role in optical image processing.
Formation of nitrogen-vacancy centers in 4H-SiC and their near infrared photoluminescence properties
Authors: Sato Shin-ichiro , Narahara Takuma , Abe Yuta , Hijikata Yasuto , Umeda Takahide , Ohshima Takeshi
Published: August 2019

NCVSi− centers in SiC [nitrogen-vacancy (NV) centers], which produce near-infrared (NIR) photoluminescence (PL) at room temperature, is expected to have applications as quantum sensors for in vivo imaging and sensing. To realize quantum sensing using NV centers, clarification of the formation mechanism as well as control of the high-density formation is necessary. This paper reports a comprehensive investigation on the NIR-PL properties originating from NV centers in high purity semi-insulating and nitrogen (N) contained 4H-SiC substrates formed by ion beam irradiation and subsequent thermal annealing. It is shown that NV centers are exclusively formed by the contained N as impurities rather than the implanted N, and also the heavier ion irradiations induce the NV center formation effectively than the lighter ion irradiations. The study on thermal annealing at different temperatures reveals that the optimal temperature is 1000 °C. From the results of temperature dependence on the PL intensity, it is shown that little thermal quenching of the PL intensity appears at room temperature and the PL signal is collected even at 783 K. The formation mechanism of NV centers is also discussed based on the obtained results.
First-principles study of coupled effect of ripplocations and S-vacancies in MoS2
Authors: Tritsaris Georgios A. , Şensoy Mehmet Gökhan , Shirodkar Sharmila N. , Kaxiras Efthimios
Published: August 2019

Recent experiments have revealed ripplocations, atomic-scale ripplelike defects on samples of MoS2 flakes. We use quantum mechanical calculations based on density functional theory to study the effect of ripplocations on the structural and electronic properties of single-layer MoS2, and, in particular, the coupling between these extended defects and the most common defects in this material, S-vacancies. We find that the formation of neutral S-vacancies is energetically more favorable in the ripplocation. In addition, we demonstrate that ripplocations alone do not introduce electronic states into the intrinsic bandgap, in contrast to S-vacancies. We study the dependence of the induced gap states on the position of the defects in the ripplocation, which has implications for the experimental characterization of MoS2 flakes and the engineering of quantum emitters in this material. Our specific findings collectively aim to provide insights into the electronic structure of experimentally relevant defects in MoS2 and to establish structure-property relationships for the design of MoS2-based quantum devices.
Synthesis and microwave-absorption properties of organic-inorganic Sm2Co14B/polyaniline composites with embedded structure
Authors: Chen Peng , Jiang Linwen , Li Jiangtao , Chen Hongbing , He Jun , Wang Yu
Published: August 2019

Organic-inorganic composites Sm2Co14B/polyaniline (Sm2Co14B/PA) with an embedded structure were synthesized by combining the arc-melting process and the in situ oxidative polymerization method. The phase identification, morphology, and magnetic properties of as-synthesized samples were investigated in detail. The microwave-absorption properties of pure Sm2Co14B and Sm2Co14B/PA in paraffin were studied in the 1–18 GHz frequency range. The sample of 40 wt. % Sm2Co14B/PA in paraffin exhibited rather good absorption performances. The reflection loss (RL) exceeding −10 dB is obtained in the 8.8–11.4 GHz range for a given thickness of 2.3 mm, which covered almost half of the X-band (8–12 GHz), and the maximum RL could reach −23.1 dB. The Sm2Co14B/PA composites have great potential for applications in the microwave-absorption field due to their excellent microwave-absorption performances. Besides, a physical model was illustrated to explain the special embedded structure, which has the multipolarization phenomenon at interfaces and multireflections inside the materials leading to excellent microwave-absorption performances.
Ferrite based antennae for launching Alfvén waves
Authors: Gekelman W. , Pribyl P. , Vincena S. , Tang S. W. , Papadopoulos K.
Published: August 2019

Whistler and Alfvén waves are known to scatter mirror-trapped electrons and protons into the loss cone of the earth’s dipole magnetic field. An array of satellites with properly phased antennas can be used to artificially reduce the flux of energetic particles from regions where their flux has been naturally or artificially pumped. In any space based system, the power required to drive antennas is at a premium. We present here experimental evidence that the efficiency of an antenna can be greatly enhanced with the use of ferrite cores with high relative magnetic permeability μ. Ferrite-based antennas were constructed to launch Alfvén waves in a magnetized plasma. The wave magnetic field of shear Alfvén waves launched with a ferrite core was by the magnetization factor μ larger than that of a similar antenna without a ferrite. Combining multiple ferrite antennas allowed control of the injected perpendicular wavelength. This novel technique can be used to efficiently launch low frequency waves with amplitude above the threshold required for nonlinear triggering.
A new way to represent atomic species improves molecular machine learning models
Authors: Patrick Chris
Published: August 2019

The creation of elemental modes to represent atomic species enables transfer learning and lowers computational cost, bringing chemical modeling closer to a single machine learning model that can be fine-tuned for different systems.
Analyzing the effects of small channel width on cell concentration in blood flow
Authors: Mandel Savannah
Published: August 2019

Physicists studied how particle and red blood cell concentration moves through microchannels, shedding light on how blood flows through the body and how medicine might best be delivered.
Integrated weed management using row arrangements and herbicides in pigeonpea (Cajanus cajan) in Australia
Authors: Mahajan Gulshan , Rachaputi Rao C. N. , Chauhan Bhagirath Singh
Published: August 2019

In Australia, efforts are under way to revive the pigeonpea (Cajanus cajan (L.) Millsp.) industry, which has high export potential because of an increased demand in the international market. However, weeds are a major constraint to achieve high yield in pigeonpea. This study was designed to assess the effect of row arrangement and herbicide treatment on weed suppression and pigeonpea grain yield. Row arrangements included row spacing (narrow, 25 cm; wide, 50 cm) and paired rows (rows 25 cm apart within a pair, each pair separated from the next by 75 cm). Herbicide treatments were: untreated control; pre-emergent pendimethalin at 910 g a.i. ha–1; post-emergent imazapic at 84 g a.i. ha–1; and pre-emergent pendimethalin followed by post-emergent imazapic (rates as above). In the first year, Trianthema portulacastrum was the dominant weed, and infestation was 100% in the non-treated control plots. In the second year, other weeds (Setaria viridis, Eragrostis cilianensis and Chloris virgata) comprised 30% of the weed population. Averaged over row arrangements, grain yield varied from 2088 to 2689 kg ha–1 in 2017 and from 835 to 2145 kg ha–1 in 2018, and was lowest in the untreated control and highest in the plots treated with the sequential application of pendimethalin and imazapic. Averaged over years and herbicide treatments, yield was lower in paired rows (1850 kg ha–1) than in narrow (2225 kg ha–1) and wide (2165 kg ha–1) row spacings. In the first year, all herbicide treatments provided >50% control of T. portulacastrum in the narrow and wide row spacings and increased yield by >22% over the untreated control. In the second year, the single application of imazapic proved inferior for controlling weeds, resulting in a 21% reduction in grain yield compared with sequential application of pendimethalin and imazapic. In both years, grain yield was similar for the single application of pendimethalin and sequential application of pendimethalin and imazapic. Despite the complex weed flora in 2018, the single application of imazapic provided acceptable weed control only when the crop was planted at 25 cm row spacing. Our results suggest that the single application of pendimethalin was effective on T. portulacastrum. However, in a complex weed flora situation, the sequential application of pendimethalin and imazapic provided effective weed control and resulted in improved yield.
Lazy electrons in graphene
Authors: Mohanty Vaibhav , Heller Eric J.
Published: August 2019

Within a tight-binding approximation, we numerically determine the time evolution of graphene electronic states in the presence of classically vibrating nuclei. There is no reliance on the Born–Oppenheimer approximation within the

p

-orbital tight-binding basis, although our approximation is “atomically adiabatic”: the basis

p

-orbitals are taken to follow nuclear positions. Our calculations show that the strict adiabatic Born–Oppenheimer approximation fails badly. We find that a diabatic (lazy electrons responding weakly to nuclear distortions) Born–Oppenheimer model provides a much more accurate picture and suggests a generalized many-body Bloch orbital-nuclear basis set for describing electron–phonon interactions in graphene.
Pore-modulating toxins exploit inherent slow inactivation to block K
+
channels
Authors: Karbat Izhar , Altman-Gueta Hagit , Fine Shachar , Szanto Tibor , Hamer-Rogotner Shelly , Dym Orly , Frolow Felix , Gordon Dalia , Panyi Gyorgy , Gurevitz Michael , Reuveny Eitan
Published: August 2019

Voltage-dependent potassium channels (K
v
s) gate in response to changes in electrical membrane potential by coupling a voltage-sensing module with a K
+
-selective pore. Animal toxins targeting K
v
s are classified as pore blockers, which physically plug the ion conduction pathway, or as gating modifiers, which disrupt voltage sensor movements. A third group of toxins blocks K
+
conduction by an unknown mechanism via binding to the channel turrets. Here, we show that Conkunitzin-S1 (Cs1), a peptide toxin isolated from cone snail venom, binds at the turrets of K
v
1.2 and targets a network of hydrogen bonds that govern water access to the peripheral cavities that surround the central pore. The resulting ectopic water flow triggers an asymmetric collapse of the pore by a process resembling that of inherent slow inactivation. Pore modulation by animal toxins exposes the peripheral cavity of K
+
channels as a novel pharmacological target and provides a rational framework for drug design.
Tikkun Olam: exploring a spiritual path to sustainability
Authors: Grzeda Maurice
Published: August 2019

What should be the role of business in society? Broad-ranging initiatives, e.g. Principles for Responsible Management Education and the Sustainable Development Goals, attempt to reshape business as a force for good, yet evidence of scandalous business behavior continues to raise troubling doubts. This literature review introduces a healing perspective grounded in spirituality as applied in the health professions. This perspective aligns with Judaism’s principle of Tikkun Olam, the obligation to repair and perfect the world, proposed as a basis for business transformation. Invoking Tikkun Olam potentially impacts current understandings of Corporate Social Responsibility and reveals a sacred dimension to the adoption of sustainability initiatives. The article contributes to the literature on transformational approaches to exercising responsibility and embedding sustainability in contemporary business.
Experimental Investigation on Shape Dependence for Flow past Shallow Cavities
Authors: Khan Samreen , Khurana Shashank
Published: August 2019

Relative motion between a bluff body having a cavity and the fluid surrounding it causes the fluid flow gets modified due to the presence of the cavity. The properties of flows past cavities are analysed, and various control techniques are devised and employed over the years. The present study aimed at experimentally analysing the flows and their features past three different shapes of cavities i.e., rectangular, hemispherical as well as triangular cavities under similar boundary conditions. The study consists of experimental investigation carried on cavities for similar length-to-depth ratios and the visualization of flow characteristics using a two-dimensional water channel apparatus. In this technique, the free surface of the water stream in the test-section is used in visualizing and analysing the flow characteristics including the formation of vortices, through dye injection, around cavities. The comparative study performed at varying Reynolds number for different cavities indicated the suitability of hemispherical cavities towards creating maximum amount of boundary layer suction.
CFD Analysis of Scramjet Engine Combustion Chamber with Diamond-Shaped Strut Injector at Flight Mach 4.5
Authors: Roga Sukanta
Published: August 2019

The present work address the CFD analysis for scramjet combustor with diamond-shaped strut injectors at supersonic Mach 4.5 and it’s based on species transport combustor which is standard k-epsilon turbulence model. It is implied for supersonic combustion that the ramjet engine is focused for operating high speed engines. The combustion chamber assists as an envelope to clutch the propellant for a satisfactory period to certify complete mixing as well as combustion. The diamond-shaped strut injector gives the maximum temperature and pressure of 3517 K and 1.487 MPa respectively whereas the combustion efficiency is found to be 87.2%. The shear layers losses are extremely minimize the performance of the engine, thus interpreting trade-off programmes in a very difficult way to achieve maximum combustion efficiency. Further firmness by machines is essential for achieving higher combustion efficiency.
The MHD based numerical analysis of Rayleigh-Bénard convection flow of liquid metal in the smoothly constricted enclosure from the top using OpenFOAM
Authors: Singh Ranjit J. , Gohil Trushar B.
Published: August 2019

The influence of the existence of the Lorentz force in the Rayleigh-Bénard (RB) convection flow in the smoothly constricted cavity from the top is presented in this paper. The liquid metal with Prandtl number of Pr = 0.02 is used with the Rayleigh number of Ra = 105, and the magnetic field is imposed in terms of Hartmann number (Ha) = 0-50. The vertically driven buoyancy force is kept constant for all simulation by maintaining the same Ra. The present flow solver with magnetohydrodynamics (MHD) principle is developed in the open source CFD toolkit OpenFOAM. The Navier-Stokes equation is coupled with Maxwell’s equation of electrodynamics to cope up the MHD based flow physics in the cavity. The thermal energy equation with Boussinesq approximation is added in the solver to study natural convection flow in the presence of the magnetic field. The orientation of magnetic field has different nature and direction of induced Lorentz force in the cavity. The imposed magnetic field normal to the gravity has the tendency to suppress the convection roll formation. Conversely, it has been observed that the magnetic field imposed in the direction to parallel to gravity bifurcates the flow and assist in the formation of several convection rolls. The detail discussion of the variation of Lorentz force in the cavity and its effect on the streamlines, isotherms, and the average Nusselt number is reported.
Improvements in the Rheological Characteristics of the Complex Coal-Water Suspension Using Gasification Derived Waste Water
Authors: Singh Harmanpreet , Kumar Satish , Kumar Mohapatra Saroj
Published: August 2019

The area of application of coal as a source of energy is expanding to sophisticated devices such as internal combustion engines, liquid fuel-based furnaces, gasification, pyrolysis, etc. The coal reserves in the developing countries are mainly young and of low rank, which have poor slurrying and rheological characteristics. The present research presents a novel methodology to improve the slurrying and rheological characteristics of the coal water suspension using the gasification derived waste water. The gas produced by a gasifier contains a lot of tars, which are washed down along with the sprayed water; this water is known as gasification derived waste water. In the present case, the waste water is collected from the gas cleaning unit of a 10 kg/h downdraft biomass gasifier. This waste water contains some amount of dissolved tars. When this water is used for the preparation of the coal water suspension, an improvement in the slurrying and rheological characteristics of the suspension is observed. The tars are observed to the choke the pores on surface of the coal particles; this checks the flow of water into the pores. So, the maximum amount of water remains in the particle’s surroundings, thereby reducing the particle to particle interaction and hence the viscosity by ∼41-55%. This study thus provides a base and a novel method to utilize the waste water, which otherwise is of no use and quite harmful.
Comparison of Linear Regression and ANN of Fish Oil Biodiesel Properties Prediction
Authors: Ganeshmoorthy V , Muthukannan M , Thirugnanasambandam M
Published: August 2019

The straight fish oil based biodiesel is used as fuel in CI engines by adjusting physical properties such as density and viscosity and increasing the temperature. In the present study, the variation of density and viscosity of fish oil based biodiesel blend with temperature are studied. The volumetric fraction of biodiesel in the range of 10 to 100% is added with diesel and change in the properties of viscosity and densities are investigated. From the experimental results, density (ρ) and kinematic viscosity (ʋ) of fish oil are synchronized with diesel properties at B40 at 40-50ºC. Artificial Neural Network (ANN) and linear regression modeling are employed for predicting the density and viscosity of fish oil biodiesel blends. For training the ANN, 60% of data has been used a training set, 30% of data has been used a testing set and the remaining 10% of total data has been used for validation. It is observed that the MAPE (Mean Absolute Percentage Error) obtained from the ANN is only 5.27% whereas in the regression prediction the error is 23.9 %. Hence, it is established that ANN gives the best performance over regression analysis and found suitable for predicting the biodiesel properties with better accuracy. Thus, it eliminates instrumental usage and man-hours.
A sustainable energy source from microbes using microbial fuel cells
Authors: Potdar Shaunak V , Shazin Mohamed , Kannan Geetha
Published: August 2019

A microbial fuel cell (MFC) is a sustainable energy source which hopes to meet the growing demand of energy in the world by providing bioelectricity. The microbes like bacteria help produce current and voltage by metabolizing the carbon source into ions which are accepted at their respective electrodes. The prototype cell designed by our team is novel, cost effective, portable and environment friendly. This microbial fuel cell is a two chambered setup containing four graphite electrodes as the anode and four aluminum electrodes as the cathode. The MFC has been optimized under various experimental condition which includes sugar concentration, surface area of the electrodes, material of the electrodes as well as the effects of reducing salts on the current and voltage.
Assessment of optimum energy demand for non-centrifugal sugar production through an alternate process
Authors: Srinvas Morapakala , Prudhvi Raj Sunkara , Marie Louis F , Reddy K S , O’Donovan Tadhg S
Published: August 2019

Non-centrifugal sugar (NCS), known conventionally as Jaggery, obtained by concentrating cane juice in large boiling pans using traditional furnaces. In the traditional process, cane juice at 20 Brix is heated in pan(s) to 70 Brix to evaporate the water in it. Traditional furnaces used for concentration of sugarcane juice have low heat utilization efficiency about 15%. In the quest of improving energy efficiency, freeze pre-concentrating operation could be done at the start to remove water in the form of ice and the remaining proportion of water could be removed by heating for production of NCS. A thermal model has been developed for assessing optimum energy demand for a prior freezing technique up to a certain intermediate Brix and further by a heating technique. The obtained analytical data indicate that 1880.83 KJ/kg of cane juice is required when the juice concentration is increasing from 20 to 70 Brix while heating. The energy demand is significantly low (i.e. 536.10 KJ/kg of cane juice) when prior juice concentration is done through freezing technique from 20 to 63 Brix and later the juice is concentrated through heating technique from 63 to 70 Brix . Since, the energy required for latent heat of fusion is quite low when compared with the latent heat of vaporization so; combination of freezing and heating technique for juice concentration seems to be a viable option for improving energy efficiency in NCS production.
Optical clock spectroscopy in weakly bound molecules
Authors: Borkowski Mateusz
Published: August 2019

With relative accuracies reaching 10−18, optical atomic clocks are currently the most sensitive physical instruments known to man. Weakly bound ultracold molecules enable the study of fundamental physics through their sensitivity to e.g. the proton-to-electron mass ratio or hypothetical Yukawa-type fifth forces predicted by several extensions of the Standard Model. These applications, however, require precision measurements of molecular transitions that are beyond current experimental capabilities. Here we propose to construct an ‘optical molecular clock’ that would solve this problem by bringing the experimental techniques used in optical atomic clocks to the realm of cold molecules. We show that such a clock could utilize ultracold ytterbium molecules and we predict the positions and properties of Yb2 clock lines. A successful experimental realization of this proposal could pave the way towards sub-Hz level molecular spectroscopy.
Vibrational effects in the photo-ion yield spectrum of the SiH2
+ molecular ion following 2p inner-shell excitation
Authors: Kennedy E T , Mosnier J P , Van Kampen P , Bizau J M , Cubaynes D , Guilbaud S , Carniato S , Puglisi A , Sisourat N
Published: August 2019

We report on complementary theoretical and laboratory investigations of the 2p ion yield cross sections for the molecular-ion series SiHn
+ (n = 1, 2, 3), in the 95-108 eV photon energy range, below the L-shell threshold. The experiments used an electron cyclotron resonance (ECR) plasma molecular-ion source coupled with monochromatised synchrotron radiation in a merged-beam configuration. The experimental spectra are compared with total photoabsorption cross-sectional profiles calculated using an ab initio configuration interaction method inclusive of spin-orbit coupling and the vibrational dynamics. The experimental results show vibrationally resolved resonances for SiH2
+ in the 98-102 eV range. The calculations indicate twenty four core-excited states below the energy of 102 eV, of which only four contribute significantly to the observed spectrum. These states correspond to the excitation of an atomic-like 2p electron to the SiH2
+ (5a1) valence orbital.
Quantitative analysis on tungsten spectra of W6+ to W45+ ions
Authors: Morita S. , Dong C.F. , Kato D. , Liu Y. , Zhang L. , Cui Z.Y. , Goto M. , Kawamoto Y. , Murakami I. , Oishi T.
Published: August 2019

Tungsten ion densities are determined by measuring radial profiles of line emissions in LHD. Zn-(W44+) and Cu-like (W45+) ion densities are determined from line emission at 60.9 Å and 127.0 Å, respectively. Ion densities of W24+, W25+ and W26+ are also determined from tungsten pseudo-continuum (a so-called unresolved transition array (UTA)) at 29-33 Å. Observations of magnetic dipole (M1) forbidden lines at 3377Å enable evaluation of the ion density of W27+. In EAST tokamak the tungsten concentration is estimated by a combination of the UTA and total radiation loss. In HL-2A the tungsten influx is evaluated from line emission of W6+ ions at 216.2 Å and 261.4 Å, which are measured during the tungsten reappearance phase after tungsten laser blow-off. All these results demonstrate a good approach towards quantitative tungsten analysis.
A new analysis of spectral line shapes in white dwarf atmospheres
Authors: Rosato J , Kieu N , Meireni M , Koubiti M , Marandet Y , Stamm R , Kovačević-Dojčinović J , Dimitrijević M S , Č Popović L , Simić Z
Published: August 2019

We present an analysis of hydrogen Balmer line shapes observed in two white dwarf spectra. One spectrum presents singlet lines while the second one presents lines with a triplet structure. The latter is a feature of the presence of a strong magnetic field. Using both Stark and Zeeman effects, we infer the density and the magnetic field. Our line shape calculations employ a computer simulation technique. The radiative transfer is accounted for through a onedimensional slab model.
Space integrated, time resolved studies of the formation of aluminium (II) oxide in laser produced plasmas
Authors: Kelly T J , Walsh N , Costello J T
Published: August 2019

We present time resolved, spatially integrated spectra of aluminium II oxide formed from the condensation of an aluminium laser plasma in air. The spectra show a revival of the emission from aluminium oxide molecules at 35µs after the plasma ignition. Thermodynamic calculations, together with temperature measurements, indicates that as the plasma cools, the aluminium oxide molecule forms through two different channels, explaining its increased presence.
The Stark Broadening Parameters of the Nitrogen HF RF-CCPs
Authors: Erözbek Güngör Ü
Published: August 2019

This paper presents the experimental Stark-broadening and shifting analysis of 40.68 MHz nitrogen RF-CCPs. The non-thermal plasmas were generated in a cylindrical parallel plate plasma reactor under 0.2-0.8 Torr and 50-200 Watt. The physical and chemical spectral analyses of the system were performed by using the OES method. Many N I and N II lines were detected in the UV-Vis-NIR region. The diagnostic measurements of the plasmas were done according to the Saha relation and the Boltzmann plot method, under the LTE assumption. The calculated Te, Tgas, ne and n0 take values in the range of (10748 ± 742 – 16144 ± 653) K, (690 ± 82 – 833 ± 22) K, (0.598 ± 0.024 – 2.87 ± 0.03) × 1014 cm−3 and (2.32 ± 0.06 – 11.37 ± 1.44) × 1015 cm−3, respectively. The normalized Stark-broadening parameters (ωe and de) of the vacuum visible N II multiplets (653.445, 659.749 and 661.545 nm) were determined for 10.000 and 15.000 K.
Contribution from dimers to the collision-induced absorption spectra in an Ar–Kr gas mixture
Authors: Fakhardji Wissam , El-Kader M.S.A. , Haskopoulos Anastasios , Maroulis George , Gustafsson Magnus
Published: August 2019

We have developed an empirical Barker, Fisher and Watts (BFW) interatomic potential for the Ar–Kr pair along with a dipole moment computed from first principles using Møller–Plesset perturbation theory to second order (MP2). Using these results, we performed molecular dynamics calculations to compute the Ar–Kr collision induced absorption (CIA) spectrum at different temperatures. By comparing them to other calculations using a two body interaction treated with quantum mechanics, we have shown that the difference is due to the dimer’s contribution which grows in importance as the temperature is lowered.
Effect of Wave Collapse on Lyman and Balmer lines
Authors: Hannachi I , Meireni M , Rosato J , Stamm R , Marandet Y
Published: August 2019

The nonlinear coupling of Langmuir, ion sound and electromagnetic waves can create wave collapse conditions in a plasma, and modify the line shapes emitted by hydrogen atoms. Such conditions may appear in the presence of a strong source of energy, and create numerous regions where wave packets localize and the plasma density is decreased. We use a model of envelope solitons for the electric field acting on the emitter, and calculate the dipole autocorrelation function and the line shape with a numerical simulation. We investigate the role of the frequency of wave packets, and propose an approach retaining a dispersion relation ω(k).
Polarization measurement of hydrogen Lyman-α in the Large Helical Device
Authors: Ramaiya N , Goto M , Oishi T , Morita S
Published: August 2019

We have investigated the polarization of the Lyman-α line due to anisotropic electron collisions in the Large Helical Device (LHD). Optical components provided by the CLASP (Chromospheric Lyman-αlpha Spectro-Polarimeter) project [Kano R 2017 ApJL 839 L10] team have been incorporated into a VUV spectrometer so that linearly polarized light spectra at different angles can be obtained sequentially. The steady-state phase of an ECH (electron cyclotron heating) discharge has been analyzed, and it is confirmed that the Lyman-α line is polarized. From a temporal variation analysis of the intensity, integrated over the line profile, the polarization degree is evaluated to be 3.4%. A simple theoretical model calculation shows that this polarization degree can be explained by approximately 10% anisotropy in the electron temperature between the parallel and perpendicular directions with respect to the magnetic field.
Meeting GHG reduction targets requires accounting for all forest sector emissions
Authors: Hudiburg Tara W , Law Beverly E , Moomaw William R , Harmon Mark E , Stenzel Jeffrey E
Published: August 2019

Atmospheric greenhouse gases (GHGs) must be reduced to avoid an unsustainable climate. Because carbon dioxide is removed from the atmosphere and sequestered in forests and wood products, mitigation strategies to sustain and increase forest carbon sequestration are being developed. These strategies require full accounting of forest sector GHG budgets. Here, we describe a rigorous approach using over one million observations from forest inventory data and a regionally calibrated life-cycle assessment for calculating cradle-to-grave forest sector emissions and sequestration. We find that Western US forests are net sinks because there is a positive net balance of forest carbon uptake exceeding losses due to harvesting, wood product use, and combustion by wildfire. However, over 100 years of wood product usage is reducing the potential annual sink by an average of 21%, suggesting forest carbon storage can become more effective in climate mitigation through reduction in harvest, longer rotations, or more efficient wood product usage. Of the ∼10 700 million metric tonnes of carbon dioxide equivalents removed from west coast forests since 1900, 81% of it has been returned to the atmosphere or deposited in landfills. Moreover, state and federal reporting have erroneously excluded some product-related emissions, resulting in 25%–55% underestimation of state total CO2 emissions. For states seeking to reach GHG reduction mandates by 2030, it is important that state CO2 budgets are effectively determined or claimed reductions will be insufficient to mitigate climate change.
Community behavior analysis of electricity consumption in rural areas (a case study of Batang Regency)
Authors: Rarasati A D , Ardian M D , Setiawan E A , Mohammad I H
Published: August 2019

The need for electricity linearly increases despite the lack of accessibility to electric power, especially in rural or downtown area. Since electricity has several positive impacts such as supporting human activities, increasing competitiveness and improving the economy, lack of access to it could lead to an area being underdeveloped. The government expected that procuring a 35,000 Mega Watt generator would overcome this problem. However, from the consumer’s perspective, it is important to avoid over or under design during the infrastructure development lead. This study aims to analyze the energy reserve needs from the villagers’ own perspectives by determining peak loads, electricity consumption, and the reliability of the power distribution systems. The research took place in Batang Regency, Central Java, Indonesia. It used interviews to deeply explore consumer behavior in energy consumption presented in commonly demanded factors, diversity factors, SAIDI and SAIFI values, and the respondent’s understanding of energy saving. The results of this study revealed some unique characteristic behaviors of Batang electricity consumers based on their locations.
Monitoring of AH-11A fused-silica drift in RCM-LIPI and its implementation
Authors: Khairiyati L , Yayienda N F , Azzumar M
Published: August 2019

We have been monitoring our standard capacitors of AH-1100 fused-silica drift for 8 years to maintain and obtain the actual values of them. One of the advantages of the standard capacitors is to be used as a reference standard for ensuring the performance of an AC high voltage capacitive divider, that is commonly used to assess a voltage level on a power distribution from plants to end-users. This paper describes the monitoring of AH-1100 and its validation performed by comparing to the calibration results of KRISS, the national metrology institute of The Republic of Korea. The AH-1100 drifts is found to be less than 0.0052μF/F/year, and the comparison results show a good agreement, making the monitoring results have been validated. Moreover, the implementation has been performed with expanded uncertainties of 1.7 fF for 10 pF and about 22 fF for 100 pF.