bluuebunny/crossref_metadata_2025 huggingface dataset:
Land Water-Storage Variability over West Africa: Inferences from Space-Borne Sensors
Authors: Ferreira Vagner , Asiah Zibrila , Xu Jia , Gong Zheng , Andam-Akorful Samuel
Published: March 2018

The potential of terrestrial water storage (TWS) inverted from Gravity Recovery and Climate Experiment (GRACE) measurements to investigate water variations and their response to droughts over the Volta, Niger, and Senegal Basins of West Africa was investigated. An altimetry-imagery approach was proposed to deduce the contribution of Lake Volta to TWS as “sensed” by GRACE. The results showed that from April 2002 to July 2016, Lake Volta contributed to approximately 8.8% of the water gain within the Volta Basin. As the signal spreads out far from the lake, it impacts both the Niger and Senegal Basins with 1.7% (at a significance level of 95%). This figure of 8.8% for the Volta Basin is approximately 20% of the values reported in previous works. Drought analysis based on GRACE-TWS (after removing the lake’s contribution) depicted below-normal conditions prevailing from 2002 to 2008. Wavelet analysis revealed that TWS changes (fluxes) and rainfall as well as vegetation index depicted a highly coupled relationship at the semi-annual to biennial periods, with common power covariance prevailing in the annual frequencies. While acknowledging that validation of the drought occurrence and severity based on GRACE-TWS is needed, we believe that our findings shall contribute to the water management over West Africa.
Simultaneous Treatment of Agro-Industrial and Industrial Wastewaters: Case Studies of Cr(VI)/Second Cheese Whey and Cr(VI)/Winery Effluents
Authors: Tatoulis Triantafyllos , Michailides Michail , Tekerlekopoulou Athanasia , Akratos Christos , Pavlou Stavros , Vayenas Dimitrios
Published: March 2018

Hexavalent chromium (Cr(VI)) was co-treated either with second cheese whey (SCW) or winery effluents (WE) using pilot-scale biological trickling filters in series under different operating conditions. Two pilot-scale filters in series using plastic support media were used in each case. The first filter (i.e., Cr-SCW-filter or Cr-WE-filter) aimed at Cr(VI) reduction and the partial removal of dissolved chemical oxygen demand (d-COD) from SCW or WE and was inoculated with indigenous microorganisms originating from industrial sludge. The second filter in series (i.e., SCW-filter or WE-filter) aimed at further d-COD removal and was inoculated with indigenous microorganisms that were isolated from SCW or WE. Various Cr(VI) (5–100 mg L−1) and SCW or WE (d-COD, 1000–25,000 mg L−1) feed concentrations were tested. Based on the experimental results, the sequencing batch reactor operating mode with recirculation of 0.5 L min−1 proved very efficient since it led to complete Cr(VI) reduction in the first filter in series and achieved high Cr(VI) reduction rates (up to 36 and 43 mg L−1 d−1, for SCW and WW, respectively). Percentage d-COD removal for SCW and WE in the first filter was rather low, ranging from 14 to 42.5% and from 4 to 29% in the Cr-SCW-filter and Cr-WE-filter, respectively. However, the addition of the second filter in series enhanced total d-COD removal to above 97% and 90.5% for SCW and WE, respectively. The above results indicate that agro-industrial wastewater could be used as a carbon source for Cr(VI) reduction, while the use of two trickling filters in series could effectively treat both industrial and agro-industrial wastewaters with very low installation and operational costs.
Pluvial Flood Risk Assessment Tool (PFRA) for Rainwater Management and Adaptation to Climate Change in Newly Urbanised Areas
Authors: Szewrański Szymon , Chruściński Jakub , Kazak Jan , Świąder Małgorzata , Tokarczyk-Dorociak Katarzyna , Żmuda Romuald
Published: March 2018

The aim of this research is to develop the Pluvial Flood Risk Assessment tool (PFRA) for rainwater management and adaptation to climate change in newly urbanised areas. PFRA allows pluvial hazard assessment, as well as pluvial flood risk mapping. The original model was created using ArcGIS software with the ArcHydro extension, and the script was written using the Python programming language. The PFRA model effectively combines information about land cover, soils, microtopography (LiDAR data), and projected hydro-meteorological conditions, which enables the identification of the spatial and temporal distribution of pluvial flood risks in newly developed areas. Further improvements to the PFRA concern the quantification of pluvial flood-related damages, the application of high resolution precipitation data, and the optimisation of coding.
Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor
Authors: van Schie Morten M C H , Pedroso de Almeida Tiago , Laudadio Gabriele , Tieves Florian , Fernández-Fueyo Elena , Noël Timothy , Arends Isabel W C E , Hollmann Frank
Published: March 2018

The biocatalytic preparation of trans-hex-2-enal from trans-hex-2-enol using a novel aryl alcohol oxidase from Pleurotus eryngii (PeAAOx) is reported. As O2-dependent enzyme PeAAOx-dependent reactions are generally plagued by the poor solubility of O2 in aqueous media and mass transfer limitations resulting in poor reaction rates. These limitations were efficiently overcome by conducting the reaction in a flow-reactor setup reaching unpreceded catalytic activities for the enzyme in terms of turnover frequency (up to 38 s−1) and turnover numbers (more than 300000) pointing towards preparative usefulness of the proposed reaction scheme.
KNOWLEDGE-BASED FIS AND ANFIS MODELS DEVELOPMENT AND COMPARISON FOR RESIDENTIAL REAL ESTATE VALUATION
Authors: YALPIR Sukran , OZKAN Gulgun
Published: March 2018

There has been an increasing concern on the development of alternative approaches to overcome the problems and deficiencies that occur during the application of real-estate valuation methods. This study was established to investigate the usability of the expert knowledge based fuzzy logic methodology in determining real-estates values. In addition, valuation with the Adaptive Neuro-Fuzzy Inference System (ANFIS) method provided model comparison. Samples were administered a questionnaire for the parameters planned for these models regarding the parameters that affect real estate values. To make value estimations for the Fuzzy Inference System (FIS) model by using the parameters obtained from the questionnaire analyses, the criteria that produced the best results were acquired from the various criteria alternatives. An algorithm was created and the valuation process for real estate was performed using the FIS in Konya/Turkey. As a result of poll studies the area, age, floor conditions, physical properties and location of the real-estate property were considered as the input variables and the market value as the output variable. The memberships were established with poll analysis and were rule based on expert knowledge. The model structure was formed by using the Mamdani structure in the MATLAB fuzzy toolbox. Model prediction performance was evaluated statistically with the Mean Absolute Percentage Error (MAPE) and a high accuracy of the model results to the market values indicated the reliability of the established model for residential real-estate valuation.
An Extreme Protocluster of Luminous Dusty Starbursts in the Early Universe
Authors: Oteo I. , Ivison R. J. , Dunne L. , Manilla-Robles A. , Maddox S. , Lewis A. J. R. , Zotti G. de , Bremer M. , Clements D. L. , Cooray A. , Dannerbauer H. , Eales S. , Greenslade J. , Omont A. , Perez–Fournón I. , Riechers D. , Scott D. , van der Werf P. , Weiss A. , Zhang Z-Y.
Published: March 2018

We report the identification of an extreme protocluster of galaxies in the early universe whose core (nicknamed Distant Red Core, DRC, because of its very red color in Herschel SPIRE bands) is formed by at least 10 dusty star-forming galaxies (DSFGs), spectroscopically confirmed to lie at

z

spec

=
4.002

via detection of [C i](1–0), 12CO(6–5), 12CO(4–3), 12CO(2–1), and

H

2

O
(

2

11

–

2

02

)

emission lines with ALMA and ATCA. These DSFGs are distributed over a

260

kpc
×
310

kpc

region and have a collective obscured star formation rate (SFR) of

∼
6500

M

⊙

yr

−
1

, considerably higher than those seen before in any protocluster at

z
≳
4

. Most of the star formation is taking place in luminous DSFGs since no Lyα emitters are detected in the protocluster core, apart from a Lyα blob located next to one of the DRC components, extending over

60

kpc

. The total obscured SFR of the protocluster could rise to

SFR
∼
14,400

M

⊙

yr

−
1

if all the members of an overdensity of bright DSFGs discovered around DRC in a wide-field Large APEX BOlometer CAmera 870 μm image are part of the same structure. [C i](1–0) emission reveals that DRC has a total molecular gas mass of at least

M

H

2

∼
6.6
×

10

11

M

⊙

, and its total halo mass could be as high as

∼
4.4
×

10

13

M

⊙

, indicating that it is the likely progenitor of a cluster at least as massive as Coma at z = 0.
Coronal Elemental Abundances in Solar Emerging Flux Regions
Authors: Baker Deborah , Brooks David H. , Driel-Gesztelyi Lidia van , James Alexander W. , Démoulin Pascal , Long David M. , Warren Harry P. , Williams David R.
Published: March 2018

The chemical composition of solar and stellar atmospheres differs from the composition of their photospheres. Abundances of elements with low first ionization potential (FIP) are enhanced in the corona relative to high-FIP elements with respect to the photosphere. This is known as the FIP effect and it is important for understanding the flow of mass and energy through solar and stellar atmospheres. We used spectroscopic observations from the Extreme-ultraviolet Imaging Spectrometer on board the Hinode observatory to investigate the spatial distribution and temporal evolution of coronal plasma composition within solar emerging flux regions inside a coronal hole. Plasma evolved to values exceeding those of the quiet-Sun corona during the emergence/early-decay phase at a similar rate for two orders of magnitude in magnetic flux, a rate comparable to that observed in large active regions (ARs) containing an order of magnitude more flux. During the late-decay phase, the rate of change was significantly faster than what is observed in large, decaying ARs. Our results suggest that the rate of increase during the emergence/early-decay phase is linked to the fractionation mechanism that leads to the FIP effect, whereas the rate of decrease during the later decay phase depends on the rate of reconnection with the surrounding magnetic field and its plasma composition.
Magnetic Structure of a Composite Solar Microwave Burst
Authors: Lee Jeongwoo , White Stephen M. , Liu Chang , Kliem Bernhard , Masuda Satoshi
Published: March 2018

A composite flare consisting of an impulsive flare SOL2015-06-21T01:42 (GOES class M2.0) and a more gradual, long-duration flare SOL2015-06-21T02:36 (M2.6) from NOAA Active Region 12371, is studied using observations with the Nobeyama Radioheliograph (NoRH) and the Solar Dynamics Observatory (SDO). While composite flares are defined by their characteristic time profiles, in this paper we present imaging observations that demonstrate the spatial relationship of the two flares and allow us to address the nature of the evolution of a composite event. The NoRH maps show that the first flare is confined not only in time, but also in space, as evidenced by the stagnation of ribbon separation and the stationarity of the microwave source. The NoRH also detected another microwave source during the second flare, emerging from a different location where thermal plasma is so depleted that accelerated electrons could survive longer against Coulomb collisional loss. The AIA 131 Å images show that a sigmoidal EUV hot channel developed after the first flare and erupted before the second flare. We suggest that this eruption removed the high-lying flux to let the separatrix dome underneath reconnect with neighboring flux and the second microwave burst follow. This scenario explains how the first microwave burst is related to the much-delayed second microwave burst in this composite event.
Hunting Faint Dwarf Galaxies in the Field Using Integrated Light Surveys
Authors: Danieli Shany , van Dokkum Pieter , Conroy Charlie
Published: March 2018

We discuss the approach of searching the lowest mass dwarf galaxies,

, in the general field, using integrated light surveys. By exploring the limiting surface brightness-spatial resolution (μ
eff,lim−θ) parameter space, we suggest that faint field dwarfs in the Local Volume, between 3 and 10 Mpc, are expected to be detected very effectively and in large numbers using integrated light photometric surveys, complementary to the classical star counts method. We use a sample of dwarf galaxies in the Local Group to construct relations between their photometric and structural parameters, M
*–μ
eff,V
and M
*–R
eff. We use these relations, along with assumed functional forms for the halo mass function and the stellar mass–halo mass (SMHM) relation, to calculate the lowest detectable stellar masses in the Local Volume and the expected number of galaxies as a function of the limiting surface brightness and spatial resolution. The number of detected galaxies depends mostly on the limiting surface brightness for distances >3 Mpc, while spatial resolution starts to play a role for galaxies at distances >8 Mpc. Surveys with μ
eff,lim ∼ 30 mag arcsec−2 should be able to detect galaxies with stellar masses down to ∼104
M
⊙ in the Local Volume. Depending on the form of the SMHM relation, the expected number of dwarf galaxies with distances between 3 and 10 Mpc is 0.04–0.35 per square degree, assuming a limiting surface brightness of ∼29–30 mag arcsec−2 and a spatial resolution <4″. We plan to search for a population of low-mass dwarf galaxies in the field by performing a blank wide field photometric survey with the Dragonfly Telephoto Array, an imaging system optimized for the detection of extended ultra low surface brightness structures.
LensFlow: A Convolutional Neural Network in Search of Strong Gravitational Lenses
Authors: Pourrahmani Milad , Nayyeri Hooshang , Cooray Asantha
Published: March 2018

In this work, we present our machine learning classification algorithm for identifying strong gravitational lenses from wide-area surveys using convolutional neural networks; LensFlow. We train and test the algorithm using a wide variety of strong gravitational lens configurations from simulations of lensing events. Images are processed through multiple convolutional layers that extract feature maps necessary to assign a lens probability to each image. LensFlow provides a ranking scheme for all sources that could be used to identify potential gravitational lens candidates by significantly reducing the number of images that have to be visually inspected. We apply our algorithm to the HST/ACS i-band observations of the COSMOS field and present our sample of identified lensing candidates. The developed machine learning algorithm is more computationally efficient and complimentary to classical lens identification algorithms and is ideal for discovering such events across wide areas from current and future surveys such as LSST and WFIRST.
Future Cosmological Constraints From Fast Radio Bursts
Authors: Walters Anthony , Weltman Amanda , Gaensler B. M. , Ma Yin-Zhe , Witzemann Amadeus
Published: March 2018

We consider the possible observation of fast radio bursts (FRBs) with planned future radio telescopes, and investigate how well the dispersions and redshifts of these signals might constrain cosmological parameters. We construct mock catalogs of FRB dispersion measure (DM) data and employ Markov Chain Monte Carlo analysis, with which we forecast and compare with existing constraints in the flat ΛCDM model, as well as some popular extensions that include dark energy equation of state and curvature parameters. We find that the scatter in DM observations caused by inhomogeneities in the intergalactic medium (IGM) poses a big challenge to the utility of FRBs as a cosmic probe. Only in the most optimistic case, with a high number of events and low IGM variance, do FRBs aid in improving current constraints. In particular, when FRBs are combined with CMB+BAO+SNe+H
0 data, we find the biggest improvement comes in the

constraint. Also, we find that the dark energy equation of state is poorly constrained, while the constraint on the curvature parameter, Ω
k
, shows some improvement when combined with current constraints. When FRBs are combined with future baryon acoustic oscillation (BAO) data from 21 cm Intensity Mapping, we find little improvement over the constraints from BAOs alone. However, the inclusion of FRBs introduces an additional parameter constraint,

, which turns out to be comparable to existing constraints. This suggests that FRBs provide valuable information about the cosmological baryon density in the intermediate redshift universe, independent of high-redshift CMB data.
Parameterizing the Supernova Engine and Its Effect on Remnants and Basic Yields
Authors: Fryer Chris L. , Andrews Sydney , Even Wesley , Heger Alex , Safi-Harb Samar
Published: March 2018

Core-collapse supernova science is now entering an era in which engine models are beginning to make both qualitative and, in some cases, quantitative predictions. Although the evidence in support of the convective engine for core-collapse supernova continues to grow, it is difficult to place quantitative constraints on this engine. Some studies have made specific predictions for the remnant distribution from the convective engine, but the results differ between different groups. Here we use a broad parameterization for the supernova engine to understand the differences between distinct studies. With this broader set of models, we place error bars on the remnant mass and basic yields from the uncertainties in the explosive engine. We find that, even with only three progenitors and a narrow range of explosion energies, we can produce a wide range of remnant masses and nucleosynthetic yields.
Star Formation Histories of the LEGUS Dwarf Galaxies. I. Recent History of NGC 1705, NGC 4449, and Holmberg II*
Authors: Cignoni M. , Sacchi E. , Aloisi A. , Tosi M. , Calzetti D. , Lee J. C. , Sabbi E. , Adamo A. , Cook D. O. , Dale D. A. , Elmegreen B. G. , Gallagher J. S. , Gouliermis D. A. , Grasha K. , Grebel E. K. , Hunter D. A. , Johnson K. E. , Messa M. , Smith L. J. , Thilker D. A. , Ubeda L. , Whitmore B. C.
Published: March 2018

We use Hubble Space Telescope observations from the Legacy Extragalactic UV Survey to reconstruct the recent star formation histories (SFHs) of three actively star-forming dwarf galaxies, NGC 4449, Holmberg II, and NGC 1705, from their UV color–magnitude diagrams (CMDs). We apply a CMD fitting technique using two independent sets of stellar isochrones, PARSEC-COLIBRI and MIST, to assess the uncertainties related to stellar evolution modeling. Irrespective of the adopted stellar models, all three dwarfs are found to have had almost constant star formation rates (SFRs) in the last 100–200 Myr, with modest enhancements (a factor of ∼2) above the 100 Myr averaged SFR. Significant differences among the three dwarfs are found in terms of the overall SFR, the timing of the most recent peak, and the SFR/area. The initial mass function of NGC 1705 and Holmberg II is consistent with a Salpeter slope down to ≈5 M
⊙, whereas it is slightly flatter, s = −2.0, in NGC 4449. The SFHs derived with the two different sets of stellar models are consistent with each other, except for some quantitative details, attributable to their input assumptions. They also share the drawback that all synthetic diagrams predict a clear separation in color between the upper main-sequence and helium-burning stars, which is not apparent in the data. Since neither differential reddening, which is significant in NGC 4449, nor unresolved binaries appear to be sufficient to fill the gap, we suggest this calls for a revision of both sets of stellar evolutionary tracks.
H i Kinematics along the Minor Axis of M82
Authors: Martini Paul , Leroy Adam K. , Mangum Jeffrey G. , Bolatto Alberto , Keating Katie M. , Sandstrom Karin , Walter Fabian
Published: March 2018

M82 is one of the best-studied starburst galaxies in the local universe, and is consequently a benchmark for studying star formation feedback at both low and high redshift. We present new VLA H i observations that reveal the cold gas kinematics along the minor axis in unprecedented detail. This includes the detection of H i up to 10 kpc along the minor axis toward the south and beyond 5 kpc to the north. A surprising aspect of these observations is that the line-of-sight H i velocity decreases substantially from about 120 to

from 1.5 to 10 kpc off the midplane. The velocity profile is not consistent with the H i gas cooling from the hot wind. We demonstrate that the velocity decrease is substantially greater than the deceleration expected from gravitational forces alone. If the H i consists of a continuous population of cold clouds, some additional drag force must be present, and the magnitude of the drag force places a joint constraint on the ratio of the ambient medium to the typical cloud size and density. We also show that the H i kinematics are inconsistent with a simple conical outflow centered on the nucleus, but instead require the more widespread launch of the H i over the ∼1 kpc extent of the starburst region. Regardless of the launch mechanism for the H i gas, the observed velocity decrease along the minor axis is sufficiently great that the H i may not escape the halo of M82. The inferred H i outflow rate at 10 kpc off the midplane is much less than 1

yr−1.
A Multiple Ejecta-circumstellar Medium Interaction Model and Its Implications for Superluminous Supernovae iPTF15esb and iPTF13dcc
Authors: Liu Liang-Duan , Wang Ling-Jun , Wang Shan-Qin , Dai Zi-Gao
Published: March 2018

In this paper, we investigate two hydrogen-poor superluminous supernovae (SLSNe), iPTF15esb and iPTF13dcc, whose light curves (LCs) show significant deviation from the smooth rise and fall. The LC of iPTF15esb exhibits two peaks and a post-peak plateau, and furthermore the late-time spectrum of iPTF15esb shows a strong, broad Hα emission line. The early-time LC of iPTF13dcc shows a long-duration bump followed by the second peak. Here, we propose an ejecta-circumstellar medium interaction model involving multiple shells/winds and use it to explain the LCs of iPTF15esb and iPTF13dcc. We find that the theoretical LCs reproduced by this model can match observations of iPTF15esb and iPTF13dcc. Based on our results, we infer that the progenitors have undergone multiple violent mass-loss processes before the SN explosion. In addition, we find that the variation trend of our inferred densities of the shells is consistent with that predicted by the stellar mass-loss history before an SN explosion. Further investigations for other bumpy SLSNe/SNe would shed light on their nature and provide a probe for the mass-loss history of their progenitors.
Study of the Abundance Features of the Metal-poor Star HD 94028
Authors: Han Wanqiang , Zhang Lu , Yang Guochao , Niu Ping , Zhang Bo
Published: March 2018

Recent work has found that the metal-poor star HD 94028 shows interesting abundance features. The s-process material (e.g., Ba, La, Ce, and Pb) and r-process material (e.g., Eu, Os, Pt) are mildly overabundant while the element C is not enhanced. However, the observed supersolar ratio [As/Ge] (=0.99 ± 0.23) and subsolar ratio [Se/As] (=−0.16 ± 0.22) could not be fitted by the combination of s- and r-process abundances. In this work, adopting the abundance decomposition method, we investigate the astrophysical origins of the elements in this star. We find that the primary process of massive stars dominates the production of the light elements and iron-group elements. The lighter neutron-capture elements from Ge to Te mainly come from the weak r-process. The elements from Ba to Pb are synthesized dominantly by the main s- and main r-process. The observed abundance features of Ge, As, and Se in HD 94028 are mainly produced by the weak r-process, which possesses the features of the supersolar ratio [As/Ge] and subsolar ratio [Se/As]. Because Ge is not synthesized solely by the neutron-capture process, As should be the lightest neutron-capture element. Although the i-process has been suggested in several astrophysical environments, it should be superfluous to explaining the abundances of the lighter neutron-capture elements in HD 94028.
Jets in Hydrogen-poor Superluminous Supernovae: Constraints from a Comprehensive Analysis of Radio Observations
Authors: Coppejans D. L. , Margutti R. , Guidorzi C. , Chomiuk L. , Alexander K. D. , Berger E. , Bietenholz M. F. , Blanchard P. K. , Challis P. , Chornock R. , Drout M. , Fong W. , MacFadyen A. , Migliori G. , Milisavljevic D. , Nicholl M. , Parrent J. T. , Terreran G. , Zauderer B. A.
Published: March 2018

The energy source powering the extreme optical luminosity of hydrogen-stripped superluminous supernovae (SLSNe-I) is not known, but recent studies have highlighted the case for a central engine. Radio and/or X-ray observations are best placed to track the fastest ejecta and probe the presence of outflows from a central engine. We compile all the published radio observations of SLSNe-I to date and present three new observations of two new SLSNe-I. None were detected. Through modeling the radio emission, we constrain the subparsec environments and possible outflows in SLSNe-I. In this sample, we rule out on-axis collimated relativistic jets of the kind detected in gamma-ray bursts (GRBs). We constrain off-axis jets with opening angles of 5° (30°) to energies of

E

k

<
4
×

10

50

erg

(

E

k

<

10

50

erg

) in environments shaped by progenitors with mass-loss rates of

M

˙

<

10

−
4

M

⊙

yr

−
1

(

M

˙

<

10

−
5

M

⊙

yr

−
1

) for all off-axis angles, assuming fiducial values

ϵ

e

=
0.1

and

ϵ

B

=
0.01

. The deepest limits rule out emission of the kind seen in faint uncollimated GRBs (with the exception of GRB 060218) and from relativistic SNe. Finally, for the closest SLSN-I, SN 2017egm, we constrain the energy of an uncollimated nonrelativistic outflow like those observed in normal SNe to

E

k

≲

10

48

erg.
The Inhomogeneous Reionization Times of Present-day Galaxies
Authors: Aubert Dominique , Deparis Nicolas , Ocvirk Pierre , Shapiro Paul R. , Iliev Ilian T. , Yepes Gustavo , Gottlöber Stefan , Hoffman Yehuda , Teyssier Romain
Published: March 2018

Today’s galaxies experienced cosmic reionization at different times in different locations. For the first time, reionization (50% ionized) redshifts, z

R
, at the location of their progenitors are derived from new, fully coupled radiation-hydrodynamics simulation of galaxy formation and reionization at z > 6, matched to N-body simulation to z = 0. Constrained initial conditions were chosen to form the well-known structures of the local universe, including the Local Group and Virgo, in a (91 Mpc)3 volume large enough to model both global and local reionization. Reionization simulation CoDa I-AMR, by CPU-GPU code EMMA, used (2048)3 particles and (2048)3 initial cells, adaptively refined, while N-body simulation CoDa I-DM2048, by Gadget2, used (2048)3 particles, to find reionization times for all galaxies at z = 0 with masses M(z = 0) ≥ 108
M
⊙. Galaxies with

reionized earlier than the universe as a whole, by up to ∼500 Myr, with significant scatter. For Milky Way–like galaxies, z

R
ranged from 8 to 15. Galaxies with

typically reionized as late or later than globally averaged 50% reionization at

, in neighborhoods where reionization was completed by external radiation. The spread of reionization times within galaxies was sometimes as large as the galaxy-to-galaxy scatter. The Milky Way and M31 reionized earlier than global reionization but later than typical for their mass, neither dominated by external radiation. Their most-massive progenitors at z > 6 had z

R
 =9.8 (MW) and 11 (M31), while their total masses had z

R
 = 8.2 (both).
The Excited Spin State of 1I/2017 U1 ‘Oumuamua
Authors: Belton Michael J. S. , Hainaut Olivier R. , Meech Karen J. , Mueller Beatrice E. A. , Kleyna Jan T. , Weaver Harold A. , Buie Marc W. , Drahus Michał , Guzik Piotr , Wainscoat Richard J. , Waniak Wacław , Handzlik Barbara , Kurowski Sebastian , Xu Siyi , Sheppard Scott S. , Micheli Marco , Ebeling Harald , Keane Jacqueline V.
Published: March 2018

We show that ‘Oumuamua’s excited spin could be in a high-energy long axis mode (LAM) state, which implies that its shape could be far from the highly elongated shape found in previous studies. CLEAN and ANOVA algorithms are used to analyze ‘Oumuamua’s lightcurve using 818 observations over 29.3 days. Two fundamental periodicities are found at frequencies (2.77 ± 0.11) and (6.42 ± 0.18) cycles/day, corresponding to (8.67 ± 0.34) hr and (3.74 ± 0.11) hr, respectively. The phased data show that the lightcurve does not repeat in a simple manner, but approximately shows a double minimum at 2.77 cycles/day and a single minimum at 6.42 cycles/day. ‘Oumuamua could be spinning in either the LAM or short axis mode (SAM). For both, the long axis precesses around the total angular momentum vector with an average period of (8.67 ± 0.34) hr. For the three LAMs we have found, the possible rotation periods around the long axis are 6.58, 13.15, or 54.48 hr, with 54.48 hr being the most likely. ‘Oumuamua may also be nutating with respective periods of half of these values. We have also found two possible SAM states where ‘Oumuamua oscillates around the long axis with possible periods at 13.15 and 54.48 hr. In this case any nutation occurs with the same periods. Determination of the spin state, the amplitude of the nutation, the direction of the total angular momentum vector (TAMV), and the average total spin period may be possible with a direct model fit to the lightcurve. We find that ‘Oumuamua is “cigar-shaped,” if close to its lowest rotational energy, and an extremely oblate spheroid if close to its highest energy state.
Two new species of Ephysteris Meyrick, 1908, from Asia with brachypterous males (Lepidoptera, Gelechiidae)
Authors: Bidzilya Oleksiy , Karsholt Ole
Published: March 2018

Two new species of Gelechiidae:Ephysteriskullbergisp. n.from Tuva (Russia) andEphysterisustjuzhaninisp. n.from Mongolia are described. In both species the hindwings in both sexes are distinctly reduced. The adults and genitalia are illustrated. Brachyptery in Gelechiidae andEphysterisis briefly discussed, and type locality ofE.kullbergisp. n.is illustrated. The locomotion ofE.kullbergisp. n.is described.
Mantophasmatodea from the Richtersveld in South Africa with description of two new genera and species
Authors: Wipfler Benjamin , Theska Tobias , Predel Reinhard
Published: March 2018

Two new species and two new genera (Kuboesphasma, Minutophasma) of Mantophasmatodea that occur in the Richtersveld region of South Africa are described. Kuboesphasmacompactum gen. n., sp. n. was found only in a small area near the village of Kuboes, while Minutophasmarichtersveldense gen. n., sp. n. apparently inhabits a larger area in the Richtersveld. With these two new species, a total of four different mantophasmatodeans are known to live in this area. This is a remarkable exception to the remaining representatives of this order, where even a common occurrence of only two species is rare. We discuss this sympatry in the context of the phylogeny of the group. Additionally, we provide a map of the known distributions and a table with the most important taxonomic features of the mantophasmatodeans in the Richtersveld.
THE DISTRIBUTIONS OF AIRFLOW WITHIN THE UPPER AIRWAY AND POSTURE CHANGES OF SOFT PALATE IN PATIENTS WITH OSAHS AFTER NASAL STRUCTURAL CORRECTION
Authors: Wang Gang , Yu Chi , Wang Ying
Published: March 2018

Nasal obstruction frequently has been associated with obstructive sleep apnea-hypopnea syndrome (OSAHS). Based on the CT data before and after the operation of the three Chinese patients, 3D numerical models involving the upper airway and the soft palate are established. Computational modeling for inspiration and expiration was performed by using fluid–structure interaction (FSI) method. The airflow characteristics such as velocity and pressure drop, and displacement distribution of soft palate are selected for comparison. The distribution of airflow in the upper airway and the motion changes of the soft palate are analyzed quantitively before and after the surgery. From the results, that the inner connection between the both upper and lower part of the upper airway is very complex due to the individual difference of own unique feature of upper airway. Whether can it treat OSAHS only through nasal surgery, which depends primarily on the improvement of ventilation in upper part of upper airway giving a beneficial effect on the lower part (especially in the velopharyngeal region). The simulation results correspond with the monitoring results of polysomnography (PSG) and the patient's presenting complaint. Moreover, the mechanical parameters obtained by numerical simulation can support the improvement of OSAHS symptoms after surgery, which provides quantitative and referential evidence for further study the role of nasal structure in OSAHS and the treatment effect of nasal surgery on OSAHS.
Surface Modification for Detection of Liver Cancer Biomarker
Authors: Wangkham Thidarat
Published: March 2018

Materials modification with surface functional group for bioactive film or sensor surface is important in many applications. A suitable surface for each system can be shown high efficiency of detection. In this work, two different surfaces via covalent binding are created on gold substrate for finding the suitable surface in medical applications. The liver cancer biomarker, alpha-fetoprotein (AFP) was detected on two surfaces; one is carboxy dextran and another is a modified polymethyl metacrylate (PMMA). The substrates were improved by physical and chemical binding for AFP antibody immobilization. Contact angle and surface Plasmon resonance (SPR) were used to study the characteristic of surfaces. The result was found that the carboxy dextran gave higher detection than PMMA. Moreover, the dextran surface was studied in real serum samples. It was shown the significantly different between positive and negative AFP serum which is preliminary results for testing in more clinical samples further.
Stress-Strain Responses of Multi-Phase CoCrCuMnNi and CoCrMnFeCu Alloys
Authors: Kang You Bin , Oh Seung Min , Lee Kap Ho , Hong Sun Ig
Published: March 2018

Stress-strain responses and microstructure of multi-phase CoCrCuMnNi and CoCrMnFeCu alloys in which Fe or Ni was replaced by Cu from Cantor alloy were studied. The deformation mechanisms of CoCrCuMnNi and CoCrMnFeCu were observed to be influenced by the presence of brittle sigma phase and the separated Cu-rich and the matrix phase. CoCrCuMnNi exhibited the relatively lower strength and excellent deformability, while CrMnFeCoCu alloy exhibited higher strength and lower ductility. The higher strength and the lower ductility of CoCrCuMnNi is associated with the presence more frequent and coarser sigma phase than those in CoCrCuMnNi.
Effect of Tantalum (Ta) Addition to Zinc-Aluminum Alloy 5 (ZA5) on its Microstructure and Fatigue Life
Authors: Zaid Adnan I.O. , Weraikat Dua O.
Published: March 2018

Due to their resistance to wear and corrosion, the use of Zinc-Aluminum (Zn-Al) alloys in general and Zinc-Aluminum 5 (ZA5) alloys, in particular, have spread in the last two decades in industrial applications. These alloys normally solidify in a coarse dendritic structure which affects their surface quality and mechanical behavior. Therefore, their structure is normally refined by rare earth materials, such as Titanium (Ti), Titanium-Boron (Ti-B) or zirconium (Zr). In this research, the effect of adding Tantalum (Ta) to ZA5, at the following percentages: 0.02%, 0.04%, 0.06%, 0.08%, and 0.10%, on its microstructure and fatigue life is investigated. The results of this work revealed, within the experimental range, that the addition of Ta as a grain refiner at all rates could change the coarse dendritic structure of ZA5 into a fine nodular one. It was also found that adding Ta at 0.04% to ZA5 increased its fatigue life at a stress level of 160 MPa. However, adding Ta at a rate percentage higher than 0.04% and at stress level exceeding 160 MPa resulted in deterioration of its fatigue life.
Visualization of Contact-Pressure Distribution between Material and Backing Plate in Friction Stir Processing
Authors: Ohashi Takahiro , Tong Xin , Zhao Zi Jie , Mofidi Tabatabaei Hamed , Nishihara Tadashi
Published: March 2018

In this study, the authors evaluated pressure distribution on a backing plate in friction-stir processing (FSP) utilizing an embedded pressure pin connected to a load sensor. They conducted FSP on aluminum alloy plates repeatedly offsetting the path-lines from the center of the pin and recorded change of forming pressure with tool position, which was compiled from the bearing load of the pin. The authors mapped the results to visualize the two-dimensional contact pressure distribution on a backing plate during FSP. They then compared the height distribution of the wall fabricated by friction-stir forming (FSF) utilizing a die having a groove with the observed distribution of pressure. Consequently, maximum pressure was observed beneath the rim of the tool probe at the retreating side (RS), and the highest points of the wall were observed at the RS.
3-D FEM Simulation of Laser Peening Straightening for Shaft Straightness
Authors: Su Bo Yong , Zhang Yong Kang , Sun Gui Fang , Xu Pei , Zhu Ran , Ni Zhong Hua
Published: March 2018

The straightness is an important indicator in measuring the quality of shaft parts. Laser peening straightening (LPS) is a new mechanical method to straight the shaft through inducing residual compressive stress into the shaft surface. Compared with the traditional method, the process of laser peening correction is high efficiency and can be controlled precisely. In the present work, the mechanism of laser peening straightening for shaft straightness is revealed and a three-dimensional finite model is developed to investigate the effects of laser parameters for shaft straightness correction. The results show that the peak pressure and pulse duration should be more than 4 GPa and 8 ns when laser peening straightening is used to correct the shaft straightness. The straightening amount increases with laser power density, laser pulse duration, multiple laser peening. The maximum correction amount for shaft straightness with LPS is no more than 0.01mm.
Improvement of Bending Strength of Resin Coated Sand
Authors: Jariyajirawatana Jakkapan , Osothsilp Napassavong
Published: March 2018

This research proposed a method to improve bending strength of RCS used in hollow core production by finding the optimal levels of factors in the mixing process. Process factors under study were temperature of sand, time to release phenolic resin, time to release hexamine solution, time to start air blowing, air blowing time duration, and time to release calcium stearate. Experiments with Central Composite Face-centered (CCF) design were performed to save the number of experimental runs. Then, backward elimination regression analysis was performed to find out the relationship equation of bending strength and significant process factors. Next, the optimization technique was applied to determine the optimal setting of those significant process factors. The comfirmatory result showed that bending strength was significantly improved.
Effects of Resin Coated Sand Mixture on Bending Strength and Cost
Authors: Sirivimonpan Puvadol , Osothsilp Napassavong
Published: March 2018

This research proposed a method to find out the relationship between bending strength of resin coated sand and the proportion of different types of sand and resin. It was figured out that Central Composite Design (CCD) was suitable to be used to save the number of experimental runs. Then, backward elimination regression analysis was used to determine the relationship equation of bending strength and proportion of different types of sand and resin. Next, optimization technique was applied to determine the optimal new setting, which provided any targeted level of bending strength with the minimal total cost of sand and resin. The results showed that the experimental results obtained from the CCD experiments provided the regression model, which had less than 6% error from the actual bending strength value. With this proposed method the total cost of sand and resin was reduced by 28.6% on average and it also provided the bending strength on any required target level.
Design of Alternating Current Abrasive Magnetic Fluid Jet Generator Based on Permanent Magnet
Authors: Li Chang Peng , Chen Hai Bin
Published: March 2018

During the test of DC(direct current) abrasive magnetic fluid technology,many bubbles and noises were generated near the graphite electrode , and the yellow green liquid was produced, which affected the further test.Through the study of graphite electrode, it was found that NaCl solution magnetic fluid produced hydrogen and chlorine gas after electrolysis. At the same time, chlorine gas dissolved in water to form yellow green liquid.The magnetic field of neodymium boron permanent magnet was equivalent to a mechanical stirring, which inhibited the production of chlorine gas.According to the difference of impressed current system, the abrasive magnetic fluid jet technology was divided into DC and AC(alternating current) .There was no electrode in AC abrasive magnetic fluid jet technology, so no gas or noise would be produced.The rotating magic ring permanent magnet produced alternating magnetic field, acting on the abrasive magnetic fluid to form an induced current.Under the action of the magnetic field, the electromagnetic force was applied to move along the circumferential direction to promote the motion of the abrasive magnetic fluid.
Degree of Reaction and Alkali-Leaching of Geopolymer Containing Ca-Rich Source Material and Dipotassium Hydrogen Phosphate
Authors: Rahman Norbaizurah , Kusbiantoro Andri , Muthusamy Khairunisa , Al Bakri Abdullah Mohd Mustafa
Published: March 2018

Disparity of anion and cation in geopolymer framework may result in the formation of efflorescence on the surface of hardened geopolymer specimen. The existence of efflorescence would be intensified with the use of dipotassium hydrogen phosphate (K2HPO4) as a chemical retarder for geopolymer mixture. In this study, paper mill sludge ash (PMSA) was used as a Ca-rich aluminosilicate source to reduce the development of efflorescence crystals. PMSA was utilized to partially replace fly ash at 5% and 10% (by weight of fly ash). Meanwhile, K2HPO4 was used as the external agent with various proportions, which were 0.1%, 0.3%, and 0.5% (by weight of fly ash). The external agent in this study was purposed to extend the setting time and enhance the mechanical properties of geopolymer. Fly ash and PMSA (if any) were activated by reacting them with 6M sodium hydroxide and sodium silicate solution. Freshly cast specimens were cured for 24 hours in electronic oven with the temperature setting of 30°C and 90°C. They were demoulded after 24 h and kept at room temperature (28±2 °C) until the testing day. Evaluation on the setting time characteristic of fresh geopolymer mortar was conducted with Vicat test while degree of reaction was performed on the hardened specimens to measure the reaction of fly ash during geopolymerization. Based on the experimental result, the inclusion of 5% PMSA shows the greatest effect in reducing the development of efflorescence crystal and increase the degree of reaction of geopolymer system. It is presumed that PMSA has altered the geopolymerization process by activating calcium oxide precursors to form three tetrahedral structures in the framework.
Tensile Strength of Green Self-Consolidating Concrete
Authors: Mohamed Osama Ahmed , Najm Omar Fawwaz , Al Hawat Waddah
Published: March 2018

The environmental footprint of the construction industry in general must be reduced. The process of manufacturing cement involves the release of appreciable amounts of CO2 into the atmosphere. This paper summarizes the findings of an experimental study aiming at assessing the splitting tensile strength of self-consolidating concrete (SCC) in which 90% of the cement was replaced with various amounts of the industrial by-products including silica fume, fly ash, and ground granulated blast furnace slag (GGBS). Due to the high replacement ratio of cement with recycled industrial by-products, the produced SCC is referred in this study as green concrete. The compressive strength ranged between 30 MPa and 50 MPa and was produced with water/cementitious material ratios of 0.33 and 0.36. The splitting tensile strength was determined and a correlation was developed using regression analysis between the splitting tensile strength and compressive strength.
Preparation and Characterization of Magnetic Force Microscopy Tips Coated with Nickel Films by e-Beam Evaporation
Authors: Damrongsak Badin , Coomkaew Samutchar , Saengkaew Karnt , Cheowanish Ittipon , Jantaratana Pongsakorn
Published: March 2018

In this work, magnetic force microscopy (MFM) tips coated with a nickel thin-film were prepared and characterized for applications in the measurement of the magnetic write field. Nickel films with various thicknesses in a range of 20 – 80 nm were deposited on silicon substrates and silicon atomic force microscopy (AFM) tips by electron beam evaporation. Film surface morphologies and magnetic properties of the coated nickel films were investigated by using AFM and vibrating sample magnetometry (VSM). The rms roughness increased with the film thickness and was in a range between 0.1 and 0.3 nm. VSM results revealed that the mean coercive field of the nickel films was 20 Oe and there was an increase in the coercivity as the film thickness increased. In addition, the prepared MFM tips were evaluated for the tip response to the dc and ac magnetic field generated from perpendicular write heads. It was found that the MFM tip had the best response to the write field when coated with 60 nm thick nickel film. The coating thickness over 60 nm was inapplicable due to the cantilever bending caused by the film stress.