bluuebunny/crossref_metadata_2025 huggingface dataset:
POLA LEMBAGA KEAGAMAAN DALAM MERESPON WABAH COVID-19
Authors: Anam Ahmad Misbahul
Published: September 2020

Tujuan Penelitian: Penelitian ini bertujuan untuk mengungkap pola lembaga keagamaan dalam merespon wabah Covid-19. Metode Penelitian: Kualitatif. Hasil Penelitian: Terdapat pola yang sama dari masing-masing lembaga untuk menempatkan hasil Fatwa MUI sebagai pondasi pijakan, kemudian dilanjutkan dengan penerbitan himbauan yang lebih teknis oleh masing-masing lembaga. Himbauan tersebut mengajak seluruh komponen unit dibawahnya untuk menyiapkan berbagai hal yang memungkin, akibat dampak Civid-19. Ada satu implikasi yang berharga dari kasus ini, yaitu mulai berangsur-angsur menempatkan posisi MUI sebagai perekat dan penyatu ummat, khususnya dalam hal-hal yang bersinggungan dengan pemerintah. Jika pola hirarki menempatkan MUI sebagai dasar hukum dalam aspek yang luas, maka akan memudahkan persatuan umat kedepan. Pola seperti ini sebenarnya bukan kali pertama MUI mengambil peran dan lembaga mitra berpartisipasi, sudah banyak Fatwa yang telah diputuskan dan mendapat respon dukungan dari lembaga keagamaan. Tapi pada kali ini, karena fenomena masail fiqiyahnya berskala nasional, peran lembaga keagamaan juga semakin maksimal.
APPLICATION OF ENERGY AND EXERGY ANALYSIS TO INVESTIGATE THE OPERATION OF AN AIR HANDLING UNIT WITH HEAT PUMP
Authors: Streckienė Giedrė , Kropas Tomas
Published: September 2020

With the growth of energy-efficient building sector, ventilation systems are becoming increasingly important not only of fresh air supply but also in terms of energy consumption. The aim of this paper is to describe and analyse the operation of an air handling unit (AHU) with a heat pump using energy and exergy analyses under the variable environmental temperature (from –30 °C to 10 °C). The application of selected methods is illustrated in a case study of an AHU using environmental temperatures of Vilnius city during heating season (from the beginning of October to the end of April). An analytical method for determining distribution of the environmental (outdoor air) temperature is used. Energy and exergy analyses showed periods when the highest amounts of energy and exergy were consumed and the greatest exergy losses occurred. This allowed to reveal the component of the system with the highest exergy losses – the heat pump evaporator. Therefore, further research is needed for its design and application. At the end of the article, the seasonal indicators of the AHU with heat pump operation were calculated: coefficient of performance and exergy efficiency. The presented research procedure could be applied to the analysis of other energy systems and processes in them.
The Most Metal-poor Stars in the Inner Bulge*
Authors: Reggiani Henrique , Schlaufman Kevin C. , Casey Andrew R. , Ji Alexander P.
Published: September 2020

The bulge is the oldest component of the Milky Way. Since numerous simulations of Milky Way formation have predicted that the oldest stars at a given metallicity are found on tightly bound orbits, the Galaxy’s oldest stars are likely metal-poor stars in the inner bulge with small apocenters (i.e., R
apo ≲ 4 kpc). In the past, stars with these properties have been impossible to find due to extreme reddening and extinction along the line of sight to the inner bulge. We have used the mid-infrared metal-poor star selection of Schlaufman & Casey (2014) on Spitzer/Galactic Legacy Infrared Mid-Plane Survey Extraordinaire data to overcome these problems and target candidate inner bulge metal-poor giants for moderate-resolution spectroscopy with Anglo-Australian Telescope/AAOmega. We used those data to select three confirmed metal-poor giants ([Fe/H] = −3.15, −2.56, −2.03) for follow-up high-resolution Magellan/Magellan Inamori Kyocera Echelle spectroscopy. A comprehensive orbit analysis using Gaia DR2 astrometry and our measured radial velocities confirms that these stars are tightly bound inner bulge stars. We determine the elemental abundances of each star and find high titanium and iron-peak abundances relative to iron in our most metal-poor star. We propose that the distinct abundance signature we detect is a product of nucleosynthesis in the Chandrasekhar-mass thermonuclear supernova of a CO white dwarf accreting from a helium star with a delay time of about 10 Myr. Even though chemical evolution is expected to occur quickly in the bulge, the intense star formation in the core of the nascent Milky Way was apparently able to produce at least one Chandrasekhar-mass thermonuclear supernova progenitor before chemical evolution advanced beyond

.
Unusual Galactic H ii Regions at the Intersection of the Central Molecular Zone and the Far Dust Lane
Authors: Anderson L. D. , Sormani M. C. , Ginsburg Adam , Glover Simon C. O. , Heywood I. , Rammala I. , Schuller F. , Csengeri T. , Urquhart J. S. , Bronfman Leonardo
Published: September 2020

Sgr E is a massive star formation complex found toward the Galactic center that consists of numerous discrete, compact H ii regions. It is located at the intersection between the central molecular zone (CMZ) and the far dust lane of the Galactic bar, similar to “hot spots” seen in external galaxies. Compared with other Galactic star formation complexes, the Sgr E complex is unusual because its H ii regions all have similar radio luminosities and angular extents, and they are deficient in ∼10 μm emission from their photodissociation regions (PDRs). Our Green Bank Telescope radio recombination line observations increase the known membership of Sgr E to 19 H ii regions. There are 43 additional H ii region candidates in the direction of Sgr E, 26 of which are detected for the first time here using MeerKAT 1.28

data. Therefore, the true H ii region population of Sgr E may number >60. Using APEX SEDIGISM 13CO

data we discover a 3.0 × 105

molecular cloud associated with Sgr E, but find few molecular or far-infrared concentrations at the locations of the Sgr E H ii regions. Comparison with simulations and an analysis of its radio continuum properties indicate that Sgr E formed upstream in the far dust lane of the Galactic bar a few million years ago and will overshoot the CMZ, crashing into the near dust lane. We propose that the unusual infrared properties of the Sgr E H ii regions are caused by their orbits about the Galactic center, which have possibly stripped their PDRs.
Evidence from the H3 Survey That the Stellar Halo Is Entirely Comprised of Substructure
Authors: Naidu Rohan P. , Conroy Charlie , Bonaca Ana , Johnson Benjamin D. , Ting 丁 Yuan-Sen 源森 , Caldwell Nelson , Zaritsky Dennis , Cargile Phillip A.
Published: September 2020

In the ΛCDM paradigm, the Galactic stellar halo is predicted to harbor the accreted debris of smaller systems. To identify these systems, the H3 Spectroscopic Survey, combined with Gaia, is gathering 6D phase-space and chemical information in the distant Galaxy. Here we present a comprehensive inventory of structure within 50 kpc from the Galactic center using a sample of 5684 giants at

and

. We identify known structures including the high-α disk, the in situ halo (disk stars heated to eccentric orbits), Sagittarius (Sgr), Gaia–Sausage–Enceladus (GSE), the Helmi Streams, Sequoia, and Thamnos. Additionally, we identify the following new structures: (i) Aleph ([Fe/H] = −0.5), a low-eccentricity structure that rises a surprising 10 kpc off the plane, (ii) and (iii) Arjuna ([Fe/H] = −1.2) and I’itoi ([Fe/H] < −2), which comprise the high-energy retrograde halo along with Sequoia, and (iv) Wukong ([Fe/H] = −1.6), a prograde phase-space overdensity chemically distinct from GSE. For each structure, we provide [Fe/H], [α/Fe], and orbital parameters. Stars born within the Galaxy are a major component at

(≈60%), but their relative fraction declines sharply to ≲5% past 15 kpc. Beyond 15 kpc, >80% of the halo is built by two massive (M
⋆ ∼ 108–109
M
⊙) accreted dwarfs: GSE ([Fe/H] = −1.2) within 25 kpc and Sgr ([Fe/H] = −1.0) beyond 25 kpc. This explains the relatively high overall metallicity of the halo ([Fe/H] ≈ −1.2). We attribute ≳95% of the sample to one of the listed structures, pointing to a halo built entirely from accreted dwarfs and heating of the disk.
A Comparative Study of Mid-infrared Star Formation Rate Tracers and Their Metallicity Dependence
Authors: Whitcomb C. M. , Sandstrom K. , Murphy E. J. , Linden S.
Published: September 2020

We present a comparative study of a set of star formation rate (SFR) tracers based on mid-infrared emission in the 12.81 μm [Ne ii] line, the 15.56 μm [Ne iii] line, and emission features from polycyclic aromatic hydrocarbons (PAHs) between 5.2 and 14.7 μm. We calibrate our tracers with the thermal component of the radio continuum emission at 33 GHz from 33 extranuclear star-forming regions observed in nearby galaxies. Correlations between mid-IR emission features and thermal 33 GHz SFRs show significant metallicity-dependent scatter and offsets. We find similar metallicity-dependent trends in commonly used SFR tracers such as Hα and 24 μm. As seen in previous studies, PAH emission alone is a poor SFR tracer owing to a strong metallicity dependence: lower-metallicity regions show decreased PAH emission relative to their SFR compared to higher-metallicity regions. We construct combinations of PAH bands, neon emission lines, and their respective ratios to minimize metallicity trends. The calibrations that most accurately trace SFR with minimal metallicity dependence involve the sum of the integrated intensities of the 12.81 μm [Ne ii] line and the 15.56 μm [Ne iii] line combined with any major PAH feature normalized by dust continuum emission. This mid-IR calibration is a useful tool for measuring SFR, as it is minimally sensitive to variations in metallicity and is composed of bright, ubiquitous emission features. The Mid-Infrared Instrument (MIRI) on the James Webb Space Telescope will detect these features from galaxies as far as redshift z ∼ 1. We also investigate the behavior of the PAH band ratios and find that subtracting the local background surrounding a star-forming region decreases the ratio of PAH 11.3 μm to 7.7 μm emission. This implies that PAHs are more ionized in star-forming regions relative to their surroundings.
The Role of Successive and Interacting CMEs in the Acceleration and Release of Solar Energetic Particles: Multi-viewpoint Observations
Authors: Zhuang Bin , Lugaz Noé , Gou Tingyu , Ding Liuguan , Wang Yuming
Published: September 2020

Gradual and large solar energetic particle (SEP) events (flux of ions with energy >10 MeV above 10 pfu) are primarily produced in shocks driven by fast and wide coronal mass ejections (CMEs). Past research, both in theory and statistics, has found that the situation where a fast primary CME (priCME) is preceded by previous CMEs (preCMEs) is favorable to a more efficient particle acceleration. However, the physical causes of this association is still a matter of debate, including the association of the acceleration and release of SEPs with the interaction of successive CMEs. Taking advantage of the twin Solar TErrestrial RElations Observatory spacecraft, we study 41 large SEP events in solar cycle 24 by multi-viewpoint observations. Although 21 events (∼51%) have a preCME identifiable in the Large Angle and Spectrometric Coronagraph, we determine that the priCMEs overlap the preCMEs in three dimension (3D) for only 11 events (∼27%). We further investigate the acceleration (using type II radio bursts) and release (using velocity dispersion analysis) of the particles for all potential instances of CME–CME interaction in 3D. We find that, for six of 11 events, the priCME is far away from catching up with the preCME when the particles are released. However, for the limited samples, the SEP peak intensity is significantly higher in the events in which the priCME is closest to impacting the preCME, indicating the potential for the increased seed population or more enhanced turbulence levels occurring closer to the preCME.
Microwave Study of a Solar Circular Ribbon Flare
Authors: Lee Jeongwoo , White Stephen M. , Chen Xingyao , Chen Yao , Ning Hao , Li Bo , Masuda Satoshi
Published: September 2020

A circular ribbon flare (CRF) SOL2014-12-17T04:51 is studied using the 17/34 GHz maps from the Nobeyama Radioheliograph along with (E)UV and magnetic data from the Solar Dynamics Observatory. We report the following three findings as important features of the microwave CRF. (1) The first preflare activation comes in the form of a gradual increase of the 17 GHz flux without a counterpart at 34 GHz, which indicates thermal preheating. The first sign of nonthermal activity occurs in the form of stepwise flux increases at both 17 and 34 GHz about 4 minutes before the impulsive phase. (2) Until the impulsive phase, the microwave emission over the entire active region is in a single polarization state matching the magnetic polarity of the surrounding fields. During and after the impulsive phase, the sign of the 17 GHz polarization state reverses in the core region, which implies a magnetic breakout–type eruption in a fan–spine magnetic structure. (3) The 17 GHz flux around the time of the eruption shows quasi-periodic variations with periods of 1–2 minutes. The pre-eruption oscillation is more obvious in total intensity at one end of the flare loop, and the post-eruption oscillation, more obvious in the polarized intensity at a region near the inner spine. We interpret this transition as transfer of oscillatory power from kink mode oscillation to torsional Alfvén waves propagating along the spine field after the eruption. We argue that these three processes are interrelated and indicate a breakout process in a fan–spine structure.
Potential for Liquid Water Biochemistry Deep under the Surfaces of the Moon, Mars, and beyond
Authors: Lingam Manasvi , Loeb Abraham
Published: September 2020

We investigate the prospects for the past or current existence of habitable conditions deep underneath the surfaces of the Moon and Mars, as well as generic bound and free-floating extrasolar rocky objects. We construct a simple model that takes into account the thermal limits of life as well as the size, surface temperature, and relative radionuclide abundance of a given object and yields the spatial extent of the subsurface habitable region. We also investigate the constraint imposed by pressure on habitability, and show that it is unlikely to rule out the prospects for life altogether. We estimate the maximum biomass that might be sustainable in deep subsurface environments as a function of the aforementioned parameters from an energetic perspective. We find that it might be a few percent that of Earth’s subsurface biosphere, and three orders of magnitude smaller than Earth’s global biomass, under ideal circumstances. We conclude with a brief exposition of the prevalence of rocky objects with deep biospheres and methods for detecting signatures of biological activity through forthcoming missions to visit the Moon and Mars.
Detection of Coherent Pulsation Modes in the Strongly Magnetic Of?p Star NGC 1624-2 using TESS Observation
Authors: Kurtz D. W. , Hubrig S. , Järvinen S. P. , Schöller M.
Published: September 2020

High-cadence Transiting Exoplanet Survey Satellite (TESS) observations are promising for studies of short-term pulsational variability in magnetic O stars, which usually have long rotation periods of the order of months or years. The Of?p star NGC 1624-2 is of special interest as it possesses the strongest magnetic field measured among O stars, together with a giant magnetosphere. We detect three significant low-frequency peaks in TESS 2 minute cadence data, probably corresponding to coherent g mode pulsations. At present, this is the only magnetic O star for which pulsational variability is detected.
Some multivariate polynomials for doubled permutations
Authors: Han Bin
Published: September 2020

Flajolet and Françon [European. J. Combin. 10 (1989) 235-241] gave a combinatorial interpretation for the Taylor coefficients of the Jacobian elliptic functions in terms of doubled permutations. We show that a multivariable counting of the doubled permutations has also an explicit continued fraction expansion generalizing the continued fraction expansions of Rogers and Stieltjes. The second goal of this paper is to study the expansion of the Taylor coefficients of the generalized Jacobian elliptic functions, which implies the symmetric and unimodal property of the Taylor coefficients of the generalized Jacobian elliptic functions. The main tools are the combinatorial theory of continued fractions due to Flajolet and bijections due to Françon-Viennot, Foata-Zeilberger and Clarke-Steingrímsson-Zeng.
A Structural Econometric Analysis of Network Formation Games Through Subnetworks
Authors: Sheng Shuyang
Published: September 2020

The objective of this paper is to identify and estimate network formation models using observed data on network structure. We characterize network formation as a simultaneous‐move game, where the utility from forming a link depends on the structure of the network, thereby generating strategic interactions between links. With the prevalence of multiple equilibria, the parameters are not necessarily point identified. We leave the equilibrium selection unrestricted and propose a partial identification approach. We derive bounds on the probability of observing a subnetwork, where a subnetwork is the restriction of a network to a subset of the individuals. Unlike the standard bounds as in Ciliberto and Tamer (2009), these subnetwork bounds are computationally tractable in large networks provided we consider small subnetworks. We provide Monte Carlo evidence that bounds from small subnetworks are informative in large networks.
Heterogeneous Markups, Growth, and Endogenous Misallocation
Authors: Peters Michael
Published: September 2020

Markups vary systematically across firms and are a source of misallocation. This paper develops a tractable model of firm dynamics where firms' market power is endogenous and the distribution of markups emerges as an equilibrium outcome. Monopoly power is the result of a process of forward‐looking, risky accumulation: firms invest in productivity growth to increase markups in their existing products but are stochastically replaced by more efficient competitors. Creative destruction therefore has pro‐competitive effects because faster churn gives firms less time to accumulate market power. In an application to firm‐level data from Indonesia, the model predicts that, relative to the United States, misallocation is more severe and firms are substantially smaller. To explain these patterns, the model suggests an important role for frictions that prevent existing firms from entering new markets. Differences in entry costs for new firms are less important.
Analysis of Testing‐Based Forward Model Selection
Authors: Kozbur Damian
Published: September 2020

This paper analyzes a procedure called Testing‐Based Forward Model Selection (TBFMS) in linear regression problems. This procedure inductively selects covariates that add predictive power into a working statistical model before estimating a final regression. The criterion for deciding which covariate to include next and when to stop including covariates is derived from a profile of traditional statistical hypothesis tests. This paper proves probabilistic bounds, which depend on the quality of the tests, for prediction error and the number of selected covariates. As an example, the bounds are then specialized to a case with heteroscedastic data, with tests constructed with the help of Huber–Eicker–White standard errors. Under the assumed regularity conditions, these tests lead to estimation convergence rates matching other common high‐dimensional estimators including Lasso.
Bootstrap‐Based Inference for Cube Root Asymptotics
Authors: Cattaneo Matias D. , Jansson Michael , Nagasawa Kenichi
Published: September 2020

This paper proposes a valid bootstrap‐based distributional approximation for
M‐estimators exhibiting a Chernoff (1964)‐type limiting distribution. For estimators of this kind, the standard nonparametric bootstrap is inconsistent. The method proposed herein is based on the nonparametric bootstrap, but restores consistency by altering the shape of the criterion function defining the estimator whose distribution we seek to approximate. This modification leads to a generic and easy‐to‐implement resampling method for inference that is conceptually distinct from other available distributional approximations. We illustrate the applicability of our results with four examples in econometrics and machine learning.
Sanín Cano y España: antiimperialismo, americanismo y las tesituras de un congreso frustrado
Authors: Andrés García Manuel
Published: September 2020

Baldomero Sanín Cano es, sin lugar a dudas, uno de los eruditos más relevantes de la intelectualidad latinoamericana contemporánea. Sus múltiples inquietudes hicieron que dejase una huella transversal en campos tan diversos como el ensayo, el periodismo, la crítica literaria, la educación o la política. Este artículo indaga en el ámbito ideológico del autor y, más concretamente, en su vertiente unionista continental, manifiesta en sus constantes críticas al expansionismo estadounidense. Partiendo de una prospectiva sobre la personalidad, formación y experiencia política de Sanín, el trabajo incide en lo que fue la manifestación de su antiimperialismo militante dentro de los medios españoles y, en particular, durante su corresponsalía en Madrid, de 1922 y 1924, para el diario argentino La Nación. Finalmente pasaremos a analizar el impacto que tuvo su propuesta para celebrar un congreso iberoamericano con el que aunar posturas frente a las resoluciones de la Conferencia de Génova.
EFFECTS OF COLLABORATION NETWORKS ON TECHNOLOGY INNOVATION IN THE SOLAR PHOTOVOLTAIC (PV) SECTOR: A CASE STUDY OF CHINA
Authors: Liang Xinning , Lu Weisheng , Wu Zezhou
Published: September 2020

Efficient use of energy is an essential aspect of green building development. In order to achieve a more energy efficient society, innovation of solar photovoltaic (PV) technologies is a necessity. Collaboration between innovators is regarded as important for innovation; however, the existing literature has made few attempts to investigate how a collaboration network can affect technology innovation in the context of the solar PV sector. This study aims to fill this research gap. In this study, innovation activities are categorized as exploratory innovation and exploitative innovation. A conceptual framework and a series of hypotheses are proposed from the perspectives of network structure (including direct ties, indirect ties, and network efficiency) and network composition (such as geographical proximity, institutional proximity, and technological proximity). The empirical results show that in the solar PV sector of China, collaboration networks with different kinds of structure and composition can imply diverse effects on exploratory innovation and exploitative innovation. Followed with the derived results, it can be concluded that network collaboration is not always beneficial for PV technology innovation. The research findings could convey useful information to both practitioners and policy-makers to adopt appropriate strategies for promoting effective innovation collaboration.
RELOCATABLE MODULAR BUILDINGS FOR A SHORT-TERM INTERNATIONAL EVENT: THE PYEONG-CHANG WINTER OLYMPIC GAMES
Authors: Shin Hyun Kyu , Lee Joo Sung , Jung Chan Woo , Ahn Yong Han
Published: September 2020

Modular methods based on the use of prefabricated structures are increasingly popular for construction projects as they contribute to sustainability by reducing waste and maintenance costs as well as improving time efficiency. For short-term international events, the use of relocatable modular buildings is a potential solution to the problem of “White Elephant” structures built specially for the events that serve no useful purpose once the event is over. This paper focuses on a representative relocatable modular project created for the 2018 Winter Olympic Games in South Korea using a single case study approach to develop an in-depth understanding of the advantages and disadvantages of relocatable modular construction from a practitioner’s perspective and examine how this approach supports sustainability and the Olympic legacy. Important considerations are identified for each of the five main stages: 1) planning, 2) design and engineering, 3) manufacturing, 4) construction and 5) disassembly and reconstruction. These findings show how the use of relocatable modular facilities can be a useful approach for international events.
EVALUATING THE WEIGHTED-SUM APPROACH FOR MEASURING BUILDINGS’ ADAPTABILITY
Authors: Becker Anna K. , Ross Brandon E. , Albright Dustin
Published: September 2020

As urban populations increase worldwide and more demands are placed on infrastructure and buildings, the topic of adaptable building design has experienced increased interest as a way to embed adaptability into the urban building stock and avoid unnecessary demolition and waste. Evaluation tools for judging building adaptability based on physical characteristics have recently been proposed. The most common approach for these tools is to use a weighted-sum of scores for different criteria. The primary purpose of this paper was to compare a weighted-sum measurement approach against a more rigorous, less abstract measurement that involved judgements about simulated adaptation projects (called an example-based approach). These measurements were performed through expert elicitation and an analytic hierarchy process (AHP) survey, where participants evaluated the relative adaptability of four case study buildings from the Clemson University campus. The results showed significant correlation between the weighted-sum approach and the example-based approach, supporting the reasonableness of using weighted-sum approaches to evaluate the adaptive potential of building designs. In addition, a separate group of experts rated adaptability of the case study buildings by providing qualitative reasons for their rankings. Unlike the other approaches, this group was not given a specific tool to guide their ratings. The qualitative data provided additional context for understanding results from the quantitative approaches.
ENERGY ASSESSMENT OF URBAN BUILDINGS BASED ON GEOGRAPHIC INFORMATION SYSTEM
Authors: Tian Wei , Zhu Chuanqi , Liu Yunliang , Yin Baoquan , Shi Jiaxin
Published: September 2020

Urban building energy analysis has attracted more attention as the population living in cities increases as does the associated energy consumption in urban environments. This paper proposes a systematic bottom-up method to conduct energy analysis and assess energy saving potentials by combining dynamic engineering-based energy models, machine learning models, and global sensitivity analysis within the GIS (Geographic Information System) environment for large-scale urban buildings. This method includes five steps: database construction of building parameters, automation of creating building models at the GIS environment, construction of machine learning models for building energy assessment, sensitivity analysis for choosing energy saving measures, and GIS visual evaluation of energy saving schemes. Campus buildings in Tianjin (China) are used as a case study to demonstrate the application of the method proposed in this research. The results indicate that the method proposed here can provide reliable and fast analysis to evaluate the energy performance of urban buildings and determine effective energy saving measures to reduce energy consumption of urban buildings. Moreover, the GIS-based analysis is very useful to both create energy models of buildings and display energy analysis results for urban buildings.
A Study on Particle Weight Fraction and Extrusion on the Mechanical Properties and Microstructural Evaluation of Al-Cu/Fly Ash Composite
Authors: Lokesh G.N. , Prasad G.P. , Raghavendra Subramanya , Prashanth K.P.
Published: September 2020

Fly ash is the waste product coming out from thermal power plant is an increasingly urgent problem due to its storage and disposal. At the same time Metal Matrix composites (MMCs) reinforced with ceramic particles such as SiC, Al2O3 and B4C has their partial use in engineering application due to higher cost. The study focuses on the Al-Cu alloy reinforced fly ash particles produced by stir casting followed by hot extrusion. The composites produced by incorporation of fly ash reinforcements by varying 2%, 4%, 6%, 8% and 10wt% is hot extruded with an extrusion temperature of 400°C, extrusion rate of 5mm/s and extrusion ratio of 1.77:1. The extrusion composites have been evaluated based on the investigation of mechanical properties and microstructure. The results showed that, the amount of porosity increased with increasing the percentage of fly ash reinforcements in stir cast and the extruded composites is almost gratis from porosity. Hardness and tensile strength of composites increases with increases in percentage of reinforcement by stir and extruded composites. But extruded composites show better mechanical properties than stir cast composites. Wear test under different loads and for 45 minutes duration have been conducted on both cast and extruded composites. The worn surfaces have been observed under Scanning electron microscope (SEM) to understand the mechanism of wear. Extruded composites possess lower wear rates under all studied loads with constant sliding velocities when compared with cast composites. Microstructural study using SEM shows that the fly ash particulates in the molten matrix forms strong matrix reinforcement interface and their distribution might have led to the increase in mechanical properties of the composites due to fine grain structure during extrusion and dislocation density in the matrix.
Structure and Optical Properties of Quantum Confined Pure and Cu Doped SnO2
Authors: Sheeba J.R. , Radhika Sathasivam , Padma C.M.
Published: September 2020

Pure and copper doped tin oxide nanoparticles were synthesized by co-precipitation method and are characterized by XRD, SEM, EDAX, UV-Visible, photoluminescence, and FT-IR analysis techniques. Tetragonal rutile structure is confirmed from XRD and the crystallite size is found to be between 3.8nm and 4.8nm. The optical band gap is observed from UV-Vis spectrum and is found to be 3.99eV and 3.93eV for tin oxide and copper doped tin oxide respectively. The optical band gap of pure and Copper doped tin oxide were blue shifted due to quantum confinement. Photoluminescence spectrum shows UV, blue and green emission peaks.
Synthesis of SnO2 Nanoparticles Using Ficus religiosa Leaf Extract and their Application in Fabrication of OFETs for Glucose Monitoring
Authors: Narayana Ashwath , Tarannum Nazia , Shaik Mahaboob Subhani , Shobha B.N. , Sundar Raj M. , Lokesh S.V.
Published: September 2020

Organic field effect transistors (OFETs) as a sensor have gained interest of researchers due to its portable size and less expensive design in the field of medical diagnostic, food monitoring, chemical detection, wearable sensors, etc. In this present research work, we demonstrate the fabrication of OFETs from organic-inorganic SnO2 nanoparticles tailored pentacenefor glucose detection. SnO2 nanoparticles were synthesized bygreen method using Ficus religiosa leaf extract. The as-synthesized SnO2 NPs with cassiterite crystal structure was analysed using X-Ray Diffraction (XRD) and the energy bandgap of ~3.8 eV was calculated using Tauc relation with absorption spectra so obtained from UV-vis spectroscopy (UV-vis). The structure and morphological analysis of SnO2 NPs with size of ~15 nm was confirmed by Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) analysis. The sensor characteristics of OFET device fabricated using pentacene layer (soluble pentacene precursor of DMP) and as-synthesized SnO2 nanoparticles confirmed the aqueous glucose (glucose in water) detection at room temperature (27 °C). The extracted electrical parameters such as mobility (μ), On-current (Ion), saturation current (IDsat) and the sensor response were discussed to support the sensor characteristics.
Investigation of the Various Binders’ Effect on the Lime Binder Carbonate Hardening Process for its Use in Additive Technologies
Authors: Bakhtin Alexander , Lyubomirskiy Nikolay , Bakhtina Tamara , Nikolaenko Vitaliy
Published: September 2020

The obtaining carbonized material experimental studies’ results based on lime carbonate systems by 3D inkjet printing are presented. Some types of materials used as binders for inorganic binders have been studied. An effective method of hardening the model obtained in the 3D printing process is determined. The physical and mechanical characteristics of the prototypes hardened in the carbon dioxide medium or high concentration are determined. It was found that artificial carbonization of the samples obtained on various types of binders for 90 min contributes to the formation of a fairly strong structure of insoluble calcium carbonate, the hydrated lime carbonation product, and the carbonization degree depends on the type of binder and its mass fraction in the solution. The most effective types of binders were selected and the optimal content of the studied binders in the solution was determined.
Fiber Foam Tuffcrete Structure and Properties Formation on the Basis of Volcanic Tuff Dusting Waste
Authors: Khezhev Tolya , Ansokov Asker , Kerefov Ibragim , Malkarov Rustam
Published: September 2020

The results of studies on the foam concrete and fiber concrete development based on volcanic tuff dusting waste are presented. The foam concrete compositions that can significantly reduce the Portland cement consumption and at the same time increase its strength properties are proposed. To study the dispersed reinforcement parameters’ effect on the properties of fiber-reinforced concrete, an experiment with a second-order composite rotatable plan such as a regular hexagon was conducted. The use of fosta nylon fibers in foam concrete increases their strength properties and positively affects the structure. Dispersed fibers not only reinforce the matrix, but also significantly change its structure indicators, in particular, porosity indicators (uniformity of pore diameter distribution, average pore size), which in turn affects the strength characteristics of the material.
Structural Formation of the Cement Pastes Based on the Concrete Modified Dispersed Mineral Components
Authors: Khalyushev A. , Stelmakh Sergey , Shcherban Evgeniy , Chernilnik A.
Published: September 2020

With the increase in the number of finely dispersed mineral additives in concrete, their water demand increases and the effect of micro-filling weakens. To solve this problem, various methods of dry surface modification are proposed. As a result of the finely dispersed mineral powders’ surface modification, an improvement in their rheological characteristics, a decrease in wettability, a change in granulometry and other properties are achieved.
This article discusses the surface modification effect’s laws in a high-voltage electric field on the autogenous properties of mineral dispersed concrete components, structure formation processes, mechanical properties, and cement stone hydration products. According to the results of the study, it was found that the surface modification of bulk materials - concrete components - in a high-voltage electric field changes autohesion properties in comparison with control samples.
The data indicate lower values ​​of bulk density and angle of repose. This is due to a change in the balance of forces that arise during the mutual contact of particles after surface modification. With a certain balance of these forces, autohesion will contribute to the dense packing of particles and thereby affect the structure formation processes.
The results of changes in the plastic strength of cement pastes confirm that there is an intensification of the structure formation process. Moreover, a more intense increase in plastic strength is observed during bipolar charging of particles in comparison with unipolar charging. This is due to an increase in the number of heterogeneous charges in the system and, as a consequence, an increase in the strength of adhesive contacts, as evidenced by the data of X-ray phase analysis.
Some Questions of Shrinking Concrete Deformations with Extending Additive on Porous Fillers in Kabardino-Balkaria
Authors: Beshtokov Beslan , Tsipinov Aues
Published: September 2020

The article is devoted to the study of the light concrete shrinkage deformations’ development patterns on porous aggregates of the volcanic tuff Kamensky deposit in Kabardino-Balkaria, prepared on quartz and tuff sands, using an expanding additive of sulfo-aluminate type in the amount of 12.5% Portland cement mass, the composition and amount of which was determined by the DSTU method.
Cement Composites’ Biostability
Authors: Rodin Alexander , Karpushin Sergej , Smirnov Vasiliy
Published: September 2020

The studies to establish the species composition of micro-mycetes inhabiting the surface of cement composites after aging in sea water have been carried out. Cement stone made on the basis of Portland cement clinker, a mineral additive and a fungicidal preparation was considered as the studied material. To determine the materials’ fouling by microorganisms, their species composition, imprints and sampling methods were used. A change in the species composition of mycobiota isolated from the cement composites’ surface modified with sodium sulfate and sodium fluoride depending on the amount of active filler, gypsum, and biocidal additives was experimentally revealed. The effectiveness of using the biocidal cement composites with an active mineral additive has been confirmed. It was found that the composites on the developed compositions showed higher resistance compared to the materials on ordinary cement. The compositions modified with biocidal additives showed a fungicidal effect.
The Study of the Quartz Sand Bio Consolidation Processes as a Result of Carbonate Mineralization by Urolithic Bacteria
Authors: Strokova Valeria , Duhanina Ulyana , Balitsky Dmitriy
Published: September 2020

The complexity and a large number of variable factors of the bacterial carbonate mineralization process in the cement stone system, which is a polylineal and polydisperse system, has led to the question of each component’s role in bio consolidation processes. For carbonate biomineralization occurring in cement concrete during its restoration, it is impossible to fully describe the bio consolidation mechanism without studying the effect on individual components of the cement system (aggregate and binder). In the environment of quartz sand (the most common type of aggregate in cement concrete) there is no direct source of calcium, which is found in cement stone, which excludes the influence of abiotic factors (alkalinity of the medium) on the calcium carbonate production by bacterial cultures. This article presents the results of the study of carbonate biomineralization by urolithic bacterial cultures in a filler medium, in which quartz sand of three fractions (1.25–0.63; 0.63–0.315; 0.315–0.16) was used to assess degree and intensity of induction processes. As a result of the study, the physical and chemical factors of the bacterial carbonate mineralization process intensification in quartz sand samples were established. The time boundaries of the appearance of a consolidated layer were revealed within two fractions (0.63–0.315 and 0.315–0.16), which are directly related to the penetration depth of the solution with precursors and the bacterial inoculum by the percolation method. The analysis of the cemented layers’ microstructure is carried out, the features of neoplasms are considered. The type of bacterial culture that exhibits the most active cementing properties - Bacillus pumilus (VKM B-23).
The Production Technology of the Ceramic Brick Soft Molding Based on Opoka-Like Rocks
Authors: Bozhko J. , Teryokhina J. , Lapunova Kira , Yashchenko Roman
Published: September 2020

The results of the scientific research and pilot tests on the production technology of soft molded ceramic bricks based on siliceous opoka-like rocks are presented. A description of soft-molded brick, which is distinguished by a huge variety of appearance and unusual design, which has earned recognition from architects and designers, is given. It is emphasized that the main limiting factor for the wide distribution of this type of brick is its high cost, due to the very small volumes of its production in Russia. It is indicated that the current situation poses a very difficult and urgent task for the wall ceramics industry - to establish the widespread production of soft-molded bricks, which in addition to the aesthetic properties will have the good operational properties. The opoka-like rocks’ characteristics and the results of studying their ceramic properties in relation to the technology of soft molding are given. The classification of the soft molded brick front surface types is presented for discussion. The main technological parameters of production, the relationship and the influence of various technological factors on the properties of the products obtained, as well as the mechanism for forming the structure of the calcined products are determined. A variable technological scheme for the production of soft molded ashlar brick has been developed. It is emphasized that the presented research results will be of interest to a wide circle of the molded ceramic bricks’ manufacturers and will help to establish the wide production of soft-molded bricks in Russia.
Structural Formation of a Clinkless Cement Binding Alkali Battery with Thermoactived Margel
Authors: Salamanova Madina , Murtazayev S-A. , Alaskhanov A. , Gacayev Zurab
Published: September 2020

Currently, construction volumes around the world are growing rapidly. Because of this fact the anthropogenic load on the natural resource potential of our planet is increasing, so special attention is paid to the development of less resource and energy-consuming technologies for building production, the development of new building composites based on the use of local secondary and substandard raw materials, the receipt of which high-temperature and expensive processing is not required. In this regard, the Grozny Scientific School of Energy and Resource Saving in the production of modern building materials has carried out the comprehensive studies to study the effectiveness of clinker-free alkaline binders as an alternative to traditional cement binders. The results presented in this article were obtained in the framework of the research on the implementation of scientific project No. 05. 607.21.0320. “Development of technology for new building composites on clinkerless alkaline binders using substandard natural and secondary raw materials” that received support from the federal target program “Research and Development in Priority Directions for the Development of the Russian Science and Technology Complex for 2014-2020”. Unique Agreement Identifier RFMTFI60719X0320
The Glass Powders’ Dispersion Effect on the Glass-Reinforced Concrete Performance Properties
Authors: Bessmertniy Vasiliy , Puchka Oleg , Bondarenko Marina , Gorety Vladimir
Published: September 2020

The influence of the glass powder dispersion and its amount on the operational properties of glass-reinforced concrete is investigated. Box and plate glasses, which were crushed and ground in a ball mill, were used as the starting material. Portland cement manufactured by Serebryakovcement, a brand of CEM IIA 42.5N, was used as a binder. The developed technology for the glass-reinforced concrete manufacturing provided at the final stage for a joint grinding of Portland cement and glass powder. At the same time, the specific surface area of ​​Portland cement increased from 3200 to 6500 cm2/g. The optimum amount of fine glass powder in glass-reinforced concrete is established. It is shown that at the content of 30 wt.% glass powder with a dispersion of 5872 cm2/g the glass-reinforced concrete density is 1915 kg/m3 and the compressive strength is 45.09 MPa. When superplasticizer is introduced into glass concrete, a synergistic effect is observed, as a result of which the compressive strength increases to 50.88 MPa. Using the synchronous thermal analysis, the effect of finely dispersed glass powder on phase transformations in glass-reinforced concrete under non-isothermal heating conditions was studied. It was shown that the processes of ettringite dehydration in glass-reinforced concrete are shifted to the region of high temperatures, and the processes of calcium hydro silicates dehydration and calcite destruction are shifted to lower temperatures.
Socio Demographic Determinants Behind Conspicuous Consumption of Luxury Automobiles in Sri Lanka
Authors: Karunanayake Chathurga
Published: September 2020

Conspicuousness is a phenomenon which is in wide praxis today, and we need not to go far to observe such consumption conducts that are rooted upon the motives to exhibit one’s monetary strength, to showcase exclusiveness or belongingness to a specific crowd while gaining prestige, respect and status. Yet, much little attention has been devoted towards this obtrusive consumer desire in Sri Lanka and elsewhere in the world. In the light of this, the purpose of this study was to explore the impact of socio-demographic cohorts on the conspicuousness of luxury automobiles in Sri Lanka. This paper reports the outcomes of an exploratory survey conducted using a sample of 200 luxury automobile owners in Sri Lanka to examine the reflection of conspicuousness under different age groups, gender, religions, educational attainment levels, occupations, and monthly incomes. The results highlighted that; there is a downward trend on conspicuous consumption in luxury automobiles as the owners grow older, males are more conspicuous than females, the level of educational attainment and conspicuousness has a negative relationship, employers are more conspicuous than employees and respondents in the lowest income band are most prone towards conspicuousness when compared to other income groups. In the context of Sri Lanka, all socio-demographic antecedents that were incorporated in the scope of the present study showcased to have a significant impact on conspicuous consumption of luxury automobiles. However, the reasoning behind such behavioral patterns warrant further research.
Systemic Debt Crises in International Disequilibrium System
Authors: Senanayake Hema , Wimalaratana W. , David Kumar
Published: September 2020

Global Savings Glut (GSG) hypothesis has become the predominant and official theory attempted to explain the global financial crisis of 2008 and the Great Recession of 2008 – 2009. “… it is impossible to understand this crisis without reference to the global imbalances” (Bernanke, 2009). Any possible “global imbalance” must be connected to the international terms of trade and international exchange rate mechanism. GSG theory argues that the overwhelming credit (debt) growth occurred in the U.S. prior 2008, was due to savings made by certain trading partners, which resulted for the U.S. to have a persistent Current Account deficit and prevented the ability to increase interest rates by the U.S. monetary authorities to reduce current account deficit, as significant capital inflows from those countries took place. Yet, the paper observes that debt crises take place in countries where there are Current Account surpluses. This conundrum needs to be examined. Hence, the paper finds that another empirically verifiable proposition could possibly be used to explain the systemic debt crises better.
People, Power and Profits: Progressive Capitalism for an Age of Discontent
Authors: Padmakanthi N. P. Dammika , Jayaweera G. K. Roshini
Published: September 2020

No abstract available