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Araujo, Rafael Barros Neves de
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Publications (10 of 21) Show all publications
Das, S., Swain, D., Araujo, R. B., Shi, S., Ahuja, R., Row, T. N. G. & Bhattacharyya, A. J. (2018). Alloying in an Intercalation Host: Metal Titanium Niobates as Anodes for Rechargeable Alkali-Ion Batteries. Chemistry - An Asian Journal, 13(3), 299-310
Open this publication in new window or tab >>Alloying in an Intercalation Host: Metal Titanium Niobates as Anodes for Rechargeable Alkali-Ion Batteries
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2018 (English)In: Chemistry - An Asian Journal, ISSN 1861-4728, E-ISSN 1861-471X, Vol. 13, no 3, p. 299-310Article in journal (Refereed) Published
Abstract [en]

We discuss here a unique flexible non-carbonaceous layered host, namely, metal titanium niobates (M-Ti-niobate, M: Al3+, Pb2+, Sb3+, Ba2+, Mg2+), which can synergistically store both lithium ions and sodium ions via a simultaneous intercalation and alloying mechanisms. M-Ti-niobate is formed by ion exchange of the K+ ions, which are specifically located inside galleries between the layers formed by edge and corner sharing TiO6 and NbO6 octahedral units in the sol-gel synthesized potassium titanium niobate (KTiNbO5). Drastic volume changes (approximately 300-400%) typically associated with an alloying mechanism of storage are completely tackled chemically by the unique chemical composition and structure of the M-Ti-niobates. The free space between the adjustable Ti/Nb octahedral layers easily accommodates the volume changes. Due to the presence of an optimum amount of multivalent alloying metal ions (50-75% of total K+) in the M-Ti-niobate, an efficient alloying reaction takes place directly with ions and completely eliminates any form of mechanical degradation of the electroactive particles. The M-Ti-niobate can be cycled over a wide voltage range (as low as 0.01V) and displays remarkably stable Li+ and Na+ ion cyclability (>2 Li+/Na+ per formula unit) for widely varying current densities over few hundreds to thousands of successive cycles. The simultaneous intercalation and alloying storage mechanisms is also studied within the density functional theory (DFT) framework. DFT expectedly shows a very small variation in the volume of Al-titanium niobate following lithium alloying. Moreover, the theoretical investigations also conclusively support the occurrence of the alloying process of Li ions with the Al ions along with the intercalation process during discharge. The M-Ti-niobates studied here demonstrate a paradigm shift in chemical design of electrodes and will pave the way for the development of a multitude of improved electrodes for different battery chemistries.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2018
Keywords
alloying, anode, intercalation, rechargeable battery, synergy
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-345713 (URN)10.1002/asia.201701602 (DOI)000424106500016 ()29280560 (PubMedID)
Funder
Swedish Research CouncilStandUp
Available from: 2018-03-14 Created: 2018-03-14 Last updated: 2018-03-14Bibliographically approved
Shukla, V., Araujo, R. B., Jena, N. K. & Ahuja, R. (2018). Borophene's tryst with stability: exploring 2D hydrogen boride as an electrode for rechargeable batteries. Physical Chemistry, Chemical Physics - PCCP, 20(34), 22008-22016
Open this publication in new window or tab >>Borophene's tryst with stability: exploring 2D hydrogen boride as an electrode for rechargeable batteries
2018 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 34, p. 22008-22016Article in journal (Refereed) Published
Abstract [en]

Graphene's emergence can be viewed as a positive upheaval in 2D materials research. Along the same line, the realization of a related elemental 2D material, borophene, is another breakthrough. To circumvent the stability issues of borophene, which is reported to have been synthesized on metallic substrates under extreme conditions, hydrogenation of borophene (otherwise called as borophane or hydrogen boride or boron hydride) has been a plausible solution, but only proposed computationally. A recent report (H. Nishino, T. Fujita, N. T. Cuong, S. Tominaka, M. Miyauchi, S. Iimura, A. Hirata, N. Umezawa, S. Okada, E. Nishibori, A. Fujino, T. Fujimori, S. Ito, J. Nakamura, H. Hosono and T. Kondo, J. Am. Chem. Soc., 2017, 139(39), 13761-13769) brings to fore its experimental realization. Our current study delves into the possibilities of employing this intriguing 2D hydrogen boride as anodes in Li/Na ion batteries. Using first-principles density functional theory methods, we computed relevant properties such as the ion (Li/Na) adsorption behavior, the possible pathways of ionic diffusion with the estimation of barriers as well as the theoretical specific capacities and average voltages to uniquely demonstrate that this material is of particular significance for battery applications. It is noted that the use of hydrogen boride leads to a high specific capacity of 861.78 mA h g(-1) for Li ions, which is remarkably higher than the value reported in relation to its computationally predicted structure. Furthermore, Na ion intercalation leads to negative voltage profiles, implying the unsuitability of 2D hydrogen boride for this particular ion. Our findings are timely and pertinent towards adding insightful details relevant to the progress of applications of 2D materials for energy storage.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2018
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-369513 (URN)10.1039/c8cp03686a (DOI)000449394100021 ()30109880 (PubMedID)
Funder
Swedish Research CouncilCarl Tryggers foundation StandUp
Available from: 2018-12-17 Created: 2018-12-17 Last updated: 2019-01-05Bibliographically approved
Chakraborty, S., Banerjee, A., Watcharatharapong, T., Araujo, R. B. & Ahuja, R. (2018). Current computational trends in polyanionic cathode materials for Li and Na batteries. Journal of Physics: Condensed Matter, 30(28), Article ID 283003.
Open this publication in new window or tab >>Current computational trends in polyanionic cathode materials for Li and Na batteries
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2018 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 30, no 28, article id 283003Article, review/survey (Refereed) Published
Abstract [en]

A long-standing effort has been devoted for the development of high energy density cathodes both for Li-and Na-ion batteries (LIBs and SIBs). The scientific communities in battery research primarily divide the Li- and Na-ion cathode materials into two categories: layered oxides and polyanionic compounds. Researchers are trying to improve the energy density of such materials through materials screening by mixing the transition metals or changing the concentration of Li or Na in the polyanionic compounds. Due to the fact that there is more stability in the polyanionic frameworks, batteries based on these materials mostly provide a prolonged cycling life as compared to the layered oxide materials. Nevertheless, the bottleneck for such compounds is the weight penalty from polyanionic groups that results into the lower capacity. The anion engineering could be considered as an essential way out to design such polyanionic compounds to resolve this issue and to fetch improved cathode performance. In this topical review we present a systematic overview of the polyanionic cathode materials used for LIBs and SIBs. We will also present the computational methodologies that have become significantly relevant for battery research. We will make an attempt to provide the theoretical insight with a current development in sulfate (SO4), silicate (SiO4) and phosphate (PO4) based cathode materials for LIBs and SIBs. We will end this topical review with the future outlook, that will consist of the next generation organic electrode materials, mainly based on conjugated carbonyl compounds.

Keywords
Li-ion batteries, Na-ion batteries, energy storage, polyanionic cathode materials, organic cathode materials, DFT investigation
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-368909 (URN)10.1088/1361-648X/aac62d (DOI)000436088400001 ()29932053 (PubMedID)
Funder
Swedish Research CouncilCarl Tryggers foundation StandUp
Available from: 2018-12-10 Created: 2018-12-10 Last updated: 2019-04-05Bibliographically approved
Banerjee, A., Araujo, R. B., Sjödin, M. & Ahuja, R. (2018). Identifying the tuning key of disproportionation redox reaction in terephthalate: A Li-based anode for sustainable organic batteries. Nano Energy, 47, 301-308
Open this publication in new window or tab >>Identifying the tuning key of disproportionation redox reaction in terephthalate: A Li-based anode for sustainable organic batteries
2018 (English)In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 47, p. 301-308Article in journal (Refereed) Published
Abstract [en]

The ever-increasing consumption of energy storage devices has pushed the scientific community to realize strategies toward organic electrodes with superior properties. This is owed to advantages such as economic viability and eco-friendliness. In this context, the family of conjugated dicarboxylates has emerged as an interesting candidate for the application as negative electrodes in advanced Li-ion batteries due to the revealed thermal stability, rate capability, high capacity and high cyclability. This work aims to rationalize the effects of small molecular modifications on the electrochemical properties of the terephthalate anode by means of first principles calculations. The crystal structure prediction of the investigated host compounds dilithium terephthalate (Li2TP) and diethyl terephthalate (Et2Li0TP) together with their crystal modification upon battery cycling enable us to calculate the potential profile of these materials. Distinct underlying mechanisms of the redox reactions were obtained where Li2TP comes with a disproportionation reaction while Et2Li0TP displays sequential redox reactions. This effect proved to be strongly correlated to the Li coordination number evolution upon the Li insertion into the host structures. Finally, the calculations of sublimation enthalpy inferred that polymerization techniques could easily be employed in Et2Li0TP as compared to Li2TP. Similar results are observed with methyl, propyl, and vinyl capped groups. That could be a strategy to enhance the properties of this compound placing it into the gallery of the new anode materials for state of art Li-batteries.

Keywords
Li-ion organic battery, Lithium terephthalate, Disproportionation, Redox potential
National Category
Physical Chemistry Materials Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-354095 (URN)10.1016/j.nanoen.2018.02.038 (DOI)000430057000031 ()
Funder
Swedish Research Council, 2016-06014
Available from: 2018-06-19 Created: 2018-06-19 Last updated: 2018-12-19Bibliographically approved
Araujo, R. B., Banerjee, A., Panigrahi, P., Yang, L., Sjödin, M., Strömme, M., . . . Ahuja, R. (2017). Assessing Electrochemical Properties of Polypyridine and Polythiophene for Prospective Application in Sustainable Organic Batteries. Physical Chemistry, Chemical Physics - PCCP, 19(4), 3307-3314
Open this publication in new window or tab >>Assessing Electrochemical Properties of Polypyridine and Polythiophene for Prospective Application in Sustainable Organic Batteries
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2017 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, no 4, p. 3307-3314Article in journal (Refereed) Published
Abstract [en]

Conducting polymers are being considered promising candidates for sustainable organic batteries mainly due to their fast electron transport properties and high recyclability. In this work, key properties of polythiophene and polypyridine have been assessed through a combined theoretical and experimental study focusing on such applications. A theoretical protocol has been developed to calculate redox potentials in solution within the framework of the density functional theory and using continuous solvation models. Here, the evolution of the electrochemical properties of solvated oligomers as a function of the length of the chain is analyzed and then the polymer properties are estimated via linear regressions using ordinary least square. The predicted values were verified against our electrochemical experiments. This protocol can now be employed to screen a large database of compounds in order to identify organic electrodes with superior properties.

National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-311276 (URN)10.1039/C6CP07435A (DOI)000394940400071 ()28091636 (PubMedID)
Funder
Swedish Foundation for Strategic Research Swedish Energy AgencyStandUpSwedish Research Council
Available from: 2016-12-22 Created: 2016-12-22 Last updated: 2018-12-19Bibliographically approved
Jena, N. K., Araujo, R. B., Shukla, V. & Ahuja, R. (2017). Borophane as a Benchmate of Graphene: A Potential 2D Material for Anode of Li and Na-Ion Batteries. ACS Applied Materials and Interfaces, 9(19), 16148-16158
Open this publication in new window or tab >>Borophane as a Benchmate of Graphene: A Potential 2D Material for Anode of Li and Na-Ion Batteries
2017 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 19, p. 16148-16158Article in journal (Refereed) Published
Abstract [en]

Borophene, single atomic-layer sheet of boron (Science 2015, 350, 1513), is a rather new entrant into the burgeoning class of 2D materials. Borophene exhibits anisotropic metallic properties whereas its hydrogenated counterpart borophane is reported to be a gapless Dirac material lying on the same bench with the celebrated graphene. Interestingly, this transition of borophane also rendered stability to it considering the fact that borophene was synthesized under ultrahigh vacuum conditions on a metallic (Ag) substrate. On the basis of first-principles density functional theory computations, we have investigated the possibilities of borophane as a potential Li/Na-ion battery anode material. We obtained a binding energy of -2.58 (-1.08 eV) eV for Li (Na)-adatom on borophane and Bader charge analysis revealed that Li(Na) atom exists in Li+(Na+) state. Further, on binding with Li/Na, borophane exhibited metallic properties as evidenced by the electronic band structure. We found that diffusion pathways for Li/Na on the borophane surface are anisotropic with x direction being the favorable one with a barrier of 0.27 and 0.09 eV, respectively. While assessing the Li-ion anode performance, we estimated that the maximum Li content is Li0.445B2H2, which gives rises to a material with a maximum theoretical specific capacity of 504 mAh/g together with an average voltage of 0.43 V versus Li/Li+. Likewise, for Na-ion the maximum theoretical capacity and average voltage were estimated to be 504 mAh/g and 0.03 V versus Na/Na+, respectively. These findings unambiguously suggest that borophane can be a potential addition to the map of Li and Na-ion anode materials and can rival some of the recently reported 2D materials including graphene.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
Keywords
borophene, borophane, Dirac material, Li-ion battery, Na-ion battery, Li/Na-diffusion
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-327151 (URN)10.1021/acsami.7b01421 (DOI)000401782500026 ()28443653 (PubMedID)
Funder
Swedish Research CouncilStandUpCarl Tryggers foundation
Available from: 2017-08-25 Created: 2017-08-25 Last updated: 2019-01-05Bibliographically approved
Araujo, R. B., Banerjee, A., Panigrahi, P., Yang, L., Strömme, M., Sjödin, M., . . . Ahuja, R. (2017). Designing strategies to tune reduction potential of organic molecules for sustainable high capacity batteries application. Journal of Materials Chemistry A, 5(9), 4430-4454
Open this publication in new window or tab >>Designing strategies to tune reduction potential of organic molecules for sustainable high capacity batteries application
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2017 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 5, no 9, p. 4430-4454Article in journal (Refereed) Published
Abstract [en]

Organic compounds evolve as a promising alternative to the currently used inorganic materials in rechargeable batteries due to their low-cost, environmentally friendliness and flexibility. One of the strategies to reach acceptable energy densities and to deal with the high solubility of known organic compounds is to combine small redox active molecules, acting as capacity carrying centres, with conducting polymers. Following this strategy, it is important to achieve redox matching between the chosen molecule and the polymer backbone. Here, a synergetic approach combining theory and experiment has been employed to investigate this strategy. The framework of density functional theory connected with the reaction field method has been applied to predict the formal potential of 137 molecules and identify promising candidates for the referent application. The effects of including different ring types, e.g. fused rings or bonded rings, heteroatoms, [small pi] bonds, as well as carboxyl groups on the formal potential, has been rationalized. Finally, we have identified a number of molecules with acceptable theoretical capacities that show redox matching with thiophene-based conducting polymers which, hence, are suggested as pendent groups for the development of conducting redox polymer based electrode materials.

National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-314502 (URN)10.1039/C6TA09760J (DOI)000395926100022 ()
Funder
Swedish Foundation for Strategic Research Swedish Energy AgencyStandUpSwedish Research Council
Available from: 2017-02-02 Created: 2017-02-02 Last updated: 2018-12-19Bibliographically approved
Araujo, R. B., Banerjee, A. & Ahuja, R. (2017). Divulging the Hidden Capacity and Sodiation Kinetics of NaxC6Cl4O2: A High Voltage Organic Cathode for Sodium Rechargeable Batteries. The Journal of Physical Chemistry C, 121(26), 14027-14036
Open this publication in new window or tab >>Divulging the Hidden Capacity and Sodiation Kinetics of NaxC6Cl4O2: A High Voltage Organic Cathode for Sodium Rechargeable Batteries
2017 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, no 26, p. 14027-14036Article in journal (Refereed) Published
Abstract [en]

In the current emerging sustainable organic battery field, quinones are seen as one of the prime candidates for application in rechargeable battery electrodes. Recently, C6Cl4O2, a modified quinone, has been proposed as a high voltage organic cathode. However, the sodium insertion mechanism behind the cell reaction remained unclear due to the nescience of the right crystal structure. Here, the framework of the density functional theory (DFT) together with an evolutionary algorithm was employed to elucidate the crystal structures of the compounds NaxC6Cl4O2 (x = 0.5, 1.0, 1.5 and 2). Along with the usefulness of PBE functional to reflect the experimental potential, also the importance of the hybrid functional to divulge the hidden theoretical capacity is evaluated. We showed that the experimentally observed lower specific capacity is a result of the great stabilization of the intermediate phase Na1.5C6Cl4O2. The calculated activation barriers for the ionic hops are 0.68, 0.40, and 0.31 eV, respectively, for NaC6Cl4O2, Na1.5C6Cl4O2, and Na2C6Cl4O2. These results indicate that the kinetic process must not be a limiting factor upon Na insertion. Finally, the correct prediction of the specific capacity has confirmed that the theoretical strategy used, employing evolutionary simulations together with the hybrid functional framework, can rightly model the thermodynamic process in organic electrode compounds.

National Category
Materials Engineering Physical Sciences
Identifiers
urn:nbn:se:uu:diva-329995 (URN)10.1021/acs.jpcc.7b03621 (DOI)000405252800007 ()
Funder
Swedish Energy AgencySwedish Research CouncilStandUp
Note

Divulging the Hidden Capacity and Sodiation Kinetics of NaxC6Cl4O2: A High Voltage Organic Cathode for Sodium Rechargeable Batteries

Available from: 2017-10-13 Created: 2017-10-13 Last updated: 2018-12-19Bibliographically approved
Araújo, R. B. (2017). Energy Storage Materials: Insights From ab Initio Theory: Diffusion, Structure, Thermodynamics and Design.. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Energy Storage Materials: Insights From ab Initio Theory: Diffusion, Structure, Thermodynamics and Design.
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The development of science and technology have provided a lifestyle completely dependent on energy consumption. Devices such as computers and mobile phones are good examples of how our daily life depends on electric energy. In this scenario, energy storage technologies emerge with strategic importance providing efficient ways to transport and commercialize the produced energy. Rechargeable batteries come as the most suitable alternative to fulfill the market demand due to their higher energy- and power- density when compared with other electrochemical energy storage systems. In this context, during the production of this thesis, promising compounds for advanced batteries application were investigated from the theoretical viewpoint. The framework of the density functional theory has been employed together with others theoretical tools to study properties such as ionic diffusion, redox potential, electronic structure and crystal structure prediction.

Different organic materials were theoretically characterized with quite distinct objectives. For instance, a protocol able to predict the redox potential in solution of long oligomers were developed and tested against experimental measurements. Strategies such as anchoring of small active molecules on polymers backbone have also been investigated through a screening process that determined the most promising candidates. Methods such as evolutionary simulation and basin-hopping algorithm were employed to search for global minimum crystal structures of small molecules and inorganic compounds working as a cathode of advanced sodium batteries. The crystal structure evolution of C6Cl4O2 upon Na insertion was unveiled and the main reasons behind the lower specific capacity obtained in the experiment were clarified. Ab initio molecular dynamics and the nudged elastic band method were employed to understand the underlying ionic diffusion mechanisms in the recently proposed Alluaudite and Eldfellite cathode materials. Moreover, it was demonstrated that electronic conduction in Na2O2, a byproduct of the Na-O2 battery, occurs via hole polarons hopping. Important physical and chemical insights were obtained during the production of this thesis. It finally supports the development of low production cost, environmental friendliness and efficient electrode compounds for advanced secondary batteries. 

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2017. p. 83
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1584
Keywords
Density Functional Theory, Defects Diffusion, Thermodynamics and Batteries.
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-331399 (URN)978-91-513-0122-8 (ISBN)
Public defence
2017-12-07, Polhemsalen, Ångström Laboratory, Lägerhyddsvägen 1, Uppsala, 13:15 (English)
Opponent
Supervisors
Available from: 2017-11-15 Created: 2017-10-19 Last updated: 2018-03-07
Dwibedi, D., Gond, R., Dayamani, A., Araujo, R. B., Chakraborty, S., Ahuja, R. & Barpanda, P. (2017). Na2.32Co1.84(SO4)(3) as a new member of the alluaudite family of high-voltage sodium battery cathodes. Dalton Transactions, 46(1), 55-63
Open this publication in new window or tab >>Na2.32Co1.84(SO4)(3) as a new member of the alluaudite family of high-voltage sodium battery cathodes
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2017 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 46, no 1, p. 55-63Article in journal (Refereed) Published
Abstract [en]

Electrochemical energy storage has recently seen tremendous emphasis being placed on the large-scale (power) grid storage. Sodium-ion batteries are capable of achieving this goal with economic viability. In a recent breakthrough in sodium-ion battery research, the alluaudite framework (Na2Fe2(SO4)(3)) has been reported, with the highest Fe3+/Fe2+ redox potential (ca. 3.8 V, Barpanda, et al., Nat. Commun., 2014, 5, 4358). Exploring this high-voltage sodium insertion system, we report the discovery of Na2+2xCo2-x(SO4)(3) (x = 0.16) as a new member of the alluaudite class of cathode. Stabilized by low-temperature solid-state synthesis (T <= 350 degrees C),this novel Co-based compound assumes a monoclinic structure with C2/c symmetry, which undergoes antiferromagnetic ordering below 10.2 K. Isotypical to the Fe-homologue, it forms a complete family of solid-solution Na2+2x(Fe1-yCoy)(2-x)(SO4)(3) [ y = 0-1]. Ab initio DFT analysis hints at potential high voltage operation at 4.76-5.76 V (vs. Na), depending on the degree of desodiation involving a strong participation of the oxygen sub-lattice. With the development of safe organic electrolytes, Na2+2xCo2-x(SO4)(3) can work as a cathode material (similar to 5 V) for sodium-ion batteries.

National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-315835 (URN)10.1039/c6dt03767d (DOI)000391570700008 ()
Funder
Carl Tryggers foundation Swedish Research CouncilStandUp
Available from: 2017-02-21 Created: 2017-02-21 Last updated: 2017-11-29Bibliographically approved
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