352 research outputs found
People from Brač, emigrant press in Chile and newspaper Domovina - from the late 19th century to the beginning of World War I
Cilj je rada postaviti ishodišta za proučavanje povijesti hrvatskog iseljeničkog novinstva u Čileu od najranijeg razdoblja doseljenja Hrvata do kraja 1914. godine, među kojima je brojčano dominantnu grupaciju činilo stanovništvo s Brača. Radilo se prvenstveno o ekonomskoj migraciji uzrokovanoj ekonomskim promjenama u društvu općenito, ali i ekonomskim promjenama kao posljedicama političkih kretanja. U novu domovinu donose tradicionalnu potrebu organiziranja u razna društva, ali i svijest o vlastitoj nacionalnoj pripadnosti s vlastitim jezikom. Neobično brza asimilacija (već u prvoj generaciji) dovodi u pitanje opstojnost te potrebu očuvanja baštine. Iseljeničke novine u kojima surađuju, uređuju ih i pokreću Bračani – novinari, među kojima se ističu Ivan Krstulović i Luka Bonačić s novinama „Domovina“ iz Punta Arenasa, u dosadašnjoj literaturi sagledavane su gotovo isključivo s aspekta političke orijentacije i borbe. Cilj je rada kroz primjer rubrike „Iz mjesta i okolice“, koja je održala kontinuitet tijekom cijelog razdoblja izlaženja lista „Domovina“ i čijim je sastavnim dijelom bila, prikazati, s aspekta socijalne povijesti, da su lokalne novine odražavale i bilježile pojave i događanja značajna za svakodnevni život zajednice sa svrhom očuvanja njezina identiteta.The topic of this paper is to set the starting point for studying the history of Croatian emigrant journalism in Chile from the earliest period of the settlement of Croats until the end of 1914, including the dominant population group from Brač. It was primarily the economic migration, which was caused by economic changes in the society in general, and economic changes as a consequence of political movements. The immigrants had the need for organizing themselves in various societies in the new country, and they also had the awareness of their own nationality and language. The unusually rapid assimilation (already in the first generation) calls into question the viability and the need to preserve heritage. Immigrant newspapers edited and run by Brač emigrant journalists, most notably Ivan Krstulović and Luka Bonačić, with the newspaper Domovina from Punta Arenas, were in the current literature perceived almost exclusively in terms of political orientation and struggle. The aim of this paper is to show that the local newspaper Domovina reflected and recorded phenomena and events significant for the daily life of the community with the intention of preservation its identity from the perspective of social history, especially in the section From the town and surrounding areas
Slow Magnetic Relaxation in a Trigonal Prismatic Uranium(III) Complex
Slow Magnetic Relaxation in a Trigonal Prismatic Uranium(III) Comple
Strong H<sub>2</sub> Binding and Selective Gas Adsorption within the Microporous Coordination Solid Mg<sub>3</sub>(O<sub>2</sub>C-C<sub>10</sub>H<sub>6</sub>-CO<sub>2</sub>)<sub>3</sub>
The synthesis of Mg3(NDC)3(DEF)4 (NDC = 2,6-naphthalenedicarboxylate, DEF = N,N-diethylformamide, 1), the first porous metal−organic framework solid incorporating Mg2+ ions, is reported. Its structure consists of linear Mg3 units linked via NDC bridges to form a three-dimensional framework, featuring one-dimensional channels filled with DEF molecules. Significantly, its framework is fully analogous to that observed within Zn3(NDC)3(CH3OH)2·2DMF·H2O (2), demonstrating that Mg2+ ions can directly substitute for the heavier Zn2+ ions. Compound 1 is readily desolvated by heating at 190 °C to give the microporous solid Mg3(NDC)3, exhibiting a BET surface area of 190 m2/g. Adsorption isotherms measured at 77 and 87 K indicate high H2 adsorption enthalpies in the range 7.0−9.5 kJ/mol, depending on the degree of loading. In addition, the material displays selective adsorption of H2 or O2 over N2 or CO, suggesting possible applications in gas separation technologies
Strong H<sub>2</sub> Binding and Selective Gas Adsorption within the Microporous Coordination Solid Mg<sub>3</sub>(O<sub>2</sub>C-C<sub>10</sub>H<sub>6</sub>-CO<sub>2</sub>)<sub>3</sub>
The synthesis of Mg3(NDC)3(DEF)4 (NDC = 2,6-naphthalenedicarboxylate, DEF = N,N-diethylformamide, 1), the first porous metal−organic framework solid incorporating Mg2+ ions, is reported. Its structure consists of linear Mg3 units linked via NDC bridges to form a three-dimensional framework, featuring one-dimensional channels filled with DEF molecules. Significantly, its framework is fully analogous to that observed within Zn3(NDC)3(CH3OH)2·2DMF·H2O (2), demonstrating that Mg2+ ions can directly substitute for the heavier Zn2+ ions. Compound 1 is readily desolvated by heating at 190 °C to give the microporous solid Mg3(NDC)3, exhibiting a BET surface area of 190 m2/g. Adsorption isotherms measured at 77 and 87 K indicate high H2 adsorption enthalpies in the range 7.0−9.5 kJ/mol, depending on the degree of loading. In addition, the material displays selective adsorption of H2 or O2 over N2 or CO, suggesting possible applications in gas separation technologies
Screening Metal–Organic Frameworks by Analysis of Transient Breakthrough of Gas Mixtures in a Fixed Bed Adsorber
Metal–organic frameworks (MOFs) offer considerable potential for separating a variety of mixtures that are important in applications such as CO2 capture and H2 purification. In view of the vast number of MOFs that have been synthesized, there is a need for a reliable procedure for comparing screening and ranking MOFs with regard to their anticipated performance in pressure swing adsorption (PSA) units. For this purpose, the most commonly used metrics are the adsorption selectivity and the working capacity. Here, we suggest an additional metric for comparing MOFs that is based on the analysis of the transient response of an adsorber to a step input of a gaseous mixture. For a chosen purity of the gaseous mixture exiting from the adsorber, a dimensionless breakthrough time τbreak can be defined and determined; this metric determines the frequency of required regeneration and influences the productivity of a PSA unit. The values of τbreak are dictated both by selectivity and by capacity metrics .By performing transient adsorber calculations for separation of CO2/H2, CO2/CH4, CH4/H2, and CO2/CH4/H2 mixtures, we compare the values of τbreak to highlight some important advantages of MOFs over conventionally used adsorbents such as zeolite NaX. For a given separation duty, such comparisons provide a more realistic ranking of MOFs than afforded by either selectivity or capacity metrics alone. We conclude that breakthrough calculations can provide an essential tool for screening MOFs
Screening Metal–Organic Frameworks by Analysis of Transient Breakthrough of Gas Mixtures in a Fixed Bed Adsorber
Metal–organic frameworks (MOFs) offer considerable potential for separating a variety of mixtures that are important in applications such as CO2 capture and H2 purification. In view of the vast number of MOFs that have been synthesized, there is a need for a reliable procedure for comparing screening and ranking MOFs with regard to their anticipated performance in pressure swing adsorption (PSA) units. For this purpose, the most commonly used metrics are the adsorption selectivity and the working capacity. Here, we suggest an additional metric for comparing MOFs that is based on the analysis of the transient response of an adsorber to a step input of a gaseous mixture. For a chosen purity of the gaseous mixture exiting from the adsorber, a dimensionless breakthrough time τbreak can be defined and determined; this metric determines the frequency of required regeneration and influences the productivity of a PSA unit. The values of τbreak are dictated both by selectivity and by capacity metrics .By performing transient adsorber calculations for separation of CO2/H2, CO2/CH4, CH4/H2, and CO2/CH4/H2 mixtures, we compare the values of τbreak to highlight some important advantages of MOFs over conventionally used adsorbents such as zeolite NaX. For a given separation duty, such comparisons provide a more realistic ranking of MOFs than afforded by either selectivity or capacity metrics alone. We conclude that breakthrough calculations can provide an essential tool for screening MOFs
Strong H<sub>2</sub> Binding and Selective Gas Adsorption within the Microporous Coordination Solid Mg<sub>3</sub>(O<sub>2</sub>C-C<sub>10</sub>H<sub>6</sub>-CO<sub>2</sub>)<sub>3</sub>
The synthesis of Mg3(NDC)3(DEF)4 (NDC = 2,6-naphthalenedicarboxylate, DEF = N,N-diethylformamide, 1), the first porous metal−organic framework solid incorporating Mg2+ ions, is reported. Its structure consists of linear Mg3 units linked via NDC bridges to form a three-dimensional framework, featuring one-dimensional channels filled with DEF molecules. Significantly, its framework is fully analogous to that observed within Zn3(NDC)3(CH3OH)2·2DMF·H2O (2), demonstrating that Mg2+ ions can directly substitute for the heavier Zn2+ ions. Compound 1 is readily desolvated by heating at 190 °C to give the microporous solid Mg3(NDC)3, exhibiting a BET surface area of 190 m2/g. Adsorption isotherms measured at 77 and 87 K indicate high H2 adsorption enthalpies in the range 7.0−9.5 kJ/mol, depending on the degree of loading. In addition, the material displays selective adsorption of H2 or O2 over N2 or CO, suggesting possible applications in gas separation technologies
Screening Metal–Organic Frameworks by Analysis of Transient Breakthrough of Gas Mixtures in a Fixed Bed Adsorber
Metal–organic frameworks (MOFs) offer considerable potential for separating a variety of mixtures that are important in applications such as CO2 capture and H2 purification. In view of the vast number of MOFs that have been synthesized, there is a need for a reliable procedure for comparing screening and ranking MOFs with regard to their anticipated performance in pressure swing adsorption (PSA) units. For this purpose, the most commonly used metrics are the adsorption selectivity and the working capacity. Here, we suggest an additional metric for comparing MOFs that is based on the analysis of the transient response of an adsorber to a step input of a gaseous mixture. For a chosen purity of the gaseous mixture exiting from the adsorber, a dimensionless breakthrough time τbreak can be defined and determined; this metric determines the frequency of required regeneration and influences the productivity of a PSA unit. The values of τbreak are dictated both by selectivity and by capacity metrics .By performing transient adsorber calculations for separation of CO2/H2, CO2/CH4, CH4/H2, and CO2/CH4/H2 mixtures, we compare the values of τbreak to highlight some important advantages of MOFs over conventionally used adsorbents such as zeolite NaX. For a given separation duty, such comparisons provide a more realistic ranking of MOFs than afforded by either selectivity or capacity metrics alone. We conclude that breakthrough calculations can provide an essential tool for screening MOFs
High-Enthalpy Hydrogen Adsorption in Cation-Exchanged Variants of the Microporous Metal−Organic Framework Mn<sub>3</sub>[(Mn<sub>4</sub>Cl)<sub>3</sub>(BTT)<sub>8</sub>(CH<sub>3</sub>OH)<sub>10</sub>]<sub>2</sub>
Exchange of the guest Mn2+ ions in Mn3[(Mn4Cl)3(BTT)8(CH3OH)10]2 (1-Mn2+; BTT = 1,3,5-benzenetristetrazolate) with selected cations results in the formation of isostructural framework compounds
1-M (M = Li+, Cu+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+). Similar to the parent compound, the new microporous
materials are stable to desolvation and exhibit a high H2 storage capacity, ranging from 2.00 to 2.29 wt %
at 77 K and 900 torr. Measurements of the isosteric heat of adsorption at zero coverage reveal a difference
of 2 kJ/mol between the weakest and strongest H2-binding materials, which is attributed to variations in the
strength of interaction between H2 molecules and unsaturated metal centers within each framework. The
Co2+-exchanged compound, 1-Co2+, exhibits an initial enthalpy of adsorption of 10.5 kJ/mol, the highest
yet observed for a microporous metal−organic framework
New Cyanometalate Building Units: Synthesis and Characterization of [Re(CN)<sub>7</sub>]<sup>3-</sup> and [Re(CN)<sub>8</sub>]<sup>3-</sup>
Two new cyanorhenate complexes of potential utility in constructing magnetic and photomagnetic materials are reported. Reaction of (Bu4N)CN with [ReCl6]2- in acetonitrile affords yellow (Bu4N)3[Re(CN)7] (1), featuring the pentagonal bipyramidal complex [Re(CN)7]3-. The spectral and magnetic properties of 1 indicate that the complex has an S = 1/2 ground state with considerable anisotropy in the g tensor. In aqueous solution, 1 reacts with Mn2+ ions to generate the three-dimensional cyano-bridged solid [fac-Mn(H2O)3][cis-Mn(H2O)2][Re(CN)7]·3H2O (2) containing diamagnetic [Re(CN)7]4-. Addition of KIO4 to the reaction solution, originally intended to prevent reduction of the rhenium during solid formation, instead yields white (Bu4N)3[Re(CN)8] (3). As crystallized in K3[Re(CN)8]·2MeCN (4·2MeCN), the diamagnetic [Re(CN)8]3- complex adopts a nearly perfect square antiprismatic coordination geometry. In solution, this species behaves analogously to the isoelectronic [M(CN)8]4- (M = Mo, W) complexes, apparently converting to a dodecahedral geometry and photooxidizing under UV radiation to give paramagnetic [Re(CN)8]2-
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