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Metal-organic framework (MOF) glasses provide new perspectives on many material properties due to their unique chemical and structural nature. Their mechanical properties are of particular interest because glasses are inherently brittle, which limits their applications as structural materials. Here we perform strain-rate-dependent uniaxial micropillar compression experiments on agZIF-62, agZIF-UC-5, and agTIF-4, a series of MOF glasses with different substituting linker molecules, and find that these glasses show substantial plasticity, at least on the micrometer scale. At a quasi-static strain rate of 0.001 s-1, the micropillars yielded at approximately 0.32 GPa and subsequently deformed plastically up to 35% strain, irrespective of the type of substituting linker. With increasing strain rate, the yield strength of agZIF-62 evolved with the strain-rate sensitivity m = 0.024 to reach a yield strength of 0.44 GPa at a strain rate of 510 s-1. On the basis of this relatively low strain-rate sensitivity and the absence of serrated flow, we conclude that structural densification is the predominant mechanism that accommodates such extensive plasticity.

Metal–organic framework crystal-glass composites (MOF-CGCs) are materials in which a crystalline MOF is dispersed within a MOF glass. In this work, we explore the room-temperature stabilization of the open-pore form of MIL-53(Al), usually observed at high temperature, which occurs upon encapsulation within a ZIF-62(Zn) MOF glass matrix. A series of MOF-CGCs containing different loadings of MIL-53(Al) were synthesized and characterized using X-ray diffraction and nuclear magnetic resonance spectroscopy. An upper limit of MIL-53(Al) that can be stabilized in the composite was determined for the first time. The nanostructure of the composites was probed using pair distribution function analysis and scanning transmission electron microscopy. Notably, the distribution and integrity of the crystalline component in a sample series were determined, and these findings were related to the MOF-CGC gas adsorption capacity in order to identify the optimal loading necessary for maximum CO2 sorption capacity.

Monolithic, nitrogen-doped carbon sorbents were prepared from resorcinol-urea-formaldehyde resins and physically activated with CO2 for different activation times. The effect of the activation time on the water sorption behavior and the physicochemical properties were investigated. Longer activation times lead to a steeper slope of the water sorption isotherm and, due to a higher specific surface area and micropore volume, an increased water sorption capacity. It was found that, after physical activation for 3 h at 800 °C, the physically activated, nitrogen-doped carbon has a high surface area (>1000 m2/g) and a high water sorption capacity (50 wt%). In a miniaturized adsorption heat pump test stand, the best candidate material was assessed alongside commercial silica gel for reference. At a temperature swing from 90 °C → 50 °C, the CO2-activated carbon exhibits a maximal specific cooling power which is a factor of 1.7 higher in comparison with the reference silica gel (429 W/kg versus 255 W/kg). At a more applicable temperature swing, 60 °C → 30 °C, the CO2-activated carbon yields a specific cooling power 3.8 times higher than that of the silica gel reference (932 W/kg versus 240 W/kg).

Earth’s deep carbon cycle affects atmospheric CO2, climate, and habitability. Owing to the extreme solubility of CaCO3, aqueous fluids released from the subducting slab could extract all carbon from the slab. However, recycling efficiency is estimated at only around 40%. Data from carbonate inclusions, petrology, and Mg isotope systematics indicate Ca2+ in carbonates is replaced by Mg2+ and other cations during subduction. Here we determined the solubility of dolomite [CaMg(CO3)2] and rhodochrosite (MnCO3), and put an upper limit on that of magnesite (MgCO3) under subduction zone conditions. Solubility decreases at least two orders of magnitude as carbonates become Mg-rich. This decreased solubility, coupled with heterogeneity of carbon and water subduction, may explain discrepancies in carbon recycling estimates. Over a range of slab settings, we find aqueous dissolution responsible for mobilizing 10 to 92% of slab carbon. Globally, aqueous fluids mobilise \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${35}_{-17}^{+20}$$\end{document}35−17+20% (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${27}_{-13}^{+16}$$\end{document}27−13+16 Mt/yr) of subducted carbon from subducting slabs., Carbonate mineral aqueous solubility decreases as carbonates become more Mg-rich during subduction. Coupled with regional variations in amounts of carbon and water subducted, this explains discrepancies in estimates of carbon recycling, suggesting that only around a third returns to the surface.

The exciton dynamics of 6,13-bis(triisopropylsilyl-ethynyl) pentacene is investigated to determine the role of excimer and aggregate formation in singlet fission in high concentration solutions.Photoluminescence spectra were measured by excitation with the evanescent wave in total internal reflection, in order to avoid reabsorption effects. The spectra over nearly two magnitudes of concentration were near identical, with no evidence for excimer emission. Time-correlated single-photon counting measurements confirm that the fluorescence lifetime shortens with concentration, and we obtain a bimolecular rate constant of $4\times10^9$\,M$^{-1}$s$^{-1}$ in chloroform. The observed rate constant grows at high concentrations. This effect is modelled in terms of the hard sphere radial distribution function.NMR measurements confirm that aggregation takes place with a binding constant of between 0.14 and 0.43M$^{-1}$. Transient absorption measurements are consistent with a diffusive encounter mechanism for singlet fission, with hints of more rapid singlet fission in aggregates at the highest concentration measured.These data show that excimers do not play the role of an emissive intermediate in exothermic singlet fission in solution, and that while aggregation occurs at higher concentrations, the mechanism of singlet fission remains dominated by diffusive encounters.

Modelling the reservoirs and fluxes of Zn in Earth's crust and mantle requires data on the solubility of its mineral hosts and ores in coexisting fluids, as well as on the complexation of Zn in these fluids as a function of fluid composition, pressure, and temperature. However, due to experimental challenges, the availability of such data is limited to pressures below 1 GPa, which are only representative of upper crust conditions. Here, we report the effects of salinity (0–4.5 m total Cl), pressure (0.5–6 GPa) and temperature (25–400 °C) on the solubility of smithsonite (ZnCO3) and speciation of Zn in aqueous fluids. Solubilities at mineral-fluid equilibria and Zn speciation in the coexisting aqueous fluids were determined in situ at high pressure-temperature (P-T) conditions by synchrotron X-ray fluorescence (XRF) and X-ray absorption spectroscopy (XAS) using resistively heated diamond anvil cells (RH-DAC). The solubility of smithsonite increases with salinity, pressure, and temperature. In agreement with previous studies, conducted at lower pressures (below 1 GPa), we observed a gradual transition from octahedral hydrated [Zn(H2O)6]2+ to tetrahedral hydrated and chlorinated [Zn(H2O)4-nCln]2-n (n = 1–4) complexes with increasing salinity and temperature. Our results suggest that these tetrahedral complexes remain stable under the conditions relevant to cold slab dehydration. This change of coordination further enhances the solubility of smithsonite in Cl-rich fluids and provides a likely mechanism for the efficient uptake of Zn by slab-derived fluids.

Recent progress in manufacturing now enables the efficient fabrication of complex oxide-glass components at the micrometer– to sub-micrometer scale. This benefits both the industry and fundamental research as such miniature glass parts have numerous applications. However, at these length-scales, the mechanical properties of glasses can no longer be predicted based on bulk material characteristics. Here it is shown that fused silica micro-pillars fabricated by laser-assisted etching are almost ten times stronger than their bulk-sized counterparts. The relatively rough surface typical for this process does not much impair this strength. Additionally, it is demonstrated that annealing of the as-fabricated structures at 1200 °C in air results in significantly smoother surfaces. The accompanying increase in mechanical strength from approximately 8 GPa to 10 GPa is due to the reduction of stress concentrations at the surface, as demonstrated by finite element simulations. It is also demonstrated that the gain in mechanical resistance of glass components due to downsizing occurs already for parts as large as almost 20 µm – orders of magnitude above the critical size reported for other micro-mechanical effects. These micro-mechanical properties of selective laser-assisted etching structured fused silica components are key to a reliable use of glass micro-components.

We report the first use of a pressure-assisted sintering technique on metal–organic framework powders, allowing for the fast production of crystalline macroporous monoliths. Mechanical and microstructural characterization of the monoliths is presented. The interconnected macroporosity of the compacts can be adjusted, providing an immense interface for gas–solid interaction. The sintering technique is well-established and commercially available, allowing industrial scale-up of the process.

Khesinite, Ca 4 Mg 2 Fe 3+ 10 O 4 (Fe 3+ 10 Si 2 )O 36 , is a new member of the rhonite group of the sapphirine supergroup. Khesinite was discovered in thin veins of paralavas within fine-grained gehlenite rocks (hornfels) of the Hatrurim Complex in the Negev Desert, Israel. Paralavas are composed of rankinite, pseudowollastonite (rarely wollastonite), flamite, kalsilite, cuspidine and members of the solid-solution series: schorlomite–andradite, gehlenite–ackermanite–“Fe 3+ -gehlenite”, magnesioferrite–spinel and fluorapatite–fluorellestadite. Accessory and rare minerals are represented by baryte, walstromite, fresnoite, vorlanite, barioferrite, hematite, perovskite, gurimite, zadovite, aradite and hexacelsian. Electron-microprobe analysis of the holotype khesinite gives the following empirical formula for 40 oxygens and 28 cations: Ca 4 (Fe 3+ 8.528 Mg 1.635 Ca 0.898 Ti 4+ 0.336 Ni 2+ 0.217 Mn 2+ 0.155 Cr 3+ 0.132 Fe 2+ 0.098 ) Σ12 [(Fe 3+ 6.827 Al 2.506 Si 2.667 ) Σ12 O 40 ]. Khesinite is black to dark brown. It has semi-metallic lustre and does not show fluorescence. Cleavage and parting are not observed, fracture is irregular. Khesinite has a Mohs9 hardness of 6; microhardness VHN 50 is 943 kg mm −2 . The calculated density is 4.097 g cm −3 . In reflected light khesinite is grey with weak internal brown reflections. Reflectance data for the COM (Commission of Ore Mineralogy, IMA) wavelengths vary from ~13.4% (470 nm) to ~11.8% (700 nm). The crystal structure of khesinite [ P 1 ¯ a = 10 . 5363 ( 1 ) , b = 10.9242(2), c = 9.0612(1) A, α = 106.340(1)°, β = 95.765(1)°, γ = 124.373(1)°, V = 780.54(2) A 3 ] was refined from X-ray single-crystal data to R 1 = 0.046. The khesinite structure is close to that of the synthetic compounds SFCA and SFCAM. Khesinite crystallized in paralava from melt, sometimes forming isolated crystals, but more commonly reaction rims on magnesioferrite in association with pseudowollastonite and flamite at temperature not lower than 1200 °C.

Fe2As has been studied in situ by synchrotron powder X-ray diffraction (PXRD) over the range of temperatures 25–850 °C and under a neutral atmosphere to understand its thermal behavior, which is potentially important for gold extraction. For the first time, incongruent high-temperature reactions of Fe2As are observed as it breaks down and the existence of a previously undiscovered high-temperature FeAs phase with an NiAs-type structure has been determined experimentally. No evidence has been found for the existence of the high-temperature Fe3As2 phase. Hence, the previously published phase diagram for the Fe–As system has to be modified accordingly. Published version

We report the amorphization of three metal-organic frameworks, ZIF-4, ZIF-62, and ZIF-zni, by synchrotron X-ray radiation. Complete amorphization of these structures occurs on timescales ranging from minutes to hours. This process is non-isokinetic in all three cases, given a varying transformation rate as the transformation proceeds. The underlying mechanism bears the signature of inhomogeneous nucleation, reflected by an increasing local Avrami exponent over time. Furthermore, the amorphization rate accelerates with increasing temperature, even far below the usual thermal stability limit of each crystalline phase. These results not only have important implications for interpretation of X-ray synchrotron studies on the stability of metal-organic frameworks, they also shed light on the rarely-discussed and generally unpredictable experimental problem of beam damage in organic and inorganic compounds in general.

Black prismatic crystals of the new mineral wernerkrauseite, ideally CaFe3+2Mn4+O6 [ Pnma , a = 9.0548(2), b = 2.8718(1), c = 10.9908(2) A; V = 285.80(1) A3, Z = 8/3], were found in altered xenoliths within alkaline basalts of the Bellerberg volcano, Eifel, Rhineland-Palatinate, Germany. Fluorellestadite, wadalite, andradite–schorlomite, perovskite, gehlenite, magnesioferrite, cuspidine, ettringite–thaumasite, hydrocalumite, jennite, katoite, and portlandite are the main associated minerals. Wernerkrauseite crystals up to 0.5 mm in size show strong submetallic lustre; the streak is black. Wernerkrauseite appears grey in reflected light. Pleochroism is very weak, bireflectance and anisotropy are weak. Reflectance data for the COM wavelengths vary from ~31 % (400 nm) to ~19 % (700 nm). The calculated density is 4.66 g/cm3, microhardness VHN25 is 154(5) kg/mm2. Wernerkrauseite is a Ca-deficient structural analogue of harmunite, CaFe2O4, and therefore is one of the four known minerals with post-spinel structures. The empirical chemical formula of the holotype wernerkrauseite is Ca0.994(Fe3+1.057Mn4+1.025 Mn3+0.878Mg0.030Al0.016)∑3.006O6. The end-member chemical formula can also be given on the basis of spinel stoichoimetry ( Z = 4): Ca2/3[Fe3+4/3Mn4+2/3]O4, which better reflects its non-stoichiometry. The crystal structure was determined using single-crystal X-ray diffraction ( R 1 = 0.0233 for 800 observed reflections [ I >2σ( I )]). The diffraction pattern shows evidence of short-range ordering of Ca-vacancies. The strongest diffraction lines of the calculated powder diffraction pattern are [ d hkl ( I )]: 2.646 (100), 2.450 (77), 2.748 (62), 4.527 (54), 4.698 (44), 1.818 (43), 2.425 (37), 1.778 (30). Raman spectra of wernerkrauseite were measured and analysed in comparison to the spectra of harmunite and marokite, CaMn2O4. Crystallisation of wernerkrauseite took place at temperatures below 850–900°C under high oxygen fugacity. Furthermore, Mn4+-bearing non-stoichiometric harmunite Ca0.862(Fe3+1.719 Mn4+0.265Ti4+0.012 Mg0.008)∑2.004O4 was found at the same locality, which suggests the existence of a continuous solid solution between wernerkrauseite, harmunite and Ca2/3Mn3+4/3Mn4+2/3O4, described by the formula Ca1−x/2(Fe3+, Mn3+)2−xMn4+xO4, with × ranging from 0 to 2/3.

Metal-organic frameworks (MOFs) are microporous materials with huge potential as host structures for chemical processes, including retention, catalytic reaction, or separation of guest molecules. Structural collapse at high-pressure, and unusual behaviours at elevated temperatures, such as melting and transitions to liquid states, have recently been observed in the family. Here, we show that the effect of the application of simultaneous high-pressure and -temperature on a MOF can be understood in terms of silicate analogues, with crystalline, amorphous and liquid states occurring across the pressure - temperature phase diagram. The response of ZIF-62, the MOF on which we focus, to simultaneous pressure and temperature reveals a complex behaviour with distinct high- and low- density amorphous phases occurring over different regions of the pressure-temperature space. In-situ powder X-ray diffraction, Raman spectroscopy and optical microscopy reveal that the stability of the liquid MOF-state expands significantly towards lower temperatures at intermediate, industrially achievable pressures. Our results imply a novel route to the synthesis of functional MOF glasses at low temperatures, avoiding decomposition upon heating at ambient pressure.

The recently accepted new mineral flamite IMA No. 2013–122, (Ca,Na,K) 2 (Si,P)O 4 , found in the pyrometamorphic rocks of the Hatrurim Formation, Israel, was reported to crystallize in the hexagonal space group P 6 3 with unit-cell parameters a = 43.3726(18), c = 6.8270(4) A. A careful re-examination of single crystals from the type locality and holotype material, however, shows that flamite is better described by the formula Ca 8−x (Na,K) x (SiO 4 ) 4−x (PO 4 ) x and that it crystallizes in the space group Pnm 2 1 , a = 9.3845(6), b = 21.7310(14), c = 6.8346(4) A, V = 1393.81(15) A3, Z =4 and is isostructural with the known synthetic P-doped clinker phase Ca 15 □(SiO 4 ) 6 (PO 4 ) 2 . The structure is a derivative of the hexagonal high-temperature variety of dicalcium-silicate, α-C 2 S, and is characterized by a cyclic triplet of individuals rotated 120° around c , interpreted as symplectite-like transformation “twinning” derived from α-C 2 S. The composition of intergrown flamite lamellae is chemically variable concerning the degree of Na, K and P substitution. We present the structure of flamite and discuss its close relationship to nagelschmidtite, Ca 7 (SiO 4 ) 2 (PO 4 ) 2 , and the high-temperature polymorphs of C 2 S.

Two intermediate compounds of the system Ca2SiO4–Ca3(PO4)2–CaNaPO4 were synthesized by reaction sintering at 1600°C and analyzed structurally, chemically, and optically. The structure of Ca7(PO4)2(SiO4)2 nagelschmidtite (space group P61, a = 10.7754(1) A, c = 21.4166(3) A) was determined by single crystal X-ray analysis. Its unit cell can be interpreted as a supercell (≈ 2 × a, 3 × c) of the high-temperature polymorph α-Ca2SiO4. Evidence for pseudo-hexagonal symmetry is shown. Using electron microprobe, the solid solution Ca7−xNax(PO4)2+x(SiO4)2−x, (x ≤ 2), of nagelschmidtite was confirmed. Volume thermal expansion coefficients of Ca6.8Na0.2(PO4)2.2(SiO4)1.8 and Ca5.4Na1.5(PO4)3.7(SiO4)0.3 were determined using high-temperature X-ray powder diffraction, yielding mean αV = 3.95 and 5.21 [×10−5/°C], respectively. Ca15(PO4)2(SiO4)6 is a distinct phase in the binary section Ca2SiO4–Ca3(PO4)2 and was found to extend into the ternary space according to Ca15−xNax(PO4)2+x(SiO4)6−x, (x ≤ 0.1). Quenching experiments of the latter allowed for structural analysis of a strongly disordered, defective high-temperature polymorph of the α-Ca2SiO4–α-Ca3(PO4)2 solid solution. Structural relations between nagelschmidtite, Ca15(PO4)2(SiO4)6 and the end-member compounds of the system are discussed.

We describe the fabrication of thermoelectric modules based on Half-Heusler TiNiSn and FeNbSb and their performance assessment under different boundary conditions. Module design is guided by a multiphysics model implementing experimentally determined thermoelectric materials properties. We consider two types of boundary conditions: first, imposing fixed cold- and hot-side temperatures onto the module, and second, imposing fixed values for the heat transfer coefficients between module and heat sink and source, representative for a waste-heat-recovery system using the exhaust heat of an internal combustion engine. We compare the modeling results with experimental data obtained from Half-Heusler modules integrated into a heat exchanger mounted to the exhaust of a compact van.

In solid-state-transformer technology, the isolation and power transfer between low voltage and medium voltage side is performed by a high power DC/DC converter. This DC/DC converter provides a defined ratio between input and output voltages, whereby, in order to reduce switching losses, zero-current-switching modulation schemes are often mandatory. The series-resonant-converter operated in half-cycle discontinuous-conduction-mode possesses all the aforementioned features, thus making it highly attractive for solid-state-transformer applications. For this reason, a comprehensive analytical model of the converter's static and dynamic behavior is provided in this paper. In addition, a method to model the switching losses under ZCS conditions, which is based on the behavior of the stored charge in the semiconductors, is presented. This enables an efficiency/power density (η-ρ) Pareto optimization of the aforementioned converter system.

A research program directed at developing technology for compact shipboard incinerators for sludges is described. The concept utilizes previously developed Vortex Containment Combustor (VCC) as a primary unit with an active combustion control afterburner (AB). The overall power scale of the combined system is 0.15MJoule/sec and has a target sludge processing rate of 0.75 liter/min. Tests were undertaken to evaluate the particulate suspension qualities of the VCC and the overall performance of the combined VCC I active control AB processing intermediate levels of a surrogate sludge.

A demonstration of a solar detoxification system was conducted for the U.S. Army Environmental Center (USAEC) at Science Applications International Corporation's (SAIC's) test site near Golden, Colorado, in June 1997. The purpose of this demonstration test was to evaluate the use of solar energy for thermally detoxifying organic compounds representative of soil contamination found at U.S. Army sites. The demonstration test was carried out under the third of three tasks conducted under contract by SAIC. Under Tasks I and II, the conceptual and detailed design of a pilot-scale system was completed. Under Task III, fabrication and testing of the system were accomplished. This document presents the results obtained during the Task III demonstration test. The purpose of this demonstration test was to evaluate the use of solar energy to thermally detoxify organic compounds removed from contaminated media by ex situ (such as thermal desorption) or in situ (such as soil vapor extraction) treatment systems, or desorbed from pretreatment matrices (such as activated carbon). Extraction systems are commercially available so the step of directly extracting organic from contaminated soil was excluded from the pilot-scale demonstration. Rather, the pilot-scale demonstration test focused on evaluating ultraviolet (UV)-rich solar destruction of volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) by a solar incinerator and the environmental control of the resulting off gases.

1. 1. Antisera to hog pancreatic amylase, having enzyme-inhibiting properties, were produced in goats. 2. 2. More cross-reactions of the goat antisera with various mammalian amylases were noted, compared to previous studies using rabbit antisera, although similarities in enzyme inhibition patterns seemed to follow expected phylogenetic relationships. 3. 3. Enzyme inhibition studies using these antisera showed that the liver amylases of various mammalian species are different from the pancreatic and salivary amylases of these species. 4. 4. Although in previous studies with rabbit antisera to amylase no inhibition of liver amylase had been notes, some inhibition of liver amylase by goat antisera was seen. 5. 5. Differences in the reaction rates of amylase with rabbit antibodies and goat antibodies were noted as were differences in the levels of maximal enzyme inhibition which could be achieved.