Aktivno lužnati kompoziti dobiveni od troske željezne i čelične industrije

Slag as a secondary raw material from metallurgy is most often heaped in slag disposal areas without any profit. This paper deals with alkali activated slag from iron and steel production which can be used in the building industry. Products of alkali slag activation fulfill the role of inorganic binders.Kao sekundarna sirovina, troska od metalurškog procesa najčešće se odlaže na deponije bez ikakve financijske dobiti. Ovaj rad se bavi lužnato aktiviranom troskom iz proizvodnje željeza i čelika, koja kao anorgansko vezivo može biti korištena u građevinskoj industriji

Electronic Structures of Reduced and Superreduced Ir_2(1,8-diisocyanomenthane)_4^(n+) Complexes

Molecular and electronic structures of Ir_2(1,8-diisocyanomenthane)_4^(n+) (Ir(dimen)^(n+)) complexes have been investigated by DFT for n = 2, 1, 0 (abbreviated 2+, 1+, 0). Calculations reproduced the experimental structure of 2+, ν(C≡N) IR, and visible absorption spectra of all three oxidation states, as well as the EPR spectrum of 1+. We have shown that the two reduction steps correspond to successive filling of the Ir–Ir pσ orbital. Complexes 2+ and 1+ have very similar structures with 1+ having a shorter Ir–Ir distance. The unpaired electron density in 1+ is delocalized along the Ir–Ir axis and over N atoms of the eight C≡N– ligands. The second reduction step 1+ → 0 changes the Ir(CN−)_4 coordination geometry at each Ir site from approximately planar to seesaw whereby one −N≡C–Ir–C≡N– moiety is linear and the other bent at the Ir (137°) as well as N (146°) atoms. Although complex 0 is another example of a rare (pσ)2 dimetallic species (after [Pt_2(μ-P_2O_5(BF_2)_2)_4]^(6–), J. Am. Chem. Soc. 2016, 138, 5699), the redistribution of lower lying occupied molecular orbitals increases electron density predominantly at the bent C≡N– ligands whose N atoms are predicted to be nucleophilic reaction centers

Tryptophan to Tryptophan Hole Hopping in an Azurin Construct.

Electron transfer (ET) between neutral and cationic tryptophan residues in the azurin construct [ReI(H126)(CO)3(dmp)](W124)(W122)CuI (dmp = 4,7-Me2-1,10-phenanthroline) was investigated by Born-Oppenheimer quantum-mechanics/molecular mechanics/molecular dynamics (QM/MM/MD) simulations. We focused on W124•+ ← W122 ET, which is the middle step of the photochemical hole-hopping process *ReII(CO)3(dmp•-) ← W124 ← W122 ← CuI, where sequential hopping amounts to nearly 10,000-fold acceleration over single-step tunneling (ACS Cent. Sci. 2019, 5, 192-200). In accordance with experiments, UKS-DFT QM/MM/MD simulations identified forward and reverse steps of W124•+ ↔ W122 ET equilibrium, as well as back ET ReI(CO)3(dmp•-) → W124•+ that restores *ReII(CO)3(dmp•-). Strong electronic coupling between the two indoles (≥40 meV in the crossing region) makes the productive W124•+ ← W122 ET adiabatic. Energies of the two redox states are driven to degeneracy by fluctuations of the electrostatic potential at the two indoles, mainly caused by water solvation, with contributions from the protein dynamics in the W122 vicinity. ET probability depends on the orientation of Re(CO)3(dmp) relative to W124 and its rotation diminishes the hopping yield. Comparison with hole hopping in natural systems reveals structural and dynamics factors that are important for designing efficient hole-hopping processes

Light-Induced Nanosecond Relaxation Dynamics of Rhenium-Labeled Pseudomonas aeruginosa Azurins.

Time-resolved phosphorescence spectra of Re(CO)3(dmp)+ and Re(CO)3(phen)+ chromophores (dmp = 4,7-dimethyl-1,10-phenanthroline, phen = 1,10-phenanthroline) bound to surface histidines (H83, H124, and H126) of Pseudomonas aeruginosa azurin mutants exhibit dynamic band maxima shifts to lower wavenumbers following 3-exponential kinetics with 1-5 and 20-100 ns major phases and a 1.1-2.5 μs minor (5-16%) phase. Observation of slow relaxation components was made possible by using an organometallic Re chromophore as a probe whose long phosphorescence lifetime extends the observation window up to ∼3 μs. Integrated emission-band areas also decay with 2- or 3-exponential kinetics; the faster decay phase(s) is relaxation-related, whereas the slowest one [360-680 ns (dmp); 90-140 ns (phen)] arises mainly from population decay. As a result of shifting bands, the emission intensity decay kinetics depend on the detection wavelength. Detailed kinetics analyses and comparisons with band-shift dynamics are needed to disentangle relaxation and population decay kinetics if they occur on comparable timescales. The dynamic phosphorescence Stokes shift in Re-azurins is caused by relaxation motions of the solvent, the protein, and solvated amino acid side chains at the Re binding site in response to chromophore electronic excitation. Comparing relaxation and decay kinetics of Re(dmp)124K122Cu II and Re(dmp)124W122Cu II suggests that electron transfer (ET) and relaxation motions in the W122 mutant are coupled. It follows that nanosecond and faster photo-induced ET steps in azurins (and likely other redox proteins) occur from unrelaxed systems; importantly, these reactions can be driven (or hindered) by structural and solvational dynamics

Utilization of casting ladle lining enthalpy for heating gas savings in the course of ladle preheating

During the long-term staying of steel in ladle within the period from the tap until the end of continuous casting takes place a great amount of heat accumulates in lining. For its utilization is necessary to optimize heat operation of ladle lining. The demanded enthalpy of ladle before tap and the real enthalpy of ladle as things stand are needed for heating gas savings during the preheating. The enthalpy changes of ladle lining are in the course of their cycling in steelworks solved by the model of lining thermal state. For that purpose were conducted the operation measurements to find out the ladle lining thermal field within the whole technological flow

Hydraulic properties of ladle slags

The article presents results of examining of hydraulic properties of ladle slags formed during production of steel. The studied ladle slags were subjected to different cooling mode from the molten state. Based on the ability of the slag react with the water was assessed their hydraulic activity. The hydraulic properties are caused by the presence of minerals dicalcium silicate, tricalcium aluminate, mayenite, brownmillerite and dicalcium ferite. The emergence of required hydrating phases in the ladle slags is conditioned by a sufficient CaO content and their cooling rate. The contact the slag with water during processing and their ageing has a negative effect. The experiment has shown that the phase transformation of the mineral dicalcium silicate which occurs during cooling of the ladle slags cause their volume instability

Ultrafast Excited-State Dynamics of Rhenium(I) Photosensitizers [Re(Cl)(CO)_(3)(N,N)] and [Re(imidazole)(CO)_(3)(N,N)]^+: Diimine Effects

Femto- to picosecond excited-state dynamics of the complexes [Re(L)(CO)_(3)(N,N)]^n (N,N = bpy, phen, 4,7-dimethyl-phen (dmp); L = Cl, n = 0; L = imidazole, n = 1+) were investigated using fluorescence up-conversion, transient absorption in the 650−285 nm range (using broad-band UV probe pulses around 300 nm) and picosecond time-resolved IR (TRIR) spectroscopy in the region of CO stretching vibrations. Optically populated singlet charge-transfer (CT) state(s) undergo femtosecond intersystem crossing to at least two hot triplet states with a rate that is faster in Cl (~100 fs)^(−1) than in imidazole (~150 fs)^(−1) complexes but essentially independent of the N,N ligand. TRIR spectra indicate the presence of two long-lived triplet states that are populated simultaneously and equilibrate in a few picoseconds. The minor state accounts for less than 20% of the relaxed excited population. UV−vis transient spectra were assigned using open-shell time-dependent density functional theory calculations on the lowest triplet CT state. Visible excited-state absorption originates mostly from mixed L;N,N^(•−) → Re^(II) ligand-to-metal CT transitions. Excited bpy complexes show the characteristic sharp near-UV band (Cl, 373 nm; imH, 365 nm) due to two predominantly ππ*(bpy^(•−)) transitions. For phen and dmp, the UV excited-state absorption occurs at 305 nm, originating from a series of mixed ππ* and Re → CO;N,N•− MLCT transitions. UV−vis transient absorption features exhibit small intensity- and band-shape changes occurring with several lifetimes in the 1−5 ps range, while TRIR bands show small intensity changes (≤5 ps) and shifts (~1 and 6−10 ps) to higher wavenumbers. These spectral changes are attributable to convoluted electronic and vibrational relaxation steps and equilibration between the two lowest triplets. Still slower changes (≥15 ps), manifested mostly by the excited-state UV band, probably involve local-solvent restructuring. Implications of the observed excited-state behavior for the development and use of Re-based sensitizers and probes are discussed

Volume and diagnosis: an approach to cross-border care in eight European countries

Objectives: Mobility of patients is a pertinent issue on the European Union's agenda. This study aimed to estimate the volume and main diagnoses of cross-border care in eight European countries, in order to provide policy makers with background information about the nature of patient mobility in Europe. Methods: This article reports the combined findings from three independent studies that compiled self-reported information on admissions data and main diagnoses from more than 200 hospitals in eight European countries. Results: The average volume of cross-border patients accounted for less than 1% of total admissions in the hospitals studied here. Diseases of the circulatory system (mainly acute myocardial infarction) and fractures were the most common reasons for hospitalisation of European patients abroad. Deliveries and other diagnoses related to pregnancy, pneumonia, appendicitis and other diseases of the digestive system, aftercare procedures, and disorders of the eye and adnexa were also common diagnoses for this population. Conclusions: Hospitals should reinforce their efforts to adapt the care provided to the needs of foreign patients in treatment areas that cover the most frequent pathologies identified in this populatio