Surface reaction kinetics of the methanol synthesis and the water gas shift reaction on Cu/ZnO/Al₂O₃

A three-site mean-field extended microkinetic model was developed based on ab initio DFT calculations from the literature, in order to simulate the conversion of syngas (H2/CO/CO2) to methanol on Cu (211) and Cu/Zn (211). The reaction network consists of 25 reversible reactions, including CO and CO2 hydrogenation to methanol and the water-gas shift reaction. Catalyst structural changes are also considered in the model. Experiments were performed in a plug flow reactor on Cu/ZnO/Al2O3 at various gas hourly space velocities (24–40 L h−1 gcat−1), temperatures (210–260 °C), pressures (40–60 bar), hydrogen feed concentrations (35–60% v/v), CO feed concentrations (3–30% v/v), and CO2 feed concentrations (0–20% v/v). These experiments, together with experimental data from the literature, were used for a broad validation of the model (a total of 690 points), which adequately reproduced the measurements. A degree of rate control analysis showed that the hydrogenation of formic acid is the major rate controlling step, and formate is the most sensitive surface species. The developed model contributes to the understanding of the reaction kinetics, and should be applicable for industrial processes (e.g. scale-up and optimization)

A Detailed Process and Techno-Economic Analysis of Methanol Synthesis from H₂ and CO₂ with Intermediate Condensation Steps

In order to increase the typically low equilibrium CO₂ conversion to methanol using commercially proven technology, the addition of two intermediate condensation units between reaction steps is evaluated in this work. Detailed process simulations with heat integration and techno-economic analyses of methanol synthesis from green H₂ and captured CO₂ are presented here, comparing the proposed process with condensation steps with the conventional approach. In the new process, a CO₂ single-pass conversion of 53.9% was achieved, which is significantly higher than the conversion of the conventional process (28.5%) and its equilibrium conversion (30.4%). Consequently, the total recycle stream flow was halved, which reduced reactant losses in the purge stream and the compression work of the recycle streams, lowering operating costs by 4.8% (61.2 M€·a$^−$¹). In spite of the additional number of heat exchangers and flash drums related to the intermediate condensation units, the fixed investment costs of the improved process decreased by 22.7% (94.5 M€). This was a consequence of the increased reaction rates and lower recycle flows, reducing the required size of the main equipment. Therefore, intermediate condensation steps are beneficial for methanol synthesis from H₂/CO₂, significantly boosting CO₂ single-pass conversion, which consequently reduces both the investment and operating costs

Predictors of noncompliance to pulmonary tuberculosis treatment : an insight from South America

To investigate the factors associated with a higher risk of noncompliance to tuberculosis (TB) treatment in Porto Alegre, Brazil. Methods We identified 478 adult patients for this case-control study undergoing treatment for confirmed pulmonary TB. Cases (noncompliance) were defined as patients who stopped treatment for more than 30 consecutive days (n = 118). Controls were defined as all patients who completed treatment and were cured (n = 360). Factors associated with noncompliance were calculated with unadjusted and adjusted odds ratio (OR). Results The rate of noncompliance in our study was 25%. The factors of noncompliance after adjustments in the overall population were, in order of magnitude, living in an area of lower income (OR = 4.35, 95%CI: 2.50±7.58), abuse of drugs (OR = 2.73, 95%CI: 1.47±5.09), nonadherence to a previous treatment regimen (OR = 2.1, 95%CI: 1.28±3.45), and history of smoking (OR = 1.72, 95%CI: 1.00±3.00). Age, race, gender, level of education, HIV infection or diabetes status were not associated with a higher risk of noncompliance. In the subgroup of retreatment cases, poverty (OR = 2.65; 95%CI = 1.06±6.66), smoking history (OR = 2.94; 95%CI = 1.09±7.92), male gender (OR = 3.25; 95%CI = 1.32±8.0), and younger age (OR = 4.3; 95%CI = 1.15±16.07) were also associated with a higher risk of dropout. Conclusion Predictors of poor compliance to TB treatment were low income, abuse of drugs, re-treatment cases and history of smoking

Impact of ERT and follow-up of 17 patients from the same family with a mild form of MPS II

Background: Mucopolysaccharidosis type II, also known as Hunter syndrome, is a rare X-linked recessive disorder caused by deficiency of the lysosomal enzyme Iduronate-2- Sulfatase (IDS), leading to progressive accumulation of Glycosaminoglycans (GAGs) in several organs. Over the years, Enzyme Replacement Therapy (ERT) has provided significant benefits for patients, retarding the natural progression of the disease. Results: The authors evaluated 17 patients from the same family with a mild form of MPS type II; the proband had developed acute decompensated heart failure refractory to clinical measurements at 23 years and needed a rather urgent heart transplant; however, he died from surgical complications shortly after the procedure. Nevertheless, subsequent to his tragic death, 16 affected male relatives were detected after biochemical tests identifying the low or absent activity of the IDS enzyme and confirmed by molecular analysis of the IDS gene. Following diagnosis, different options of treatment were chosen: 6 patients started ERT with Elaprase® (Idursulfase) soon after, while the other 10 remained without ERT. Eventually, 4 patients in the latter group began ERT with Hunterase® (Idursulfase Beta). None presented adverse effects to either form of the enzyme. Among the 6 individuals without any ERT, two died of natural causes, after reaching 70 years. Despite the variable phenotype within the same family (mainly heart dysfunctions and carpal tunnel syndrome), all 14 remaining patients were alive with an independent lifestyle. Conclusion: Here, the authors report the variable progress of the disease with and without ERT in a large Brazilian family with a slowly progressive form of MPS II, harboring the same missense variant in the IDS gene

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO