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Solubility measurements of sulfides in aqueous solutions are necessary to understand the behaviour of these scaling minerals in geothermal and oil reservoirs. The low solubility levels of Zinc Sulfide (ZnS), Lead Sulfide (PbS) and Iron Sulfide (FeS) make the solubility measurements a challenging task. Consequently existing data are rare and scattered. The aim of this work is to develop a reliable experimental procedure and to measure solubility of sulfides at high temperature and pressures. Additionally the experimental data are used for estimation of the solid-liquid equilibrium using the Extended UNIQUAC model. The experimental determination of the solubility of ZnS, PbS and FeS is carried out at temperatures up to 200°C and pressures up to 60 bars. The minerals in their pure form are added to ultra-pure water previously degassed with nitrogen. The aqueous solution is prepared in a reduced oxygen atmosphere to avoid the risk of oxidation of sulfide minerals. The solution is kept in an equilibrium cell at constant temperature and pressure with continuous stirring. The concentration of Zn2+, Pb2+, Fe2+ and S2- are measured using Inductively Coupled Plasma Optical Emission spectrometry (ICP-OES) as analytical technique. The solid-liquid equilibria is calculated using the Extended UNIQUAC model. The Extended UNIQUAC model is a local composition model and features several advantages compared to other models when describing the behaviour of aqueous electrolytes systems and it was presented by Thomsen and Rasmussen in 1999 1. The model accounts for the dependency of the solubility on pressure and temperature. The pressure parameters were proposed by Villafáfila et al (2005; 2006) 2 on their study on sulfate scaling minerals. The parameter estimation of the model is carried out based on the experimental data produced in our laboratory. The results show that the Extended UNIQUAC model can correlate the solubilit

The enzyme Carbonic Anhydrase (CA) can accelerate the absorption rate of CO2 into aqueous solutions by several-fold. It exist in almost all living organisms and catalyses different important processes like CO2 transport, respiration and the acid-base balances. A new technology in the field of carbon capture is the application of enzymes for acceleration of typically slow ternary amines or inorganic carbonates. There is a hidden potential to revive currently infeasible amines which have an interesting low energy consumption for regeneration but too slow kinetics for viable CO2 capture. The aim of this work is to discuss the measurements of kinetic properties for CA promoted CO2 capture solvent systems. The development of a rate-based model for enzymes will be discussed showing the principles of implementation and the results on using a well-known ternary amine for CO2 capture. Conclusions will be drawn revealing basic unexpected process conditions which are beneficial to enzyme promoted amines like water presence, temperatures, and similar basic variables.

Post-combustion carbon capture technologies seem to be necessary to realize the CO2 mitigation policies internationally shared for the next future, despite none of them appears to be ready for full-scale applications. This work considers the aqueous ammonia based process for a coal-fired Ultra Super Critical power plant. Two layouts are simulated with Aspen Plus employing the recently recalibrated Extended UNIQUAC thermodynamic model. The first one operates at chilling conditions, which yield to salt precipitation, and is taken as reference because already analyzed in previous studies. The second layout operates at cooled conditions, which does not yield any salt precipitation. The Chilled layout reveals low specific heat duty and SPECCA equal to 2.2 and 2.86 MJ/kgco2, respectively. In contrast, the Cooled layout presents a higher specific heat duty of almost 3 MJ/kgco2 but, importantly, a lower SPECCA of 2.58 MJ/kgco2. The latter layout is a better choice also from the perspective of the plant operation since it does not present the salt precipitation.

Introduction: Undergraduate research among medical students is essential in the education of future physicians and scientists. This study aimed to evaluate the scientific yield of extracurricular undergraduate research among medical students. Methods: Medical students at the University of Copenha - gen who completed an extracurricular research year be - tween January 2004 and June 2013 were evaluated through a manual search in PubMed MEDLINE. The primary focus was the number of peer-reviewed, published articles. r esults: Of the 363 included students, 3.1% did their re - search in 2004-2005 compared with 46.5% in 2012-2013. After three years, 70.4% of the students had published a peer-reviewed article; and of all the 363 students, 36.5% had published as a first author. In total, 87.7% had a medi - cal specialty as their research area versus a surgical special - ty. Most students were involved in cardiology (14.1%). Car - diology was also associated with the greatest scientific yield with a median number of 0.8 publications per year after the students concluded their undergraduate research period. Three or more years after concluding their undergraduate research, 32.8% of the students had continued with re - search in the context of a PhD programme. c onclus I on: Overall, the number of medical students who engage in extracurricular research follows an increasing trend, and more than two-thirds of these students publish a peer-reviewed paper within three years. Cardiology was the most popular specialty and also the specialty with the greatest scientific yield. A third of the undergraduate re - search students continued doing research in the context of a PhD programme.

Background—The transition of scientific knowledge from discovery into practice is less than ideal. A key step in this translation occurs when presentations from major meetings are published in peer-reviewed literature, yet the completeness and speed of this process are not known. We performed a systematic and automated evaluation of rates, timing, and correlates of publication from scientific abstracts presented at 3 major cardiovascular conferences. Methods and Results—Using an automated computer algorithm, we searched the ISI Web of Science to identify peer-reviewed publications of abstracts presented at the American Heart Association (AHA), American College of Cardiology (ACC), and European Society of Cardiology (ESC) scientific sessions from 2006 to 2008. We compared abstract publication rates and journal impact factor between the 3 meetings using multivariable logistic regression modeling. From 2006 to 2008, 11 365, 5005, and 10 838 abstracts were presented at the AHA, ACC, and ESC meetings, respectively. Overall, 30.6% of presented abstracts were published within 2 years of the conference; ranging from 34.5% for AHA to 29.5% for ACC to 27.0% for ESC (P0.0001). Five years after conference presentation in 2005, these rates had risen slightly to 49.7% for AHA, 42.6% for ACC, and 37.6% for ESC (P0.0001). After adjustment for abstract characteristics and contributing countries, abstracts presented at the AHA meeting remained more likely for publication relative to the ESC (adjusted odds ratio, 1.24; 95% confidence interval, 1.16–1.34) and the ACC (adjusted odds ratio, 1.20; 95% confidence interval, 1.11–1.29). Median impact factors for subsequent publications varied from 4.8 (interquartile range, 3.8–10.1) for AHA to 4.0 (interquartile range, 3.1–7.5) for ACC and 3.9 (quartile 1–3, 2.5–5.8) for ESC (P for difference between groups 0.01). Clinical science and population science were less likely to be published comp

The climate is in a critical state due to the impact of pollution by CO2 and similar greenhouse gasses. Action needs to be taken in order reduce the emission of harmful components. CO2 capture is one process to help the world population back on track in order to return to normal condition, obtaining a sustainable use of natural organic resources. In this work the solid solubility has been measured for the promoted hot carbonate process using piperazine and K2CO3/KHCO3. It entails a comparison of several newly developed methods in order to guarantee the accuracy of determined experimental work. Interesting and difficult phenomena has been observed in the analysis of the piperazine solvent. Various hydrates and complexes are formed. The loaded solutions are analysed using the same techniques. Guidelines for solvent handling are set up. These define a simple boundary for safe solvent handling in order to prevent precipitation during mixing. At the same time these can actively be used in the development in the process. Slurry formation is a core issue in these processes and need to be addressed carefully. The outcome of thermodynamic modelling by using the extended UNIQUAC model will be shown with the purpose of simulating the CO2 capture process. This involves equilibrium studies on physical properties in the activated carbonate solvent. Energy consumption while applying the promoted carbonate solutions using piperazine is given in overview.

In this work the solid–liquid equilibrium (SLE) and freezing-point depression (FPD) in the electrolytic binary aqueous systems piperazine (PZ, CAS No. 110-85-0) and aqueous 2-amino-2-methyl-1-propanol (AMP, CAS No. 124-68-5) were measured. The FPD and solubility were also determined in the ternary AMP–PZ–H2O system. A method was developed by which solubility can be determined at higher temperatures using the FPD setup. A total of 86 data points are listed in the full concentration range from (−35 to 90) °C. The solid phases piperazine hexahydrate (PZ·6H2O), piperazine hemihydrate (PZ·1/2H2O), and anhydrous PZ precipitated during the experiments. The data can be used in the formulation, prevention, or intentional formation of slurries in piperazine solvents for promoting CO2 capture using absorption and desorption.

In this work, the rate of absorption of carbon dioxide by aqueous ammonia solvent has been studied by applying a newly built wetted wall column. The absorption rate in aqueous ammonia was measured at temperatures from 279 to 304K for 1 to 10wt% aqueous ammonia with loadings varying from 0 to 0.8molCO2/molNH3. The absorption rate in 30wt% aqueous mono-ethanolamine (MEA) was measured at 294 and 314K with loadings varying from 0 to 0.4 as comparison.It was found that at 304K, the rate of absorption of carbon dioxide by 10wt% NH3 solvent was comparable to the rates for 30wt% MEA at 294 and 314K (a typical absorption temperature for this process). The absorption rate using ammonia was however significantly lower at temperatures of 294K and lower as applied in the Chilled Ammonia Process. However, at these low temperatures, the rate of absorption in ammonia has only a small temperature dependency.The rate of absorption decreases strongly with decreasing ammonia concentrations and increasing CO2 loadings.The rate of absorption of carbon dioxide by aqueous ammonia solvent was modeled using the measurements of the unloaded solutions and the zwitter-ion mechanism. The model could successfully predict the experimental measurements of the absorption rate of CO2 in loaded ammonia solutions.

Freezing points for aqueous monoethanolamine (MEA), methyl diethanolamine (MDEA), and MEA−MDEA solutions were measured in the concentration range from 0 to 0.4 mass fractions of the alkanolamines. For the aqueous MEA−MDEA system, freezing points for 1:4, 1:2, 1:1, 2:1, and 4:1 molar ratios of MEA/MDEA were determined. The experimental values indicate that the MDEA−water interaction is stronger than the MEA−water interaction. Measurements were carried out by a new modified Beckmann apparatus, which has not previously been described. The apparatus and method proved to have good repeatability and accuracy. A correlation of the freezing points as functions of the solution composition was made. Measurements of aqueous MEA and aqueous MDEA were compared to experiments found in the open literature.