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Background This study is the first part of a register-based research program with the overall aim to increase the knowledge of the health status among geriatric patients and to identify risk factors for readmission in this population. The aim of this study was two-fold: 1) to evaluate the validity of the study cohorts in terms of health care utilization in relation to regional cohorts; 2) to describe the study cohorts in terms of health status and health care utilization after discharge. Methods The project consist of two cohorts with data from patient records of geriatric in-hospital stays, health care utilization data from Stockholm Regional Healthcare Data Warehouse 6 months after discharge, socioeconomic data from Statistics Sweden. The 2012 cohort include 6710 patients and the 2016 cohort, 8091 patients; 64% are women, mean age is 84 (SD 8). Results Mean days to first visit in primary care was 12 (23) and 10 (19) in the 2012 and 2016 cohort, respectively. Readmissions to hospital was 38% in 2012 and 39% in 2016. The validity of the study cohorts was evaluated by comparing them with regional cohorts. The study cohorts were comparable in most cases but there were some significant differences between the study cohorts and the regional cohorts, especially regarding amount and type of primary care. Conclusion The study cohorts seem valid in terms of health care utilization compared to the regional cohorts regarding hospital care, but less so regarding primary care. This will be considered in the analyses and when interpreting data in future studies based on these study cohorts. Future studies will explore factors associated with health status and re-admissions in a population with multi-morbidity and disability.

Background The aim of the current study was to explore the changing interrelationships among clinical variables through the stages of schizophrenia in order to assemble a comprehensive and meaningful disease model. Methods Twenty-nine centers from 25 countries participated and included 2358 patients aged 37.21 ±Â 11.87 years with schizophrenia. Multiple linear regression analysis and visual inspection of plots were performed. Results The results suggest that with progression stages, there are changing correlations among Positive and Negative Syndrome Scale factors at each stage and each factor correlates with all the others in that particular stage, in which this factor is dominant. This internal structure further supports the validity of an already proposed four stages model, with positive symptoms dominating the first stage, excitement/hostility the second, depression the third, and neurocognitive decline the last stage. Conclusions The current study investigated the mental organization and functioning in patients with schizophrenia in relation to different stages of illness progression. It revealed two distinct cores of schizophrenia, the Positive and the Negative, while neurocognitive decline escalates during the later stages. Future research should focus on the therapeutic implications of such a model. Stopping the progress of the illness could demand to stop the succession of stages. This could be achieved not only by both halting the triggering effect of positive and negative symptoms, but also by stopping the sensitization effect on the neural pathways responsible for the development of hostility, excitement, anxiety, and depression as well as the deleterious effect on neural networks responsible for neurocognition. © 2021 Cambridge University Press. All rights reserved.

Additional file 1: Table S1. Multivariable analysis for complete cases (backward stepwise selection, p

International audience; The Radio and Plasma Waves (RPW) instrument on the ESA Solar Orbiter mission is designed to measure in situ magnetic and electric fields and waves from the continuum up to several hundred kHz. The RPW also observes solar and heliospheric radio emissions up to 16 MHz. It was switched on and its antennae were successfully deployed two days after the launch of Solar Orbiter on February 10, 2020. Since then, the instrument has acquired enough data to make it possible to assess its performance and the electromagnetic disturbances it experiences. In this article, we assess its scientific performance and present the first RPW observations. In particular, we focus on a statistical analysis of the first observations of interplanetary dust by the instrument’s Thermal Noise Receiver. We also review the electro-magnetic disturbances that RPW suffers, especially those which potential users of the instrument data should be aware of before starting their research work.

Context.On December 27, 2020, Solar Orbiter completed its first gravity assist manoeuvre of Venus (VGAM1). While this flyby was performed to provide the spacecraft with sufficient velocity to get closer to the Sun and observe its poles from progressively higher inclinations, the Radio and Plasma Wave (RPW) consortium, along with other operational in situ instruments, had the opportunity to perform high cadence measurements and study the plasma properties in the induced magnetosphere of Venus.Aims.In this paper, we review the main observations of the RPW instrument during VGAM1. They include the identification of a number of magnetospheric plasma wave modes, measurements of the electron number densities computed using the quasi-thermal noise spectroscopy technique and inferred from the probe-to-spacecraft potential, the observation of dust impact signatures, kinetic solitary structures, and localized structures at the bow shock, in addition to the validation of the wave normal analysis on-board from the Low Frequency Receiver.Methods.We used the data products provided by the different subsystems of RPW to study Venus’ induced magnetosphere.Results.The results include the observations of various electromagnetic and electrostatic wave modes in the induced magnetosphere of Venus: strong emissions of ∼100 Hz whistler waves are observed in addition to electrostatic ion acoustic waves, solitary structures and Langmuir waves in the magnetosheath of Venus. Moreover, based on the different levels of the wave amplitudes and the large-scale variations of the electron number densities, we could identify different regions and boundary layers at Venus.Conclusions.The RPW instrument provided unprecedented AC magnetic and electric field measurements in Venus’ induced magnetosphere for continuous frequency ranges and with high time resolution. These data allow for the conclusive identification of various plasma waves at higher frequencies than previously observed and a detailed investigation regarding the structure of the induced magnetosphere of Venus. Furthermore, noting that prior studies were mainly focused on the magnetosheath region and could only reach 10–12 Venus radii (RV) down the tail, the particular orbit geometry of Solar Orbiter’s VGAM1, allowed the first investigation of the nature of the plasma waves continuously from the bow shock to the magnetosheath, extending to ∼70RVin the far distant tail region.

Context. Rosetta followed comet 67P at heliocentric distances from 1.25 to 3.6 au. The solar wind was observed for much of this time, but was significantly deflected and to some extent slowed down by the interaction with the coma. Aims. We use the different changes in the speed of H+ and He2+ when they interact with the coma to estimate the upstream speed of the solar wind. The different changes in the speed are due to the different mass per charge of the particles, while the electric force per charge due to the interaction is the same. A major assumption is that the speeds of H+ and He2+ were the same in the upstream region. This is investigated. Methods. We derived a method for reconstructing the upstream solar wind from H+ and He2+ observations. The method is based on the assumption that the interaction of the comet with the solar wind can be described by an electric potential that is the same for both H+ and He2+. This is compared to estimates from the Tao model and to OMNI and Mars Express data that we propagated to the observation point. Results. The reconstruction agrees well with the Tao model for most of the observations, in particular for the statistical distribution of the solar wind speed. The electrostatic potential relative to the upstream solar wind is derived and shows values from a few dozen volts at large heliocentric distances to about 1 kV during solar events and close to perihelion. The reconstructed values of the solar wind for periods of high electrostatic potential also agree well with propagated observations and model results. Conclusions. The reconstructed upstream solar wind speed during the Rosetta mission agrees well with the Tao model. The Tao model captures some slowing down of high-speed streams as compared to observations at Earth or Mars. At low solar wind speeds, below 400 km s−1, the agreement is better between our reconstruction and Mars observations than with the Tao model. The magnitude of the reconstructed electrostatic potential is a good measure of the slowing-down of the solar wind at the observation point.

Desulfurization at medium temperature was investigated with focus on impacts of temperature and CO 2 concentration under Oxyfuel firing and Regenerative Calcium Cycle (RCC) conditions. Investigation started with thermodynamic analysis and ThermoGravimetric Analysis (TGA). Tests were then conducted by a bench-scale fixed-bed type reactor, using a synthetic gas mixture. Various parameters were evaluated. The envelope covered temperature variation of 150-450 °C, CO 2 concentrations in the gas stream up to 60% and water concentrations between 0 to 25%. These tests were done having SO 2 concentrations in the gas of 2000 ppm SO 2 . Furthermore different types of lime samples were screened. It was found that CO 2 had strong impact on medium temperature desulfurization. Capture of CO 2 by the lime was enhanced by increasing temperature. CO 2 competed with SO 2 and the relative extent to react with lime varied with temperature. Rate of reaction increased with temperature, the capacity of lime-to-SO 2 and lime-to-CO 2 increased as well. Optimum temperature windows were searched and will be discussed. Based on the tests results, scenarios of desulfurization options at medium temperature range for Oxy and RCC are evaluated, and will be discussed in details. The testing results show issues related to high concentration of CO 2 under the Oxy conditions at temperature over 250 °C. Though capacity of lime for SO 2 increases with temperature, the amount is limited due to reaction with CO 2 at high concentration. Desulfurization at medium temperature range, 250 - 450 °C, should be aiming at moderate SO 2 removal, and the reuse of the spent reagent is considered in the downstream wet desulfurization process. With about 10% CO 2 , in the RCC conditions, it is more optimistic to remove SO 2 in the medium temperature range. Optimum temperature range is discussed for achieving moderate SO 2 removal. Reuse of the spent reagent is considered in the downstream wet desulfurization process.

With increasing emphasis on the control of greenhouse gases, power plants may move towards oxy-fuel technologies rather than air-fired plants. This move leads to a change in the feed to the desulfurization unit, which also needs to be adapted along with the power plant. Most existing plants already have functioning desulfurization units, which need to be retrofitted for the new conditions. In the present study, three different limes have been examined as sorbents for sulfur capture in oxy-fuel conditions with varying residence times at medium temperature (150&ndash, 450 ∘ C). Parameters indicative of the kinetics and competition between SO 2 and CO 2 , like SO 2 breakthrough time, total lime conversion, yield for sulfur capture and sulfur selectivity have been evaluated. The results of this study lead to the recommendation that medium temperature desulfurization should be used for moderate SO 2 capture, in combination with already existing sulfur capture systems. The effects of CO 2 and water vapor have also been analyzed. In addition, the performance of the unit irrespective of temperature strongly depends on the lime type. In addition, absence of water vapor strongly favored the desulfurization process when there was high concentration of CO 2 .

We use Magnetosphere Multiscale (MMS) mission data to investigate a small number of magnetosheath jets, which are localized and transient increases in dynamic pressure, typically due to a combined increase in plasma velocity and density. For two approximately hour-long intervals in November, 2015 we found six jets, which are of two distinct types. (a) Two of the jets are associated with the magnetic field discontinuities at the boundary between the quasi-parallel and quasi-perpendicular magnetosheath. Straddling the boundary, the leading part of these jets contains an ion population similar to the quasi-parallel magnetosheath, while the trailing part contains ion populations similar to the quasi-perpendicular magnetosheath. Both populations are, however, cooler than the surrounding ion populations. These two jets also have clear increases in plasma density and magnetic field strength, correlated with a velocity increase. (b) Three of the jets are found embedded within the quasi-parallel magnetosheath. They contain ion populations similar to the surrounding quasi-parallel magnetosheath, but with a lower temperature. Out of these three jets, two have a simple structure. For these two jets, the increases in density and magnetic field strength are correlated with the dynamic pressure increases. The other jet has a more complicated structure, and no clear correlations between density, magnetic field strength and dynamic pressure. This jet has likely interacted with the magnetosphere, and contains ions similar to the jets inside the quasi-parallel magnetosheath, but shows signs of adiabatic heating. All jets are associated with emissions of whistler, lower hybrid, and broadband electrostatic waves, as well as approximately 10 s period electromagnetic waves with a compressional component. The latter have a Poynting flux of up to 40 µW m−2 and may be energetically important for the evolution of the jets, depending on the wave excitation mechanism. Only one of the jets is likely to have modified the surrounding magnetic field into a stretched configuration, as has recently been reported in other studies. None of the jets are associated with clear signatures of either magnetic or thermal pressure gradient forces acting on them. The different properties of the two types also point to different generation mechanisms, which are discussed here. Their different properties and origins suggest that the two types of jets need to be separated in future statistical and simulation studies. Keywords. Magnetospheric physics (magnetosheath; plasma waves and instabilities; solar wind–magnetosphere interactions)

Background: Enhanced recovery program for pancreaticoduodenectomy have become standard care. Little is known about adherence rates and sustainability of the program, especially when pancreaticogastrostomy is used in reconstruction. The aim of this study was, therefore, to evaluate adherence rates and continued outcome, after implementation of an enhanced recovery program. Methods: Consecutive patients undergoing pancreaticoduodenectomy at the Department of Surgery, Skåne University Hospital, Lund, Sweden were followed, after implementation of enhanced recovery program, October 2012. In April 2015, some items in the enhanced recovery program were modified, namely earlier removal of nasogastric tubes and abdominal drain. The patients were analyzed in three groups, the implementation group (control) and two post-implementation groups; intermediate and modified group. Sustainability was assessed according to length of stay and adherence rate. Results: In total, 160 patients were identified. The overall protocol adherence rate increased from 65% to 72%, p = 0.035. While the pre- and intraoperative protocol items were fulfilled to more than >90%, the postoperative were lower, but increasing over time; 48%, 50%, and 58%, p = 0.033. Postoperative complications and hospital length of stay did not change significantly. Conclusion: The positive outcome of an enhanced recovery program for pancreaticoduodenectomy was reasonably well sustained. Compliance with the protocol has increased, but strict adherence remains a challenge, especially with the postoperative items.

Viability and sensitivity of the great crested newt Triturus cristatus were simulated under different scenarios with a demographically and spatially structured stochastic model in an area of 144 km2 in southeastern Sweden. Eighteen ponds were monitored using drift fences with pitfall traps, funnel traps, visual observation and netting during the spring and summer of 2004. Estimated adult population sizes ranged between 0 and 620 individuals and the mean (±SD) local population size was 297 ± 233 individuals. Due to uncertainty of the data, the model was simulated with parameter ranges to estimate upper and lower bounds of viability. Estimated quasi-extinction risk (the risk of each population in the study area falling below 10 females) within a 50-yr period ranged from 100% to 0%, with a “best” estimate of 19.2%. The parameter most sensitive for the model outcome was fecundity, followed by juvenile survival, adult survival and transition from juvenile to adult. When these parameters were set at their lower bound, the quasi-extinction risk increased to 80–100%, while simulating these parameters at their higher bound inferred no or nearly no risk of quasi-extinction. This highlights the importance of focusing conservation efforts and research on the early life cycle stages. Management measures such as restoration of ponds and increased pond density decreased the risk for the great crested newt to end up quasi-extinct in the study area after 50 yr. The results may have implications on management measures of great crested newts throughout its distribution area.

Information is required on the heat of absorption for the correct design and optimization of absorption processes for the removal of CO 2 from gas streams. The heat of absorption affects the temperature profile in the absorber, and consequently the capacity of the absorption unit and the achievable purity of the gas from which CO 2 is removed. It is also associated with the energy requirement of the stripper. This usually accounts for the greatest operating cost in the absorption process, and if the amine could be regenerated using less energy or with low-grade energy, i.e. waste heat (70–90 °C), significant savings could be made. This paper presents experimental data on the heat of absorption of CO 2 in solutions of 2-amino-2-methyl-1-propanol (AMP) and an organic solvent, either N-methyl-2-pyrrolidone or triethylene glycol dimethyl ether, at different amine concentrations (15 wt% and 25 wt%) and temperatures (25 °C and 50 °C). The heat of absorption was greatly affected by the formation of a precipitate, which was observed during some of the experiments, and was significantly lower at CO 2 loadings above 0.5 mol CO 2 /mol AMP, as physical absorption of CO 2 became the dominating absorption process.

Sterically hindered amines, such as 2-amino-2-methyl-1-propanol (AMP), are an interesting alternative to the amines used in conventional CO2 absorption processes in industrial applications. One reason for this is because the carbamate formed is not stable, which may be beneficial during the regeneration of the amine solution in terms of a reduced energy requirement. This paper presents experimental data on the solubility of CO2 in solutions of AMP in one of two organic solvents: N-methyl-2-pyrrolidone or triethylene glycol dimethyl ether, at different amine concentrations (15 wt% and 25 wt%) and temperatures (25 °C and 50 °C). A solid precipitate was observed during some of the experiments. The absorption capacity of the solution increased with AMP concentration and was higher at lower temperatures. (Less)

This work presents a novel concept for CO 2 absorption with an amine solution forming a precipitate when absorbing CO 2 . The systems consist of the sterically hindered amine, 2-amino-2-methyl-1-propanol, and an organic solvent, N-methyl-2-pyrrolidone or triethylene glycol dimethyl ether. The precipitate is formed when CO 2 is absorbed and reacts with the amine. In order to design an absorption process using precipitating solutions, detailed knowledge on when and where the precipitate will form is needed. The onset of precipitation in four different amine solutions has been investigated in this work, and the composition of the precipitate was also determined using NMR spectroscopy.

Solutions of the amines N-methyldiethanolamine (MDEA) and piperazine (PZ) are commonly used for CO2 removal in industrial applications. This is mainly due to the low heat of reaction of MDEA, reducing the heat required for regeneration, and the high reaction rate of PZ, which reduces the size of the absorption tower. However, the effect of PZ on the heat of absorption in a mixture of these two solutions has not previously been investigated. This paper presents experimental data on the heat developed during the absorption of CO2 in aqueous solutions of MDEA and PZ, and mixtures thereof, at low loading and temperatures from 35 °C to 65 °C. The results indicate that PZ affects the amount of heat developed to a higher degree than previously thought, resulting in a significant increase compared to pure MDEA solutions. This effect is more pronounced at low carbon dioxide loadings. The impact of the temperature on the heat of absorption is weak for MDEA, as has been found in previous studies. The present study also demonstrated a weak temperature dependence for PZ.

A biohythane process based on wheat straw including: i) pretreatment, ii) H2 production using Caldicellulosiruptor saccharolyticus, iii) CH4 production using an undefined consortium, and iv) gas upgrading using an amine solution, was assessed through process modelling including cost and energy analysis. According to simulations, a biohythane gas with the composition 46–57% H2, 43–54% CH4 and 0.4% CO2, could be produced at high production rates (2.8–6.1 L/L/d), with 93% chemical oxygen demand (COD) reduction, and a net energy yield of 7.4–7.7 kJ/g dry straw. The model was calibrated and verified using experimental data from dark fermentation (DF) of wheat straw hydrolysate, and anaerobic digestion of DF effluent. In addition, the effect of gas recirculation was investigated by both wet experiments and simulation. Sparging improved H2 productivities and yields, but negatively affected the net energy gain and cost of the overall process.

A bottle screening method to detect smuggling drugs was developed based on a series of rapid and automated magnetic resonance measurements. Liquid alteration is detected by evaluating chemical and physical properties of the liquid, scanning the bottle with a compact, non-contact magnetic resonance probe. Chemical and molecular diffusion changes are detected by means of the magnetic resonance relaxation time. The inspection device automatically detects the presence of concealed powders dissolved in liquids in a second timescale. The non-ionizing, non-contact method effectively screens bottles, regardless of their shape, size, and color. The proposed system configuration does not require a large magnet generating uniform magnetic fields; rather it inspects the liquid using a compact probe positioned on the wall of the bottle. For a variety of samples tested, the screening does not require detailed information on the expected content of the bottle.

To determine the reliability and validity of a previously identified "suicide cluster" in the Percept-genetic Object-Relation Test (PORT), which test documents subliminal perception of object-relation pictures, 20 suicide attempters and 70 controls were investigated. The correspondence between scores assigned by two judges was 95%-100%. The suicide-cluster signs in PORT, notably "lack of attachment relationships" and "Motor activity," were significant. Differences between the results of this and the previous study are discussed as is the role of psychiatric disorder in suicide. (Bulletin of the Menninger Clinic, 75[4], 295-314)

An integrated system for the production of hydrogen by gasification of biomass and electrolysis of water has been designed and cost estimated. The electrolyser provides part of the hydrogen product as well as the oxygen required for the oxygen blown gasifier. The production cost was estimated to 39 SEK/kg H-2 at an annual production rate of 15 000 ton, assuming 10% interest rate and an economic lifetime of 15 years. Employing gasification only to produce the same amount of hydrogen, leads to a cost figure of 37 SEK/kg H-2, and for an electrolyser only a production cost of 41 SEK/kg H-2. The distribution of capital and operating cost is quite different for the three options and a sensitivity analyses was performed for all of these. However, the lowest cost hydrogen produced with either method is at least twice as expensive as hydrogen from natural gas steam reforming. (c) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved. (Less)

Metallic nanoparticles of gold functionalized with oligonucleotides conventionally use a terminal thiol modification and have been used in a wide range of applications. Although readily available, the oligonucleotide-nanoparticle conjugates prepared in this way suffer from a lack of stability when exposed to a variety of small molecules or elevated temperatures. If silver is used in place of gold then this lack of stability is even more pronounced. In this study we report the synthesis of highly stabilized oligonucleotide-nanoparticle conjugates using a simple oligonucleotide modification. A modified solid support was used to generate 3'-thioctic acid modified oligonucleotides by treatment with an N-hydroxysuccimidyl ester of thioctic acid. Unusually, both gold and silver nanoparticles have been investigated in this study and show that these disulphide-modified oligonucleotide probes offer significant improvements in nanoparticle stability when treated with dithiothreitol (DTT) compared with monothiol analogues. This is a significant advance in oligonucleotide-nanoparticle conjugate stability and for the first time allows silver nanoparticles to be prepared that are more stable than standard gold-thiol functionalized nanoparticles. This opens up the possibility of using silver nanoparticles functionalized with oligonucleotides as an alternative to gold.

The diffusion rate of a species, in a dense matrix of methane-producing microorganisms, was determined experimentally. To this end, a specially designed diaphragm diffusion cell was utilized. The experimental results revealed that the effective diffusion coefficient in a microorganism matrix was 22–33% of the diffusion coefficient in pure water.

In this work the Arrhenius parameters and heat of reaction for the esterification of acetic anhydride by methanol and the esterification of propionic anhydride by 2-butanol were determined using a CPA 202 reaction calorimeter (ChemiSens). Three reaction rate models were tested for each of the esterification reactions, two of which assumed autocatalytic behaviour. The autocatalytic models were based on a carboxylic acid dependency; acetic acid and propionic acid being side products in the reactions studied. The two catalytic models gave excellent fits to the experimental results thus indicating autocatalytic behaviour.

Intense high-latitude electric fields (>150 mV/m mapped to ionospheric altitude) at 4–7 RE geocentric distance have been investigated in a statistical study, using data from the Cluster satellites. The orbit of the Cluster satellites limits the data collection at these altitudes to high latitudes, including the poleward part of the auroral oval. The occurrence and distribution of the selected events have been used to characterize the intense electric fields and to investigate their dependance on parameters such as MLT, CGLat, altitude, and also Kp. Peaks in the local time distribution are found in the evening to morning sectors but also in the noon sector, corresponding to cusp events. The electric field intensities decrease with increasing latitude in the region investigated (above 60 CGLat). A dependence on geomagnetic activity is indicated since the probability of finding an event increases up to Kp=5–6. The scales sizes are in the range up to 10 km (mapped to ionospheric altitude) with a maximum around 4–5km, consistent with earlier findings at lower altitudes and Cluster event studies. The magnitudes of the electric fields are inversely proportional to the scale sizes. The type of electric field structure (convergent or divergent) is consistent with the FAC direction for a subset of events with electric field intensities in the range 500–1000 mV/m and with clear bipolar signatures. The FAC directions are also consistent with the Region 1 and NBZ current systems, the latter of which prevail only during northward IMF conditions. For scale sizes less than 2 km the majority of the events were divergent electric field structures. Both converging and diverging electric fields were found throughout the investigated altitude range (4–7 RE geocentric distance). Keywords. Magnetospheric physics (Electric fields; Auroral phenomena; Magnetosphere-ionosphere interactions)

Biotechnological leaching has been proposed as a suitable method for extraction of vanadium from spent catalysts and oil ash. In the biological leaching process, the vanadium(V) can be reduced to vanadium(IV), which is a less toxic and more soluble form of the vanadium. The present investigation showed that Acidithiobacillus ferrooxidans efficiently reduced vanadium(V) in the form of vanadium pentaoxide, to vanadyl(IV) ions, and tolerated high concentrations of vanadium(IV) and vanadium(V). A. ferrooxidans was compared with Acidithiobacillus thiooxidans, which has previously been utilized for vanadium leaching and reduction. Vanadium pentaoxide and sodium vanadate were used as model compounds. The results of this study indicate possibilities to develop an economical and technically feasible process for biotechnological vanadium recovery.

The mechanical properties of a laminate consisting of aluminum-foil, adhesive, and polymer layers were studied in relation to the adhesion level. A special application for liquid-food packaging materials was considered. In experiments, laminates with and without adhesive layers were tested. Tensile tests were first run for every layer of the laminate, and the data obtained were then used in analyzing the results of tensile tests on the entire laminate, as well as in theoretical and finite-element calculations. Relations between different mechanical properties (such as Young's modulus, the peak stress, and the strain at the peak stress) and the adhesion level were analyzed. It was found that the tensile strength and the strain at the peak stress increased with adhesion level. Only slight differences in Young's modulus were observed at different adhesion levels.

Dipolar recoupling pulse sequences are of great importance in magic angle spinning solid-state NMR. Recoupling sequences are used for excitation of double-quantum coherence, which, in turn, is employed in experiments to estimate internuclear distances and molecular torsion angles. Much effort is spent on the design of recoupling sequences that are able to produce double-quantum coherence with high efficiency in demanding spin systems, i.e., spin systems with small dipole-dipole couplings and large chemical-shift anisotropies (CSAs). The sequence should perform robustly under a variety of experimental conditions. This paper presents experiments and computer calculations that extend the theory of double-quantum coherence preparation from the strong coupling/small CSA limit to the weak coupling limit. The performance of several popular dipole-dipole recoupling sequences-DRAWS, POST-C7, SPC-5, R1, and R2-are compared. It is found that the optimum performance for several of these sequences, in the weak coupling/large CSA limit, varies dramatically, with respect to the sample spinning speed, the magnitude and orientation of the CSAs, and the magnitude of dipole-dipole couplings. It is found that the efficiency of double-quantum coherence preparation by gamma-encoded sequences departs from the predictions of first-order theory. The discussion is supported by density-matrix calculations.

The removal of chemical oxygen demand (COD) from wastewater-containing phenol was investigated using three-phase three-dimensional electrode reactor. Special attention was paid to experimentally probe the performance of the reactor in COD removal in the process of repeated batch runs. The experimental results showed that the reactor could remove COD from phenol-containing wastewater much more efficiently than both granulated activated carbon (GAC) adsorption bed and conventional three-dimensional electrode. For 200th batch run, the three-phase three-dimensional electrode reactor with an airflow of 5 l min(-1) and a cell voltage of 30 V could remove 1350 ppm COD from the wastewater in 30 min while conventional three-dimensional electrode reactor with a same cell voltage and GAC adsorption bed with a same airflow only could remove 610 and 1000 ppm, respectively, at the same reaction duration. Although it was found that COD removal decreased with increasing repeated batch runs in our experimental range, due to adsorption saturation of GAC and electrode passivation, the extent of decrease for the three-phase three-dimensional electrode is much less than those for conventional three-dimensional electrodes and GAC adsorption beds. The passivated reactor could be partly re-activated by electrolysis in the presence of MnO2.

A new electrochemical reactor, three-phase three-dimensional electrode reactor, was designed and used to investigate theremoval of formic acid from simulated wastewater. The experimental results were assessed in term of Chemical OxygenDemand (COD) removal efficiency. The results showed that the three-phase three-dimensional electrodes could effectively removeformic acid. Its COD removal efficiency was much higher than those of two-dimensional electrodes and common three-dimensionalelectrodes, respectively. The COD removal efficiency of the three-phase three-dimensional electrodes using air as a spargegas increased 13.5% relative to that using nitrogen as a spargegas. The observation indicated that the sparged air in the three-phase three-dimensional electrodes not only participated insome physical processes but also played an important role in electrochemical reactions to assist COD removal.

The removal of chemical oxygen demand (COD) from wastewater containing oxalic acid was experimentally investigated using a three-phase three-dimensional electrode reactor. The experimental results show that the removal efficiency depends on the applied cell voltage, airflow, electrolysis time and the number of repeated runs. The former four factors all had a positive effect while the last factor generally had a negative effect on the COD removal in the experimental range. However, for electrolyses under the conditions of 30.0 V cell voltage, 7.01 min(-1) airflow and 60.0 min, the negative effect was negligible. After 50 runs, the electrochemical reactor could maintain a COD removal efficiency of more than 90%.

We examine the double-quantum magic angle spinning NMR spectra of pairs of 13C nuclei coupled to one or more 14N nuclei. The experimental spectra of 13C(2)-glycine and glycyl-[13C(2)]-glycyl-glycine are used to demonstrate the sensitivity of the spectra to the orientation of 14N quadrupole interaction tensors and to the molecular torsional angles.

The RuII spectrum emitted from a hollow cathode discharge has been recorded in the region 12500-55500cm(-1) (8000-1800Angstrom) using a Fourier transform spectrometer. 538 RuII lines have been measured with high accuracy (+/- 0.003-0.020cm(-1)). Improved energy level values have been derived from the lines and 17 new even levels have been found. The level structure has been interpreted by means of parametric calculations.

1:2 Cocrystals of piperazine (PPN) with o- and p-nitrophenol (oNPH and pNPH) were obtained from aqueous solution. The co-crystal structure of PPN, 2pNPH, and 2H(2)O is triclinic space group P (1) over bar: a = 6.401(1) Angstrom, b = 6.7515(1) Angstrom, c = 11.219(1) Angstrom, alpha = 100.37(1)degrees, beta = 97.10(1)degrees, gamma = 99.99(1)degrees,V= 465.5(1) Angstrom(3), Z = 2. Refinement led to a final conventional R value of 0.0365 for 2081 reflections. PPN, 2oNPH, and 2H(2)O cocrystallize in the monoclinic space group P2(1) : a = 7.753(1) Angstrom, b = 10.888(2) Angstrom, c = 11.378(2) Angstrom, beta = 92.89(1)degrees, V = 953.1(3) Angstrom(3), Z = 2. Refinement led to a final conventional R value of 0.0347 for 1978 reflections. It was found in both cocrystals that the hydroxyl H-atom of pNPH and oNPH was transferred to a N-atom of PPN, forming new ionic complexes PPNH22+.2(oNP(-)) and PPNH22+.2(pNP(-)), respectively. (Less)

The indium spectrum emitted from a hollow cathode discharge has been recorded using a Fourier transform spectrometer. Accurate wavelengths have been determined for 54 In II lines, and improved In II energy levels have been derived. The hyperfine structure of 42 lines has been analysed, yielding hyperfine constants A and B for 23 In II levels. The spin-forbidden In I transition 5s25p 2P-5s5p2 4P has also been analysed and absolute wavelengths, hyperfine constants A and B and improved energy level values are reported.

The densities and viscosities of ternary mixtures of mono(ethylene glycol) (MEG) + 2-amino-2-methyl-1-propanol (AMP) + water have been measured at temperatures of 25 to 40 degreesC. The water content varied in the range 1.4 to 15.6 mol %, and the amine concentration varied from 0 to 11.8 mol %. The excess volumes were calculated from the experimental data and fitted to a simple Redlich-Kister type polynomial relation. The equation of Grunberg and Nissan for the viscosity of liquid mixtures was used to correlate the viscosity data.

The treatment of simulated wastewater containing Acid Scarlet BS was tested with a two-step process that the pretreatment of Fe(II)-mediated decolorization was followed by the electrochemical oxidation with a three-phase three-dimensional electrodes. The experimental results showed that the decolorization mechanism was reductive destruction for the azo group of the dye molecular rather than flocculation or absorption and that the three-phase three-dimensional electrode can effectively reduce COD in the decolorized wastewater simultaneously by several mechanisms such as absorption, air-oxidation, anodic oxidation, cathodic electrogenerated H2O2 and so on. It was also observed that COD for the decolorized wastewater was easier removed as compared with the original dye wastewater, implying that the first and second stage act synergistically to destroy the organic pollutants.

Hyperfine and isotope structure have been studied in 18 Ga II lines, recorded with Fourier transform spectroscopy. For 12 of the lines the observed patterns could be analysed, yielding magnetic hyperfine structure constants A for eight Ga II levels. Improved wavelengths are given for a number of prominent Ga II lines, including centres of gravity and the individual hyperfine and isotope components of the lines with significant structure. The components of the spin-forbidden transition 4s24p 2P-4s4p2 4P in Ga I have also been analysed and absolute wavelengths and hyperfine constants A are reported.

We present a new technique for double-quantum excitation in magic-angle-spinning solid-state NMR. The method involves (i) preparation of nonequilibrium longitudinal magnetization; (ii) mechanical excitation of zero-quantum coherence by spinning the sample at rotational resonance, and (iii) phase-coherent conversion of the zero-quantum coherence into double-quantum coherence by frequency-selective spin inversion. The double-quantum coherence is converted into observable magnetization by reversing the excitation process, followed by a pi/2 pulse. The method is technically simple, does not require strong RF fields, and is feasible at high spinning frequencies. In [(13)C(2),(15)N]-glycine, with an internuclear (13)C-(13)C distance of 0.153 nm, we achieve a double-quantum filtering efficiency of approximately 56%. In [11, 20-(13)C(2)]-all-E-retinal, with an internuclear (13)C-(13)C distance of 0.296 nm, we obtain approximately 45% double-quantum filtering efficiency.

A time-temperature-transformation (TTT) diagram, with respect to the formation of intermetallic phase in the range from 700 °C to 1000 °C, has been assessed by point counting for a recently developed 29Cr-6Ni-2Mo-0.38N superduplex stainless steel (SDSS). Using a computer program previously developed by the authors, a continuous cooling-transformation (CCT) diagram was calculated from the TTT diagram, assuming that the transformation can be described by an Avrami-type equation. Controlled cooling experiments were made to confirm the validity of this computer model. Mechanical testing showed that the minimum acceptable impact toughness of 27 J corresponded to 5 vol pct of intermetallic phase. A comparison of impact toughness to hardness showed that toughness was a very sensitive measure of intermetallic phase formation, while hardness was insensitive and showed no significant increase until the material was catastrophically brittle. The thermodynamic computer program Thermo-Calc was used to predict microstructures and compare microstructures obtained after aging for 72 hours. It was found that this program could be used in a qualitative manner for predicting microstructural changes at various temperatures, but was unable to predict variables such as dissolution temperature and volume percentage with precision. The intermetallic phase was found to consist entirely of tetragonal σ phase with a P42/mnm crystal structure. The absence of χ phase as a precursor of σ phase provided an explanation for the delayed formation of intermetallic phase, as compared to that of more molybdenum-rich SDSSs.

Barium spectra emitted from hollow cathode discharges and recorded with Fourier transform spectrometers in the region 1700–31 000 A have been used for measuring 294 Ba I lines and 52 Ba II lines with uncertainties in the range ±0.001 cm-1 to ±0.01 cm-1. Energy level values have been derived from the measurements. The energy levels have been used for an improved determination of the Ba II ionization limit, giving the value 80686.30 ± 0.10 cm-1.

A time temperature transformation (TTT)-diagram with respect to the formation of intermetallie phase in the range 700-1000°C has been assessed by point counting for a 29Cr-6Ni-2Mo-0.38N super duplex stainless steel. Using a computer program developed by the authors a continuous cooling transformation (CCT)-diagram was calculated from the TTT-diagram assuming that the transformation can be described by an Avrami type equation. A comparison of impact toughness and hardness showed that toughness was a very sensitive measure of intermetallic phase formation while hardness was insensitive and showed no significant increase until the material was catastrophically brittle. It was found that Thermo-Cale could be used in a qualitative manner for predicting microstructural changes at various temperatures but was unable to predict variables such as dissolution temperature and volume percentage with accuracy.

We determine the decay rate constants of zero-, double- and single-quantum coherence for 13C spin pairs in magic-angle-spinning solid-state NMR. The double-quantum coherence is excited by a C7 pulse sequence and converted into zero-quantum coherence by a frequency-selective pair of pi/2 pulses. The zero-quantum coherence is reconverted into observable magnetization by a second pair of pi/2 pulses followed by a second C7 sequence. In a magnetically dilute system where the 13C-13C distance is 0.296 nm, the relaxation rate constants are consistent with a model of uncorrelated random fields at the two labeled 13C sites. In a fully-labelled system with a short 13C-13C distance of 0.153 nm, the measured rate constants are inconsistent with the uncorrelated random field model.

A packed column has been used to study the absorption of nitrogen oxide in an alkaline solution of sodium chlorite. The reactions taking place during the absorption have been examined and a lumped reaction model has been used to estimate rate constants from experimental data. Several parallel and consecutive reactions were found to take place during the absorption. NO was found to be oxidized to NO2 and/or to NO2-, and ClO2- was reduced to Cl- and/or to ClO-. The pH value of the absorbing liquid was found to have a great impact both on the absorption rate and on the extent of the different redox reactions within the liquid. Experimental results indicate that sodium chlorite mainly works as an agent to oxidize NO to NO: and that the major part of the nitrogen oxides are absorbed via the hydrolysis of N2O3 and N2O4. (Less)

A model has been developed to predict the dissolution rate of a limestone slurry as a function of particle size distribution and limestone conversion. The model is based on basic mass-transfer theory and includes a factor allowing the flux of calcium ions from the limestone surface to vary with the fraction dissolved. Changes in the flux with the fraction dissolved have been reported to be caused by the presence of sulfite but can also be caused by accumulation of inerts at the liquid-solid interface and/or by changes in the effective mass-transfer area. Calculations show that the decrease in flux reported for sulfites can have a significant impact on the slurry conditions within the reaction tank, i.e., impact on the limestone conversion and the relationship between liquid and solid alkalinity. In the absence of sulfites, the flux from limestone particles has been assumed to be constant with respect to the degree of dissolution. The modeling results have been found to be in good agreement with the measured values of a continuous stirred tank reactor. The model was able to accurately predict the impact of both the particle size distribution and reaction tank residence time on limestone conversion and dissolution rate.