Pure hydrogen from pyrolysis oil using the steam-iron process

The novelty of using pyrolysis oil in the steam-iron process to produce pure hydrogen is introduced. In this process, products of pyrolysis oil gasification are used to reduce iron oxides which are subsequently oxidized with steam, resulting in pure hydrogen. Two process alternatives are considered: (i) a once-through concept in which cheap iron oxide (in our case sintered pellets of natural iron ore, Fe₂O₃) is used in one cycle, before further processing in a blast furnace, and (ii) a continuous system, in which specially developed iron oxides (in our case an ammonia catalyst) are cycled between a reduction and oxidation reactor. By injecting pyrolysis oil in a fluidized bed filled with Fe₃O₄ at 800 °C, it has been shown that CO and H₂ as well as coke by the gasification reactions contribute to the reduction. Experiments including a complete redox cycle with the ammonia catalyst have shown that a hydrogen production in the oxidation of 0.84 N m³/kg dry pyrolysis oil (LHV H₂/LHV oil = 0.4) can be obtained when the conversion of iron oxides are low (1.0%). The gas produced in the reduction step under these conditions contains 38% of the heating value of the input and has an LHV of 7.8 MJ/N m³ gas product. Deactivation of the iron oxides has been observed by a decreasing reduction rate in subsequent redox cycles. BET and SEM analysis showed a decrease in surface area, which could partly explain the observed deactivation.     

Aktive Thermosonde zur Messung des Energieeinstromes

A active thermal probe for the measurement of the energy influx A continuously working active thermal probe for the determination of the energy influx at plasma‐technological processes is presented. The principle of mesurement is based on the compensation of the incoming energy influx. Key benefits are the application for continuous measurement and the suitability for thin film deposition. A calibration is not needed. At selected positions of the reactor the energy influx to the probe can be measured and the correlation with properties of the growing layer or the treated surface, respectively, can be determined. Since the thermal probe reacts sensitively to the process parameters at the substrate surface it is very well qualified for control and monitoring of layer growth or surface treatment processes. The probe is a ost‐efficient, particularly suitable device for quality control in plasma‐technological applications.     

Photocatalytic Activity of Protein‐Conjugated CdS Nanoparticles

Colloidal CdS nanoparticles are conjugated with a variety of proteins, including enhanced yellow fluorescent protein, tobacco etch virus protease (TEV), lysozyme, and bacterial cytochrome P450 CYP152A1, and the photochemical properties of the resulting conjugates are analyzed by EPR spectroscopy and hydroxyl radical‐specific fluorimetric assay. While irradiation of bare CdS colloids leads to photogeneration of hydroxyl and superoxide radicals, it is surprisingly observed that coating of the CdS particles with proteins effectively suppresses the production of these radical species and instead leads to increased formation of a long‐lived reactive oxygen species, most likely H₂O₂. A mechanism for the observed results is suggested. The empirical results are capitalized on for the assembly of a CdS–TEV nanohybrid, which shows significantly higher performance as a photocatalytic mediator for fatty acid hydroxylation by CYP152A1 than bare CdS nanoparticles.     

Electroless synthesis of 3 nm wide alloy nanowires inside Tobacco mosaic virus

We show that 3 nm wide cobalt-iron alloy nanowires can be synthesized by simple wet chemical electroless deposition inside tubular Tobacco mosaic virus particles. The method is based on adsorption of Pd(II) ions, formation of a Pd catalyst, and autocatalytic deposition of the alloy from dissolved metal salts, reduced by a borane compound. Extensive energy-filtering TEM investigations at the nanoscale revealed that the synthesized wires are alloys of Co, Fe, and Ni. We confirmed by high-resolution TEM that our alloy nanowires are at least partially crystalline, which is compatible with typical Co-rich alloys. Ni traces bestow higher stability, presumably against corrosion, as also known from bulk CoFe. Alloy nanowires, as small as the ones presented here, might be used for a variety of applications including high density data storage, imaging, sensing, and even drug delivery.     

Comparison of direct and alternating current vacuum ultraviolet lamps in atmospheric pressure photoionization

A direct current induced vacuum ultraviolet (dc-VUV) krypton discharge lamp and an alternating current, radio frequency (rf) induced VUV lamp that are essentially similar to lamps in commercial atmospheric pressure photoionization (APPI) ion sources were compared. The emission distributions along the diameter of the lamp exit window were measured, and they showed that the beam of the rf lamp is much wider than that of the dc lamp. Thus, the rf lamp has larger efficient ionization area, and it also emits more photons than the dc lamp. The ionization efficiencies of the lamps were compared using identical spray geometries with both lamps in microchip APPI mass spectrometry (μAPPI-MS) and desorption atmospheric pressure photoionization-mass spectrometry (DAPPI-MS). A comprehensive view on the ionization was gained by studying six different μAPPI solvent compositions, five DAPPI spray solvents, and completely solvent-free DAPPI. The observed reactant ions for each solvent composition were very similar with both lamps except for toluene, which showed a higher amount of solvent originating oxidation products with the rf lamp than with the dc lamp in μAPPI. Moreover, the same analyte ions were detected with both lamps, and thus, the ionization mechanisms with both lamps are similar. The rf lamp showed a higher ionization efficiency than the dc lamp in all experiments. The difference between the lamp ionization efficiencies was greatest when high ionization energy (IE) solvent compositions (IEs above 10 eV), i.e., hexane, methanol, and methanol/water, (1:1 v:v) were used. The higher ionization efficiency of the rf lamp is likely due to the larger area of high intensity light emission, and the resulting larger efficient ionization area and higher amount of photons emitted. These result in higher solvent reactant ion production, which in turn enables more efficient analyte ion production.     

Theoretical and experimental investigation into the explosive boiling potential of thermally stratified liquid-liquid systems

The occurrence of a rapid phase transition, or so-called explosive boiling, when a cold volatile liquid comes into contact with a hot liquid or hot surface is a potential hazard in industry. This study was focused on the explosive boiling potential of thermally stratified liquid-liquid systems that result from a runaway reaction. The experimental runs were performed on both a non-reacting and a reacting system. The experimental results showed that under the analysed conditions, the cold phase was superheated but did not evaporate explosively, as the limits of superheat of the phase were not achieved. The response of the cold phase appeared to be completely controlled by the interface temperature between the hot and the cold phase. In general, based on the order of magnitude of temperature differences that result from a runaway reaction in a multi-phasic system and the fact that the system is pressurised by its own vapour pressure, the occurrence of explosive boiling under runaway conditions appears unlikely for these type of systems.     

Hydrogen production from pyrolysis oil using the steam-iron process: a process design study

The overall energy efficiency of the production of pure hydrogen using the pyrolysis oil driven steam-iron process is evaluated for different process conditions. The process consists of a two-step process (reduction with pyrolysis oil, oxidation with steam) from which pure hydrogen can be obtained, without purification steps. An optimum energy efficiency of 53% is achieved when the equilibrium conversion is obtained in the redox cycle at 800°C. When assuming chemical equilibrium, increasing the process temperature results in a low process efficiency due to a large amount of unreacted steam that needs to be condensed to separate the hydrogen product. Using experimental data in the process simulation, a high-energy efficiency is obtained at 920°C (39%) compared with the efficiency at 800°C (29%). This is caused by the low conversion in the reduction at 800°C. Improving the iron oxide material to enhance the reduction with pyrolysis oil at 800°C, is therefore suggested.     

Propofol, but not thiopentone or etomidate, enhances isoflurane-induced coronary vasodilatation in dogs

PURPOSE: To test the hypothesis that thiopentone, propofol, and etomidate alter the coronary vascular effects of abruptly administered isoflurane. METHODS: Dogs (n = 6) received inspired isoflurane 5% in the presence of thiopentone (20 mg.kg-1 induction dose and 20 mg.kg-1.hr-1 infusion), propofol (5 mg.kg-1 induction dose and 40 mg.kg-1.hr-1 infusion), etomidate (2 mg.kg-1 induction dose and 5 mg.kg-1.hr-1 infusion), or isoflurane (1.0 MAC) anaesthesia in a random fashion. Haemodynamics were assessed in the conscious state, during baseline anaesthesia, and at 30 sec intervals for five minutes after beginning isoflurane 5%. RESULTS: Rapidly administered isoflurane caused greater (P < 0.05) reductions in coronary vascular resistance in thiopentone- or propofol--than in isoflurane-anaesthetized dogs. Isoflurane produced greater (P < 0.05) increases in the ratio of coronary blood flow velocity to pressure-work index (an index of myocardial oxygen consumption; +109 +/- 19% during isoflurane alone vs +182 +/- 27% change from baseline during propofol and isoflurane) consistent with relatively greater direct coronary vasodilatation during baseline propofol than during baseline isoflurane anaesthesia. Isoflurane caused larger increases in coronary blood flow velocity in dogs anaesthetized with etomidate concomitant with higher coronary perfusion pressure and pressure-work index than in those anaesthetized with isoflurane alone. CONCLUSIONS: The results suggest that thiopentone, propofol, and etomidate each uniquely modify the coronary vascular responses to abrupt administration of high inspired concentrations of isoflurane in chronically instrumented dogs.     

Effects of protraction mechanics on the midface

A sensitive enantioselective high-performance chromatographic (HPLC) method was developed validated to determine low levels of (-)-R and (+)-S-albuterol in plasma. Baseline resolution was achieved by using a teicoplanin-based chiral stationary phase with a polar organic mobile phase consisting of methanol/ acetonitrile/glacial acetic acid/diethylamine, 40:60:0.3:0.2, (v/v/v/v) and a flow-rate of 1.0 ml/min. Enantioselectivity (alpha) equaled 1.18 and resolution (RS) equaled 1.8. By using fluorescence detection maximized at 230 and 310 nm for excitation and emission, respectively, concentrations of each enantiomer could be measured down to 125 pg/ml from a 1-ml plasma sample. Initially, the method was applied to plasma samples from a small single-dose inhalation study of racemic albuterol in a human volunteer and, later, to in vivo samples from a canine inhalation study of the single enantiomer, (-)-R-albuterol. Results from the canine study showed that no chiral inversion of (-)-R-albuterol occurs in the dog.     

Intravitreal injection of cidofovir in cytomegalovirus retinitis

BACKGROUND: CMV retinitis is the most common opportunistic ocular infection and the main cause of blindness in AIDS patients with a T-helper cell count < or = 50/microliter. Cidofovir is a nucleotide analogue with a long half-life time after phosphorylation intracellularly. It is effective against CMV and can be given intravenously and intravitreally. The aim was to offer an alternative therapy for CMV retinitis to patients who could not receive standard treatment because of contraindications or refused it. The efficacy and tolerance of intravitreal injections of cidofovir should be evaluated. PATIENTS AND METHODS: We treated 16 eyes of 12 patients. The total number of injections with 15 micrograms of cidofovir each was 49, with an average of 3 injections per eye. The duration of follow-up was 75-295 days (median 170 days). Probenecid was given concomitantly. Injections were repeated after 6-10 weeks. Secondary prophylaxis of CMV organ infection was done with oral ganciclovir. RESULTS: Within a few days all areas with active retinitis turned into scars following the first injection. Under consequent treatment no reactivation was observed. Four eyes developed a mild iritis with hypotony within a mean time of 12 days after injection. All responded rapidly to topical steroids. None had a persisting loss of vision. Two eyes developed cystoid macular edema (CME). Two patients stopped anti-CMV treatment (ganciclovir orally and injections), followed by a recurrence after an average of 64-days. CONCLUSIONS: Intravitreal injection therapy with 15 micrograms cidofovir and concomitant oral probenecid is a valuable and safe alternative treatment for CMV retinitis in AIDS patients. Its main complication is iritis with hypotony, which is effectively treatable with topical steroids. No complications caused by the injection technique itself were noted. The occasional observation of CME in otherwise quiet eyes, however, is probably drug-related.