Highly stable external short-circuit-assisted oxygen ionic transport membrane reactor for carbon dioxide reduction coupled with methane partial oxidation

A membrane reactor allows for simultaneous separation and reaction, and thus, can play a good role to produce value-added chemicals. In this work, we demonstrated such a membrane reactor based on fluorite oxide samarium-doped ceria (SDC) using an external short-circuit concept for oxygen permeation. The fluorite phase was employed to impart its high structural stability, while its limited electronic conductivity was overcome by the application of an external short circuit to function the SDC membrane for oxygen transport. On one side of the membrane, i.e., feed side, carbon dioxide decomposition into carbon monoxide and oxygen was carried out with the aid of a Pt or Ag catalyst. The resultant oxygen was concurrently depleted on the membrane surface and transported to the other side of the membrane, favorably shifting this equilibrium-limited reaction to the product side. The transported oxygen on the permeate side with the aid of a GdNi/Al2O3 catalyst was then consumed by the reaction with methane to form syngas, i.e., carbon monoxide and hydrogen. As such, the required driving force for gas transport through the membrane can be sustained by coupling two different reactions in one membrane reactor, whose stability to withstand these different gases at high temperatures is attained in this paper. We also examined the effect of the membrane thickness, oxygen ionic transport rate, and CO2 and CH4 flow rates to the membrane reactor performance. More importantly, here, we proved the feasibility of a highly stable membrane reactor based on an external short circuit as evidenced by achieving the constant performance in CO selectivity, CH4 conversion, CO2 conversion, and O2 flux during 100 h of operation and unaltered membrane structure after this operation together with the coking resistance.

Discordance between lung function of Chinese university students of 20-year-old established norms

Objective: We examined the validity of the 20-year-old established Asian norms for pulmonary function in a contemporary cohort of Hong Kong Chinese university students. Design and participants: Pulmonary function testing was conducted in university students (n = 805). Setting: A university campus in Hong Kong. Measurements and results: Parameters recorded included gender, age, height, weight, standard lung function variables (ie, FEV1, FVC, and peak expiratory flow rate [PEFR]), and exhaled carbon monoxide (CO) level. Subjects completed a questionnaire on pulmonary health, smoking history, and their dietary and exercise habits within 3 months of the study. Data were compared with the established norms for lung function for Chinese persons from Hong Kong. On average, subjects were taller than those reported in the original cohort, on whom the established norms are based; however, FEV1, FVC, and PEFR were lower. As predicted, the exhaled CO level was higher in smokers. Those who exercised regularly had a higher FEV1 and FVC, and reported fewer respiratory complaints. Conclusions: Our findings support the idea that lung function norms not only differ across ethnic groups, but that they may be susceptible to change over a single generation within an ethnic group living in the same geographic region. Assuming the equivalence of our testing methods and those on which established norms are based, our findings shed further insight into the dynamic nature of lung function, and have implications regarding the definition of normal pulmonary function and its variance over the short term.

Does environmental quality influence health expenditures? empirical evidence from a panel of selected OECD countries

In this paper we examine the role of environmental quality in determining per capita health expenditures. We take a panel cointegration approach in order to explore the possibility of estimating both short-run and long-run impacts of environmental quality. Our empirical analysis is based on eight OECD countries, namely Austria, Denmark, Iceland, Ireland, Norway, Spain, Switzerland, and the UK for the period 1980–1999. We find that per capita health expenditure, per capita income, carbon monoxide emissions, sulphur oxide emissions and nitrogen oxide emissions are panel cointegrated. While short-run elasticities reveal that income and carbon monoxide emissions exert a statistically significant positive effect on health expenditures, in the long-run in addition to income and carbon monoxide, we find that sulphur oxide emissions have a statistically significant positive impact on health expenditures.

High rates of oxygen reduction over a vapor phase-polymerized PEDOT electrode

The air electrode, which reduces oxygen (O₂), is a critical component in energy generation and storage applications such as fuel cells and metal/air batteries. The highest current densities are achieved with platinum (Pt), but in addition to its cost and scarcity, Pt particles in composite electrodes tend to be inactivated by contact with carbon monoxide (CO) or by agglomeration. We describe an air electrode based on a porous material coated with poly(3,4-ethylenedioxythiophene) (PEDOT), which acts as an O₂ reduction catalyst. Continuous operation for 1500 hours was demonstrated without material degradation or deterioration in performance. O₂ conversion rates were comparable with those of Pt-catalyzed electrodes of the same geometry, and the electrode was not sensitive to CO. Operation was demonstrated as an air electrode and as a dissolved O₂ electrode in aqueous solution.

SLC6A4 STin2 VNTR genetic polymorphism is associated with tobacco use disorder, but not with successful smoking cessation or smoking characteristics: a case control study.

The aim of this study was to determine if variable number of tandem repeats (VNTR) in the second intron (STin2) of the serotonin transporter (SLC6A4) gene was associated with tobacco use disorder, successful smoking cessation, or smoking characteristics. In this case-control study, patients with current tobacco use disorder, diagnosed according to DSM IV criteria (n = 185), and never-smokers, diagnosed according to CDC criteria (n = 175), were recruited and received 52 weeks of combined pharmacotherapy and cognitive therapy. Successful smoking cessation was defined as exhaled carbon monoxide < 6 ppm. SLC6A4 gene STin2 VNTR polymorphism was assessed using a Multiplex-PCR-based method. At baseline, participants were evaluated using the Fagerström Test for Nicotine Dependence (FTND) and the ASSIST scale.

N-acetylcysteine for therapy-resistant tobacco use disorder: a pilot study

Introduction N-Acetylcysteine (NAC) may have efficacy in treating tobacco use disorder (TUD) by reducing craving and smoking reward. This study examines whether treatment with NAC may have a clinical efficacy in the treatment of TUD. Methods A 12-week double blind randomized controlled trial was conducted to compare the clinical efficacy of NAC 3 g/day versus placebo. We recruited 34 outpatients with therapy resistant TUD concurrently treated with smoking-focused group behavioral therapy. Participants had assessments of daily cigarette use (primary outcome), exhaled carbon monoxide (COEXH) (secondary outcome), and quit rates as defined by COEXH<6 ppm. Depression was measured with the Hamilton Depression Rating Scale (HDRS). Data were analyzed using conventional and modified intention-to-treat endpoint analyses. Results NAC treatment significantly reduced the daily number of cigarettes used (Δ mean±SD = -10.9 ± 7.9 in the NAC-treated versus -3.2 ± 6.1 in the placebo group) and COEXH (Δ mean± SD = -10.4 ± 8.6 ppm in the NAC-treated versus -1.5 ± 4.5 ppm in the placebo group); 47.1% of those treated with NAC versus 21.4% of placebo-treated patients were able to quit smoking as defined by COEXH<6 ppm. NAC treatment significantly reduced the HDRS score in patients with tobacco use disorder. Conclusions These data show that treatment with NAC may have a clinical efficacy in TUD. NAC combined with appropriate psychotherapy appears to be an efficient treatment option for TUD.

Nervous control of circulation--the role of gasotransmitters, NO, CO, and H2S.

The origins and actions of gaseous signaling molecules, nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H(2)S) in the mammalian cardiovascular system have received considerable attention and it is evident that these three "gasotransmitters" perform a variety of homeostatic functions. The origins, actions and disposition of these gasotransmitters in the piscine vasculature are far from resolved. In most fish examined to date, NO or NO donors are generally in vitro and in vivo vasodilators acting via soluble guanylyl cyclase, although there is evidence for NO-mediated vasoconstriction. Injection of sodium nitroprusside into trout causes hypotension that is attributed to a reduction in systemic resistance. Unlike mammals, NO does not appear to have an endothelial origin in fish blood vessels as an endothelial NO synthase has not identified. However, neural NO synthase is prevalent in perivascular nerves and is the most likely source of NO for cardiovascular control in fish. CO is a vasodilator in lamprey and trout vessels, and it, like NO, appears to exert its action, at least in part, via guanylyl cyclase and potassium channel activation. Inhibition of CO production increases resting tone in trout vessels suggestive of tonic CO activity, but little else is known about the origin or control of CO in the fish vasculature. H(2)S is synthesized by fish vessels and its constrictory, dilatory, or even multi-phasic actions, are both species- and vessel-specific. A small component of H(2)S-mediated basal activity may be endothelial in origin, but to a large extent H(2)S affects vascular smooth muscle directly and the mechanisms are unclear. H(2)S injected into the dorsal aorta of unanesthetized trout often produces oscillations in arterial blood pressure suggestive of H(2)S activity in the central nervous system as well as peripheral vasculature. Collectively, these studies hint at significant involvement of the gasotransmitters in piscine cardiovascular function and hopefully provide a variety of avenues for future research.

Descriptive evaluation of smoking cessation

Introduction: The Northern Alliance HARP smoking cessation program provides support to chronic disease participants who desired to quit smoking. This is an individualised program with pharmacotherapy and behavioural support, delivered by specialist clinicians.

Aims: The aims of this descriptive evaluation were to explore factors that affect abstinence rates, record those rates, and describe the impact of anxiety, depression, self-efficacy, quality of life and motivation on quit rates at three months.

Methods: Data was collected prospectively from clients enrolled in the service. Participants were assessed for abstinence at three months, six months and one year by carbon monoxide (CO) monitoring and self-reporting. Factors predictive of quitting were analysed using logistic regression; factors with a p value < 0.05 and 95% CI not containing one were considered statistically significant.

Results: 103 clients were assessed and 86 were enrolled in the program. The odds of successful quitting at three months CO verified was higher amongst completers of the program compared to non-completers (OR = 6.6, 95% CI = 2.03–21.57, p = 0.002). The probability of sustained quitting at one year was over 18 times higher in the group who completed the program (n = 16/21 completers and n = 1/4 non-completers) (OR 18.5, 95% CI, 2.32–147.34, p = 0.006). No other factors predicted quitting.

The rate of quitting was 28.7% at three months, 19.5% at six months and 10.3% at one year, CO verified. Measures of anxiety and depression, self-efficacy, quality of life and motivation did not influence either the quit rate or the likelihood of completing the course of treatment at three months.

Performance and gaseous and particle emissions from a liquefied petroleum gas (LPG) fumigated compression ignition engine

In this study, an LPG fumigation system was fitted to a Euro III compression ignition (CI) engine to explore its impact on performance, and gaseous and particulate emissions. LPG was introduced to the intake air stream (as a secondary fuel) by using a low pressure fuel injector situated upstream of the turbocharger. LPG substitutions were test mode dependent, but varied in the range of 14-29% by energy. The engine was tested over a 5 point test cycle using ultra low sulphur diesel (ULSD), and a low and high LPG substitution at each test mode. The results show that LPG fumigation coerces the combustion into pre-mixed mode, as increases in the peak combustion pressure (and the rate of pressure rise) were observed in most tests. The emissions results show decreases in nitric oxide (NO) and particulate matter (PM2.5) emissions; however, very significant increases in carbon monoxide (CO) and hydrocarbon (HC) emissions were observed. A more detailed investigation of the particulate emissions showed that the number of particles emitted was reduced with LPG fumigation at all test settings – apart from mode 6 of the ECE R49 test cycle. Furthermore, the particles emitted generally had a slightly larger median diameter with LPG fumigation, and had a smaller semi-volatile fraction relative to ULSD. Overall, the results show that with some modifications, LPG fumigation systems could be used to extend ULSD supplies without adversely impacting on engine performance and emissions.

Influence of fuel-borne oxygen on European stationary cycle: diesel engine performance and emissions with a special emphasis on particulate and NO emissions

Exploration of sustainable fuels and their influence on reductions in diesel emissions are nowadays a challenge for the engine and fuel researchers. This study investigates the role of fuel-borne oxygen on engine performance and exhaust emissions with a special emphasis on diesel particulate and nitric oxide (NO) emissions. A number of oxygenated-blends were prepared with waste cooking biodiesel as a base oxygenated fuel. Triacetin, a derivative from transesterified biodiesel was chosen for its high oxygen content and superior fuel properties. The experimental campaign was conducted with a 6-cylinder, common rail turbocharged diesel engine equipped with highly precise instruments for nano and other size particles and other emissions. All experiments were performed in accordance with European Stationary Cycle (ESC 13-mode). A commercial diesel was chosen as a reference fuel with 0% oxygen and five other oxygenated blends having a range of 6.02–14.2% oxygen were prepared. The experimental results revealed that the oxygenated blends having higher a percentage of fuel-borne oxygen reduced particulate matter (PM), particle number (PN), unburned hydrocarbon (UBHC) and carbon monoxide (CO) emissions to a significantly low level with a slight penalty of NO emissions. The main target of this study was to effectively utilise triacetin as an additive for waste cooking biodiesel and suppress emissions without deteriorating engine performance. The key finding of this investigation is the significant reductions in both particle mass and number emissions simultaneously without worsening engine performance with triacetin-biodiesel blends. Reductions in both particle mass and number emissions with a cost-effective additive would be a new dimension for the fuel and engine researchers to effectively use triacetin as an emission suppressor in the future.

Substitution reactions of carbon nanotube template

Substitution reactions between carbon nanotube (CNT) template and SiO with the formation of carbon rich silicon oxide nanowires (SiO–C-NWs) have been investigated using transmission electron microscopy and x-ray energy dispersive spectroscopy. The reaction was carried out by thermal annealing at 1200 °C for 1 h of a mixture of silicon monoxide (SiO) and iron (II) phthalocyanine, FeC32N8H16 (FePc) powders. Multiwalled CNTs were produced first via pyrolysis of FePc at a lower temperature (1000 °C). SiO vapors reacted with the CNTs at higher temperatures to produce amorphous SiO–C-NWs with a uniform diameter and a length in tens of micrometers. The special bamboolike structure of the CNTs allows the reaction to start from the external surface of the tubes and transform each CNT into a solid nanowire section by section.

Transmission electron microscopy investigation of substitution reactions from carbon nanotube template to silicon carbide nanowires

Substitution reactions between multiwalled carbon nanotubes and silicon monoxide vapour have been investigated using transmission electron microscopy. Different reactions occurred inside the multiwalled nanotubes and on the nanotube external surfaces, resulting in the formation of silicon carbide nanowires with a core–shell structure. The substitution reaction process and end products are strongly affected by nanotube structures and a ball milling treatment of the starting materials.