Atmospheric pressure chemical vapour deposition of boron doped titanium dioxide for photocatalytic water reduction and oxidation

Boron-doped titanium dioxide (B-TiO) films were deposited by atmospheric pressure chemical vapour deposition of titanium(iv) chloride, ethyl acetate and tri-isopropyl borate on steel and fluorine-doped-tin oxide substrates at 500, 550 and 600 °C, respectively. The films were characterised using powder X-ray diffraction (PXRD), which showed anatase phase TiO at lower deposition temperatures (500 and 550 °C) and rutile at higher deposition temperatures (600 °C). X-ray photoelectron spectroscopy (XPS) showed a dopant level of 0.9 at% B in an O-substitutional position. The ability of the films to reduce water was tested in a sacrificial system using 365 nm UV light with an irradiance of 2 mW cm. Hydrogen production rates of B-TiO at 24 μL cm h far exceeded undoped TiO at 2.6 μL cm h. The B-TiO samples were also shown to be active for water oxidation in a sacrificial solution. Photocurrent density tests also revealed that B-doped samples performed better, with an earlier onset of photocurrent. © 2013 The Owner Societies.

Investigating the dynamics of laser induced sparks in atmospheric helium using Rayleigh and Thomson scattering

We have used optical Rayleigh and Thomson scattering to investigate the expansion dynamics of laser induced plasma in atmospheric helium and to map its electron parameters both in time and space. The plasma is created using 9 ns duration, 140 mJ pulses from a Nd:YAG laser operating at 1064 nm, focused with a 10 cm focal length lens, and probed with 7 ns, 80 mJ, and 532 nm Nd:YAG laser pulses. Between 0.4 μs and 22.5 μs after breakdown, the electron density decreases from 3.3 × 1017 cm−3 to 9 × 1013 cm−3, while the temperature drops from 3.2 eV to 0.1 eV. Spatially resolved Thomson scattering data recorded up to 17.5 μs reveal that during this time the laser induced plasma expands at a rate given by R ∼ t0.4 consistent with a non-radiative spherical blast wave. This data also indicate the development of a toroidal structure in the lateral profile of both electron temperature and density. Rayleigh scattering data show that the gas density decreases in the center of the expanding plasma with a central scattering peak reemerging after about 12 μs. We have utilized a zero dimensional kinetic global model to identify the dominant particle species versus delay time and this indicates that metastable helium and the He2 + molecular ion play an important role.

Interactions of a non-thermal atmospheric pressure plasma effluent with PC-3 prostate cancer cells

The effect of a radio-frequency driven, microscale non thermal atmospheric pressure plasma jet operated in helium with vol. 0.3% molecular oxygen gas admixture, on PC-3 prostate cancer cells has been investigated. The viability of cells exposed to the plasma was found to decrease with increasing plasma exposure time, with apoptosis through caspase and PARP cleavage being observed. High concentrations of nitrite and nitrate were detected in growth media exposed to the plasma and were found to increase in a time dependent manner post exposure. This indicates a slow release of reactive nitrogen species into the growth media, which is likely to influence cellular response to plasma exposure.

Evolution of Hot Loops in an Active Region Core Observed with the SDO Atmospheric Image Assembly

Evidence has accumulated of high temperature (> 4 MK) coronal emission in active region cores that corresponds to structures in equilibrium. Other studies have found evidence of evolving loops. We investigate the EUV intensity and temperature variations of short coronal loops observed in the core of NOAA Active Region 11250 on 13 July 2011. The loops, which run directly between the AR opposite polarities, are first detectable in the 94Å band of Fe XVIII, implying an effective temperature ~ 7 MK. The low temperature component of the 94 Å signal is modeled in terms of a linear superposition of the 193 Å and 171 Å signals in order to separate the hot component. After identifying the loops we have used contemporaneous HMI observations to identify the corresponding inter-moss regions, and we have investigated their time evolution in six AIA EUV channels. The results can be separated into two classes. Group 1 (94Å, 335Å, 211Å) is characterized by hotter temperatures (~2-7 MK), and Group 2 (193Å, 171Å, 131Å) by cooler temperatures (0.4 - 1.6 MK). For Group 1 the intensity peaks in the 94Å channel are followed by maxima in the 335 Å channel with a time lag of ~8 min, suggestive of a cooling pattern with an exponential decay. While the 211Å maxima follow those in the 335 Å channel, there is no systematic relation which would indicate a progressive cooling process through the lower temperatures, as has been observed in other investigations. In Group 2 the signals in the 171 and 131Å channels track each other closely, and lag behind the 193Å. In the inter-moss region of the loop the peak temperature and peak emission measure have opposite trends. The hot 94Å brightenings occur in the central part of the loops with maximum temperatures ~7 MK. Subsequently the loops appear to fill with plasma with an emission measure compatible with the 193 Å signal and temperature in the range ~ 1.5-2 MK. Although the exact details of the time evolution are still under investigation, these non static loops show high levels of intermittency in the 94Å signal (please see poster "Intermittent and Scale-Invariant Intensity Fluctuations in Hot Coronal Loops," by Lawrence et al. in this session).

Enhancing performance: The moderating effect of environmental integration and environmental capabilities on the performance outcomes of pollution prevention

Over the last two decades there has been ongoing debate about the impact of environmental practices on operational performance. In recent years, studies have started to move beyond assessing the direct impact of environmental management on different dimensions of performance to consider factors that might moderate or mediate this relationship. This study considers the extent to which environmental integration and environmental capabilities moderate the relationship between pollution prevention and environmental performance outcomes. The mediating influence of environmental performance on the relationship between pollution prevention and cost and flexibility performance is also considered. Data were collected from a sample of UK food manufacturers and analysed using multiple regression analysis. The findings indicate the existence of some moderated and mediated relationships suggesting that there is more to improving performance than implementing environmental practices.

The effects of pollution prevention on performance

As pressure for companies to improve their environmental performance has intensified in recent years, research attention has shifted away from establishing a link between environmental practices and performance towards consideration of other factors that might facilitate performance improvements. This paper has two key purposes; firstly, to investigate whether internal support processes interact with pollution prevention by positively moderating the relationship between pollution prevention and environmental performance, and; secondly, to assess whether the relationship between pollution prevention and cost performance is mediated by environmental performance.

Design/methodology/approach
It uses a cross-sectional survey of 1,200 UK-based food processing firms to gather information on environmental practices and performance. Regression analysis was conducted on a sample of 149 responding firms to assess the hypothesised relationships.

Findings
Support was found for two of the four moderated relationships hypothesised namely, suggesting that internal support processes support the environmental performance of some pollution prevention practices. Strong support for a mediated relationship between pollution prevention, environmental performance and cost performance was provided by the results.

Originality/value
This study provides an original contribution to the literature on the performance outcomes of environmental practices by considering a number indirect relationships between environmental practices and performance. This has implications for the interpretation of the relationship between environmental practices and performance.

Bactericidal efficacy of atmospheric pressure non-thermal plasma (APNTP) against the ESKAPE pathogens

The emergence of multidrug-resistant pathogens within the clinical environment is presenting a mounting problem in hospitals worldwide. The 'ESKAPE' pathogens (Enterococcusfaecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) have been highlighted as a group of causative organisms in a majority of nosocomial infections, presenting a serious health risk due to widespread antimicrobial resistance. The stagnating pipeline of new antibiotics requires alternative approaches to the control and treatment of nosocomial infections. Atmospheric pressure nonthermal plasma (APNTP) is attracting growing interest as an alternative infection control approach within the clinical setting. This study presents a comprehensive bactericidal assessment of an in-house-designed APNTP jet both against biofilms and planktonic bacteria of the ESKAPE pathogens. Standard plate counts and the XTT metabolic assay were used to evaluate the antibacterial effect of APNTP, with both methods demonstrating comparable eradication times. APNTP exhibited rapid antimicrobial activity against all of the ESKAPE pathogens in the planktonic mode of growth and provided efficient and complete eradication of ESKAPE pathogens in the biofilm mode of growth within 360 s, with the exception of A. baumannii where a >4log reduction in biofilm viability was observed. This demonstrates its effectiveness as a bactericidal treatment against these pathogens and further highlights its potential application in the clinical environment for the control of highly antimicrobial-resistant pathogens.

Atmospheric Pressure DC Plasma Processing of TIO2/PEDOT:PSS Nanocomposites

In this work we demonstrate the synthesis of a TiO2/PEDOT:PSS nanocomposite material in aqueous solution through atmospheric pressure direct current (DC) plasma processing at room temperature. The dispersion of the TiO2 nanoparticles is enhanced after microplasma processing, and TiO2/polymer hybrid nanoparticles with a distinct core shell structure have been obtained. We have observed increased TiO2/PEDOT:PSS nanocomposite electrical conductivity due to microplasma processing. The improvement in nanocomposite properties is due to the enhanced dispersion and stability in liquid polymer of microplasma treated TiO2 nanoparticles. Both plasma induced surface charge and nanoparticle surface termination with specific plasma chemical species are thought to provide an enhanced barrier to nanoparticle agglomeration and promote nanoparticle-polymer bonding, which is expected to have a significant benefit in materials processing with inorganic nanoparticles for wide range of applications.

Use of an earthworm lysosomal biomarker for the ecological assessment of pollution from an industrial plastics fire

A low-cost field technique employing retention of the dye neutral-red by lysosomes in coelomocyte cells taken from earthworms (Lumbricus castaneus), was used as a means of assessing the ecological effects (if any) of an industrial accident. Earthworms and soil samples were collected at the site of a large industrial plastics fire in Thetford, UK along a 200 m transect leading from the factory perimeter fence, over a layer of molten plastic impregnated soil and into the surrounding forest. Coelomic fluid extracted from the earthworms was dye-loaded with neutral-red and lysosomal leaking observed. Metal residues in soil and earthworms were found to be highly elevated close to the factory perimeter and to rapidly drop to background levels within the first 50 m of the transect. Coelomocyte cells taken from earthworms adjacent to the factory perimeter showed the shortest period of neutral-red retention (2 min); cells taken from worms further into the surrounding forest had a longer retention time (12 min), whilst cells taken from worms from a control site showed even greater retention times (25 min). Thus, the neutral-red retention times correlated negatively with measured residues of heavy metals in the earthworms, the higher the body metal concentration the shorter the retention time. This field trial has demonstrated the validity of using an in vitro cellular biomarker technique for use in biological impact assessment along gradients of contamination.

Heavy metals as markers for assessing environmental pollution from chemical warehouse and plastics fires

Case histories of large, accidental fires are presented to illustrate that heavy metals may be used as markers to assess the extent of localized environmental contamination resulting from fires. Due to the complexity of fire chemistry with respect to organic pollutants, determination of organic pollutants in the environment following a fire would be time consuming and expensive. Using heavy metals as markers on the other hand is much cheaper and can be done very rapidly. © 1995.

Plasmid DNA damage following exposure to atmospheric pressure non-thermal plasma: kinetics and influence of oxygen admixture

The nature and kinetics of plasmid DNA damage after DNA exposure to a kHz-driven atmospheric pressure nonthermal plasma jet has been investigated. Both single-strand break (SSB) and double-strand break (DSB) processes are reported here. While SSB had a higher rate constant, DSB is recognized to be more significant in living systems, often resulting in loss of viability. In a helium-operated plasma jet, adding oxygen to the feed gas resulted in higher rates of DNA DSB, which increased linearly with increasing oxygen content, up to an optimum level of 0.75% oxygen, after which the DSB rate decreased slightly, indicating an essential role for reactive oxygen species in the rapid degradation of DNA.

Magnetospheric Structure and Atmospheric Joule Heating of Habitable Planets Orbiting M-dwarf Stars

We study the magnetospheric structure and the ionospheric Joule Heating of planets orbiting M-dwarf stars in the habitable zone using a set of magnetohydrodynamic models. The stellar wind solution is used to drive a model for the planetary magnetosphere, which is coupled with a model for the planetary ionosphere. Our simulations reveal that the space environment around close-in habitable planets is extreme, and the stellar wind plasma conditions change from sub- to super-Alfvénic along the planetary orbit. As a result, the magnetospheric structure changes dramatically with a bow shock forming in the super-Alfvénic sectors, while no bow shock forms in the sub-Alfvénic sectors. The planets reside most of the time in the sub-Alfvénic sectors with poor atmospheric protection. A significant amount of Joule Heating is provided at the top of the atmosphere as a result of the intense stellar wind. For the steady-state solution, the heating is about 0.1%-3% of the total incoming stellar irradiation, and it is enhanced by 50% for the time-dependent case. The significant Joule Heating obtained here should be considered in models for the atmospheres of habitable planets in terms of the thickness of the atmosphere, the top-side temperature and density, the boundary conditions for the atmospheric pressure, and particle radiation and transport. Here we assume constant ionospheric Pedersen conductance similar to that of the Earth. The conductance could be greater due to the intense EUV radiation leading to smaller heating rates. We plan to quantify the ionospheric conductance in future study.

Atmospheric cold plasma process for vegetable leaf decontamination: A feasibility study on radicchio (red chicory, Cichorium intybus L.)

Cold plasma is an emerging non-thermal processing technology that could be used for large scale leaf decontamination as an alternative to chlorine washing. In this study the effect of an atmospheric cold plasma apparatus (air DBD, 15 kV) on the safety, antioxidant activity and quality of radicchio (red chicory, Cichorium intybus L.) was investigated after 15 and 30 min of treatment (in afterglow at 70 mm from the discharge, at 22 °C and 60% of RH) and during storage. Escherichia coli O157:H7 inoculated on radicchio leaves was significantly reduced after 15 min cold plasma treatment (-1.35 log MPN/cm²). However, a 30 min plasma treatment was necessary to achieve a significant reduction of Listeria monocytogenes counts (-2.2 log CFU/cm²). Immediately after cold plasma treatment, no significant effects emerged in terms of antioxidant activity assessed by the ABTS and ORAC assay and external appearance of the radicchio leaves. Significant changes between treated and untreated radicchio leaves are quality defects based on the cold plasma treatment. Atmospheric cold plasma appears to be a promising processing technology for the decontamination of leafy vegetables although some criticalities, that emerged during storage, need to be considered in future studies.