Search

The wet flue gas desulfurization (WFGD) system is widely used in coal-fired power plants worldwide. Improving its efficiency is very important for economical running. In this study, SO2 removal by the spray scrubber by adding a new sieve tray was studied and compared to that by the traditional spray scrubber without a sieve tray (the WFGD system). The effects of gas flow rate, liquid flow rate, inlet SO2 concentration, and pH value on both types of scrubbers were evaluated. Pore diameter and porosity of the sieve tray in the sieve-tray spray scrubber were determined, and its enhanced efficiency under different experimental conditions was calculated. The results showed that the enhanced efficiency increased with the increasing liquid flow rate, gas flow rate under the same liquid/gas ratio (L/G), and pH value. Compared to the spray scrubber without a sieve tray, the sieve-tray spray scrubber had significantly higher efficiency. The enhanced efficiencies were mostly between 20% and 60% in the experimental range.

Introduction: A safety data sheet (SDS) is an established hazard communication tool for chemicals, for which no comparable document exists in the biotherapeutics industry. As the cell and gene therapy (CGT) field expands, industry leaders have identified a growing need to address this gap in communication of the unique occupational health and safety risks posed by CGT materials and products. Methods: Following the sections of a traditional chemical SDS, information was modified by industry subject matter experts, relevant to CGT biological materials. This guide was developed based on assumptions of a maximum biosafety level 2, and any chemical components present in the material were excluded from the hazard classification. Results: The guide contains necessary information to conduct a workplace risk assessment and communicate the unique workplace hazards posed by potential exposures to the material. The target audience is intended to be entities handling and producing these materials, plus collaborators, contractors, or operations sites receiving and handling the CGT material. An example of a CGT SDS is provided in Table 1. Discussion: The CGT SDS provides industry with a best practice to address an existing gap in hazard communication for CGT. We expect that, as the field evolves, so may the contents. The CGT SDS can be used as a reference for other biological modalities in the field. Conclusions: This initial CGT SDS communicates workplace hazards and assesses the unique risks posed by these biological materials and can assist in creating exposure control plans specific to the workplace hazards. [ABSTRACT FROM AUTHOR]

Effective microchip extraction of deoxyribonucleic acid (DNA) from crude biological matrixes has been demonstrated using silica beads or hybrid phases composed of beads and sol--gel. However, the use of monolithic sol--gels alone for extraction of human genomic DNA has been more difficult to define. Here we describe, for the first time, the successful use of monolithic tetramethyl ortho-silicate-based sol--gels for effective micro-solid-phase extraction ([micro]SPE) of DNA in a glass microchip format. A functional monolithic silica phase with micrometer-scale pores in the silica matrix resulted from addition of poly-(ethylene glycol), a poragen, to the precursor mixture. This allowed a monolithic sol--gel bed to be established in a microchip channel that provided large surface area for DNA extraction with little flow-induced back pressure. DNA extraction efficiencies for simple systems ([lambda]-phage DNA) were ~85%, while efficiencies for the reproducible extraction of human genomic DNA from complex biological matrixes (human blood) were ~70%. Blockage of the sol--gel pores by components in the lysed blood was observed in repeat extraction on a single device as a decrease in the extraction efficiency. The developed [micro]SPE protocol was further evaluated to show applicability to clinical samples and bacterial cultures, through extraction of PCR-amplifiable DNA.

The dynamic adsorption isotherms of CO2‐EGR were measured by using an Intelligent Gravimetric Analysis system. In the initial CO2 injecting stage, all the injected CO2 enters into the adsorbent and the mole fraction of CH4 in the gas phase (yCH4) is maintained at 1.0. The CH4 recovery factor (RCH4) increases. The duration of this stage (tCD) depends on the selectivity of CO2 over CH4 (SCO2/CH4). An adsorbent with large SCO2/CH4 has long tCD. In the second stage, the injected CO2 competes with CH4 for adsorption. The cumulative RCH4 of the second stage is much larger than that of the initial stage. However, yCH4 decreases sharply. pCH4 in the whole CO2 injection is always larger than that before CO2 injection, suggesting that CH4 desorption results from the displacement of CO2 rather than from pressure depletion. [ABSTRACT FROM AUTHOR]

Studying the heat transfer characteristics of alternating current (AC) arc-fault to electrodes is a key issue in electrical fires. In this paper, an instantaneous heat transfer numerical model of AC arc-fault is developed based on the magneto-hydrodynamic principle. The temperature distribution of the AC arc at the microseconds level and the influence of heat transfer on electrodes at the seconds level when the arc heats are studied. The numerical simulation of the axial temperature of the electrodes is verified by experiments, and the temperature variation in the electrodes at different currents and times is discussed. The results show that the arc temperature varies periodically similar to the current at the microseconds level but it does not go out when the current passes zero. The high-temperature region of electrodes diffuses with the increase in current or time. However, the axial temperature gradient of the electrode decreases with time and increases with current. Furthermore, the range of temperature increase in the electrode position decreases with the increase in current and time, but the electrode position near the arc has a higher initial temperature increase. [ABSTRACT FROM AUTHOR]

• Particles emitted from WFGD system are mainly carried from the SiO 2 inlet gas flow. • The inlet particle characteristics and the L/G ratio affect the particle emissions. • Ca and S are the dominant elements in particles that are carried from slurry. • The particles emitted from the WFGD system were dominated by fine particles. • The mean diameter of the emitted particles were between 0.6 and 1.2 μm. The chemical composition and morphology of particles emitted from a WFGD system were analyzed. The inlet particle diameter, inlet particle concentration and liquid/gas ratio (L/G), were all found to affect particle emissions. Smaller diameter particles and higher inlet particle concentrations resulted in increases Si and total particle mass concentrations. The elemental mass concentrations of the emitted particles were mainly derived from inlet components, along with low levels of Ca, S, AL, Mg and other trace elements carried from slurry in the spray scrubber, with the Ca and S content of emitted particles predominantly being carried from the slurry. The particles emitted from WFGD were mainly fine particles, with up to 96% and 50% of particles being below 2.5μm and 1μm, respectively. Particles with a diameter below 0.5μm accounted for only 8.89%, 7.6% and 16.4% of particle emissions when the inlet particles sizes were 38.55μm 13.42μm and 6.16, respectively. The mean diameter of particles emitted from the WFGD system ranged between 0.6 and 1.2μm. These results confirm the particle removal ability of the WFGD system and improve our understanding of the chemical composition and morphology of particles emitted from WFGD systems, as well as their impact on the atmospheric environment. [ABSTRACT FROM AUTHOR]

Poisoning effects by alkali metal chlorides is one of the major reasons for the deactivation of SCR catalyst in biomass-fired plants. In this study, the influence of KCl on two vanadium-based catalysts with different promoters, V2O5-WO3/TiO2 and V2O5-Ce(SO4)2/TiO2, was investigated. The catalytic activity of the fresh V2O5-WO3/TiO2 was higher than that of V2O5-Ce(SO4)2/TiO2 at low temperatures. V2O5-Ce(SO4)2/TiO2 performed better than V2O5-WO3/TiO2 when KCl was deposited on the catalyst surface. Both poisoned catalysts were efficiently regenerated by SO2 treatment. The characterization results show that the reducibility and acidity of the catalysts were weakened by KCl deposition but regenerated by SO2. [ABSTRACT FROM AUTHOR]

Coal is still a major energy source, mostly used in power plants. However, the coal combustion emits harmful SO 2 and fly ash. Wet flue gas desulfurization (WFGD) technology is extensively used to control SO 2 emissions in power plants. However, only limited studies have investigated the synergistic dust removal by the WFGD system. Spray scrubbers and sieve-tray spray scrubbers are often used in WFGD systems to improve the SO 2 removal efficiency. In this study, the synergistic dust removal of WFGD systems for a spray scrubber and a sieve-tray spray scrubber was investigated using the experimental and modelling approaches, respectively. For the spray scrubber, the influence of parameters, including dust particle diameters and inlet concentrations of dust particles, and the flow rates of flue gas and slurry of limestone/gypsum on the dust removal efficiency, was investigated. For the sieve-tray spray scrubber, the influence of parameters such as the pore diameter and porosity of sieve trays on the dust removal efficiency was examined. The study found that the dust removal efficiency in the sieve-tray spray scrubber was approximately 1.1-10.6% higher than that of the spray scrubber for the same experimental conditions. Based on the parameters investigated and geometric parameters of a scrubber, a novel droplets swarm model for dust removal efficiency was developed from the single droplet model. The enhanced dust removal efficiency of sieve tray was expressed by introducing a strength coefficient to an inertial collision model. The dust removal efficiency model for the sieve-tray spray scrubber was developed by combining the droplets swarm model for the spray scrubber with the modified inertial collision model for the sieve tray. The results simulated using both models are consistent with the experimental data obtained., Competing Interests: We declare we have no competing interests.

The purpose of the present study was to investigate the effect of the A(2A) receptor antagonist (SCH 442416) on the mRNA expression of glutamate aspartate transporter (GLAST) and glutamine synthetase (GS) in rat retinal Müller cells under hypoxic conditions in vitro. Immunofluorescent staining of GS and GFAP was used for the identification of Müller cells. The GLAST and GS mRNA expression of Müller cells treated with 0.1, 1 and 10 μM SCH 442416 under hypoxic conditions was examined by real-time PCR. Müller cells increased the mRNA expression of GLAST under hypoxic conditions; those treated with 0.1 μM SCH 442416 showed a further significant increase in the mRNA expression of GLAST in vitro. Although the mRNA expression of GS was decreased under hypoxic conditions, the mRNA expression was increased when Müller cells were treated with 0.1 μM SCH 442416. A(2A) receptor antagonist increased the GLAST and GS expression of Müller cells and accelerated the clearance of extracellular glutamate under hypoxic conditions in vitro.

The aim of this study was to investigate the expression of Kir 2.1 and Kir 4.1 channels at an elevated hydrostatic pressure in vitro, and to determine whether adenosine may modulate the mRNA expression of Kir 2.1 and Kir 4.1 channels in retinal Müller cells at an elevated hydrostatic pressure in vitro. Müller cells treated with 1 μM adenosine at 40 mmHg/24 h, and mRNA expression of Kir 2.1 and Kir 4.1 channels were examined using real-time PCR. Müller cells significantly increased the mRNA expression of Kir 2.1 and Kir 4.1 channels at 40 mmHg/24 h. When further treated with 1 μM adenosine at 40 mmHg/24 h, the mRNA expression of the Kir 2.1 channels decreased, while the mRNA expression of the Kir 4.1 channels continued to increase. When the pressure was elevated, Müller cells were still able to take up K(+) and mediate the potassium concentration of the retina. Adenosine upregulated the expression of the Kir 4.1 channels, but weakly affected the expression of the Kir 2.1 channels.