Construction of an airborne chemiluminescence ozone monitor for volcanic plumes

<p>Volcanic plumes contain traces of bromine monoxide, BrO, which catalyze destruction of ozone, O<sub>3</sub>, mixed into the plume. Therefore, local depletion of O<sub>3 </sub>in the plume could be possible. However, calculations comparing mixing with the rate of O<sub>3 </sub>destruction suggest that no significant decline in the O<sub>3</sub> concentration should be expected. On the other hand several studies at different volcanoes have found varying degrees of O<sub>3</sub> depletion inside the plume. So far, ozone and its concentration distribution in volcanic plumes have only been insufficiently determined. Reliable ozone measurements would make a decisive contribution to the understanding of volcanic plume chemistry.</p> <p>The standard technique for ambient O<sub>3</sub> monitoring is the short-path ultraviolet (UV) absorption instrument. But in volcanic plumes this technique suffers from strong interference of the overlapping SO<sub>2</sub> absorption features in the UV. SO<sub>2</sub> is one of the major compounds in volcanic plumes.</p> <p>We want to overcome this problem by relying on the chemiluminescence (CL) reaction between ozone and ethene, a standard technique for O<sub>3</sub> measurement in the 1970s and 1980s, which we found to have no interference from trace gases abundant in volcanic plumes. The key component of a CL O<sub>3</sub>-instrument is a reaction chamber, where ethene is mixed into the ambient air and a photomultiplier tube detects the resulting photons.</p> <p>Field measurements with existing CL O<sub>3</sub>-monitors are complicated, because they are usually heavy and bulky. Therefore we designed a more compact and lightweight version (10 kg backpack size CL instrument), which was used in a field study at Mount Etna. However, the campaign was restricted to plumes that are pushed down to ground in areas accessible by foot.</p> <p>Here we report on a further improved version of the instrument weighing around 1 kg, which we can mount onto a drone to carry it into the plume. In particular, we describe the design advances making the reduction in weight and size possible.</p>

FORMULATION AND IMPROVEMENT OF TECHNOLOGICAL SOLUTIONS FOR WASTEWATER TREATMENT OF AGRICULTURAL REPAIR ENTERPRISES

The article presents the main production cycles of engine repair at a repair and mechanical plant. The main production cycle of engine repair at the repair and mechanical plant consists of external steaming of the unit in the steaming chamber with the discharge of the formed effluent into the pre-fabricated well. Next the disassembly of the en-gine into individual components is carried out, then they are cleaned in cross washing machines with periodic discharge of spent detergent solutions into the prefabricated tanks. After restoration of details the assembly of the diesel engine and its test on stands is carried out. The necessary parts are electrochemically galvanized, chrome-plated or coated with iron. Several local wastewater treatment schemes on the plant with utilization of valuable components and their reuse are offered. Wastewater and waste process solutions are conventionally divided into low-concentrated and concentrated. Low-concentrated wastewater includes effluents from the diesel test site, flushing water from plating baths, and discharge of a revolving diesel cooling system. A scheme for wastewater treatment from petrole-um products and substances in the form of suspensions has been developed and researched, which allows reusing wastewater from the re-verse water supply to the diesel test site. The schematic diagram of the reverse water supply of the diesel test area will consist of a column electrical flotation coagulator, contaminated water collectors, saturators and pumps. A scheme of electrochemical purification of waste detergents has been developed, which includes receivers of detergent solution, preliminary settling of coarse impurities, column electrical coagulator-floater with soluble aluminum electrodes, electrolyte collection. The peculiarity of the device is the operation of the electrode system in a pure electrolyte, which eliminates the possibility of contamination and passivation of electrical and chemical processes. The electrically generated coagulant is dosed into the reaction chamber, mixed with the detergent solution, coagulates and floats the contamination, which allows to extend the service life of the detergent solutions in two or three times.

High-Performance 3D Semiconductor-Based Heterostructure Photocatalyst in Sustained Control of Harmful Gas-Phase Pollutants Under Visible-Light Illumination

Herein, a highly efficient three-dimensional (3D) semiconductor-based heterostructure photocatalyst (i.e., WO3–g-C3N4 monolithic architecture; WOCNM) was developed by immobilizing a WO3–g-C3N4 heterostructure powder on a melamine foam (MF) framework. Subsequently, the sustained control of two harmful model gas-phase pollutants (i.e., n-butanol and o-xylene) over WOCNM and selected monolithic counterparts (i.e., MF-supported WO3 monolith and MF-supported g-C3N4 monolith) was investigated under visible-light irradiation. WOCNM exhibited higher photocatalytic capabilities in the sustained control of the two model pollutants than those of individual WO3 and g-C3N4 monoliths because the WO3–g-C3N4 heterojunction enhanced its charge-separation ability. Notably, WOCNM exhibited highly efficient photocatalytic capabilities in the sustained control of n-butanol (up to 97%) and o-xylene (up to 86%). Moreover, no noticeable changes were observed in the WOCNM photocatalytic capability after the final run of successive applications. The fresh and successively used WOCNMs were nearly identical, and the photocatalyst powder was not observed in the reaction chamber after its successive application. As a result, WOCNM was a highly efficient and stable 3D heterostructure photocatalyst for the sustained control of gas-phase n-butanol and o-xylene, without significant catalyst powder loss. Promisingly, this study will expedite the future development of 3D photocatalysts for the sustained control of harmful gas-phase pollutants.

The structural basis for the phospholipid remodeling by lysophosphatidylcholine acyltransferase 3

As the major component of cell membranes, phosphatidylcholine (PC) is synthesized de novo in the Kennedy pathway and then undergoes extensive deacylation-reacylation remodeling via Lands’ cycle. The re-acylation is catalyzed by lysophosphatidylcholine acyltransferase (LPCAT) and among the four LPCAT members in human, the LPCAT3 preferentially introduces polyunsaturated acyl onto the sn-2 position of lysophosphatidylcholine, thereby modulating the membrane fluidity and membrane protein functions therein. Combining the x-ray crystallography and the cryo-electron microscopy, we determined the structures of LPCAT3 in apo-, acyl donor-bound, and acyl receptor-bound states. A reaction chamber was revealed in the LPCAT3 structure where the lysophosphatidylcholine and arachidonoyl-CoA were positioned in two tunnels connected near to the catalytic center. A side pocket was found expanding the tunnel for the arachidonoyl CoA and holding the main body of arachidonoyl. The structural and functional analysis provides the basis for the re-acylation of lysophosphatidylcholine and the substrate preference during the reactions.

Chemical Engineering for Improvement of the Efficiency of Microwave Energy Use in Processing of Plant Biomass

Combined coaxial-circular waveguide equipped with protective module allowing the transmission of microwave energy of three magnetrons with the output of 0.9 kW per each into the pressurized reaction chamber and capable of operating at temperatures of up to 250 °C and a pressure of up to 10 bars was designed and tested. Choke flange junction of the waveguide sections was used instead of contact flange connection. The developed waveguide construction allows to place the radio transparent partition inside the free space volume of a choke flange junction performing protection of emitters and summing of microwave energy of three magnetrons with an efficiency close to 100% that was proven by tests with fresh water as a microwave energy absorber. The extraction set-up equipped with the above-mentioned waveguide has demonstrated the stable and safety operation of the transmitting block and the accurate automatic control of the temperature and pressure inside the reaction chamber in the presence of a strong electromagnetic field. The construction of the microwave extraction set-up allows to use the impact of the combination of temperature and pressure on the cell wall, promoting the high rate isolation of secondary metabolites from biomass that was demonstrated by water extraction of black alder bark.

Oligomerization state of the functional bacterial twin arginine translocation (Tat) receptor complex

The twin-arginine translocation (Tat) system transports folded proteins across bacterial and plastid energy transducing membranes. Ion leaks are generally considered to be mitigated by the creation and destruction of the translocation conduit in a cargo-dependent manner, a mechanism that enables tight sealing around a wide range of cargo shapes and sizes. In contrast to the variable stoichiometry of the active translocon, the oligomerization state of the receptor complex is considered more consistently stable, but has proved stubbornly difficult to establish. Here, using a single molecule photobleaching analysis of individual inverted membrane vesicles, we demonstrate that Tat receptor complexes are tetrameric in native membranes with respect to both TatB and TatC. This establishes a maximal diameter for a resting state closed pore. A large percentage of Tat-deficient vesicles explains the typical low transport efficiencies observed. This individual reaction chamber approach will facilitate examination of the effects of stochastically distributed molecules.

How to Control the Microfluidic Flow and Separate the Magnetic and Non-Magnetic Particles in the Runner of a Disc

Biochips play an important role in both medical and food industry safety testing. Moreover, magnetic activated cell sorting is a well-established technology for biochip development. However, biochips need to be manufactured by precision instruments, resulting in the high cost of biochips. Therefore, this study used magnetic-activation and mechanics theories to create a novel disc that could manipulate the microfluidic flow, mixing, reaction, and separation on the runner of the disc. The goal of the research was to apply in the field of biomedical detection systems to reduce the cost of biochips and simplify the operation process. The simulation and experimental investigation showed that the pattern of the reaction chamber was stomach-shaped and the reservoir chamber was rectangular-shaped on the disc. The microfluid could be controlled to flow to the reaction chamber from the buffer and sample chamber when the disc spun at 175~200 rpm within three minutes. This was defined as the first setting mode. The microfluid could then be controlled to flow to the reservoir chamber from the reaction chamber when the disc spun at 225 rpm within five to ten minutes. This was defined as the second setting mode. This verified that the pattern design of the disc was optimized for control of the microfluid flow, mixing, reaction, and separation in the runner of the disc by different setting modes.

Controllable Synthesis of Enhanced Visible Light Responded Fe, N, Co Tri-TiO2@MCM-41 Nanocomposites and Its Photocatalytic Performance

A novel method for in situ synthesis of Fe, N, Co tri-TiO2 (DT) loading on MCM-41 composite photocatalyst was proposed. Fe, N, Co tri-TiO2@MCM-41 (DTM) with adsorption-degradation synergy was prepared by adjusting tetrabutyl titanate (TBOT) concentrations, the alcohol-water ratio in the atmosphere of the reaction chamber. The influence of preparation parameters on the texture structure, catalytic activity, and the synergism of adsorption and degradation of the DTM was discussed, the optimal parameters were determined. The DTM was characterized by XRD, TEM, BET, FT-IR, and UV-Vis. Besides, the DTM exhibited obvious redshift and visible catalytic activity compared with undoped TiO2@MCM-41 (TM), which possessed excellent performance in the degradation of gaseous and liquid pollutants. The degradation rate of methylene blue (MB) and nitric oxide (NO) was 96.39% and 56.75%, respectively. Furthermore, DTM photocatalyst exhibited excellent reusability. The degradation efficiency of MB and NO after five cycles decreased by 4.54% and 5.89%, respectively.

Impact of ozone and inlet design on the quantification of isoprene-derived organic nitrates by thermal dissociation cavity ring-down spectroscopy (TD-CRDS)

We present measurements of isoprene-derived organic nitrates (ISOP-NITs) generated in the reaction of isoprene with the nitrate radical (NO3) in a 1 m3 Teflon reaction chamber. Detection of ISOP-NITs is achieved via their thermal dissociation to nitrogen dioxide (NO2), which is monitored by cavity ring-down spectroscopy (TD-CRDS). Using thermal dissociation inlets (TDIs) made of quartz, the temperature-dependent dissociation profiles (thermograms) of ISOP-NITs measured in the presence of ozone (O3) are broad (350 to 700 K), which contrasts the narrower profiles previously observed for, for example, isopropyl nitrate (iPN) or peroxy acetyl nitrate (PAN) under the same conditions. The shape of the thermograms varied with the TDI's surface-to-volume ratio and with material of the inlet walls, providing clear evidence that ozone and quartz surfaces catalyse the dissociation of unsaturated organic nitrates leading to formation of NO2 at temperatures well below 475 K, impeding the separate detection of alkyl nitrates (ANs) and peroxy nitrates (PNs). The use of a TDI consisting of a non-reactive material suppresses the conversion of isoprene-derived ANs at 473 K, thus allowing selective detection of PNs. The potential for interference by the thermolysis of nitric acid (HNO3), nitrous acid (HONO) and O3 is assessed.