Increase In Energy Release Research Articles

Microorganisms of Microbial Mats from an Alkaline Hot Spring of Baikal Rift Zone as Bioagents in a Biofuel Cell

The microbial diversity, transformation potential and ability of microorganisms of the microbial mat consortium of the Kucheger thermal spring (Baikal Rift Zone) to generate electricity were studied. High-throughput sequencing showed the predominance of representatives of the Proteobacteria phylum in the microbial mat community (85.5% of the number of classified bacterial sequences). Among Proteobacteria, filamentous sulfur bacteria of the genus Thiothrix are the most numerous (66.1%). In addition, bacteria of the families Rhodocyclaceae (3%) and Comamonadaceae (7.3%) were present in the mat community. The Bacteroidetes phylum was represented by sequences belonging mainly to the Flavobacteriaceae family (6.8%). The sequences of other phyla accounted for no more than 0.5% of the total number of classified sequences. A wide metabolic activity of microorganisms of mat Kucheger-15 was revealed. The high electrogenic ability of microorganisms of the consortium of microbial mats Kucheger-15 in biofuel cells (BFCs) is shown. Mat-based BFCs generated electricity by adding substrates such as peptone, cellulose, starch. Peptone, glucose, tween-80, starch, sodium acetate, and cellulose were used as substrates. Peptone turned out to be the most effective substrate for the production of electricity in BFCs based on Kucheger microbial mat microorganisms. The addition of a mixture of these substrates to the anolyte (the concentration of each of them is 2.5 g/l) made it possible to achieve some increase in energy release (especially the output current) compared to BFC based on each of these substrates separately. The presence of a wide variety of different microorganisms with broad substrate specificity, the ability to function under extreme conditions (high temperature, high pH values), their well-coordinated work and adaptation to each other and to the resulting metabolites, and stability over time allow us to speak of high prospects for the use of hot spring mats in BFC technologies.

Surface-Functionalized Boron Nanoparticles with Reduced Oxide Content by Nonthermal Plasma Processing for Nanoenergetic Applications.

The development of an in situ nonthermal plasma technology improved the oxidation and energy release of boron nanoparticles. We reduced the native oxide layer on the surface of boron nanoparticles (70 nm) by treatment in a nonthermal hydrogen plasma, followed by the formation of a passivation barrier by argon plasma-enhanced chemical vapor deposition (PECVD) using perfluorodecalin (C10F18). Both processes occur near room temperature, thus avoiding aggregation and sintering of the nanoparticles. High-resolution transmission electron microscopy (HRTEM), high-angular annular dark-field imaging (HAADF)-scanning TEM (STEM)-energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) demonstrated a significant reduction in surface oxide concentration due to hydrogen plasma treatment and the formation of a 2.5 nm thick passivation coating on the surface due to PECVD treatment. These results correlated with the thermal analysis results, which demonstrated a 19% increase in energy release and an increase in metallic boron content after 120 min of hydrogen plasma treatment and 15 min of PECVD of perfluorodecalin. The PECVD coating provided excellent passivation against air and humidity for 60 days. We conclude in situ nonthermal plasma reduction and passivation lead to the amelioration of energy release characteristics and the storage life of boron nanoparticles, benefits conducive for nanoenergetic applications.

Impact on performance and emissions of the aspiration of algal biomass suspensions in the intake air of a direct injection diesel engine

Recently, the production of sustainable biofuels from algal biomass has gained significant attention and been investigated as a potential replacement of fossil fuel. However, existing downstream processes for producing biodiesel from algae cells are complex, highly energy-intensive, and have high economic and environmental cost. Therefore, this work introduces an alternative and novel method of utilizing the energy content of microalgae that precludes lipid extraction by aspirating wet algal biomass suspensions directly into the intake air of an internal combustion engine.For all engine experiments, powdered algae cells were prepared as slurries at different biomass concentrations. The impacts of (i) varying the biomass concentration with constant suspension injection flowrate into the engine intake and (ii) varying suspension injection flowrate with constant biomass concentration were investigated.A correlation between engine work produced during combustion and algal biomass aspiration was found. At constant flowrate and greater than 5% biomass concentrations, an increase of energy release during combustion from the aspirated algae could be observed. However, the aspiration of low concentration biomass suspension produced a negative impact on engine performance relative to water-only aspiration. The engine exhaust gas of nitrogen oxides (NOx) was reduced for all algae suspension tests relative to diesel-only combustion. However, the carbon monoxide (CO) emission level was much higher relative to diesel-only tests at high biomass concentrations and injection flowrate.These findings demonstrate the possibility of utilising the energy content of algal biomass in combustion without lipid extraction, with added benefits of reducing NOx emissions.

Microseismicity Induced by Fault Activation During the Fracture Process of a Crown Pillar

Shirengou iron mine in Hebei Province, China is now under transition from open pit to underground mining. During this process, the unstable failure risk of crown pillar is growing as a result of underground mining, fault activation and water seepage. To monitor the stability of the crown pillar, a microseismic monitoring system was equipped in 2006. Based on temporal and spatial distribution of microseismic events and deformation mechanism, it was found that it is the propagation of the buried fault F15 that causes the failure of the crown pillar, resulting in increased water seeping into the underground drifts. By analyzing the temporal changes in multiple microseismic parameters during the fracture process of the crown pillar, it was found that several distinct abnormalities in the microseismic data such as a rapid decrease in the b value, a sharp increase in energy release, an abnormal increase in apparent stress and a low dominant frequency, could be judged as the signal of an increasing risk. Therefore, the microseismic monitoring has been proven to be a suitable method for understanding damage and fracture process of the crown pillar during the transition from open pit to underground mining.

NON-THERMAL RESPONSE OF THE CORONA TO THE MAGNETIC FLUX DISPERSAL IN THE PHOTOSPHERE OF A DECAYING ACTIVE REGION

We analyzed Solar Dynamics Observatory line-of-sight magnetograms for a decaying NOAA active region (AR) 11451 along with co-temporal Extreme-Ultraviolet Imaging Spectrometer (EIS) data from the Hinode spacecraft. The photosphere was studied via time variations of the turbulent magnetic diffusivity coefficient, η(t), and the magnetic power spectrum index, α, through analysis of magnetogram data from the Helioseismic and Magnetic Imager (HMI). These measure the intensity of the random motions of magnetic elements and the state of turbulence of the magnetic field, respectively. The time changes of the non-thermal energy release in the corona was explored via histogram analysis of the non-thermal velocity, vnt, in order to highlight the largest values at each time, which may indicate an increase in energy release in the corona. We used the 10% upper range of the histogram of vnt (which we called Vuppnt) of the coronal spectral line of Fe xii 195 Å. A 2 day time interval was analyzed from HMI data, along with the EIS data for the same field of view. Our main findings are the following. (1) The magnetic turbulent diffusion coefficient, η(t), precedes the upper range of the vnt with the time lag of approximately 2 hr and the cross-correlation coefficient of 0.76. (2) The power-law index, α, of the magnetic power spectrum precedes Vuppnt with a time lag of approximately 3 hr and the cross-correlation coefficient of 0.5. The data show that the magnetic flux dispersal in the photosphere is relevant to non-thermal energy release dynamics in the above corona. The results are consistent with the nanoflare mechanism of the coronal heating, due to the time lags being consistent with the process of heating and cooling the loops heated by nanoflares.

Synthesis and Coating of Aluminum NanoCrystals

ABSTRACTWe show a low temperature gas-phase synthesis route to produce faceted aluminum crystals in the aerosol phase. Use of triisobutylaluminum whose decomposition temperature is below the melting point of elemental aluminum enabled us to grow nanocrystals from its vapor. Combustion tests show an increase in energy release compared to commercial nanoaluminum. Production of aluminum in an oxygen free environment resulted in a bare aluminum surface that was passivated in separate experiments with nickel and iron by decomposition of their carbonyl precursors.

Aerosol synthesis and reactive behavior of faceted aluminum nanocrystals

We show a low temperature gas-phase synthesis route to produce faceted aluminum crystals in the aerosol phase. Use of triisobutylaluminum whose decomposition temperature is below the melting point of elemental aluminum enabled us to grow nanocrystals from its vapor. TEM shows both polyhedral crystalline and spherical particle morphologies, but with the addition of an annealing furnace one can significantly enhance the production of just the polyhedral particles. The results on surface passivation with oxygen suggest that these nanocrystals are less pyrophoric than the corresponding spherical aluminum nanoparticles, and combustion tests show an increase in energy release compared to commercial nanoaluminum.

Energetics of Na +–Ca 2+ Exchange in Resting Cardiac Muscle

The energetic effect of extracellular Na + removal and readmission (in a nominally Ca 2+-free perfusate) in Langendorff-perfused ventricles of transgenic mice (TM), which overexpress the sarcolemmal Na +–Ca 2+ exchanger; normal mice (NM); young (7–12 days old) rats (YR); and older (13–20 days old) rats (OR) was studied. In all heart muscles, extracellular Na + removal induced an increase in heat production (H 1). Na + readmission further increased heat production to a peak value (H 2) followed by a decrease toward initial values. These effects were more marked in the YR and TM as compared with the OR and NM groups, respectively. Caffeine (1 mM), ryanodine (0.2 μM), and verapamil (1 μM) decreased H 1 and H 2 in both rat groups. EGTA (1 mM) decreased H 1 and H 2 in the YR but not in the OR group. Thapsigargin (1 μM) decreased H 1 and H 2 in all four hearts preparations. A possible interpretation is that Na +–Ca 2+ exchange acts as an energy-saving mechanism to prevent Ca 2+ accumulation at the junctional sarcoplasmic reticulum zone (JSR) and thus prevents further release of Ca 2+. Extracellular Na + removal lead to Ca 2+ accumulation in the JSR inducing further SR–Ca 2+ release and increased energy release. Na + readmission removes the accumulated Ca 2+ at the JSR (cleft) zone by exchanging Ca 2+ with Na + producing a transitory increase in energy release due to Na +–K pump activation.

Interaction of a shock with a sinusoidally perturbed flame

The interaction of a shock wave and a sinusoidally perturbed premixed flame was studied by solving the reactive Navier-Stokes equations with flame front resolved. An idealized chemical model was used that reproduces the combustion properties of a stoichiometric acetylene-air mixture. The interaction increases the surface area of the flame and the energy release in the system. The increase in energy release is due to two effects: the increase in surface area and the increase in the density of the compressed material. The timescale of the growth of the energy release is the Richtmyer-Meshkov characteristic timescale. The interaction creates vorticity, and the vortices act to maintain a high level of energy release long after the shock wave has passed through the flame. The strength of this vorticity is not enough to stretch and locally extinguish the flame. Three-dimensional perturbations of the same amplitude and wavelength grow a factor of ≃2 faster than the two-dimensional perturbations, and the maximum energy release rate is a factor of ≃2 larger. The calculations show that the maximum increase in the energy generation rate due to a single interaction of a shock and a flame does not exceed a factor of 20 to 30. To greatly increase the burning rate, multiple shock-flame interactions are required.

Reactivity effects (autocatalysis) in BR-1 and BR-K1 pulsed reactors

Manifestations of autocatalysis, caused by neutron-absorbing samples loaded into a cavity in the core, in explosive accidents in BR-1 and BR-K1 reactors were investigated. The investigation was conducted on the basis of calculations using a multigroup neutron-gas-dynamic program for one-dimensional calculations of fission surges in various configurations of the reactors indicated. It was shown that, even though the boron content in the screens is comparatively limited and the natural isotopic composition of boron is used in the BR-K1 screen, in the case of accidents accompanied by a chain reaction of an explosive type strong manifestations of autocatalysis with nine-fold (BR-1) and 520-fold (BR-K1) increase of energy release in accidental surges are possible.