961 research outputs found
Hydrogen sulfide emissions from cattle manure: experimental study
Animal waste products, manure, in particular, are the sources of gases harmful to
human and animal health. Hydrogen sulfide (H2S), which is produced from the breakdown of
organic matter in animal faeces, is one of them. Its concentration in the cow barn air should not
exceed 5 mg m−3
. A special laboratory setup was designed and the level of hydrogen sulfide
emissions from the cow manure was determined depending on the time and manure temperature
and moisture content. The most intensive emission of hydrogen sulfide from manure was in the
first 24 hours – the increment of H2S concentration was 0.168 mg m−3 per hour average. During
the next 24 hours, it was 0.021 mg m−3 per hour. When the manure temperature increased, H2S
concentration increased also; when the temperature manure decreased, H2S concentration
decreased also. In 48 hours, the hydrogen sulfide concentration was 1.1 mg m−3 at the manure
temperature of +3.0 °C. At the manure temperature of +23.4 °C and 21.3 °C, H2S concentration
was 6.53 mg m−3
and 4.97 mg m−3
, respectively. The higher was the manure moisture content,
the lower was the emission of hydrogen sulfide into the environment. After 24 hours under the
manure moisture content of 88.5% and 92.5% and its temperature of 21 °С ± 0.3 °С, the
difference in the hydrogen sulfide concentration was 1.18 times depending on the manure
moisture content. The selected regression equations described the dependence of the hydrogen
sulfide concentration on the considered factors. The determination coefficients and Student's
criteria proved the reliability of the results obtained at the significance level P ≤ 0.05
Electric fields in plasmas under pulsed currents
Electric fields in a plasma that conducts a high-current pulse are measured
as a function of time and space. The experiment is performed using a coaxial
configuration, in which a current rising to 160 kA in 100 ns is conducted
through a plasma that prefills the region between two coaxial electrodes. The
electric field is determined using laser spectroscopy and line-shape analysis.
Plasma doping allows for 3D spatially resolved measurements. The measured peak
magnitude and propagation velocity of the electric field is found to match
those of the Hall electric field, inferred from the magnetic-field front
propagation measured previously.Comment: 13 pages, 13 figures, submitted to PR
Density-shear instability in electron magneto-hydrodynamics
We discuss a novel instability in inertia-less electron magneto-hydrodynamics (EMHD), which arises from a combination of electron velocity shear and electron density gradients. The unstable modes have a lengthscale longer than the transverse density scale, and a growth-rate of the order of the inverse Hall timescale. We suggest that this density-shear instability may be of importance in magnetic reconnection regions on scales smaller than the ion skin depth, and in neutron star crusts. We demonstrate that the so-called Hall drift instability, previously argued to be relevant in neutron star crusts, is a resistive tearing instability rather than an instability of the Hall term itself. We argue that the density-shear instability is of greater significance in neutron stars than the tearing instability, because it generally has a faster growth-rate and is less sensitive to geometry and boundary conditions. We prove that, for uniform electron density, EMHD is "at least as stable" as regular, incompressible MHD, in the sense that any field configuration that is stable in MHD is also stable in EMHD. We present a connection between the density-shear instability in EMHD and the magneto-buoyancy instability in anelastic MHD
Contents of heavy metals in fructicose epiphytic lichens of Karelia as indicator of atmospheric transport of pollutants
Results of studies of heavy metals contents in fruticose epiphytic lichens in Karelia are presented and the influence of different sources on the elemental composition of lichens has been estimated. It has been shown, that long-range atmospheric transport influences strongly the accumulation of Pb, Zn, Cd, Sb. For Al, Fe and Co lithogenic source is the main one. In the Northern Karelia atmospheric transport of Cu, Co and Ni from metallurgic enterprises of the Murmansk Region is important source of these elements
Parametric Generation of Subharmonics in a Composite Multiferroic Resonator
Parametric generation of subharmonics in a composite multiferroic resonator is observed and investigated. The resonator has the form of a disk and contains two mechanically coupled layers, one of which is amorphous ferromagnet Fe-B-Si-C and the other piezoelectric lead zirconate titanate. The resonator is placed inside two planar electromagnetic coils with orthogonal axes. A static magnetic field of 0-100 Oe is applied parallel to the plane of the resonator. The resonator is excited in the frequency range f = 9-10 kHz by either a harmonic magnetic field with an amplitude of up to 5 Oe generated by one of the coils, or a harmonic electric field with an amplitude of up to 500 V/cm applied to the piezoelectric layer. When the pump field is above a certain threshold, generation of a subharmonic of half-frequency (f/2) is observed for three different excitation methods. The first two employed either the direct magnetoelectric effect or the converse magnetoelectric effect, while in the third a transformer system is utilized. The subharmonic is generated in a limited range of pump frequencies and its amplitude is a nonlinear function of both the pump-field amplitude and the strength of static magnetic field. A theory of parametric generation of the subharmonic in a multiferroic resonator is developed, taking into account the magnetoacoustic nonlinearity of the ferromagnetic layer of the structure and excitation of acoustic resonances near the pump and subharmonic frequencies. The theory qualitatively describes the main characteristics of the subharmonic generation.</p
Bankruptcy procedure for individuals in Russia and the USA: comparative legal analysis
This study provides a comparative analysis of the most significant aspects of bankruptcy for individuals in Russia and the United States. The objective of the study was to determine the conditions involved in declaring a citizen insolvent in US and Russian law, for which we studied the ways of filing applications in these countries, as well as some methods of abuse by creditors that reduce the effectiveness of the bankruptcy institution, and the ways to minimize the
Fate of colloids during estuarine mixing in the Arctic
The estuarine behavior of organic carbon (OC) and trace elements (TE) was
studied for the largest European sub-Arctic river, which is the Severnaya
Dvina; this river has a deltaic estuary covered in ice during several
hydrological seasons: summer (July 2010, 2012) and winter (March 2009)
baseflow, and the November–December 2011 ice-free period. Colloidal forms of
OC and TE were assessed for three pore size cutoffs (1, 10, and 50 kDa)
using an in situ dialysis procedure. Conventionally dissolved
(< 0.22 μm) fractions demonstrated clear conservative
behavior for Li, B, Na, Mg, K, Ca, Sr, Mo, Rb, Cs, and U during the mixing of
freshwater with the White Sea; a significant (up to a factor of 10)
concentration increase occurs with increases in salinity. Si and OC also
displayed conservative behavior but with a pronounced decrease in
concentration seawards. Rather conservative behavior, but with much smaller
changes in concentration (variation within ±30%) over a full range
of salinities, was observed for Ti, Ni, Cr, As, Co, Cu, Ga, Y, and heavy REE.
Strong non-conservative behavior with coagulation/removal at low salinities
(< 5‰) was exhibited by Fe, Al, Zr, Hf, and light REE.
Finally, certain divalent metals exhibited non-conservative behavior with a
concentration gain at low (~ 2–5‰, Ba, Mn) or intermediate
(~ 10–15‰, Ba, Zn, Pb, Cd) salinities, which is most likely
linked to TE desorption from suspended matter or sediment outflux.
<br><br>
The most important result of this study is the elucidation of the behavior of
the "truly" dissolved low molecular weight LMW<sub>< 1 kDa</sub>
fraction containing Fe, OC, and a number of insoluble elements. The
concentration of the LMW fraction either remains constant or increases its
relative contribution to the overall dissolved
(< 0.22 μm) pool as the salinity increases. Similarly,
the relative proportion of colloidal (1 kDa–0.22 μm) pool for the
OC and insoluble TE bound to ferric colloids systematically decreased
seaward, with the largest decrease occurring at low
(< 5‰) salinities.
<br><br>
Overall, the observed decrease in the colloidal fraction may be related to
the coagulation of organo-ferric colloids at the beginning of the mixing zone
and therefore the replacement of the
HMW<sub>1 kDa–0.22 μm</sub> portion by the
LMW<sub>< 1 kDa</sub> fraction. These patterns are highly reproducible
across different sampling seasons, suggesting significant enrichment of the
mixing zone by the most labile (and potentially bioavailable) fraction of the
OC, Fe and insoluble TE. The size fractionation of the colloidal material
during estuarine mixing reflects a number of inorganic and biological
processes, the relative contribution of which to element speciation varies
depending on the hydrological stage and time of year. In particular,
LMW<sub>< 1 kDa</sub> ligand production in the surface horizons of the
mixing zone may be linked to heterotrophic mineralization of allochthonous
DOM and/or photodestruction. Given the relatively low concentration of
particulate versus dissolved load of most trace elements, desorption from the
river suspended material was less pronounced than in other rivers in the
world. As a result, the majority of dissolved components exhibited either
conservative (OC and related elements such as divalent metals) or
non-conservative, coagulation-controlled (Fe, Al, and insoluble TE associated
with organo-ferric colloids) behavior. The climate warming at high latitudes
is likely to intensify the production of LMW<sub>< 1 kDa</sub> organic
ligands and the associated TE; therefore, the delivery of potentially
bioavailable trace metal micronutrients from the land to the ocean may
increase
3-Acetyl-6-chloro-4-phenylquinolin-2(1H)-one
The title compound, C17H12ClNO2, crystallizes with two molecules in the asymmetric unit. The main conformational difference between these two molecules is the dihedral angle between the phenyl ring and the quinoline ring system [70.5 (1)° and 65.5 (1) Å]. The crystal packing is stabilized by N—H⋯O hydrogen bonds
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