We present photometry and spectroscopy of the Type IIP supernova (SN IIP) 2009bw in UGC 2890 from a few days after the outburst to 241 d. The light curve of SN 2009bw during the photospheric phase is ...similar to that of normal SNe IIP but with a brighter peak and plateau (
mag,
mag). The luminosity drop from the photospheric to the nebular phase is one of the fastest ever observed, ∼2.2 mag in about 13 d. The radioactive tail of the bolometric light curve indicates that the amount of ejected 56Ni is ≈0.022 M⊙. The photospheric spectra reveal high-velocity lines of Hα and Hβ until about 105 d after the shock breakout, suggesting a possible early interaction between the SN ejecta and pre-existent circumstellar material, and the presence of CNO elements. By modelling the bolometric light curve, ejecta expansion velocity and photospheric temperature, we estimate a total ejected mass of ∼8-12 M⊙, a kinetic energy of ∼0.3 foe and an initial radius of ∼3.6-7 × 1013 cm.
We present the low-resolution spectroscopic and UBVRI broad-band photometric investigations of the Type IIb supernova (SN) 2011fu, discovered in UGC 01626. The photometric follow-up of this event was ...initiated a few days after the explosion and covers a period of about 175 d. The early-phase light curve shows a rise, followed by steep decay in all bands, and shares properties very similar to that seen for SN 1993J, with a possible detection of the adiabatic cooling phase. Modelling of the quasi-bolometric light curve suggests that the progenitor had an extended (∼1 × 1013 cm), low-mass (∼0.1 M) H-rich envelope on top of a dense, compact (∼2 × 1011 cm), more massive (∼1.1 M) He-rich core. The nickel mass synthesized during the explosion was found to be ∼0.21 M, slightly larger than that seen for other Type IIb SNe. The spectral modelling performed with synow suggests that the early-phase line velocities for H and Fe ii features were ∼16 000 and ∼14 000 km s−1, respectively. Then, the velocities declined up to day +40 and became nearly constant at later epochs.
Abstract
Multi-section chassis have a great potential for geometric and fifth wheel cross-country ability. An example is a model of a six-wheeled all-wheel drive planetary rover designed at VNIITM to ...study the mobility of the mobile laboratory of the Mars-94/96 project. The concept of extreme cross-country chassis involves the use of three articulated sections with a wheel mover with a removable track or a permanent track module. The rotation is carried out by changing the relative position of the sections in the plan. The article proposes mathematical models that make it possible to calculate by calculation the critical speeds and radii, according to the transverse overturning and skidding, which limit the possibility of a multi-section tracked vehicle when turning. Further development of the model implies taking into account an arbitrary scheme of external forces (including the longitudinal component of the inertia force) and caterpillar sliding, and, as a result, the transition to an iterative process in the calculations. To check the models, a calculation was made for a mass-produced two-section military transport vehicle. The prospect of using the proposed models is a preliminary assessment of the transverse stability of a three-section chassis of extreme cross-country ability.
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During the exploitation of oil reservoirs with highly mineralized waters, water separated from oil is pumped back into the reservoirs, which in some cases leads to an increase in ambient salinity ...and limits the possibility of application of biotechnologies for the enhancement of oil recovery. The microbial community of such oil fields has been relatively scarcely studied. Two strains of halophilic hydrocarbon-oxidizing bacteria,
Halomonas titanicae
TAT1 and
Marinobacter lutaoensis
KAZ22 were isolated from oil fields with mineralized formation water. Their physiological and genomic characteristics determining their presence in these habitats and the possibility of biotechnological application were investigated. The strains
H. titanicae
TAT1 and
M. lutaoensis
KAZ22 grew aerobically on crude oil in the temperature range from 4 to 42 and from 22 to 55°C, respectively, and had growth optima at salinity levels of 2–12 and 5–10% NaCl (wt/vol). Phenomenological observations of the degradation of oil
n
-alkanes were confirmed by the detection of three genes (
alkB1
,
alkB2
, and
almA
) encoding alkane1-monooxygenases in the genome of strain KAZ22 and of one
alkB
gene in the genome of strain TAT1. In the genome of the
H. titanicae
TAT1, all the genes for formation of osmoprotectants betaine, ectoine, and hydroxyectoine were annotated, and in the genome of
M. lutaoensis
KAZ22, the genes for the formation of ectoine and hydroxyectoine were annotated. The growth of strain KAZ22 on oil was accompanied by a decrease in the surface tension of the medium by more than 20 mN/m. Due to the absence of the
nirK
nitrite reductase gene, anaerobic growth of strain
H. titanicae
TAT1 in a medium with acetate and nitrate resulted in accumulation of ~100 mg/L of nitrite, which can inhibit the growth of sulfidogens. Considering the biological features of the strains and the results of genome analysis, injection of nitrate and strain
H. titanicae
TAT1 can be recommended for bioaugmentation of oil reservoirs with mineralized formation waters to suppress corrosion and decrease sulfide content, and injection of
M. lutaoensis
KAZ22, for remediation of oil pollution and increasing oil recovery from reservoirs.
The productivity of agricultural crops is determined by the choice of varieties, planting material, the optimal time of sowing and planting depending on the climatic conditions of the region, the use ...of organic and mineral fertilizers, and care methods. Planting material plays an important role in the growth and development of onions and the formation of yield. Onions are very demanding in terms of nutrition, this is due to the length of the growing season, growth rates and poorly developed root system. To obtain high and high-quality onion yields, it is necessary to use fertilizers in an accessible form. Water-soluble complex mineral fertilizers quickly and evenly penetrate deep into the soil. Fertilizers improve the growth and development of plants, regulating nutrition processes, increase the yield and quality of the resulting products. As a result of many years of research, it was found that optimizing the mineral nutrition of onions through the use of fertilizers in active form provides a significant increase in the yield of onions. A comparative assessment of the productivity of onions when grown from sets of different fractions using water-soluble complex mineral fertilizers in the conditions of the Udmurt Republic has been little studied. Materials and methods. The purpose of the research: to improve the technology of cultivating onions depending on the fraction of the set and fertilizing with water-soluble complex mineral fertilizers. In 2020–2021 On onions of the Stuttgarter Riesen variety, a two-factor experiment was carried out to study the effect of fertilizing with Aquarin and Rastvorin fertilizers when using different fractions of sets for planting. The studies were carried out using generally accepted methods. Results and its discussion. In the Udmurt Republic, the optimal for planting Stuttgarten Riesen onions is the medium and large fraction of the set, and the positive effect of water-soluble complex mineral fertilizers Aquarin and Rastvorin on the yield and its structure has been revealed. However, it is more economically profitable to use the fine fraction of sets when growing onions.
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The work was aimed at detection of potential degraders of polyethylene terephthalate (PET), polystyrene (PS), and steel 20 based on comparison of the taxonomic composition of the biofilm ...communities formed on these materials immersed in aqueous environments of diverse origin (marine, natural freshwater, and industrial) in different climatic regions. The libraries obtained by high-throughput sequencing of the 16S rRNA gene V3–V4 region were mainly grouped according to the media types. The composition and relative abundance of the taxa (both at the phylum/class and the genus levels) differed significantly between the groups of libraries; within the groups, these parameters varied depending mainly on the incubation time and on antimicrobial treatment (for industrial samples), while the material of the samples had less effect. Our results indicated that industrial recirculated water was more aggressive against polymer materials, with potential degraders of the polymers (PET and PS) belonging to the genera
Pseudomonas, Acidovorax
, and
Arenimonas.
Iron- and sulfur-oxidizing bacteria of the genera
Sulfurimonas
and
Mariprofundus
are probably involved in steel biocorrosion in seawater
.
Abstract
The main production of machine-building enterprises of various industries is the production of metal parts and products, 90-95% of which are manufactured using metal processing by pressure. ...Ensuring the stability of the technological processes of cold stamping is impossible without the use of interoperative coatings, which play the role of lubrication, preventing the diffusion “setting” (interpenetration at the atomic-molecular level) of the processed materials and tools. Therefore, one of the tasks in constructing the technology for manufacturing parts from these materials is to conduct a test cycle to establish the most acceptable coatings at the intermediate stages of processing. In the process of studying the operability and manufacturability, it is also advisable to use new methods for evaluating quality indicators at separate stages of processing semi-finished products and at the stages of control of finished products, which allows practically eliminating defects due to internal defects, ensuring the uniformity of the microstructure and predicting the operability of finished products during operation. Ensuring the quality of stamped semi-finished products made of refractory metals (niobium, molybdenum) is an urgent task due to the significant proportion of defects during cold stamping of these parts.
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The composition of microbial communities in rock samples, reservoir water, and enrichment cultures from subsurface horizons of an uranium deposit (Russia) was determined. The studied horizons were ...located in the zone of hindered water exchange at a depth of 513–544 m, characterized by moderate salinity (up to 15 g/L) of reservoir water and the presence of charry plant organic matter. The biodiversity of autochthonous subsurface prokaryotes was determined by high-throughput sequencing of the V4 region of the 16S rRNA gene. Bacterial phyla predominant in the rock samples were
Firmicutes
(24.2%),
Fusobacteriota
(23.0%),
Proteobacteria
(18.7%),
Actinobacteriota
(15.5%) and
Bacteroidota
(9.0%). The predominant bacterial phylum in the reservoir water was
Proteobacteria
(90.7%), including representatives of the genera
Methylophaga
,
Porphyrobacter
,
Roseovarius
,
Pseudomonas
, and
Methylococcus
. Sequencing of the internal transcribed spacer (ITS) revealed occurrence of lower fungi of the genera
Mucor
and
Thamnidium
(phylum
Mucoromycota
) and of the genus
Penicillium
(phylum
Ascomycota
) in the rock samples; members of these genera are known for their resistance to heavy metals and the ability to use complex organic substrates. The functional characteristics of bacterial communities of the rock and reservoir water samples, predicted by the iVicodak program and the KEGG database, showed that reservoir water bacteria had a higher potential ability to carry out the pathways of carbohydrate, nitrogen, and sulfur metabolism, degradation of xenobiotics, benzoate, polycyclic aromatic hydrocarbons and chlorinated organic compounds than the rock microbiota. Enrichment cultures of iron-reducing and sulfate-reducing bacteria and pure cultures of denitrifying bacteria of the genera
Bacillus
,
Paenibacillus
, and
Acinetobacter
were obtained. These results indicate the presence of a small but viable microbial community that can participate in the processes of transformations of carbon, nitrogen, sulfur, and metals in the subsurface horizon when water exchange is activated.
—
The work was aimed at investigation of the composition of microbial communities formed on the surface of samples of polyethylene terephthalate (PET), polystyrene (PS) and steel (ST) materials that ...were exposed in a small pond located at the territory of a solid waste landfill. The taxonomic composition of bacteria and fungi was determined by high-throughput sequencing of the V4 region of the 16S rRNA gene and of the ITS ribosomal operon, respectively. Bioinformatic analysis revealed predominance of bacteria of the phyla
Pseudomonadota
(
Proteobacteria
),
Actinomycetota, Bacteroidota
, and
Bacillota
in the biofilms formed on all samples. The observed quantitative changes in the composition of the dominant bacterial taxa were associated mainly with the exposure time, rather than the material of the samples. The iVikodak program was used to predict the functional characteristics of bacteria in the biofilms. The studied bacterial communities were shown to be potentially able to cause the degradation of polymer materials and xenobiotics and corrosion of steel. The fungal communities were dominated by saprotrophic representatives of the phyla
Ascomycota
and
Basidiomycota
. The effect of the conditions of the aquatic environment on the overall composition of the fungal community during exposure turned out to be less significant than that observed for bacteria; similar to the effect of the sample material, it could be traced for certain fungal genera. Among the dominant fungi, species potentially capable of biodegradation of polymers and corrosion of metals were identified. Microscopy confirmed the local degradation of the initial samples of materials as a result of exposure to the aquatic environment. Pure bacterial cultures of the genera
Bacillus
and
Brevundimonas
were isolated, which degraded alkanes, fatty acids, and phenols.
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