Helium Detection in Natural Gas Using Raman Spectroscopy.

Raman spectroscopy has great potential for quantitative analysis of natural gas. Helium is one of the components of natural gas and has a wide range of applications. It was believed that noble gases could not be detected using this technique due to the absence of their vibrational spectra.

Tropical peat composition may provide a negative feedback on fire occurrence and severity.

Loss of peat through increased burning will have major impacts on the global carbon cycle. In a normal hydrological state, the risk of fire propagation is largely controlled by peat bulk density and moisture content. However, where humans have interfered with the moisture status of peat either via drainage, or indirectly via climate change, we hypothesise that its botanical composition will become important to flammability, such that peats from different latitudes might have different compositionally-driven susceptibility to ignition.

Dissolved organic matter quality in thermokarst lake water and sediments across a permafrost gradient, Western Siberia.

Thermokarst (thaw) lakes of permafrost peatlands are among the most important sentinels of climate change and sizable contributors of greenhouse gas emissions (GHG) in high latitudes. These lakes are humic, often acidic and exhibit fast growing/drainage depending on the local environmental and permafrost thaw. In contrast to good knowledge of the thermokarst lake water hydrochemistry and GHG fluxes, the sediments pore waters remain virtually unknown, despite the fact that these are hot spots of biogeochemical processes including GHG generation.

CH/CH sensing using Raman spectroscopy.

The paper presents a technique for measuring the concentration of CH in natural methane using Raman spectroscopy. The peak positions and the relative scattering cross-sections of the Q-branches for the most intense vibrational bands of CH are determined. Features of the CH/CH ratio measurement methods using Q-branches of the ν and ν bands were considered.

Dryocoetiops krivetsae sp. n. (Coleoptera: Curculionidae: Scolytinae: Dryocoetini), the northernmost species of the genus: conflicts between molecular and morphological data in the tribe Dryocoetini.

A new species of bark beetle, Dryocoetiops krivetsae Kerchev, Mandelshtam, Bykov et Ilinsky, sp. n., from the southern part of Primorsky Krai (Russian Far East), is described.

Diet of the Small Cave Bear Ursus (Spelaearctos) rossicus Borissak, 1930 (Mammalia, Carnivora, Ursidae) As Revealed by C and N Isotope Analyses in Bone Collagen.

The C and N isotope contents in bone collagen were analyzed using bones of the small cave bear Ursus (Spelaearctos) rossicus Borissak, 1930 from localities in the Middle and Southern Urals. The bones date from the last interglacial (MIS 5) and glacial (MIS 3) periods. The bones were from males and females aged 3, 4, and >4 years.

Content of С and N Isotopes in Bone Collagen of Geographical, Age, and Sex Groups of the Ural Cave Bear (Mammalia, Carnivora, Ursidae, Ursus (Spelaearctos) kanivetz Verestchagin, 1973).

Data on the content of C and N isotopes in the collagen of bones of the Ural cave bear (Ursus (S.) kanivetz Verestchagin, 1973) from the North and Middle Urals were analyzed. The bones date from the first half of MIS 3.

First Data on Nutrition of the Ural Cave Bear Ursus (Spelaearctos) kanivetz Verestchagin, 1973 (Mammalia, Carnivora, Ursidae) as Based on C and N Isotope Analyses.

First data on the contents of the C and N isotopes in collagen were obtained for 16 bones of the Ural cave bear Ursus (Spelaearctos) kanivetz Verestchagin, 1973 from the Tayn (Secrets) cave (55°25' N, 57°46' E). The bones are dated to the middle MIS 3 and belonged to males and females of about 2 years, about 3 years, and older than 4 years of age. No considerable difference in isotope signatures was observed between individuals of different ages and different genders.

Natural Gas Analysis Using Polarized Raman Spectroscopy.

Raman spectroscopy is a promising tool for measuring the composition of natural gas. However, to obtain high measurement accuracy, it is necessary to take into account changes in the spectral characteristics of methane, since its spectrum overlaps the characteristic bands of other species. In this study we present a technique for natural gas analysis based on polarized Raman spectroscopy.

Broadening of the ν Raman Band of CH by CH and CH.

Raman spectroscopy is a promising method for the analysis of natural gas. It is necessary to account for the broadening effects on spectral lines to improve measurement accuracy. In this study, the broadening coefficients for methane lines in the region of the ν band perturbed by propane, n-butane, and isobutane at room temperature were measured.

Pressure broadening in Raman spectra of CH-N, CH-CO, and CH-CH gas mixtures.

Different molecular environments change the spectrum of a given gas sample involved in a mixture compared to the spectrum of a pure gas. It is necessary to account for this effect to improve the accuracy of the analysis of the natural gas composition by Raman spectroscopy. First, the change in the main components of natural gas (methane, nitrogen, carbon dioxide, and ethane) must be considered.

Raman Natural Gas Analyzer: Effects of Composition on Measurement Precision.

Raman spectroscopy is a promising method for analyzing natural gas due to its high measurement speed and the potential to monitor all molecular components simultaneously. This paper discusses the features of measurements of samples whose composition varies over a wide range (0.005-100%).

Depolarization Ratio of the ν Raman Band of Pure CH and Perturbed by N and CO.

In this work, the effect of nitrogen and carbon dioxide on the depolarization ratio of the ν band of methane in the pressure range of 0.1-5 MPa is studied. A high-sensitivity single-pass Raman spectrometer was used to obtain accurate results.

Rainfall Intensity and Quantity Estimation Method Based on Gamma-Dose Rate Monitoring.

The features of the atmospheric γ-background reaction to liquid atmospheric precipitation in the form of bursts is investigated, and various forms of them are analyzed. A method is described for interpreting forms of the measured γ-background response with the determination of the beginning and ending time of precipitation, the distinctive features of changes in the intensity of precipitation and the number of single (separate) events that form one burst. It is revealed that a change in the intensity of precipitation in one event leads to a change in the γ-radiation dose rate increase speed (time derivative).

Siberian environmental change: Synthesis of recent studies and opportunities for networking.

A recent multidisciplinary compilation of studies on changes in the Siberian environment details how climate is changing faster than most places on Earth with exceptional warming in the north and increased aridity in the south. Impacts of these changes are rapid permafrost thaw and melt of glaciers, increased flooding, extreme weather events leading to sudden changes in biodiversity, increased forest fires, more insect pest outbreaks, and increased emissions of CO and methane. These trends interact with sociological changes leading to land-use change, globalisation of diets, impaired health of Arctic Peoples, and challenges for transport.

Poplar tree (Populus balsamifera L.) as indicator of mercury emission from a point source.

The article provides original data on the ecological and geochemical characteristics of the distribution of Hg in the leaves and annual rings of balsam poplar (P. balsamifera L.) in the zone of influence of lithium production (Novosibirsk).

South-Siberian mountain mires: Perspectives on a potentially vulnerable remote source of biodiversity.

Changes in climate, land-use and pollution are having disproportionate impacts on ecosystems and biodiversity of arctic and mountain ecosystems. While these impacts are well-documented for many areas of the Arctic and alpine regions, some isolated and inaccessible mountain areas are poorly studied. Furthermore, even in well-studied regions, assessments of biodiversity and species responses to environmental change are biased towards vascular plants and cryptogams, particularly bryophytes are far less represented.

Impacts of environmental change on biodiversity and vegetation dynamics in Siberia.

Biological diversity is the basis for, and an indicator of biosphere integrity. Together with climate change, its loss is one of the two most important planetary boundaries. A halt in biodiversity loss is one of the UN Sustainable Development Goals.

The multi-photon induced Fano effect.

The ordinary Fano effect occurs in many-electron atoms and requires an autoionizing state. With such a state, photo-ionization may proceed via pathways that interfere, and the characteristic asymmetric resonance structures appear in the continuum. Here we demonstrate that Fano structure may also be induced without need of auto-ionization, by dressing the continuum with an ordinary bound state in any atom by a coupling laser.

Features of Measuring Low CO Concentrations in N-Containing Mixtures at Different Temperatures Using Spontaneous Raman Spectroscopy.

Raman spectroscopy is a promising tool for combustion processes optimization, due to the possibility of rapid determination of the exhaust gases composition. An important gas component in this task is carbon monoxide whose emission limits vary from 100 to 200 parts per million (ppm), depending on the heat generator technology. However, for the correct determination of its concentration from the sample Raman spectrum, it is necessary to take into account the contribution of nitrogen lines intensity due to their mutual overlap.

First Full-Dimensional Potential Energy and Dipole Moment Surfaces of SF.

A 15-dimensional analytical form for the potential energy and dipole moment surfaces of the SF molecule in the ground electronic state is obtained using methods. In order to calculate the equilibrium S-F distance, we applied the coupled cluster CCSD(T) method and several versions of the correlation-consistent basis sets from valence triple-zeta (VTZ) and augmented valence triple-zeta (AVTZ) to core-valence quadruple-zeta (CVQZ) with Douglas-Kroll (DK) relativistic corrections that provided good agreement with an empirical equilibrium value. electronic energies on 15D grids of nuclear geometries are computed using the CCSD(T) method with VTZ and CVQZ-DK basis sets.

New artificial network model to estimate biological activity of peat humic acids.

Purpose: This article focuses on new method to estimate biological activity of peat humic acids (HAs) using artificial neural network (ANN) to process spectroscopic measurements in infrared and visible ranges. Conventional approaches generally rely on biological models and direct detection of chemical substances related to bioactivity. These methods proved to be accurate and reliable, but at the expense of speed and simplicity.