A mathematical model of the vertical dual-mass hydroimpulsive mechanism

In this paper, the model of a hydroimpulsive mechanism for boring machines was presented. Differential equations describing the processes occurring in the mechanism were derived

Relevant issues on quality evaluation of petroleum pipeline preparation for oil product transportation

This article discusses the issue of assessment of the quality of petroleum pipeline preparation for light oil product transportation. The need to implement appropriate measures is conditioned by the requirement to maintain the quality of oil products during their transportation. We identified vulnerable indicators, which are most prone to change if oil products contact with asphaltene-resin-paraffin deposits remaining in the pipeline, as well as estimated probability of failures and emergencies if off-spec oil products are used in automotive and aviation equipment. The scope of the article includes considering variants of technical solutions for the cleanup of the line part of petroleum pipelines and process pipelines of oil pumping stations from asphaltene-resin-paraffin deposits using specially selected chemical reagents and the methodology for assessing the quality of their preparation for oil product transportation. We considered the order of estimation of the possible volume of off-spec oil products formed as a result of the oil product’s contact with residues of the cleanup products and chemical reagents located in the cavity of the pipeline and provided the results of the implementation of technical solutions to ensure the quality of petroleum pipeline cleanup at the facilities of PJSC Transneft repurposed for oil product transportation in 2014–2017

THE EFFECT OF MECHANICAL IMPACT OF HIGH ENERGY ON THE STRUCTURAL PROPERTIES OF BROWN COAL AND THE REACTIVITY FOR LIQUEFACTION

ABSTRACT The effect of preliminary mechanical activation in the energy-intensive mill-activator on the structural and chemical transformations of brown coals and their reactivity in contact with solvents has been established. Mechanical treatment of the brown coals from Kansk-Achinsk Basin was performed in a high-energy AGO-2 centrifugal planetary ball mill. Mechanical activation led to a partial destruction of the supramolecular structure of coal, reduction of the crosslinking degree of nano-sized polyaromatic clusters in the organic matter coal. This results in the increased reactivity of coal in the liquefaction processes (extraction and hydrogenation) to form liquid products

Solid Energetic Material Based on Aluminum Micropowder Modified by Microwave Radiation

The paper discusses the application of pulsed microwave radiation for the modification of crystalline components of a high-energy material (HEsM). The model aluminized mixture with increased heat of combustion was studied. The mixture contained 15 wt.% aluminum micron powder, which was modified by microwave irradiation. It was found that the HEM thermogram has an exo-effect with the maximum at 364.3 °C. The use of a modified powder in the HEM composition increased the energy release during combustion by 11% from 5.6 kJ/g to 6.2 kJ/g. The reason for this effect is the increase in the reactivity of aluminum powder after microwave irradiation. In this research, we confirmed that the powders do not lose the stored energy, even as part of the HEM produced on their basis. A laser projection imaging system with brightness amplification was used to estimate the speed of combustion front propagation over the material surface. Measurement of the burning rate revealed a slight difference in the burning rates of HEMs based on irradiated and non-irradiated aluminum micropowders. This property can be demanded in practice, allowing a greater release of energy while maintaining the volume of energetic material

mRNA Secondary Structures Fold Sequentially But Exchange Rapidly In Vivo

Self-cleavage assays of RNA folding reveal that mRNA structures fold sequentially in vitro and in vivo, but exchange between adjacent structures is much faster in vivo than it is in vitro

Phenological shifts of abiotic events, producers and consumers across a continent

Ongoing climate change can shift organism phenology in ways that vary depending on species, habitats and climate factors studied. To probe for large-scale patterns in associated phenological change, we use 70,709 observations from six decades of systematic monitoring across the former Union of Soviet Socialist Republics. Among 110 phenological events related to plants, birds, insects, amphibians and fungi, we find a mosaic of change, defying simple predictions of earlier springs, later autumns and stronger changes at higher latitudes and elevations. Site mean temperature emerged as a strong predictor of local phenology, but the magnitude and direction of change varied with trophic level and the relative timing of an event. Beyond temperature-associated variation, we uncover high variation among both sites and years, with some sites being characterized by disproportionately long seasons and others by short ones. Our findings emphasize concerns regarding ecosystem integrity and highlight the difficulty of predicting climate change outcomes. The authors use systematic monitoring across the former USSR to investigate phenological changes across taxa. The long-term mean temperature of a site emerged as a strong predictor of phenological change, with further imprints of trophic level, event timing, site, year and biotic interactions.Peer reviewe

Chronicles of nature calendar, a long-term and large-scale multitaxon database on phenology

We present an extensive, large-scale, long-term and multitaxon database on phenological and climatic variation, involving 506,186 observation dates acquired in 471 localities in Russian Federation, Ukraine, Uzbekistan, Belarus and Kyrgyzstan. The data cover the period 1890-2018, with 96% of the data being from 1960 onwards. The database is rich in plants, birds and climatic events, but also includes insects, amphibians, reptiles and fungi. The database includes multiple events per species, such as the onset days of leaf unfolding and leaf fall for plants, and the days for first spring and last autumn occurrences for birds. The data were acquired using standardized methods by permanent staff of national parks and nature reserves (87% of the data) and members of a phenological observation network (13% of the data). The database is valuable for exploring how species respond in their phenology to climate change. Large-scale analyses of spatial variation in phenological response can help to better predict the consequences of species and community responses to climate change.Peer reviewe

Supplement: "Localization and broadband follow-up of the gravitational-wave transient GW150914" (2016, ApJL, 826, L13)

This Supplement provides supporting material for Abbott et al. (2016a). We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the different bands