185 research outputs found
CALCULATION OF MATRIX CORRESPONDENCE WITH THE USE OF PARALLEL COMPUTING TECHNOLOGIES
Increasing the number of vehicles has led to urban congestion, many hours of traffic jams, obstruction of pedestrian traffic, increase the number of accidents, etc. Therefore, the importance of gaining the optimum network planning, improved traffic management, optimization of the system of public transport routes. The solution of such problems is impossible without mathematical modeling of traffic flows. An important task of modeling is to calculate the trip distribution. In this paper, we develop a program for calculating trip distribution using parallel computing technologies. The application of these technologies will improve the efficiency of simulation, increase accuracy and speed of the algorithm
Oil Production and Carbon Emissions: Spline Analysis of Relationships
Obviously, the dynamics of carbon dioxide emissions depends on the volume and structure of consumption of primary energy resources in the economy. The world’s energy consumption shows a growth trend temporarily interrupted during times of economic crisis. The most noticeable decrease in energy consumption in modern history occurred in 2020, which was due to a decline in business activity in the world due to the COVID-19 pandemic. This caused a decrease in carbon emissions (by more than 6% compared to 2019). In the structure of primary energy sources, the largest reduction was in oil consumption. The paper examines the impact of economic crises on the evolution of the mutual link between the dynamics of oil production and carbon dioxide emissions in the world. To detect correlations in local time regions, it is proposed to interpolate process dynamics with cubic splines. Using this toolkit avoids the limitations of classical econometrics on the length of time series. The differentiability of the built spline models allowed us to move on to identifying and analyzing latent correlations in fluctuations in the instantaneous growth rate of oil production volumes and carbon emissions
Macro-Regional Analysis of the Carbon Intensity of the Economy
Achieving the Sustainable Development Goals formulated by the UN is one of the priorities of modern economic policy. At the same time, its implementation should take into account the macro-regional specifics. Without this kind of accounting, due to the emerging imbalances, it will not be possible to ensure the sustainability of development. One of the components of sustainable development is the decarbonization of the economy. The purpose of the study: macro-regional analysis of the mutual impact of energy consumption, carbon dioxide emissions and economic growth trends. At a time when ensuring sustainable economic growth is an important task of economic policy, improving energy efficiency turns out to be a key factor in reducing carbon emissions. Research methods: dynamics analysis, structure analysis, methods of comparative analysis and generalization. The article studies the dynamics of changes in the carbon intensity of GDP on the example of two countries with the largest economies — the United States and China. The analysis showed that macro-regions with a high level of technological development manage to reduce carbon dioxide emissions more intensively, while ensuring economic growth
Modified high-strength concrete with the addition of CONPLAST SP430
In most high-strength concrete technologies, high-quality Portland cements are used, which is not always achievable in conditions of a shortage of such binders.
The research’s purpose is to obtain high-strength concrete based on ordinary Portland cement of the M400 brand. To achieve this goal, the possibility of using the superplasticizer Conplast SP430 was studied.
The research was carried out using standard methods, like using mathematical planning and result’s analytical processing.
The implementation of the experiment allowed us to determine the optimal values of the basic composition of concrete: the consumption of superplasticizer-1.0 % of the mass of cement; the consumption of cement-485 kg/m3, the ratio of sand/crushed stone-0.36. At the optimal value of the parameters, the achieved maximum compressive strength was 58.8 MPa.
The novelty is the justification of the possibility of obtaining high-strength concretes using Portland cement with an activity not exceeding 40 MPa based on the use of a new generation superplasticizer and the development of the basics of the method for selecting the composition of concrete.
The significance of the result is due to the expansion of the possibility of using ordinary Portland cement for the production of products and structures with the use of high-strength concrete
The Endocannabinoid System and Oligodendrocytes in Health and Disease
Cannabinoid-based interventions are being explored for central nervous system (CNS) pathologies such as neurodegeneration, demyelination, epilepsy, stroke, and trauma. As these disease states involve dysregulation of myelin integrity and/or remyelination, it is important to consider effects of the endocannabinoid system on oligodendrocytes and their precursors. In this review, we examine research reports on the effects of the endocannabinoid system (ECS) components on oligodendrocytes and their precursors, with a focus on therapeutic implications. Cannabinoid ligands and modulators of the endocannabinoid system promote cell signaling in oligodendrocyte precursor survival, proliferation, migration and differentiation, and mature oligodendrocyte survival and myelination. Agonist stimulation of oligodendrocyte precursor cells (OPCs) at both CB1 and CB2 receptors counter apoptotic processes via Akt/PI3K, and promote proliferation via Akt/mTOR and ERK pathways. CB1 receptors in radial glia promote proliferation and conversion to progenitors fated to become oligodendroglia, whereas CB2 receptors promote OPC migration in neonatal development. OPCs produce 2-arachidonoylglycerol (2-AG), stimulating cannabinoid receptor-mediated ERK pathways responsible for differentiation to arborized, myelin basic protein (MBP)-producing oligodendrocytes. In cell culture models of excitotoxicity, increased reactive oxygen species, and depolarization-dependent calcium influx, CB1 agonists improved viability of oligodendrocytes. In transient and permanent middle cerebral artery occlusion models of anoxic stroke, WIN55212-2 increased OPC proliferation and maturation to oligodendroglia, thereby reducing cerebral tissue damage. In several models of rodent encephalomyelitis, chronic treatment with cannabinoid agonists ameliorated the damage by promoting OPC survival and oligodendrocyte function. Pharmacotherapeutic strategies based upon ECS and oligodendrocyte production and survival should be considered
Pilot tests of a catalyst for the selective hydrogenation of acetylene
Pilot tests of SGA-2M promoted Pd/Al2O3 catalyst in the selective hydrogenation of acetylene are performed on an industrial ethane-ethylene fraction in a system of two serially arranged adiabatic flow reactors. The optimum process conditions under which the conversion of acetylene reaches 100% at a selectivity of 68.2% with respect to ethylene are determined: system pressure, 21 atm; hydrocarbon feedstock hourly space velocity (HSV), 1500 h-1, carbon monoxide concentration, 7 ppm; H2: C 2H2 molar ratio at the first and second hydrogenation stages, 1.0: 1.0 and 1.4: 1.0; inlet temperature of the first and second reactors, 40 and 55 C, respectively. The interregeneration service life of the SGA-2M catalyst under optimum conditions is estimated at 12 months. SGA-2M catalysts can be recommended for purifying ethane-ethylene fractions containing up to 2 vol % of acetylene. © 2013 Pleiades Publishing, Ltd
Effect of promotion with cobalt or zinc on the hydrogenating and oligomerizing activities of the Pd/Al2O3 catalyst in the hydrogenation of the BTX fraction
The promoter nature and content effects on the catalytic activity and stability of Pd-Co/δ-Al2O3 and Pd-Zn/δ-Al 2O3 bimetallic catalysts in the hydrogenation of dienic and vinyl aromatic hydrocarbons in the BTX fraction have been investigated by IR spectroscopy and temperature-programmed reduction. The Pd: Co (Zn) molar ratio in the catalysts prepared is 1.0: 0.5, 1.0: 1.0, or 1.0: 1.5, and their Pd content is 0.5 wt %. The support is δ-Al2O3 doped with sodium (0.5 wt %). Promotion of the palladium catalyst with zinc and cobalt causes the disappearance of cationic palladium species, thereby reducing the oligomerizing capacity of the active component, and, as was demonstrated by 100-h-long catalytic tests, enhances the stability of the catalyst. The Pd-Co/δ-Al2O3(Na) catalyst with Pd: Co = 1.0: 1.0 mol/mol is recommended for the hydrogenation of the BTX fraction under industrial conditions. The expected service life of this catalyst between regenerations is 16 months. © 2013 Pleiades Publishing, Ltd
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