Localization of the gamma-radiation sources using the gamma-visor

The search of the main gamma-radiation sources at the site of the temporary storage of solid radioactive wastes was carried out. The relative absorbed dose rates were measured for some of the gamma-sources before and after the rehabilitation procedures. The effectiveness of the rehabilitation procedures in the years 2006-2007 was evaluated qualitatively and quantitatively. The decrease of radiation background at the site of the temporary storage of the solid radioactive wastes after the rehabilitation procedures allowed localizing the new gamma-source

Area of effective catch of crab traps in the northwestern part of the Tartar Strait

Japanese cone-shaped traps for crabs are calibrated with the data of trawl survey in the northwestern Tartar Strait. The 100 % effective catch area for each trap in the order does not exceed 665 m2 for spiny crab, 1513 m2 for king crab, 3811 m2 for horsehair crab, and 4019 m2 for tanner crab opilio. Unification of methods for the stock assessment by trap surveys is discussed

Analytical dependence of burnup on enrichment of prospective fuel and parameters of reactors fuel campaign

The paper is devoted to the definition of an analytical expression for estimating the burnup depth of nuclear fuel depending on its enrichment level, the periodicity of refueling, thermal stressthermal stress and the duration of the time period between refueling (reactor campaign) in a wide range of changes in key parameters for different types of thermal neutron reactors. The analytical expressions obtained in the work for the burnup depth are compared with numerous neutron physics calculations and experimental data from different authors for uranium fuel enrichment up to 9%. Calculations of the fuel share of the cost of electricity of nuclear power plants with PWR type reactors were performed and its sensitivity to changes in burnup depth and enrichment of fuel, the refueling periodicity, as well as to market prices for natural uranium, conversion, enrichment, fabrication of fuel assemblies and SNF handling were determined

Calculation of the cost of enriched uranium products in multi-stream cascades of enrichment process

Modern uranium enrichment facilities can simultaneously use several raw materials as feed, including natural uranium, regenerated uranium obtained as a result of SNF reprocessing, or depleted uranium (all in the form of uranium hexafluoride). As the output of the separating cascade, several types of enriched uranium product with different levels of enrichment can be fabricated simultaneously. The paper proposes a methodology, absent in literature, for calculating the cost of each enriched uranium product in multi-stream separating cascades. The proposed methodology uses standard definitions of the isotopic value of feed and product stream and the Peierls-Dirac separation potential. Numerical calculations of the cost of enriched uranium products for three production problems are provided as examples of the methodology effectiveness: 1) involvement of depleted uranium hexafluoride (DUHF) in fabrication of enriched uranium product; 2) simultaneous fabrication of two enriched products; 3) use of depleted uranium to reduce the cost of the product with a higher enrichment level out of two (as applied, e.g., to advanced tolerant fuel). It has been shown that partial additions of DUHF as feed for a multi-product separating cascade make it possible to reduce the cost of a product with a higher level of enrichment; with the current market prices for natural uranium and separative work, there is a range of tails assays in which it is more profitable to enrich DUHF rather than natural uranium

Analytical dependence of burnup on enrichment of prospective fuel and parameters of reactors fuel campaign

The paper is devoted to the definition of an analytical expression for estimating the burnup depth of nuclear fuel depending on its enrichment level, the periodicity of refueling, thermal stressthermal stress and the duration of the time period between refueling (reactor campaign) in a wide range of changes in key parameters for different types of thermal neutron reactors. The analytical expressions obtained in the work for the burnup depth are compared with numerous neutron physics calculations and experimental data from different authors for uranium fuel enrichment up to 9%. Calculations of the fuel share of the cost of electricity of nuclear power plants with PWR type reactors were performed and its sensitivity to changes in burnup depth and enrichment of fuel, the refueling periodicity, as well as to market prices for natural uranium, conversion, enrichment, fabrication of fuel assemblies and SNF handling were determined

Effect of Alkoxy Substituents on the Regioselectivity of Catalytic C-H Activation in Benzoic Acids: Experimental and DFT Study

This work demonstrates the influence of the catalyst and alkyne nature on the regioselectivity of rhodium-catalyzed annulation of alkoxy-substituted benzoic acids (such as 3-methoxybenzoic, 3,4-dimethoxybenzoic, and piperonylic acids) with alkynes. Here, X-ray diffraction and DFT calculation data gave evidence that the observed regioselectivity is provided by both steric and coordination effects of methoxy groups. The latter is the result of weak non-covalent C–H⋯O interactions with the supporting ligand rather than with the rhodium atom. We believe that these results are also valid for other reactions of the C-H activation of methoxy-substituted arene compounds

Analysis of Theory and Practice of Evaluation of the Influence of the Results of the Modernization of Weapons and Military Equipment on the Combat Possibilities of the Armed Forces of the Armed Forces of Ukraine

Significant changes in the military-political, socio-economic and demographic state of Ukraine that have occurred in recent years have caused the need to develop new approaches to ensuring its national security, including the definition and clarification of: the tasks of the Armed Forces, their role and place in the structure the security and defense sectors of Ukraine; scientifically substantiated goals of reforming the Armed Forces; the composition and structure of the services of the Armed Forces, combat arms and special forces, which can optimally ensure armed protection of national interests, territorial integrity of Ukraine; a cost estimate of the costs required to implement plans to reform the Armed Forces and to maintain them at the required level of combat and mobilization readiness; the economic capabilities of the state to meet the needs of the Armed Forces, which are due to the need to solve the tasks assigned to them, and the like. One of the main issues of the further development of the Armed Forces of Ukraine today is the quality and completeness of the solution to the issues of military-technical policy. The degree of implementation of which directly affects the state and technical equipment of the Armed Forces and depends on many components that create both positive and negative effects on the state and further development of the Armed Forces. The main role in this process is played by the financing of the needs of the Armed Forces of Ukraine in the required volume, as well as the scientific substantiation of medium-term and long-term plans for the development of weapons and military equipment. When developing them, it is necessary to be based on the needs of ensuring the required level of defense capability by finding the optimal balance between the defensive needs and economic capabilities of the state, on the one hand, and the combat and technical characteristics of weapons and military equipment, on the other hand. It is on the state of financing of defense needs that the degree of fulfillment of the tasks of equipping the Armed Forces of Ukraine with the latest or modernized models of weapons and military equipment depends. This raises the problem of finding the most optimal (expedient), from a military and economic point of view, ways to provide the Armed Forces of Ukraine with samples of weapons and military equipment. The authors in the article present the results of the analysis of the theory and practice of assessing the impact of the results of modernization of weapons and military equipment on the combat capabilities of military formations, as well as the factors that affect them. The analysis was carried out in the following areas: analysis and assessment of the impact of modernization on the level of combat capabilities of a military formation; analysis of the modernization of the Armed Forces of Ukraine; analysis of the existing methodological apparatus for determining the requirements for quantitative and qualitative characteristics in the modernization of weapons and military equipment. Based on the results obtained, the authors have proposed a number of recommendations for further research on improving the combat capabilities of the Armed Forces of Ukraine, taking into account the results of modernization of weapons and military equipment in the formation of medium-term and long-term development programs

4-(Aryl)-Benzo[4,5]imidazo[1,2-<i>a</i>]pyrimidine-3-Carbonitrile-Based Fluorophores: Povarov Reaction-Based Synthesis, Photophysical Studies, and DFT Calculations

A series of novel 4-(aryl)-benzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles were obtained through the Povarov (aza-Diels–Alder) and oxidation reactions, starting from benzimidazole-2-arylimines. Based on the literature data and X-ray diffraction analysis, it was discovered that during the Povarov reaction, [1,3] sigmatropic rearrangement leading to dihydrobenzimidazo[1,2-a]pyrimidines took place. The structures of all the obtained compounds were confirmed based on the data from 1H- and 13C-NMR spectroscopy, IR spectroscopy, and elemental analysis. For all the obtained compounds, their photophysical properties were studied. In all the cases, a positive emission solvatochromism with Stokes shifts from 120 to 180 nm was recorded. Aggregation-Induced Emission (AIE) has been illustrated for compound 6c using different water fractions (fw) in THF. The compounds 6c and 6f demonstrated changes in emission maxima or/and intensities after mechanical stimulation