Optimal Integration of Photovoltaic Sources in Distribution Networks for Daily Energy Losses Minimization Using the Vortex Search Algorithm

This paper deals with the optimal siting and sizing problem of photovoltaic (PV) generators in electrical distribution networks considering daily load and generation profiles. It proposes the discrete-continuous version of the vortex search algorithm (DCVSA) to locate and size the PV sources where the discrete part of the codification defines the nodes. Renewable generators are installed in these nodes, and the continuous section determines their optimal sizes. In addition, through the successive approximation power flow method, the objective function of the optimization model is obtained. This objective function is related to the minimization of the daily energy losses. This method allows determining the power losses in each period for each renewable generation input provided by the DCVSA (i.e., location and sizing of the PV sources). Numerical validations in the IEEE 33- and IEEE 69-bus systems demonstrate that: (i) the proposed DCVSA finds the optimal global solution for both test feeders when the location and size of the PV generators are explored, considering the peak load scenario. (ii) In the case of the daily operative scenario, the total reduction of energy losses for both test feeders are 23.3643% and 24.3863%, respectively; and (iii) the DCVSA presents a better numerical performance regarding the objective function value when compared with the BONMIN solver in the GAMS software, which demonstrates the effectiveness and robustness of the proposed master-slave optimization algorithm.

Evidence of Carboniferous arc magmatism preserved in the Chicxulub impact structure

Determining the nature and age of the 200-km-wide Chicxulub impact target rock is an essential step in advancing our understanding of the Maya Block basement. Few age constraints exist for the northern Maya Block crust, specifically the basement underlying the 66 Ma, 200 km-wide Chicxulub impact structure. The International Ocean Discovery Program-International Continental Scientific Drilling Program Expedition 364 core recovered a continuous section of basement rocks from the Chicxulub target rocks, which provides a unique opportunity to illuminate the pre-impact tectonic evolution of a terrane key to the development of the Gulf of Mexico. Sparse published ages for the Maya Block point to Mesoproterozoic, Ediacaran, Ordovician to Devonian crust are consistent with plate reconstruction models. In contrast, granitic basement recovered from the Chicxulub peak ring during Expedition 364 yielded new zircon U-Pb laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) concordant dates clustering around 334 ± 2.3 Ma. Zircon rare earth element (REE) chemistry is consistent with the granitoids having formed in a continental arc setting. Inherited zircon grains fall into three groups: 400−435 Ma, 500−635 Ma, and 940−1400 Ma, which are consistent with the incorporation of Peri-Gondwanan, Pan-African, and Grenvillian crust, respectively. Carboniferous U-Pb ages, trace element compositions, and inherited zircon grains indicate a pre-collisional continental volcanic arc located along the Maya Block’s northern margin before NW Gondwana collided with Laurentia. The existence of a continental arc along NW Gondwana suggests southward-directed subduction of Rheic oceanic crust beneath the Maya Block and is similar to evidence for a continental arc along the northern margin of Gondwana that is documented in the Suwannee terrane, Florida, USA, and Coahuila Block of NE México.

CALCULATION OF EFFORTS RIPS FOUNDATION BOLTS IN THE BCALCULATION OF EFFORTS RIPS FOUNDATION BOLTS IN THE BASES OF CENTRAL AND ECCENTRIC COMPRESSION COLUMNASES OF CENTRAL AND ECCENTRIC COMPRESSION COLUMN

An engineering technique for calculating the tearing forces in the foundation bolts in the bases of centrally compressed columns is proposed. The calculation of the forces is based on the calculation of extra-centrally compressed rods, taking into account: the influence of the cross-section shape; the initial curvature of the neutral axis of the column; random eccentricity; nonlinear steel work. The calculation of the attachment forces (Nult and Mfic) of columns on the foundation edge is based on the method of practical calculations of centrally compressed elements using the stability coefficients at central compression φ (longitudinal bending coefficients), which are calculated depending on the flexibility l. The calculation of the attachment forces for rods with different reduced flexibility was performed by FEM in the FEMAP software package, as well as analytically using fictitious forces in centrally compressed rods. To calculate the tearing forces in the foundation bolts, a calculation model is made taking into account the contact interaction of the base and the reinforced concrete base. Graphs of the effect of the flexibility of the centrally compressed rod on the tearing force in the foundation bolts at the stage of exhaustion of the bearing capacity of the column when calculating its stability as an element of a continuous section under central compression are constructed.

Constructing smooth and fully faithful tropicalizations for Mumford curves

The tropicalization of an algebraic variety X is a combinatorial shadow of X, which is sensitive to a closed embedding of X into a toric variety. Given a good embedding, the tropicalization can provide a lot of information about X. We construct two types of these good embeddings for Mumford curves: fully faithful tropicalizations, which are embeddings such that the tropicalization admits a continuous section to the associated Berkovich space $$X^{{{\,\mathrm{an}\,}}}$$ X an of X, and smooth tropicalizations. We also show that a smooth curve that admits a smooth tropicalization is necessarily a Mumford curve. Our key tool is a variant of a lifting theorem for rational functions on metric graphs.

New data of vegetation development of North Baikal area in the Middle-Late Holocene

For the first time, a continuous section of peat was obtained from the hard-to-reach mid-mountain North-Western part of the lake Baikal. The material was studied by methods of spore-pollen analysis, analysis of plant cell residues and radiocarbon Dating (data calibrated). The least identified in the Holocene speed of peat accumulation in the Baikal area. According to the calculated sedimentation rates, the temporal resolution of the study ranges from 100 years at the bottom of the incision to 800 years at the top. With a factor analysis identified six local pallinson and five Botanic zones. Changes in the vegetation cover and ecotope moisture conditions for 7670 years were reconstructed. For the first time in a quarter of a century, the height of the upper forest boundary has been clarified.

Study of rollers thermal state at hot rolling of long products profiles at 370/150 mill of OJSC “Belorussky steel-works – UKKh “Belorusskaya metallurgical company”

In the rolling production, rolls with box passes are widely used, which is explained by the best gripping ability and high draw ratio. However, along with these advantages, there are significant drawbacks - the formation of an erosion net along the bottom of the pass and side cracks on the side outlets, since hot rolling of metals and alloys is accompanied by intense wear of the working rollers and welding fixtures, which happens due to exposure to high temperatures and stresses. Therefore, the task of elaboration of rational temperature regime to provide not only stable mill operation, but also high rollers endurance, is rather actual and requires its solution. It is very important to follow the today’s trend to increase continuous mills rolling speed, which will result in still heavier temperature conditions of rollers operation. Results of the study of the rolling process main technological parameters influence on the formation of erosion net across the bottom of the pass presented, as well as magnitude and nature of the distribution of thermal cyclic stresses along the surface layers of the bottom of pass. Study of the thermal state of roughing stands rollers of OJSC “Belorussky steel-works” 370/150 continuous wire-rod mill show, that comparing with intermediate and finished stands rollers they subject more to thermo-cyclic destruction of passes surface, but not to mechanical one. As a result of the computer simulation new data obtained on the character and peculiarities of dynamics of surface thermal state of rollers passes. The possibilities to reduce thermal cyclic stresses by improving the cooling regime of the rolls shown. Using the simulation by the finite elements method, the study of the dynamics of heating and stress state of the surface and subsurface layers of the pass bottom was accomplished. Based on the analysis results of numerical experiments and analytical calculations, isotherms of the surface layers of the bottom of the pass were compiled to select the optimal cooling mode. The data obtained can be used to control the cooling systems of roughing stands rollers of continuous section and pipe hot rolling mills.

CALCULATION OF THREE-LAYER LARGE DIAMETER PIPES ON THE PC «LIRA»

ObjectivesThis article discusses the evaluation of the possibility of application of three-layer pipelines. For this purpose, the stress-strain state of three-layer pipes under the action of internal pressure is investigated. The largest in the modern world are considered to be the main pipewater. They are mainly used to transport oil and gas from production sites to processing plants. Pipelines are intended for movement of liquid, gases and other environments and first of all it is water pipelines. As you know, main and technological pipelines are IP-elite club that cares only metal buildings, the construction of which consume Xia millions of tons of steel. On the other hand, one of the main indicators of efficiency of trunk pipelines is their material consumption. As a rule, trunk pipelines have a long length, and therefore an unreasonable increase in the even thickness of the pipe walls by at least 1 mm leads to an overspending of steel by de-siyatki and even hundreds of thousands of tons. In this regard, to the calculations of the main pipe wires for strength should be given the most serious attention.MethodsThe calculation is carried out by numerical methods, namely with the help of finite element meto-da (FEM), implemented in the PC "LIRA".ResultsThe calculation of the pipes is performed on the load from the transported medium applied to the inner contour of the pipe. In this case, for the three-layer pipe (the first option) and for the pipes of the second and third options, the ring tensile stresses and strains were determined. The isofields of tensile and shear stresses are given, the comparative graphical dependence of ring tensile stresses is constructed.Conclusion.The obtained numerical results showed that the selected calculation scheme (var.1), that is, the representation of the continuous section of the pipe in the form of a three-layer, is correct. The discrepancies between the data obtained are related to the rotation of the section along the radius of the pipe. In General, the results of calculations showed the possibility of using a three-layer pipe wall for transportation of various media.Acknowledgment.This work was supported by a grant from the President of the Russian Federation (MK-6112.2018.8)

New biocenosis model of Vendian (Ediacaran) sedimentation basin of Podilia (Ukraine)

The aim of this study is to fully research all aspects of the distribution, development, conditions of burial and preservation of the Ediacaran biocomplex. Thiswork summarizes and extends all data on the unique Vendian invertebrates that are distributed in the natural and artificial outcrops of the Dniester River Basin within Podilia (Ukraine). One of the basic locations of the annual observation was a quarry of rubble stone production near the Dniester hydroelectric station-1, Novodnistrovsk city, which exposes a continuous section of the deposits of the Lomoziv, Yampil, Lyadova and Bernashivka Beds lying on a crystalline basement. This paper shows the outcomes of long-term fieldwork of the Upper Ediacaran which include deposits of the Mogyliv-Podilsky and Kanylivka Group. The researched section is characterized by its clastic composition and the absence of carbonate formations. The basic paleontological collection has more than two thousand specimens, for instance, the imprints of molluscous fauna, traces of their live activity, the remains of flora and fossils of a problematic nature. The most numerous and informative collection of these fossils is located in the stock of the Geological Museum of the Taras Shevchenko National University of Kyiv. The collection contains unique material, including a number of Ediacaran fossils described for the first time. On the whole within Podilia region, more than 100 species have been described in detail. The main areas of biota accumulation in the outcrops are associated with argillites, argillite-siltstones and their contact with sandstones. The best preservation of the imprints is detected in the boundary of facial transitions. Research has revealed that there is a decrease in the numerical and species composition of the molluscous biota, and the dynamic increase in evolution of burrowing organisms and plants within the Podilia Basin during the late Vendian. Such a phenomenon led to an environmental change, increase in oxygen and appearance of new groups of organisms that were subsequently displaced invertebrates. This occurred at the Precambrian/Cambrian transition, and in the geological literature is described as the «Cambrian explosion». Studies have found that the total number of taxonomic composition of the Eidacaran in Podilia is similar to the orictocoenosis of Southern Australia and the White Sea. Nevertheless, the Podilia biocomplex is more ancient than the Southern Australian and the White Sea, it is much younger than the Avallonian.