GRB 221009A, The BOAT

GRB 221009A has been referred to as the Brightest Of All Time (the BOAT). We investigate the veracity of this statement by comparing it with a half century of prompt gamma-ray burst observations. This burst is the brightest ever detected by the measures of peak flux and fluence. Unexpectedly, GRB 221009A has the highest isotropic-equivalent total energy ever identified, while the peak luminosity is at the $\sim99$th percentile of the known distribution. We explore how such a burst can be powered and discuss potential implications for ultra-long and high-redshift gamma-ray bursts. By geometric extrapolation of the total fluence and peak flux distributions GRB 221009A appears to be a once in 10,000 year event. Thus, while it almost certainly not the BOAT over all of cosmic history, it may be the brightest gamma-ray burst since human civilization began.Comment: Resubmitted to ApJ

Optimization of the organizational and technological models of the construction and installation works according to the criterion of minimum duration

Due to the organizational and technological project, the selection of the optimal parameters of technological processes can be based on the results of numerical modeling of various options for the production of construction and installation works. The aim of this study is determination of the optimal sequence of construction and installation work by modeling the selection of options for the production of works. Research methods include analysis, description, measurement and comparison, as well as the application of scientific knowledge in the theory and practice of building network models. The modeling of the various scenarios of the construction and installation works allows efficient use of the resources, based on such network models. The project scheduling by formalizing a path-float-based approach was analyzed. As a result of the analysis of models of organizational and technological design of construction production, it was established that on their basis it is possible to control the temporal characteristics of both individual and complex work performed. In our research, the extended network model of the object in construction with the dependency "finish-start" was applied. One of the important tasks is to ensure the total duration of the construction during the scheduling

Determination of the optimal option for production of the convex cost function

The choice of the optimal option for the production of in the construction of buildings and structures is based on a preliminary generalization and analysis of the most promising options for the implementation of construction and installation from which the most rational optimal in the is selected conditions under consideration. The purpose of the study is to determine the optimal option for production of at the convex cost function. We used the method of the determination of costs on the duration of works, represented by a convex function showing the shorter the duration of the project the more costs are required when it is reduced by the same amount. The key parameters affecting the final result of construction are the duration cost and quality of performed. Consequently, one of the main tasks is to draw up a works schedule with close coordination of the resources necessary for their implementation. To do this we have to solve problems associated with the distribution of limited resources. In this case, the technological interdependence between the works performed, which may be of a different nature, should be taken into account. As the results, new approaches were founded to developing a strategy for the selection of options for construction and installation works in order to ensure contractual deadlines for their implementation and minimize the funds spent on their implementation taking into account the nature of the dependencies between the works performed is an urgent and important problem

Cyclobutene ring-opening of bicyclo[4.2.0]octa-1,6-dienes: access to CF3-substituted 5,6,7,8-tetrahydro-1,7-naphthyridines.

International audienceAn efficient method for the synthesis of novel CF(3)-substituted tetrahydro-1,7-naphthyridines including cyclic α-amino acid derivatives has been developed. The method is based on unusual cyclobutene ring-opening of bicyclo[4.2.0]octa-1,6-dienes with pyrrolidine to afford the corresponding 1,5-diketones followed by their heterocyclization. A convenient one-pot procedure has been also elaborated starting from readily available trifluoromethylated 1,6-allenynes

Investigation of Integral and Differential Characteristics of Variatropic Structure Heavy Concretes by Ultrasonic Methods

The article develops methods and methodology for experimental studies of centrifuged and vibro-centrifuged concrete products of annular cross-section. They assess the real variatropy of the structure and confirm the correctness of the accepted research. An original technique for experimental studies of the variatropy of the cross-sections of vibrated, centrifuged and vibro-centrifuged concretes is proposed to determine their integral (common) and differential (differing in layers) strength and strain characteristics and deformation diagrams. It has been proved that with vibro-centrifugation it becomes possible to obtain concretes with improved structure and higher characteristics compared with centrifugation and vibration techniques. Experimental studies of the differential characteristics of centrifuged and vibro-centrifuged concretes under compression and tension revealed that the outer layer of concrete had the best characteristics after centrifugation and vibro-centrifugation, and the inner layer had the worst ones. The three-layer model of the variatropic structure for centrifuged and vibro-centrifuged concrete has been experimentally confirmed. The concrete of the outer layers had the highest strength and modulus of elasticity and the least deformability; the concrete of the inner layers had the lowest strength and modulus of elasticity and the highest deformability; and the concrete of the middle layers had average characteristics. The deformation diagrams of centrifuged and vibro-centrifuged concretes were also differentiated by layers, confirming the variatropy of the structure of such concretes. The deformation diagrams for the outer concrete layer demonstrated the highest strength; the diagrams for the inner concrete layer showed the lowest strength; and the diagrams for the middle concrete layer corresponded to mean characteristics

Cyclobutene Ring-Opening of Bicyclo[4.2.0]octa-1,6-dienes: Access to CF₃‑Substituted 5,6,7,8-Tetrahydro-1,7-naphthyridines

An efficient method for the synthesis of novel CF₃-substituted tetrahydro-1,7-naphthyridines including cyclic α-amino acid derivatives has been developed. The method is based on unusual cyclobutene ring-opening of bicyclo[4.2.0]­octa-1,6-dienes with pyrrolidine to afford the corresponding 1,5-diketones followed by their heterocyclization. A convenient <i>one-pot</i> procedure has been also elaborated starting from readily available trifluoromethylated 1,6-allenynes

The Poly(chloro-p-xylylene)-Ag Metal-Polymer Nanocomposites Obtained by Controlled Vapor-Phase Synthesis for SERS Effect Realisation

Substrates based on the metal-polymer nanocomposites 2,3-dichloro-p-xylylene-silver (PCPX-Ag) that realize the effect of surface-enhanced Raman scattering (SERS) were developed. To obtain nanocomposites, the vapor-phase polymerization method was used (VDP), which makes it possible to control the nanocomposite microstructure. In the process of self-assembly during VDP, nanocomposite films with inclusions of silver particles were formed on the polycore substrates. Silver content varied from 2.5 to 16% vol. The possibility of using such substrates for the detection of low-molecular substances, for example 5,5′-dithiobis- (2-nitrobenzoic acid) (DTNB) analyte, by the SERS method with an enhancement factor of up to 104, was demonstrated. The dependence of the SERS spectra enhancement on the microstructure of the nanocomposite and the silver content was determined. The optical and morphological properties of nanocomposites were also investigated and their dependence on the silver content was shown. It has been demonstrated that the nanocomposite is SERS selective since when working with complex solutions in the presence of high molecular weight substances, signal enhancement was only observed for low molecular weight substances

Cyclobutene Ring-Opening of Bicyclo[4.2.0]octa-1,6-dienes: Access to CF₃‑Substituted 5,6,7,8-Tetrahydro-1,7-naphthyridines

An efficient method for the synthesis of novel CF₃-substituted tetrahydro-1,7-naphthyridines including cyclic α-amino acid derivatives has been developed. The method is based on unusual cyclobutene ring-opening of bicyclo[4.2.0]­octa-1,6-dienes with pyrrolidine to afford the corresponding 1,5-diketones followed by their heterocyclization. A convenient <i>one-pot</i> procedure has been also elaborated starting from readily available trifluoromethylated 1,6-allenynes

Synthesis of functionalized CF3-containing heterocycles via [2,3]-sigmatropic rearrangement and sequential catalytic carbocyclization

International audienceA new efficient access to functionalized CF3-substituted and nitrogen or sulfur-containing heterocycles has been developed directly from diazocompounds CF3C(N2)Z (Z=CO2Me, P(O)(OEt)2). The method is based on the direct selective synthesis of doubly unsaturated substrates followed by metal-mediated carbocylization. The first step has been performed by Cu(II)-catalyzed [2,3]-sigmatropic rearrangement of propargyl- or/and allyl-containing sulfur and nitrogen ylides leading to fluorinated enynes, diolefins, and especially allenynes derivatives. The second step involves their carbocyclization via ring closing metathesis and Pauson-Khand reaction