A polyurethane elastomer was synthesized using oligoethylene adipate, 2,4-diisocyanato-1-methylbenzene, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol, and 2,2′-propane-2,2-diylbis(
p
...-phenyleneoxy)diethanol as a chain extender was synthesized. It was discovered that the resulting polyurethane is amorphous and demonstrates superior properties compared to crystallized counterparts made with 1,4-butanediol or 4,4′-(propane-2,2-diyl)diphenol as a chain extender. These superior properties include hardness, breaking elongation, elasticity, and thermal stability.
Regularities of microbiological effects on the properties of polymers and polymer-composite materials in laboratory and natural conditions are considered. Specific examples show the results and main ...mechanisms of biodegradation under the influence of mold fungi and bacteria. The main disadvantage of domestic and foreign standards for testing polymeric materials for biostability is noted—the impossibility of determining the exact contribution of the action of fungi, bacteria, or other microorganisms to the change in the properties of materials from exposure to moisture, temperature, solar radiation, chemically active substances, and other abiotic environmental factors. Modern methodological approaches are shown that make it possible to perform tests with the reproduction of all aging factors and the exclusion of biological destructors from their composition. To accelerate the identification of biodestructor fungi, a technique for new-generation sequencing of DNA fragments was proposed and a variant of its successful application was considered.
A new polarized neutron interferometry facility at the NCNR Shahi, C.B.; Arif, M.; Cory, D.G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2016, Letnik:
813
Journal Article
Recenzirano
Odprti dostop
A new monochromatic beamline and facility has been installed at the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR) devoted to neutron interferometry in the ...research areas of spin control, spin manipulation, quantum mechanics, quantum information science, spintronics, and material science. This facility is possible in part because of advances in decoherence free subspace interferometer designs that have demonstrated consistent contrast in the presence of vibrational noise; a major environmental constraint that has prevented neutron interferometry from being applied at other neutron facilities. Neutron interferometry measures the phase difference between a neutron wave function propagating along two spatially separated paths. It is a practical example of self interference and due to its modest path separation of a few centimeters allows the insertion of samples and macroscopic neutron spin rotators. Phase shifts can be caused by gravitational, magnetic and nuclear interactions as well as purely quantum mechanical effects making interferometer a robust tool in neutron research. This new facility is located in the guide hall of the NCNR upstream of the existing Neutron Interferometry and Optics Facility (NIOF) and has several advantages over the NIOF including higher incident flux, better neutron polarization, and increased accessibility. The long term goal for the new facility is to be a user supported beamline and makes neutron interferometer more generally available to the scientific community. This paper addresses both the capabilities and characteristics of the new facility.
This article is devoted to the problems of business processes optimization by value engineering (FCA) method. The business processes analysis is particularly relevant in modern conditions. The ...purpose the investigation is to adapt the value engineering to the business process. The FCA is a universal and highly efficient method of parameters optimization and other structural, technological, organizational, economic characteristics of a product, work or services. The hypothesis of the applying a value engineering to a business process possibility is considered. The article discusses FCA tools as an example of a metal rolling business delivery process. A business process model is being constructed as an object structural element model. The functions decomposition is carried out. Functions are classified into basic and auxiliary on the basis of the level. In the article the significance and functional costs are determined. A functional-cost diagram is constructed to identify the functions with the most deviations needing improvement. The FCA stages are accompanied by graphical illustrations, tables that illustrate the logic of applying the method to the business process. As a result, an optimal business-process concept with the lowest cost is being developed.
At present, in mechanical engineering there is a tendency of small-scale production due to the peculiarities and requirements of the market. At the same time, machine-building enterprises have to ...account the costs of produced products accurately (both for the state defense order and for the open market). The problem of the product labor intensity calculation becomes urgent, as it is used as a basis for of the product full cost calculation. Taking into account the technology changes, equipment, peculiarities of production program formation (small or medium series), using the existing approaches, work norms manuals becomes impossible. The investigation presents an improved algorithm for the work norm calculating using for the main workers in the high-tech production. A feature of the proposed approach is taking into account the share of passive observation during the technological operations in conditions of small-scale production in the conditions of the high-tech production. The article presents the results of the proposed method testing. The approbation was realized at the industrial enterprise in the conditions of the small-scale production. Proposed algorithm for work norms calculation can be used in automation of labor rationing at the industrial enterprise.
The genetic differences between the sockeye salmon populations of the Kamchatka Peninsula were studied. The time of divergence between the resident sockeye salmon, which are reproductively isolated ...in Lake Kronotskoye, and the anadromous sockeye salmon is estimated using data on microsatellite markers. A weak unidirectional gene flow is observed from resident sockeye salmon into the population of anadromous sockeye salmon spawning in the Kronotskaya River, which is a channel of Lake Kronotskoye. The obtained point estimate of the time of divergence between the resident and anadromous sockeye forms (ca. 10 000 years) is consistent with the geological estimates for the time of formation of the modern Kronotsky lake–river drainage basin. The conclusion was made that the resident sockeye salmon of Lake Kronotskoye originated from the anadromous sockeye salmon of Lake Paleo-Kronotskoye and formed under the conditions of the reproductive isolation from other sockeye populations and the loss of connection with the sea. The necessity for conservation of the Kronotsky resident sockeye salmon, which implies prevention of its mixing with anadromous sockeye salmon, is discussed.
The genetic diversity of the resident and migratory forms of sockeye salmon is investigated in 14 populations from various water bodies of Kamchatka and the Commander Islands by ten loci of ...microsatellite DNA. There are considerable differences in the frequencies of alleles among the populations of kokanee from Lake Kronotskoe, the residual form of sockeye salmon from Lake Kopylie, and other populations analyzed. Clustering of samples corresponds to their geographic position. No differences in the frequencies of alleles of the investigated loci are found between two forms of resident sockeye salmon from Kronotskoe Lake. In the sockeye salmon from the Commander Islands, a relatively low genetic diversity is found, as well as the greatest remoteness from the other Kamchatka group.
The strong nuclear interaction is probed at short-distance and high-momenta using new measurements of the $^{12}$C$(e,e'p)$ and $^{12}$C$(e,e'pn)$ reactions, at high-$Q^2$ and $x_B>1$. The data span ...a missing-momentum range of 300-850 MeV/c and is predominantly sensitive to the dominant proton-neutron short-range correlated (SRC) pairs and complements previous $^{12}$C$(e,e'pp)$ measurements. The data are well reproduced by theoretical calculations using the Generalized Contact Formalism with both chiral and phenomenological nucleon-nucleon ($NN$) interaction models. This agreement, observed here for the first time, suggests that the measured high missing-momentum protons up to $850$ MeV/c belonged to SRC pairs. The measured $^{12}$C$(e,e'pn)$ / $^{12}$C$(e,e'p)$ ratio is consistent with a decrease in the fraction of proton-neutron SRC pairs with increasing missing-momentum. This confirms the transition from an isospin-dependent tensor $NN$ interaction at $\sim 400$ MeV/c to an isospin-independent scalar interaction at high-momentum around $\sim 800$ MeV/c.
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