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The chemical structures of Miscanthusvar. ‘Soranovskii’ lignin fractions released via extraction of lignin from the lignocellulosic feedstock using moderately heated acetone under atmospheric pressure, without acidic and alkaline catalysts, were studied. A blend of Miscanthusstems and leaves was pretreated with water under thermobaric conditions. The acetone organosolv process subsequently afforded a substance related to a lignin-like matter-acetone organosolv Miscanthuslignin (AOML). Non-destructive analytical techniques such as FTIR spectroscopy, gas chromatography-mass spectrometry, size-exclusion chromatography, and 2D NMR were used. The IR and NMR spectroscopies revealed the AOML structure to comprise all the three major types of phenylpropane units: guaiacyl (G), syringyl (S), and p-hydroxyphenyl (H). The resultant acetone-organosolv lignin exhibits good solubility in polar solvents, moderate solubility in aromatic chemicals, and is insoluble in non-polar solvents, exhibiting the physicochemical properties of a thermoplastic polymer with a softening point of 67.0°C (onset 33.0°C, endset 81.5°C).

The chemical structures of Miscanthus var. ‘Soranovskii’ lignin fractions released via extraction of lignin from the lignocellulosic feedstock using moderately heated acetone under atmospheric pressure, without acidic and alkaline catalysts, were studied. A blend of Miscanthus stems and leaves was pretreated with water under thermobaric conditions. The acetone organosolv process subsequently afforded a substance related to a lignin-like matter-acetone organosolv Miscanthus lignin (AOML). Non-destructive analytical techniques such as FTIR spectroscopy, gas chromatography-mass spectrometry, size-exclusion chromatography, and 2D NMR were used. The IR and NMR spectroscopies revealed the AOML structure to comprise all the three major types of phenylpropane units: guaiacyl (G), syringyl (S), and p-hydroxyphenyl (H). The resultant acetone-organosolv lignin exhibits good solubility in polar solvents, moderate solubility in aromatic chemicals, and is insoluble in non-polar solvents, exhibiting the physicochemical properties of a thermoplastic polymer with a softening point of 67.0°C (onset 33.0°C, endset 81.5°C).

The chemical composition of the Soranovskii Miscanthusvariety harvested in 2011 and 2012 was separately determined in the whole plant, leaves, and stem. In all cases, cellulose was found to prevail in the Miscanthusstem, and noncellulosic components (the fat-wax fraction, ash, and lignin), in leaves. Cellulose samples were for the first time obtained from leaves and stems separately by two methods (nitric-acid and combined). The best quality cellulose was derived from stems. For instance, cellulose isolated from stems by the nitric-acid process was better than that from leaves, which was expressed as a higher cellulose content (94.4% versus 91.7%) and degree of polymerization (800 versus 580), as well as low weight fractions of noncellulosic components: ash (0.07% versus 1.01%) and acid-insoluble lignin (0.45% versus 1.51%). The same tendency is observed in celluloses produced by the combined method: Cellulose from stems had better quality than that from leaves; specifically, it had higher degree of polymerization (1040 versus 640) and lower weight fractions of the noncellulosic components: ash (0.14% versus 0.75%), acid-insoluble lignin (0.88% versus 4.12%), and pentosans (6.38% versus 8.53%). It is obvious that cellulose obtained by the nitric-acid method can be suitable for chemical modifications, including nitration. Cellulose from the combined process can be utilized in paper industry.

Satellite relative position and attitude determination algorithm by video processing is developed. The algorithm is numerically simulated and studied. Relative state determination accuracy depending on a distance and pre-defined points image size is investigated. Microsatellite ‘Chibis-M’ and spaceship ‘Progress-13M’ relative motion after separation is determined by the algorithm.

The article profiles the work of Canadian-American deaconess, evangelist, and social worker Katharine Rebecca Maurer. The article states that Maurer worked at the Angel Island Immigration Station in San Francisco, California, in the early 20th century. According to the article, Maurer was affiliated with the San Francisco Methodist Woman's Home Missionary Society and, beginning in 1912, worked at Angel Island to assist Asian and European immigrants.

The review is devoted to nitramide, the first member of the nitramine homologous series. The methods of its synthesis, structure as well as physical and chemical properties are considered.

The article presents an exploration into the history of the Angel Island Immigration Station of San Francisco, California during World War I. Details are given outlining the significance of the station in the western immigration stream of the U.S. at the time. The admission policy changes which resulted from World War I are examined, highlighting various categories and cases of "enemy aliens" who were investigated or detailed at the institution, including radicals, ethnic groups, and refugees.

Genomewide DNA linkage analysis identified a susceptibility locus for intracranial aneurysm (IA) on chromosome 19q13 in the Finnish population, a region including the kallikrein gene cluster. We investigated the association of single nucleotide polymorphisms (SNPs) in the kallikrein gene cluster with IA in the Finnish population.

Methods of synthesis and properties of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.03,11.05,9]dodecane (also referred to as CL-20 or HNIW), a highly energetic polycyclic nitramine, are surveyed. The bibliography includes 49 references.

The concept of radiation safety, based on which the parameters of the radiation shielding for various schemes of a flight to Mars were calculated, is presented. The concept combines modern approaches to the regulation of radiation safety with experience in design investigations, performed by the present authors, in the field of radiation protection for cosmonauts. The general conceptual assumptions and assumptions with respect to separate aspects of the development of a radiation-safety system for a manned expedition to Mars are examined. Probabilistic approaches are absolutely necessary. Limitations on the mass of the material in the radiation shielding and taking account of other forms of the flight risk make it necessary to accept higher levels of irradiation for cosmonauts during a 1–2 yr flight than the levels established for people working with radiation sources under ground-based conditions over the same period of time. Acceptibility from the standpoint of the flight organizers and the cosmonauts is considered. In contrast to previous assessments made by the present authors, the protective role of equipment and structures in the manned module is taken into account.The concept of radiation safety, based on which the parameters of the radiation shielding for various schemes of a flight to Mars were calculated, is presented. The concept combines modern approaches to the regulation of radiation safety with experience in design investigations, performed by the present authors, in the field of radiation protection for cosmonauts. The general conceptual assumptions and assumptions with respect to separate aspects of the development of a radiation-safety system for a manned expedition to Mars are examined. Probabilistic approaches are absolutely necessary. Limitations on the mass of the material in the radiation shielding and taking account of other forms of the flight risk make it necessary to accept higher levels of irradiation for cosmonauts during a 1–2 yr flight than the levels established for people working with radiation sources under ground-based conditions over the same period of time. Acceptibility from the standpoint of the flight organizers and the cosmonauts is considered. In contrast to previous assessments made by the present authors, the protective role of equipment and structures in the manned module is taken into account.

A recursion operator is constructed for a new integrable system of coupled Korteweg–de Vries equations by the method of gauge-invariant description of zero-curvature representations. This second-order recursion operator is characterized by unusual structure of its nonlocal part.

The paper contains five examples of using cyclic bases of zero-curvature representations in studies of weak and strong Lax pairs, hierarchies of evolution systems, and recursion operators.

AbstractIntegrability of differential constraints arising from the singularity analysis of two (1+1)-dimensional second-order evolution equations is studied. Two nonlinear ordinary differential equations are obtained in this way, which are integrable by quadratures in spite of very complicated branching of their solutions.

Integrability of differential constraints arising from the singularity analysis of two (1+1)-dimensional second-order evolution equations is studied. Two nonlinear ordinary differential equations are obtained in this way, which are integrable by quadratures in spite of very complicated branching of their solutions.

AbstractA (2+1)-dimensional perturbed KdV equation, recently introduced by W.X. Ma and B. Fuchssteiner, is proven to pass the Painlevé; test for integrability well, and its 4×4 Lax pair with two spectral parameters is found. The results show that the Painlevé; classification of coupled KdV equations by A. Karasu should be revised.

A number of the corresponding 1- and 2-propargylazoles were obtained by propargylation of 5-substituted tetrazoles and 1,2,3-triazoles with various degrees of substitution. Polyazole structures with a system of two to five uncondensed azole rings were synthesized by the reaction of the 1- and 2-propargylazoles with organic azides, diazides, and azoles, as well as by oxidative dimerization.

A number of methods for the synthesis of C- and N-vinyl-substituted tetrazoles and closely related tetrazolyalkenes are examined. A preparative method for the synthesis of 5-vinyltetrazoles from the corresponding 5-(β-chloroethyl)tetrazoles by dehydrochlorination of the latter with an aqueous alcohol solution of potassium hydroxide is proposed.

To ensure that the necessary bond strength at fiber/matrix interfaces is attained during the manufacture of a carbon-aluminum composite such as that investigated in this work, the degree of chemical reaction between the components must be strictly controlled, the optimum amount of the reaction product (Al4C3) being 2–3%. For matrices of other compositions and fibers of other types, the optimum Al4C3 content may be different. A bond at a fiber/matrix interface forms mainly as a result of “mechanical” joining of the components by carbide phase particles, which leads to the appearance at this interface of numerous micro-channels capable of acting as paths of mass (e.g., water) transport into the main volume of material.

It is shown that the system of two coupled Korteweg-de Vries equations passes the Painlevé test for integrability in nine distinct cases of its coefficients. The integrability of eight cases is verified by direct construction of Laxpairs, whereas for one case it remains unknown.

AbstractIt is shown that the system of two coupled Korteweg-de Vries equations passes the Painlevé; test for integrability in nine distinct cases of its coefficients. The integrability of eight cases is verified by direct construction of Lax pairs, whereas for one case it remains unknown.

The use of potential theory to describe external flows at intermediate supersonic velocities makes it possible to construct very fast algorithms for calculating the flow even in the presence of subsonic regions [1, 2]. However, this approach involves errors associated with the neglect of the increase of entropy in the bow shock. The magnitude of these errors and their effect on the values of the various flow parameters are most easily estimated with reference to examples of conical flows. The shock-capturing projection-grid method [3] is used for integrating the conical potential equation. The results of calculating the flow past circular and elliptical cones, a triangular plate and a V-wing are compared with the corresponding solutions of the system of Euler equations. The region of applicability of the potential model is determined and it is shown that the satisfaction of the Hugoniot shock polar equation at the bow shock increases the error of the pressure calculations.

Without Abstract:

A (2+1)-dimensional perturbed KdV equation, recently introduced by W.X. Ma and B. Fuchssteiner, is proven to pass the Painlevé test for integrability well, and its 4×4 Lax pair with two spectral parameters is found. The results show that the Painlevé classification of coupled KdV equations by A. Karasu should be revised.