Dispersion Analysis Method Research Articles

Deposition of tantalum carbide on Ti6Al4V alloy by electric discharge treatment

Titanium alloys attract wide attention of researchers due to the unique combination of low density, high strength, corrosion resistance, biocompatibility, etc. Therefore, the study of new methods for processing titanium and the creation of protective coatings seems relevant. Metal-ceramic coatings were obtained by electrospark treatment of a titanium alloy Ti6Al4V in a mixture of titanium granules with tantalum carbide powder. Three mixtures of granules were prepared with a TaC content of 2.4; 4.6 and 6.7 vol.%. Coatings were deposited by rectangular pulses with an energy of 0.33 J and a frequency of 1 kHz for 8 minutes in an argon stream. The increase of the volume fraction of tantalum carbide powder in the mixture of granules from 2.4 to 6.7 vol.% does not lead to a significant increase in cathode gain. The average coating thickness ranged from 29 to 36 microns. Using scanning microscopy and energy dispersive analysis methods, it was found that the coating structure is represented by a metal Ti – Ta – C matrix with large ceramic grains. According to x-ray phase analysis, it was found that tantalum carbide TaC prevails in the coating composition. It content increases with increasing powder concentration in the mixture of granules. In addition to it, there are phases of titanium carbide and tantalum subcarbibide TaC0.6, which are the products of TaC decarburization during its interaction with the titanium melt. With an increase of the tantalum carbide concentration in the mixture of granules, the hardness of TaC/Ti coatings increased from 6.1 to 8.9 GPa, which is 2–3 times higher than that of the Ti6Al4V alloy. Coefficient of friction of coatings was in the range of 0.5–0.9. Dry sliding wear tests showed that TaC/Ti coatings had a wear rate ranging from 0.1·10–5 mm3/Nm to 1.7·10–5 mm3/Nm. Thus, the use of these coatings makes it possible to increase the wear resistance of the Ti6Al4V alloy up to 128 times.

Influence of Climate Change and Anthropogenic Impacts on Worldview of Indigenous Northern Nations (as Exemplified by the Verkhoyansk District)

This article examines global climate changes occurring in the Arctic region of Yakutia through the consciousness of the indigenous peoples of the North as expressed in their mythology. It turned out that the small numbered people native to this territory for hundreds of years preserved and continue mythologizing the changes they see in the surroundings while adapting to them and interpreting them according to the folk wisdom, mythological images, and ethnic moral standards. While the global changes have been scientifically rationalized, the locals do not see these changes as disastrous, which allows them to go on surviving in extreme climate conditions, even though adverse natural, industrial and anthropogenic impacts on their lifestyles, health, and moral standards should not be underestimated. Besides, the authors focus on the correlations between the meteorological factors and the disease rate among the local populace. The dispersion analysis methods were used and explained to illustrate this causal link. The authors pioneer in combining and comparing modern scientific knowledge of the life of the northerners, the impact of various adverse factors on their lives, and the folklore of the indigenous Northern peoples. This research used general theoretical and empirical methods, and to some extent, specialized methods including cross-subject methods to analyze the complex environmental, economic, and spiritual processes and phenomena in the lives of the indigenous peoples in the Arctic region of Yakutia.

Effect of doping of Ce4+/3+ on optical, strength and shielding properties of (0.5-x)TeO2-0.25MoO-0.25Bi2O3-xCeO2 glasses

The paper considers prospects of application of dopant CeO2 with different concentration on efficiency of gamma radiation shielding by telluride glasses of type (0.5-x)TeO2-0.25MoO-0.25Bi2O3-xCeO2. As a method for preparing glass, a solid-phase synthesis method was used, which includes grinding the initial mixtures and then sintering in a muffle furnace at a temperature of 1100 °C for 5 h. The amorphous nature of the glasses was confirmed by X-ray phase analysis. Using energy dispersion and X-ray phase analysis methods, physical structural parameters such as density, porosity, oxygen packing density were determined. Analysis of the change in these parameters showed that in the case of an increase in the concentration of dopant CeO2, an increase in glass density and a decrease in porosity were observed due to compaction of the structure and a change in elemental composition. Using the UV–Vis spectroscopy method, the dependence of the change in optical characteristics on the concentration of the dopant was determined, which showed that an increase in the concentration of the dopant leads to a decrease in the gap width by 40–44% compared to the initial values. By analyzing the optical spectra, it was found that an increase in the concentration of the dopant leads to the appearance of additional absorption bands that are associated with a change in the concentration of Ce4+/3+ ions. It was found that in the case of gamma-quantum with an energy of 136 keV, the attenuation efficiency with an increase in the dopant concentration to 0.20 and 0.25 increases by more than 1.5–1.8 times. At the same time, an increase in gamma-quantum energy leads to a decrease in absorption efficiency at the same glass thickness for all tests, and in the case of an energy of 1274 keV, the maximum absorption is not more than 40%. However, in the case of initial glasses and doped with a dopant concentration of 0.05, the absorption efficiency does not exceed 25%, which is rather low shielding values. During tests for resistance to degradation and aging, it was found that doping leads to a significant increase in crack resistance and a decrease in glass degradation, it was also found that doping CeO2 leads to an increase in resistance to degradation by more than 1.5–3 times depending on the concentration of the dopant.

Dispersion Mechanism and Mechanical Properties of SiC Reinforcement in Aluminum Matrix Composite through Stir- and Die-Casting Processes

In this study, different volume fractions of silicon-carbide-reinforced AA2024 matrix composites were successfully fabricated using stir-casting (SC) and die-casting (DC) processes. The microstructural difference and physical properties of the composites during the manufacturing process were investigated in detail. The microstructural analysis found that the composite produced by the SC process had some reinforcement clusters and pores; however, defects and clusters significantly decreased after the DC process. In particular, the degree of reinforcement dispersion was quantitatively analyzed and compared before and after the DC process using the dispersion-analysis method. As a result of quantitative evaluation, the degree of dispersion was improved 2.5, 4.6, and 4.0 times with 3 vol.%, 6 vol.%, and 9 vol.% SiC-reinforced composite after the DC process, respectively. The electron backscatter diffraction (EBSD) analysis showed that the grain size of the 9 vol.% SiC-reinforced DC composite (17.67 μm) was 75% smaller than that of the SC composite (68.06 μm). The average tensile strength and hardness of the 9 vol.% SiC-reinforced DC composite were 2 times higher than those of the AA2024 matrix. The superior mechanical properties of the DC-processed composite can be attributed to the increase in dispersivity of the SiC particles and to decreases in defects and grain size during the DC process.

A novel time–frequency transform for broadband Lamb waves dispersion characteristics analysis

Owing to carrying rich information about structure flaws, broadband Lamb waves are considered as a promising tool for non-destructive testing. However, since every Lamb wave mode has its own dispersion characteristics, the feature extraction among broadband multimodal Lamb wave is challenging. Time–frequency representation is significantly effective to analyze dispersive signals. In this article, taking advantages of the idea of dispersion compensation, two kinds of time–frequency domain dispersion analysis methods for broadband Lamb wave were proposed. The first one is based on the concept of the general parameterized time–frequency transform. A kernel function related to group delay was designed and the time–frequency compensation transform was proposed. The other one combines the segment linear mapping technique and the short-frequency Fourier transform, called the time–frequency de-dispersion transform. Both these two methods work well in representing multimodal Lamb wave signals with high resolution. However, time–frequency de-dispersion transform outperforms in representing multipath Lamb waves than time–frequency compensation transform. Moreover, a mode purification strategy was also proposed for distinguishing the interested mode from interferences. According to verification in synthetic and experimental data, not only the multimodal components but also multipath echoes are represented in time–frequency plane with high resolution. Finally, the proposed method shows a great robustness to inaccuracies in the dispersion data.

Modified frequency–Bessel transform method for dispersion imaging of Rayleigh waves from ambient seismic noise

SUMMARYAmbient noise surface wave methods have gained much attention among geophysical and civil engineering communities because of their capability of determining near-surface shear wave velocities in highly populated urban areas. Higher mode information of surface waves is important in dispersion curve inversion for shear wave velocity structure. The frequency–Bessel (F-J) transform method is an effective tool for multimode surface wave extraction, which has been applied to multiscale investigations of the Earth structure. The measured dispersion energy with the F-J method, however, would usually be contaminated by a type of ‘crossed’ artefacts at high frequencies, which are caused by spatial aliasing and bidirectional velocity scan of dispersion analysis methods. The ‘crossed’ artefacts usually cross and smear the true dispersion energy in the frequency–velocity domain. We propose a modified F-J (MFJ) transform method in which the Bessel function is replaced by the Hankel function for dispersion analysis of empirical Green's function. The MFJ method performs a unidirectional velocity scanning on the outgoing wave to avoid the ‘crossed’ artefacts. Synthetic and real-world examples demonstrate the effectiveness of the proposed MFJ method in improving the accuracy of Rayleigh wave multimode dispersion measurements.

Influence of fiber filler on the structure and properties of polyvinyl chloride / acrylonitrile-butadiene-styrene blends

The paper deals with filling polyvinyl chloride (PVC) compositions modified with acrylonitrile-butadiene-styrene (ABS) in a wide concentration range (per hundredth of PVC resin (phr) 10–20 phr ABS) with short-fiber basalt fiber, intended for production of profile mounded products of various functional purposes. The introduction of ABS into PVC compositions makes it easier to process the material, and improves the impact toughness, which for rigid PVC products is an important factor since it expands the areas of their application. However, as a rule, polymer-polymer blends are characterized by low mechanical properties under compression, tension and bending, resulting from the formation of two-phase morphology, which is often heterogeneous. To increase stiffness and strength, 7 phr of short-fiber basalt fiber was introduced into their composition. Experimental samples were made by extrusion in the form of flat profiles. Filling with short-fiber basalt fiber resulted in an increase in the bending strength of PVC specimens over the entire concentration range with an optimum in the region of 10–20 phr ABS, as compared to unfilled blended polymer compositions. The method of energy dispersion analysis established that, depending on the ABS content in the mixture, the interaction of the polymer (PVC) with the filler (fiber) is observed either at the polymer-filler boundary or through the boundary layer of the elastomer.

Development of a methodology for assessing the expediency of mine workings decommissioning based on the geomechanical factor

Purpose. Substantiation of the methodology for predicting the state of mine workings based on the study on geomechanical processes when assessing the consequences of mine closure taking into account the entire period of their existence, during which the development of displacement with various intensity occurs in the surrounding coal-bearing mass. Methodology. The study is based on methods of analysis and synthesis, methods of comparison, abstraction, analogy, calculation and construction. The methods of mine tool observations of the manifestations of rock pressure and their processing by methods of correlation and dispersion analysis for establishing the relationship of displacements of the mine working contour with geomechanical factors were used. Findings. A possibility of stage-by-stage decommissioning of mine workings when grouping mining-and-geological conditions is substantiated. An example of calculating the displacements in a mine working during its decommissioning is presented. The given calculation expressions make it possible to assess the mine working state, taking into consideration the patterns of the geomechanical factor influence on making a technical decision on the expediency of its further operation. Originality. The patterns of the rock pressure manifestation development in sequentially abandoned mine workings have been determined. Based on the methods of correlation-dispersion analysis, the dependence of the mine working contour displacements on geomechanical factors have been revealed throughout the entire period of its existence. Practical value. A methodology for assessing the state of mine workings at the time of their decommissioning has been developed, which is an integral part of the recommendations to limit the negative influence of mine closure. The peculiarity of the methodology is in taking into account the entire period of mine workings existence, which leads to a well-grounded technical decision on the possibility of dismantling the metal structures with the complete exclusion of emergency situations.

Agroecological approach to quality assessment of organic aromatic products

The developed complex scientific-methodical approach to the survey of organic agricultural enterprise was presented in order to confirm the quality of aromatic products of the “Organic” class. The analysis of agrochemical soils indicators was performed for the first time, which were cultivated according to organic technology for eleven years. It was proven that long-term use of organic farming contributes to the preservation and improvement of soil fertility. An elemental biomass analysis of the apical part of lavender plants grown by organic method was carried out, from which the essential oil was then obtained. It was confirmed that the essential oil composition depends on the place of its production and on the soil characteristics on which the plants were grown. The elemental analysis of essential oil showed that there is an intensive carry-over of all major macro- and micronutrients from the soil into plants during their growth and development. In the lavender essential oil, there are more than 50 substances that determine its uniqueness. Therefore, to confirm the quality of “Organic” class products, we propose to conduct a comprehensive assessment of all components of the organic production system “soil — plant — products”. Thermal analysis, electron microscopy with detectors for energy dispersion analysis, chromatographic analysis, potentiometry, flame photometry and chemical analytical methods were used for the research. Differences in quality indicators of organic essential oil and oil obtained with the traditional farming method were revealed. The study found that the produced lavender oil is a unique quality product grown in an organic way. At present, quality management of agricultural products is possible subject to specialists' availability in the agro-industrial complex with competence in the field of chemical-toxicological and environmental analysis knowing methods to determine the quality and safety of agricultural products, including organic products.

Study on the Analysis of Main Components of Aluminum Alloy by XRF (X-Ray Fluorescence Analysis) Method

Aluminum alloy has low density, good plasticity, and high strength. It has a large number of applications in many fields. The performance of aluminum alloy is closely related to its alloy composition. The rapid and accurate determination of the content of various elements in aluminum alloy is important for its production and processing. The experiment is based on the energy dispersive X-ray fluorescence analysis method, and analyzes the main elements in the aluminum alloy samples with different composition. The best working mode and the best measurement time of different elements are determined among the partitions. The data measured in the experiment were compared and analyzed by using one-variable, two-variable, and three-variable fitting methods, and the best multiple fitting method for different elements was determined. After ternary fitting, the average absolute errors for Al, Mg, and Si are 0.040%, 0.027%, and 0.007%, respectively, and the average relative errors are 0.040%, 2.111%, and 0.469%, respectively; after binary fitting, the average absolute errors for Cu and Zn are 0.001% and 0.001%, and the average relative errors are 0.061% and 0.070%. The average absolute errors of Zn are 0.001% and 0.001%, and the average relative errors are 0.061% and 0.070%, respectively. The experimental results prove that the XRF method can be applied to the accurate measurement of the main components of aluminum alloy.

Segregation in squeeze casting 6061 aluminum alloy wheel spokes and its formation mechanism

Segregation can seriously damage the mechanical properties of the aluminum alloys. 6061 aluminum alloy wheel spokes were prepared by squeeze casting. To investigate the formation mechanism of segregation, the microstructure of the alloy was observed using scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction and electron microprobe analysis methods. The Gibbs energy of each phase during solidification was calculated by JMatPro. Results show that the segregation phases in the R-joint of the wheel spokes are mainly composed of Mg2Si, β-AlFeSi and Al5Cu2Mg8Si6 intermetallics. During the solidification of the 6061 aluminum alloy wheels, Mg2Si and α-AlFeSi phases precipitate in the mushy zone at first. With the decrease of temperature, α-AlFeSi transforms into β-AlFeSi, while Al5Cu2Mg8Si6 precipitates from the solid-state aluminum alloy after solidification. Segregation at the R-joint of wheel spokes is mainly caused by insufficient cooling, so the cooling during alloy solidification should be enhanced to avoid segregation.

Improvements of choice of the water-chemical regime of reserve osmosis installation

The effectiveness of monitoring the composition and intensity of deposits on reverse osmosis membranes is shown. The use of test installations of the NGO “NPK Mediana-Filter” speeds up and significantly reduces the labor intensity of monitoring deposits in the conditions of industrial operation of reverse osmosis installations. The effectiveness of determining the composition and intensity of deposits on the membrane surface using the energy dispersive analysis method was revealed. The effectiveness of commercial formulations for cleaning intensely contaminated membranes is not always sufficient. The use of ready-made solutions from various manufacturers excludes the possibility of a targeted selection of the concentration of a solvent to remove deposits from the membrane surface, provided that these solutions are safe for the operating parameters of the membranes. The monitoring results made it possible to implement a targeted choice of compositions of detergent mixtures, their combinations and the regime of their effect on deposits on membranes, provided that the pH of the solutions is stable throughout the entire cleaning time. Controlling the intensity of the formation of deposits according to the data of test installations will reduce the laboriousness of choosing the optimal water-chemical regime of an industrial reverse osmosis plant, which will reduce the rate of formation of deposits, increase the service life of membrane elements of an industrial water treatment plant with a consistently high quality of demineralized water.

Гидрохимическая очистка золотосодержащих катодных осадков от примесей тяжелых цветных металлов

The purpose of this paper is to conduct the research on hydrochloric acid cleaning of gold-containing cathode deposits from the impurities of heavy non-ferrous metals and mathematical processing of the experimental data obtained by the method of dispersion analysis. The atomic absorption method is used to study the chemical composition of the cathode deposits. The method of dispersion analysis is used to process experimental data. The composition of cathode deposit impurities is studied using x-ray spectral microanalysis. The study of the chemical composition of cathode deposits has shown that their main components are gold, silver, copper, lead, as well as non-metallic impurity compounds (CaO, SiO2, etc.). It is found that the optimal concentration of hydrochloric acid for cleaning gold-containing cathode deposits from heavy non-ferrous metals is 371 kg/m3; the degree of copper transition to solution is 69.06%, lead - 93.9%. The calculation of the expected mass fraction of precious metals in the alloyed gold demonstrates an increase in the mass fraction of gold by 14.08%, silver - by 17.46%. The study of the chemical composition of cathode deposits has also revealed that the main impurities that affect their subsequent processing are copper and lead. The latter fall into the ingot of alloyed gold, which is the target product of gold-bearing ore processing and complicate subsequent refining. The dispersion analysis of experimental data shows that solvent concentration significantly affects the transition degree of heavy non-ferrous metals to the solution starting from the value of 20.1 kg/m3. It is shown that the proposed method allows to increase the content of precious metals in the alloyed gold by 31.54%, as well as to perform maximum transition of copper and lead to the solution. The use of acid leaching of impurities from cathode deposits obtained by cyanide-sorption technology is one of the promising directions for improving the quality of gold-containing alloys and hence the reduction of the cost of refining services.

Термоаналитический межлабораторный эксперимент по идентификации материалов, веществ и средств огнезащиты

Проведен межлабораторный термогравиметрический эксперимент по идентификации огнезащитных составов интумесцентного типа. Использование дисперсионного анализа позволило установить значимость/незначимость различий в поведении исследуемых материалов при нагревании, выявить лаборатории, обладающие необходимыми компетенциями для проведения идентификации. Найдено, что применение различных водно-полимерных дисперсий даже близкого строения в составе огнезащитных материалов приводит к неидентичности их свойств. Представленный подход позволил однозначно установить неидентичность исследованных огнезащитных составов. The article deals with the problem of identification of materials, substances and means of fire protection according to GOST R 53293-09 using one of the methods of thermal analysis, namely, thermogravimetric analysis. The long-term practice demonstrated that the methodology presented in the standard did not always give a clear result when identifying objects. Therefore, the evaluation experiment was conducted simultaneously in several testing laboratories with the appropriate equipment. The tests were conducted in the laboratories of the FGBU VNIIPO EMERCOM of Russia, ANO «CISIS FMT», and two CCPS of the Lomonosov Moscow State University. The most complex and controversial objects for identification were studied, namely, thermally expanding (intumescent) flame retardants based on water-polymer dispersions, which are used to protect building structures in closed premises. The purpose of the work consists in more correctly identifying the differences in the samples of the identifier and the analyzed object by using methods of dispersion analysis (GOST R ISO 5725-1, 2-202) when processing the joint interlaboratory experiment. Thermogravimetric analysis of objects was performed in platinum crucibles on samples in the form of disks with a thickness of 0,2-0,3 mm, weight 5-7 mg, at a heating rate of 20 °C/min in the air flow (50-70 ml/min). As a result of the experiment, the significance/insignificance of differences between samples should be displayed. The opinion about the competence of the laboratories participating in the experiment was made. In each laboratory there were conducted two series of thermogravimetric tests in 30-700 °C temperature range including five parallel measurements in each series. Each independent single measurement for further processing was represented by the data array formed within the temperature range of 140-650 °C with a 5° step, in total 103 points in each measurement. The results were processed using Excel spreadsheets. In the context of dispersion analysis there were evaluated both mean values of conversion rates for all laboratories, and the convergence (repeatability) variance for each laboratory using the Student's test, and the inter-laboratory variance (reproducibility variance) using the Cochran’s С test. This procedure revealed the nature of the quasi-samples and established the identity/non-identity of the samples. The results of calculations are represented by the graphical dependence of the generalized average degrees of transformation of destruction processes of objects under the temperature as well as the difference between these characteristics for laboratories I-IV. The presented identification procedure allows both to uniquely solve the problem of significance/insignificance of differences between the test object and the identifier, and to distinguish samples that have a similar composition. The statistical characteristics of a single measurement are calculated. The convergence of parallel measurements for determination of statistical outliers is identified. Determination of the overall average difference for a series of degrees of transformation allows to calculate the Student's test and accept or reject the null hypothesis. The performance of the joint evaluative (interlaboratory) experiment allows not only to establish the significance/insignificance of differences in the behavior of the materials during heating, but also to identify laboratories that have the necessary competencies for identification. The case considered in this paper revealed that the use of various water-polymer dispersions of even close structure in the composition of fire-resistant materials leads to non-identity of their properties.

Identification of Two Distinct Electron Populations in an Impulsive Solar Energetic Electron Event

Abstract We examine the release times of energetic electrons in the 2001 April 25 event. An M2.7 flare occurred on 2001 April 25, from AR 09433, located at N18W09. The flare was observed in X-rays by GOES and the Yohkoh spacecraft. The Yohkoh observation also included hard X-ray (HXR) images for all four energy channels: L, M1, M2, and H. We use Yohkoh observation times as a proxy for the release time of energetic electrons that propagated downward, which are responsible for the HXRs. In situ >∼25 keV electrons were observed by the Wind spacecraft. For these electrons, we obtain the release time at the Sun using the recently developed Fractional Velocity Dispersion Analysis method. We find that the release times of outward-propagating energetic electrons are clearly delayed from those that propagated downward. Furthermore, these delayed releases are energy dependent. The implication of this delay on the underlying acceleration and trapping process of the >∼25 keV electrons at solar flares is discussed.

Influence of hydrometeorological indices on electrolytes and trace elements homeostasis in patients with ischemic heart disease.

One hundred patients with ischemic heart disease and 70 healthy subjects were on unified regimen. Urine was collected with 4-h proportions during 3-5days (72-120h). Each portion of urine was analyzed for macro- (Na, K, P, Cl, Ca, Mg) and microelements (Fe, Cu, Zn, Cr, Cd, V). Temporal structure (biological and hydrometeorological indices) parameters have been estimated by nonlinear least squares method for sinusoidal rhythms and dispersion analysis for nonsinusoidal rhythms. Data of weather indices were received from the hydrometeorological service of the Republic of Armenia in 2015 at 3-h intervals. Statistically significant rhythms were observed in healthy subjects in 91% cases of 593 rhythmological investigations of water-mineral homeostasis. Acrophases of water-mineral homeostasis mostly had individual nature. Healthy subjects' rhythms of water-mineral excretion were depending on rhythms of hydrometeorological indices and were characterized with significant correlative connections. Acrophases of indices of water-mineral homeostasis mostly were outstripping the acrophases of the rhythms of hydrometeorological indices. Chronostructure of water-mineral homeostasis in patients with ischemic heart disease was characterized with infradian and circadian fluctuations. In case of individuals with ischemic heart disease, statistically significant correlative connections between rhythms of water-mineral excretion and rhythms of hydrometeorological indices differ in comparison with the results of practically healthy individuals. In patients with ischemic heart disease, acrophases of biorhythms often were concurrent or delayed relative to the acrophases of the rhythms of hydrometeorological indices.

The extreme factors influence on the grain quality technological indicators of spring wheat of Siberian selection

Cultivation of agricultural crops and obtaining stable yields with high technological qualities of grain are often limited by extreme environmental conditions during the plant growing season. Mongolian agriculture is characterized by a high level of dependence on natural conditions, resources, and changes in ecological systems. Sharp temperature fluctuations, high contrast and insufficient precipitation during the growing season create extreme factors for cultivating crops in Mongolia. Spring wheat varieties of Siberian selection are resistant to adverse environmental factors and have good baking qualities. In the framework of the contract between the Krasnoyarsk state agrarian university and HHK “IngetTolgoy” company (Mongolia), the research on studying extreme factors influence on the technological parameters of spring wheat grain of Siberian selection on the land of HHK “IngetTolgoy” company was conducted. The objects of research were wheat varieties of Siberian selection Novosibirskaya – 15, Novosibirskaya – 31, Kantegirskaya – 89 and varieties Selenge and Tsagaan dagliy, cultivated in HHK “IngetTolgoy” company. Recording was performed using generally accepted methods and existing State Standards. Statistical processing of the obtained data was performed by the method of dispersion and correlation analysis. The obtained results allow to conclude that despite the influence of extreme factors on wheat during the entire growing season, the highest biological yield and the best technological qualities of grain were formed by the spring wheat variety of Siberian selection Novosibirskaya – 31.

The increase of the potential agricultural landscapes fertility through the use of non-traditional organic fertilizers

In modern conditions of economic crisis, the use of mineral and organic fertilizers has sharply decreased, which leads to the soil fertility degradation and the microbial cenosis structure simplification. In this regard, there is a growing interest in the use of non-traditional fertilizers, including those obtained from wood vegetation wastes. The purpose of the research is to study the possibility of using waste oil from coniferous trees as fertilizers and growth stimulants for grain crops. The object of the research is soft spring wheat variety of Siberian selection “Krasnoyarskaya-12”. Recording was performed using generally accepted methods and existing State Standards. The influence of fir water on the germination energy, germination capacity and infection of soft spring wheat “Krasnoyarskaya-12” seeds was determined by the wet chambers method using paper rolls, as well as Petri dishes according to State Standard 12044-93. Statistical processing of the obtained data was performed by the method of dispersion and correlation analysis. The obtained results and the conducted chemical analysis of fir needles, peat and water solution of needles showed a fairly high content of nitrogen, phosphorus and potassium. Therefore, the use of waste products in the production of fir oil as non-traditional organic fertilizers requires targeted research and can be a very promising agricultural approach.

Environmental Factors Affecting the Conchological Variability of the Common River Snail Viviparus viviparus (L., 1758) (Mollusca: Gastropoda) in the Novosibirsk Reservoir, Russia

The shell variability of the common river snail (Viviparus viviparus (L., 1758)), a species alien to Western Siberia, was studied using the methods of discriminant and dispersion analysis for the population of the Novosibirsk Reservoir. In different parts of the reservoir, the subpopulations of common river snail are formed, which differ in the shell proportions. A statistically significant relationship between the spatial differentiation of the shell shape and the depth of habitat was found. Differences in temperature and food availability in the coastal and relatively deep-water areas of the reservoir may have a leading role in morphological differentiation. The morphological changes in the common river snail, which occurred in a short time after the appearance of this species in the Novosibirsk Reservoir, indicate their ability to adapt quickly and testify to a high invasive potential of the species.

A single Rayleigh mode may exist with multiple values of phase-velocity at one frequency

SUMMARYOther than commonly assumed in seismology, the phase velocity of Rayleigh waves is not necessarily a single-valued function of frequency. In fact, a single Rayleigh mode can exist with three different values of phase velocity at one frequency. We demonstrate this for the first higher mode on a realistic shallow seismic structure of a homogeneous layer of unconsolidated sediments on top of a half-space of solid rock (LOH). In the case of LOH a significant contrast to the half-space is required to produce the phenomenon. In a simpler structure of a homogeneous layer with fixed (rigid) bottom (LFB) the phenomenon exists for values of Poisson’s ratio between 0.19 and 0.5 and is most pronounced for P-wave velocity being three times S-wave velocity (Poisson’s ratio of 0.4375). A pavement-like structure (PAV) of two layers on top of a half-space produces the multivaluedness for the fundamental mode. Programs for the computation of synthetic dispersion curves are prone to trouble in such cases. Many of them use mode-follower algorithms which loose track of the dispersion curve and miss the multivalued section. We show results for well established programs. Their inability to properly handle these cases might be one reason why the phenomenon of multivaluedness went unnoticed in seismological Rayleigh wave research for so long. For the very same reason methods of dispersion analysis must fail if they imply wave number kl(ω) for the lth Rayleigh mode to be a single-valued function of frequency ω. This applies in particular to deconvolution methods like phase-matched filters. We demonstrate that a slant-stack analysis fails in the multivalued section, while a Fourier–Bessel transformation captures the complete Rayleigh-wave signal. Waves of finite bandwidth in the multivalued section propagate with positive group-velocity and negative phase-velocity. Their eigenfunctions appear conventional and contain no conspicuous feature.