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1

Applying the expert method to determine a company’s strategic goals

Satybaldiyeva Dinara, Mukhanova Gulmira, Tymbayeva Zhazira, Tyshkanbayeva Mansiya, Bolatkyzy Saltanat

Transport Problems

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2023

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T. 18, z. 2

123--132

EN

The most important factor for the success of a company in today’s competitive environment is to have clearly defined goals. Objectives define what a company strives for, what it wants to achieve, and what it wants to realize in its activities. Clearly defined goals are necessary to ensure the sustainability and effectiveness of a company’s operations and the successful achievement of its desired results. This paper proposes an expert method for determining the strategic goals of a company. The experts ranked 24 strategic goals in terms of importance, and variance and coefficient of variation were then used to determine the consistency of the experts. As a result, 15 important strategic goals were identified of the 24 goals of the assessed transport company.

2

Morphology and selected properties of NR/BR/CNT nanocomposites – effect of ethanol-assisted mixing

Zhang Juzheng, Gu Zheng, Meng Chao, Wang Jianfa, Sui Jinyong

Polimery

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2023

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Vol. 68, nr 5

251--258

EN

Carbon nanotubes (CNT) and ethanol-assisted mixing were used to obtain composites based on a mixture of natural rubber and butadiene rubber (NR/BR 80/20). The structure of the composites was determined by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Thermal aging tests were also carried out and the vulcanization process was characterized. SEM confirmed the homogeneous dispersion of CNTs in the polymer matrix. Improvements in tensile and tear strength as well as thermal stability were also achieved.

PL

Do otrzymywania kompozytów na bazie mieszaniny kauczuku naturalnego i butadienowego (NR/BR 80/20) zastosowano nanorurki węglowe (CNT) i mieszanie wspomagane etanolem. Strukturę kompozytów określono za pomocą spektroskopii w podczerwieni z transformacją Fouriera (FTIR) oraz skaningowej mikroskopii elektronowej (SEM). Przeprowadzono również badania starzenia termicznego oraz scharakteryzowano proces wulkanizacji. Metodą SEM potwierdzono jednorodną dyspersję CNT w osnowie polimerowej. Uzyskano również poprawę wytrzymałości na rozciąganie i rozdzieranie oraz stabilności termicznej.

3

Effect of ethanol-assisted mixing on the selected properties and homogeneity of NR/BR blends

Meng Chao, Gu Zheng, Sui Jinyong, Wang Jianfa, Li Peiyao, Hu Shaokai, Zhang Susu, Zhang Xiaoyi, Wang Haoyu, Han Shaolong, Yang Zhifei

Polimery

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2023

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Vol. 68, nr 3

142--148

EN

The effect of the mixing method (normal and ethanol-assisted) on selected properties of natural rubber with butadiene rubber blends (NR/BR 80/20) was investigated. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to evaluate the properties. In addition, the mechanical tensile properties, tear resistance and thermal aging, as well as vulcanization characteristic were determined. It was found that ethanol-assisted mixing can significantly improve the mechanical properties and thermal stability of the blends as a result of better dispersion of additives in the rubber matrix.

PL

Zbadano wpływ metody mieszania (tradycyjna i wspomagana etanolem) na wybrane właściwości mieszanin kauczuku naturalnego z kauczukiem butadienowym (NR/BR 80/20). Do oceny właściwości zastosowano skaningową mikroskopię elektronową (SEM), spektroskopię w podczerwieni z transformacją Fouriera (FTIR) oraz analizę termograwimetryczną (TGA). Ponadto oznaczono właściwości mechaniczne przy rozciąganiu, odporność na rozdzieranie i starzenie termiczne, a także właściwości wulkanizacyjne. Stwierdzono, że mieszanie wspomagane etanolem może znacząco poprawić właściwości mechaniczne i stabilność termiczną mieszanin NR/BR, jako efekt lepszej dyspersji dodatków w osnowie gumowej.

4

Successive dispersion, amalgamation and accretion of terranes of Myanmar from the Gondwana

Aung Hla Hla

Geotourism / Geoturystyka

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2023

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nr 1-2 (72-73)

12--13

EN

Myanmar represents an evolving continent of two crustal formation histories consisting of the Burma plate and the Indochina plate. The Burma plate (western part of Myanmar) consists of three distinct lithotectonic entities: 1) a continental fragment, 2) a subduction-related accreted complex (NeoTethys suture zone) in the westernmost part of Myanmar and 3) a coastal area. Eastern Myanmar that is western continuation of Indochina plate is composed of three tectonostratigraphic terranes: 1) Shan boundary belt (Meso-Tethys suture zone) in the western edge of Indochina plate, 2) Sibumasu terrane, 3) the Than Lwin Belt (Paleo-Tethys suture zone) in the easternmost part of Myanmar. The Than Lwin Belt is a tectonic linkage between Inthanon Zone of West Thailand in the south and Changning-Menglian belt of West Yunnan in the north (Aung, 2009). Shan Boundary Belt of Meso-Tethys suture in the western edge of Indochina plate extend to the south to Malay Peninsula. The Rakhine Western Ranges of Neo-Tethys suture at the westernmost part of Myanmar is a northern continuation of Andaman-Nicobar belt. Story of the Tethys is the story of extinctions of sea and telling that story was learned from clues in rocks and fossils. Biostratigraphic correlation between the known distribution of dominant Mesozoic representatives of Monotis, Halobia, and Daonella fauna and microfossil assemblages of Triassic age from Myanmar are made with those from neighboring countries of SE Asia for reconstruction of tectonic terranes for Myanmar. The terranes in Myanmar may have originated in Gondwana in Paleozoic (Figs 1, 2). The accretionary episodes which ended in early Tertiary, have been followed by post-accretionary deformation of strike- slip faulting of the Sagaing Fault in Myanmar; West Andaman Fault and Sumatra Fault System in Sumatra; and spreading in Andaman backarc basin. To reconstruct the palaeogeography of Myanmar terranes distribution of Mesozoic representatives of Monotis, Halobia, and Daonella faunas and Tethyan fusulinids are used. Various species of thin-shelled pectinacid bivalves of Triassic faunas are dominant family and occur in open-marine strata of allochthonous accretionary terranes. These strata are related to different parts of single ocean: Tethys, palaeoequatorial ocean populated by these faunas containing Tethyan fusulinids. Their occurrences in mudstones, sandstones, shale and limestone are very important for Triassic sedimentary succession as diagnostic fossils. Distribution of these faunas and biogeographic studies are an importance in reconstructing post-Triassic intraoceanic plate boundaries and motion. Distribution of these faunas in Triassic marine strata of Shan Massif and correlation with those of neighboring terranes of Asia gave the evidences that Shan Massif was a part of Gondwana in Carboniferous-Permian time facing Paleo-Tethys Ocean. Shan Massif probably separated from Gondwana in Early Triassic time and moved northward from equatorial position. Ophiolites thrusted onto Mesozoic sequences of Halobia shales in pre-Middle Eocene (Rangin, 1996–1999). Their position above the metasedimentary rocks is similar to the Halobia shales of Sumatra which also lies on top of metasedimentary rocks of Permo-Carboniferous Sequences (Bender, 1983). All the Tertiary sequences of Central Myanmar Basin are considered to be deposited on the underlying Burma plate as basement. Initial collision between India and Burma plate in middle Eocene (45–35-Ma) and hard collision during Oligocene to Miocene (23 Ma) and Rakhine Western Ranges became uplifted during Middle Miocene to Late Miocene (Curray, 2005) by thrusting the remnants of NeoTethys sea floor and trench deposits to become Rakhine accretionnary wedge and ophiolites belt at the western part of Burma plate.

5

Measurement of the surface reflectance of an acoustic wave using wave packets propagating in a circular waveguide

Wrzeciono Piotr, Szymański Michał

Vibrations in Physical Systems

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2022

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Vol. 33, nr 2

art. no. 2022218

EN

The main idea of the measurement presented in this paper was to separate the incident wave from the reflected wave. For this purpose, short wave packets and a sufficiently long waveguide with a circular cross-section were used. Several types of wave packets were developed and used in the experiment. We found that a wave packet of 5 ms duration could be propagated in a waveguide of length 5.6 meters without significant sound level losses. We used an audio interface operating at a sampling rate of 96 kHz in the measurements. The limit of wave propagation without dispersion phenomenon was determined. The developed measurement methodology made it possible to maintain the same air temperature along the entire length of the tested waveguide since short pulses did not cause the speaker temperature to rise. Avoiding this effect reduced the measurement uncertainty of the reflection coefficient.

6

Preparation and performance in IR and UV of transparent inorganic polysiloxane coating with dispersed TiO2 on glass substrates

Saudi S. A., Mohd A. F.

Journal of Achievements in Materials and Manufacturing Engineering

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2022

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Vol. 114, nr 2

49--56

EN

Purpose: The aim of the presented work was to develop an economical, transparent coating with dispersed TiO2 dispersion and inorganic polysiloxane resin for glass windows application and to study its effectiveness in filtering IR and UV radiations. Design/methodology/approach: Two oligomeric silanes were prepared in different molar ratios to produce inorganic polysiloxane resin. They were tested for their viscosity to reflect the completion of the reaction and form an amide linkage. FTIR was done to support the viscosity result by proving the presence of amide linkages. 10%, 20%, and 30% of compounded TiO2 were successfully dispersed in 0.3% sodium sulfosalicylate (dehydrated ethanol). Each TiO2 concentration was characterized for size distribution and polydispersity index (PDI). Additives solutions of 2-hydroxybenzophenone (HBP) and boron trifluoride (BF3) were also soluted in the same solvent. Glass substrates were coated with the formulations and tested for curing and hardness properties. Windows Energy Profiler (WEP) was used to study the UV, IR, and daylight transmission of the coated glasses. Findings: Each inorganic polysiloxane resin showed various viscosity values before reaching a constant state which designates complete formations of amide linkages. Polysiloxane resin with a viscosity value of 30.5 mPa/s was the most ideal to act as a binder. FTIR characterization proved the formation of amide linkages. The particle size distribution of TiO2 recorded the size of 87 nm after dispersion with correlating value of 1 PDI. The fastest drying time of 3 hours was recorded. The pencil hardness test quoted 6H pencil as the hardest pencil grade. WEP analysis of UV, IR, and daylight transmission gives satisfactory results of 0%, 7%, and 61%, respectively. Research limitations/implications: Laboratory analysis for viscosity tests often being held off. The test requires the samples to be transferred in a cylinder with an open-air spindle rotation. Samples react with the surrounding environment. Thus, polymerization takes place rapidly, resulting in hardened samples inside the cylinder. The different measure was taken by wrapping the testing area with aluminium foil. This research was conducted under equatorial climate. Practical implications: The obtained test results may contribute to the conclusion of transparent TiO2 nano-particles coating on glass substrates for windows application. This can reduce the electricity usage in buildings for artificial cooling to provide indoor thermal comfort. Smart coating formulations have a noticeable effect on filtering harmful solar radiation. Originality/value: This study presents the economical and undemanding ways to develop transparent smart coating formulation with superior performance against solar radiation. It is expected to have a bright potential in the architectural industry.

7

Three months of “Cumbre Vieja” : analysis of consequences of volcano eruption

Mazur Andrzej

Archives of Environmental Protection

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2022

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Vol. 48, no. 3

99--108

EN

The work describes the methodology and results of analysis for the consequences assessment of eruption from Cumbre Vieja volcano in Canary Islands. The preliminary analysis of dispersion of emitted pollutants was performed using Lagrangian trajectories model. To estimate long-term outcomes of eruption in terms of deposition and concentration of eruption products the Eulerian model of air dispersion was used. The model uses data from Global Forecasting System meteorological model launched at the NCEP-NOAA centre. The average concentration and deposition of sulfur compounds as well as the probability and time of the pollution cloud reaching all European capitals were examined. In 90 days a cloud of pollutants (SO2, volcanic ashes) spread over the northern hemisphere. Pollution reached Africa, North Sea and Europe. With an average emission of 15,000 tons of SO2/day, the maximum calculated deposition to the Earth’s surface reached 0.8g/m2, while overall deposition – 35 kilotons in the domain area.

PL

W pracy opisano metodykę i wyniki oceny skutków erupcji wulkanu Cumbre Vieja na Wyspach Kanaryjskich. Wstępną analizę dyspersji emitowanych zanieczyszczeń przeprowadzono z wykorzystaniem modelu trajektorii Lagrange’a. Do oszacowania długoterminowych skutków erupcji pod względem osadzania i koncentracji produktów erupcji wykorzystano eulerowski model dyspersji powietrza. W modelu wykorzystano dane z modelu meteorologicznego Global Forecasting System uruchomianego w ośrodku NCEP-NOAA. Zbadano średnie stężenie i depozycję związków siarki oraz prawdopodobieństwo i czas dotarcia chmury zanieczyszczeń do wszystkich stolic europejskich. W ciągu 90 dni chmura zanieczyszczeń (dwutlenek siarki, popioły wulkaniczne) rozprzestrzeniła się na półkuli północnej. Zanieczyszczenia dotarły do Afryki, Morza Północnego i Europy. Przy średniej emisji 15 000 ton dwutlenku siarki na dobę maksymalna wyliczona depozycja na powierzchni Ziemi osiągnęła 0,8 g na metr kwadratowy, a ogólna depozycja 35 kiloton w obszarze domeny.

8

Deep-neural-networks-based approaches for Biot-squirt model in rock physics

Xiong Fansheng, Liu Jiawei, Guo Zhenwei, Liu Jianxin

Acta Geophysica

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2022

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Vol. 70, no 2

593--607

EN

A new cost-effective surrogate model using deep neural network (DNN) for seismic wave propagation in rocks saturated with fluid is presented. In this field, the dispersion/attenuation analysis and wave-field simulation are two key measurements which can be carried out by solving wave equations. The Biot–squirt (BISQ) equation is a classical wave propagation model in geophysical forward modeling and has been widely used. The solution of such equation, especially by numerical method, is often complex and time-consuming. In this work, a DNN model is trained with the dataset of velocity and inverse quality factor generated from BISQ model. The results show that the relative mean square error between the predictions of DNN model and that of BISQ model on the test sets are all less than 3%. It indicates that the DNN model has learned the high-dimensional space well and then can realize the dispersion/attenuation analysis for any given rock physical parameters. Besides, the other well-trained DNN model is used to obtain the simulation results with second-order accuracy according to results by finite difference scheme with first-order accuracy. It reveals that the fast wave-field simulation can be implemented once the results with lower accuracy are obtained.

9

Impact of ground adsorption capacity on the change in chemical composition of groundwater

Aniszewski Andrzej

Archives of Environmental Protection

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2020

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Vol. 46, no. 2

35--41

EN

Demonstrating the impact of time-dependent ground adsorption capacity on the change in chemical composition of groundwater is an important issue in understanding the groundwater mass transport process. Commonly used parameters characterizing ground adsorption capacity (Ra, ux* = ux/Ra, Δ C*max) were analyzed in this work to demonstrate time-varying values of this capacity for a chosen type of ground. Analysis of values of the selected parameters showed a gradual time decline in ground adsorption capacity as well as a gradual increase of groundwater contamination. This gradual increase in groundwater contamination over time is also important in practice. It implies the necessity to use more and more advanced (expensive) methods of water treatment in groundwater intakes.

PL

Wykazanie wpływu zależnej od czasu pojemności adsorpcyjnej gruntu na zmianę składu chemicznego wód podziemnych jest ważnym zagadnieniem w zrozumieniu procesu transportu masy wód podziemnych. W niniejszej pracy przeanalizowano powszechnie stosowane parametry charakteryzujące pojemność adsorpcyjną gruntu (Ra, ux* = ux/Ra, Δ C*max ), aby wykazać zmienne w czasie wartości tej pojemności. Dokładna analiza wartości liczbowych wybranych parametrów wykazała spadkową w czasie tendencję pojemności adsorpcyjnej gruntu, a także stopniowy wzrost zanieczyszczenia wód gruntowych. Ten stopniowy w czasie wzrost zanieczyszczenia wód gruntowych jest również ważny w praktyce. Wiąże się bowiem z koniecznością stosowania coraz bardziej zaawansowanych (kosztownych) metod uzdatniania wód podziemnych pobieranych z ujęć.

10

Viscoelasticity expression and extension of seismic dispersion and attenuation in porous media with multiple fracture sets

Zhang Jinwei, Ding Renwei, Zhao Lihong, Wang Deying

Acta Geophysica

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2020

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Vol. 68, no. 6

1679--1688

EN

Intensive studies have been conducted on fuid-related seismic dispersion and attenuation in saturated anisotropic media. Most of the studies are concentrated on the transversely isotropy media. However, the fractures distribution in subsurface reservoirs is often complex. When there are multiple fracture sets developing in a porous background, the signatures of seismic dispersion and attenuation remain unclear. In this paper, we propose a method to calculate the frequency-dependent stifness matrix of a porous medium with multiple fractures sets from a perspective of viscoelasticity. Due to the favorable approximation performance of the generalized standard linear solid model and Chapman model, we use a modifed form of generalized standard linear solid model to simulate the frequency-dependent stifness tensor of porous media with multiple fracture sets. The representation of the stifness tensor utilizes the modulus defect to denote the efects the fractures including fracture density and geometry. With the procedure of calculating the stifness tensors at low- and high-frequency limits, we can easily calculate the frequency-dependent stifness tensor for media with multiple fracture sets with arbitrary orientations and directions. We then analyze the efects of the fracture parameters on the viscoelasticity characteristics taking orthotropic medium as an example. The results can help to understand the viscoelasticity and the mesoscopic seismic attenuation associated with fractures and fuids and can provide a practical rock physics model when dealing with reservoirs with complex fracture patterns.

11

Stabilność dyspersji akrylowej i właściwości powłok ochronnych z dodatkiem azotanu(V) benzalkoniowego

Kowalik Joanna

Przemysł Chemiczny

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2019

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T. 98, nr 11

1784--1788

PL

Przedstawiono wyniki badań stabilności wodnych dyspersji akrylowych z dodatkiem azotanu(V) benzalkoniowego, środka powierzchniowo czynnego (SPC) i zagęszczaczy. Zbadano właściwości fizykomechaniczne powłok ochronnych otrzymanych z tych dyspersji. Spośród analizowanych dyspersji najstabilniejsze układy i powłoki o dobrych właściwościach ochronnych uzyskano przy zastosowaniu 1% mas. cieczy jonowej, 5% SPC i zagęszczacza poliuretanowego DSX 1514.

EN

A com. available acrylic dispersion was modified by addn. of an ionic liq. (benzalkonium nitrate), a surfactant (ethoxylated lauryl alcohol) and a polyurethane thickener. The stability, surface tension and viscosity of the dispersions obtained, as well as the phys.-mech. properties of the coatings obtained from them (thickness, gloss, adhesion, impact resistance, resistance to tearing and compression test) were detd. The most stable systems and coating with good protective properties were obtained for dispersions containing the ionic liq., surfactant and the polyurethane thickener in amts. of 1, 5 and 0.3 % by mass, resp.

12

Simultaneous chemical reactions effect on dispersion of a solute in peristaltic propulsion of a Newtonian fluid in an inclined channel with wall properties

Dhange M. Y., Sankad G. C.

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 3

527--538

EN

In this paper, the dispersion of a solute in the peristaltic propulsion of an incompressible and viscous fluid through a permeable medium under the influence of wall properties with simultaneous homogeneous, heterogeneous chemical reactions in an inclined uniform channel has been studied. The issue is studied through conditions of Taylor’s limit and long wavelength hypothesis. The mean effective coefficient of scattering expression is computed and outcomes are interpreted physically through graphs.

13

Parametry opisujące zmienną pojemność adsorpcyjną gruntu jako pomocnicze narzędzia w określaniu zmian jakości wód podziemnych (w strefie saturacji)

Aniszewski Andrzej

Instal

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2019

|

nr 10

52--57

PL

Ważnym zagadnieniem w transporcie zanieczyszczeń w gruncie jest wykazanie wpływu zależnej od czasu pojemności adsorpcyjnej tego gruntu na zmianę jakości wód podziemnych (w strefie saturacji). W pracy, dla wybranego gruntu i przepływających w nim zanieczyszczeń, wykazano tendencję zmiany pojemności adsorpcyjnej tego gruntu na podstawie wybranych parametrów charakteryzujących tę pojemność (Ra, ux/Ra, ΔC*max). Analiza liczbowych wartości tych parametrów wykazała zarówno spadkową w czasie tendencję pojemności adsorpcyjnej analizowanego gruntu jak i stopniowy wzrost zanieczyszczenia wód gruntowych. Dlatego wnioski wynikające z tych badań mogą być bardzo użyteczne w praktyce, gdy wykorzystuje się zasoby tych wód do różnych celów i gdy jednocześnie czystość tych wód maleje w czasie.

EN

An important issue in the transport of pollutants in the ground is the demonstration of the impact the time-dependent adsorption capacity of this ground on the change in the quality of groundwater (in a saturated zone). At work both for the selected ground and pollutants flowing in it, there is a tendency change of the adsorption capacity of this ground based on the adopted parameters characterizing this capacity (Ra, ux/Ra, ΔC*max). The analysis of the numerical values of these parameters showed both a declining tendency in time of the adsorption capacity of the analyzed ground as well as in a gradual increase contamination of groundwater. Therefore, the conclusions of these research can be very useful in practice, when using groundwater resources for various purposes and when simultaneously the purity of these waters decreases in time.

14

The influence of surface physicochemistry of solid fillers on dispersion in polyurea systems

Dobrosielska Marta, Pakuła Daria, Sztorch Bogna, Popiół Maciej, Klonowski Bartosz, Brząkalski Dariusz, Marciniec Bogdan, Przekop Robert E.

Composites Theory and Practice

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2019

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R. 19, nr 2

83--90

EN

Polyurea coatings are obtained by hydrodynamic spraying by means of high-pressure, spray-coatingequipment. A chemical reaction between the isocyanate and amine components occurs in the time of approximately 6 seconds, which enables use of the coated object almost immediately after coating application. Polyurea coating modification results in changes in their properties and a cost reduction. In this work modifiers such as expanded graphite, talc and chalk, which are inexpensive, easily commercially obtainable fillers were employed. The curing degree was measured by FT-IR spectroscopy, thermal stability by thermogravimetric analysis (TG) and phase transition temperatures by differential scanning calorimetry (DSC). For the systems stored under different conditions, the tensile strength and Shore hardness in the D scale were also measured. SEM/EDS analysis was performed to assess the dispersion of the modifiers in the polyurea coatings. To determine the hydrophobic-hydrophilic character, contact angle analyses were performed. The addition of the fillers improves some of the parameters, e.g. the thermal stability and mechanical properties.

PL

Powłoki polimocznikowe otrzymywane są na drodze natrysku hydrodynamicznego za pomocą wysokociśnieniowych aparatów do powlekania natryskowego. Reakcja chemiczna pomiędzy składnikiem izocyjanianowym a aminowym następuje w czasie około 6 sekund, dzięki czemu możliwe jest użytkowanie powleczonego elementu niemal natychmiast po aplikacji. Modyfikacja powłok polimocznikowych powoduje zmianę ich właściwości oraz obniżenie kosztów produkcji. W pracy wykorzystano takie modyfikatory, jak grafit ekspandowany, talk oraz kredę, które są tanimi, łatwo dostępnymi komercyjnie napełniaczami. Stopień dosieciowania powłok badano za pomocą analizy spektroskopowej FT-IR, stabilność termiczną określono przy użyciu analizy termograwimetrycznej (TG), a temperatury przejść fazowych za pomocą skaningowej kalorymetrii różnicowej (DSC). Dla układów przechowywanych w różnych warunkach wykonano również badania odporności powłok na rozciąganie oraz zbadano twardość w skali Shore’a D. W celu określenia charakteru hydrofobowo-hydrofilowego przeprowadzono badania kąta zwilżania. Zbadano również dyspersję napełniaczy stałych w polimerze za pomocą skaningowej mikroskopii elektronowej (SEM) oraz określono skład chemiczny układów techniką EDS. Dodatek napełniaczy powoduje polepszenie niektórych parametrów, m.in. stabilności termicznej czy właściwości mechanicznych.

15

Dispersion of Al-Si Alloy Structure by Intensive Pulsed Electron Beam

Konovalov S., Gromov V., Zaguliyaev D., Ivanov Y., Semin A., Rubannikova J.

Archives of Foundry Engineering

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2019

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iss. 2

79--84

EN

By the method of modern physical material science (optic microscopy scanning and transmission electron microscopy) the analysis of structural phase states, the morphology of the second phase inclusions and defect substructure of Al-Si alloy (silumin) of hypoeutectic composition, subjected to electron beam processing was done with the following parameters: energy density 25-35 J/cm2, beam length 150 μs, pulse number – 3, pulse repetition rate – 0.3 Hz, pressure of residual gas (argon) 0.02 Pa. The surface irradiation results in the melting of the surface layer, the dissolution of boundary inclusions, the stricture formation of high speed cellular crystallization of submicron sizes, the repeated precipitation of the second phase nanodimentional particles. With the increased distance from the irradiation surface the layer containing the second phase inclusions of quasi-equilibrium shape along with the crystallization cells was revealed. It is indicative of the processes of Al-Si alloy structure globalization on electron beam processing.

16

Turbulent mixing and dispersion mechanisms over flexible and dense vegetation

Termini Donatella

Acta Geophysica

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2019

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Vol. 67, no. 3

961--970

EN

The present study investigates flow turbulence and dispersion processes in the presence of flexible and dense vegetation on the bed. The turbulent dispersion coefficients and the terms of the turbulent kinetic energy equation are determined by using data collected in a straight laboratory channel with living vegetation on the bed. Results show that the turbulent integral lengths assume an order of magnitude comparable to the stems’ characteristic dimension independently by the direction and the turbulence assumes an isotropic behavior. The coefficients of dispersion have a trend similar to that of the turbulent lengths and assume low values in the longitudinal, transversal and vertical directions. Results also show that, in the mixing layer, the shear and wake turbulence production terms balance the dissipation; the turbulent diffusion term also assumes low values and its sign varies along the vertical indicating a transport of turbulent energy both from the vegetation to the free surface and from the free surface to vegetation.

17

Frequency‑dependent energy attenuation and velocity dispersion in periodic layered media

Zhang Heng, Zhang Fanchang, Lu Yawei

Acta Geophysica

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2019

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Vol. 67, no. 3

799--811

EN

According to Brajanovski periodic layered model, a fractural medium can be equivalent to layered media with periodic distribution of fractural layers and background layers, but the analytical solution given by Brajanovski can only interpret the dispersion and attenuation effects of single characteristic unit model. In order to study the dispersion and attenuation features of multiple characteristic units, forward modeling methods are needed. Based on the theory of two-phase medium, Biot deduced the propagation equation of longitudinal waves in fluid-saturated porous media. However, there are two problems in the forward modeling using time-domain equation. One is the influences of boundary reflection, and the other is the introduction of cumulative error. For convenience, time-domain equation is rewritten in the frequency domain, thus constructing a one-dimensional rock physics model. Then, forward method is used to study the dispersion and attenuation features of fluid-saturated medium. Numerical simulation results are found to be in good agreement with the analytical solution. Furthermore, the frequency-domain forward method can analyze the velocity dispersion and energy attenuation of longitudinal waves in any multilayered fracture medium. By analyzing those numerical simulation results, it can be obtained that, as the length of characteristic unit increases or the number of characteristic unit decreases, both the starting frequency of dispersion and the peak frequency of attenuation shift to low, whatever the attenuation peaks are equal. In addition, the effects of porosity, permeability and fluid saturation on energy attenuation and velocity dispersion are also studied. Finally, the stress field and displacement field distributions of fluid-saturated fractural medium are given by the frequency-domain forward modeling method.

18

Edge‑based finite‑element modeling of 3D frequency‑domain electromagnetic data in general dispersive medium

Yue Mingxin, Wu Xiaoping

Acta Geophysica

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2019

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Vol. 67, no. 2

545--555

EN

The geophysical electromagnetic (EM) theories are commonly based on the assumption that the conductivity of underground media is frequency independent. However, due to the existence of induced polarization (IP) effect, many earth materials are dispersive, and their electrical conductivity varies significantly with frequency. Therefore, the conventional numerical techniques are not proper for EM forward modeling in general dispersive medium. We present a new algorithm for modeling three-dimensional (3D) EM data containing IP phenomena in frequency domain by using an edge-based finite element algorithm. In this research, we describe the dispersion behavior of earth media by using a Cole–Cole complex conductivity model. Our algorithm not only models land and airborne EM surveys but also provides more flexibility in describing the surface topography with irregular hexahedral grids. We have validated the developed algorithm using an analytic solution over a half-space model with and without IP effect. The capabilities of our code were demonstrated by modeling coupled EM induction and IP responses in controlled-source audio magnetotelluric (CSAMT) and airborne electromagnetic (AEM) examples. This algorithm will have important guiding significance for survey planning in the dispersive areas, and it could be taken as a forward solver for practical 3D inversion incorporated IP parameters.

19

Comprehensive prediction of coal seam thickness by using in‑seam seismic surveys and Bayesian kriging

Zhu Mengbo, Cheng Jianyuan, Cui Weixiong, Yue Hui

Acta Geophysica

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2019

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Vol. 67, no. 3

825--836

EN

Quantitative determination of the coal seam thickness distribution within the longwall panel is one of the primary works before integrated mining. In-seam seismic (ISS) surveys and interpolations are essential methods for predicting thickness. In this study, a new quantitative method that combines ISS and Bayesian kriging (BK), called ISS–BK, is proposed to determine the thickness distribution. ISS–BK consists of the following six steps. (1) The group velocity of Love waves is plotted by using the simultaneous iterative reconstruction technique under a constant frequency value. (2) An approximate quantitative relationship between the thickness and the group velocity is fitted based on sampling points of the coal seam thickness, which are measured during the process of entry development. (3) The group velocity map is translated into a primary thickness map according to the above-mentioned fitted equation. (4) By subtracting the ISS prediction result from the actual thickness at a sampling point, the residual variable is created. (5) The residual distribution is interpolated within the whole longwall panel by applying BK. The residual map establishes the interconnection between the ISS survey and BK. (6) A refined thickness distribution map can be obtained by overlapping the primary thickness map and the residual map. The application of this method to the No. 2408 longwall panel of Yuhua Coal Mine using ISS–BK showed a considerable improvement in thickness prediction accuracy over ISS. The residuals of ISS and ISS–BK mainly lie in the intervals (− 3.0, 3.0 m) and (− 1.0, 3.0 m), respectively. The accurate prediction rates [where the residual lies in the interval (0, 0.1 m)] of ISS and ISS–BK are 9.39% and 50.28%, respectively, and the effective prediction rates (where the residual is less than 1.0 m) of ISS and ISS–BK are 61.88% and 77.90%, respectively. All the above statistics reflect a considerable improvement in the ISS–BK method over the ISS method.

20

Zmodyfikowana trójparametryczna metoda oceny dyspersji zaopatrzenia w wodę w systemach zbiorowego zaopatrzenia w wodę

Rak J., Boryczko K.

Technologia Wody

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2018

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Nr 2 (58)

16--18

PL

Liczba podsystemów dostawy wody oraz ich udział w całości dostawy wody do SZZW daje możliwość obliczenia bezwymiarowego wskaźnika Pielou. W analogiczny sposób można określić wskaźniki dyspersji dla sieciowych zbiorników wodociągowych (znając liczbę i objętości zbiorników) oraz dla rurociągów tłocznych z pompowni II stopnia (znając liczbę rurociągów i ich powierzchnie przekroju poprzecznego). W pracy przedstawiono obliczenia wskaźników dyspersji dla wybranych SZZW na terenie Polski. Przedstawiona metodyka daje możliwość trójparametrycznej oceny jednostek osadniczych o różnym zapotrzebowaniu na wodę i różnej strukturze technicznej.

EN

The number of water supply subsystems and their share in the total water supply to the CWSS gives the opportunity to calculate the dimensionless Pielou indicator. The dispersion indicators for network water tanks (knowing the number and volume of tanks) and for the 2nd stage pumping station discharge pipelines (knowing the number of pipelines and their cross-sectional areas) can be determined in the same way. The paper presents calculations of dispersion indicators for selected CSWW in Poland. The presented methodology gives the possibility of three-parameter evaluation of settlement units with different water demand and various technical structures.