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1

Structure and properties of self-extinguishing rigid polyurethane foam with inorganic filler

Szymiczek Małgorzata, Sarraj Sara, Chomiak Monika, Chmielnicki Błażej, Gajlewicz Izabela

Polimery

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2024

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Vol. 69, nr 4

211--222

EN

The study examined the influence of selected inorganic fillers (5 and 10% by mass) on the foaming process, physicochemical properties, and structure of self-extinguishing polyurethane foam (density of approx. 35 kg/m3) obtained by reacting polyol with isocyanate (100:110). The filler used was bentonite (B), lamellar graphite (G), dendritic copper (Cu), aluminum oxide (Al2O3) and silicon carbide (SiC) and Al2O3/SiC mixture (1:1). Stereoscopic microscopy was used to determine the structure. The functional properties were examined based on density, water absorption and fire resistance. The course of the foaming reaction depends on the content, type and physicochemical properties of the filler. The addition of bentonite increases water absorption and Al2O3 reduces flammability of the foam.

PL

W pracy zbadano wpływ wybranych napełniaczy nieorganicznych (5 i 10 % mas.) na proces spieniania, właściwości fizykochemiczne i strukturę samogasnącej pianki poliuretanowej (gęstość ok. 35 kg/m3), którą otrzymano w wyniku reakcji poliolu z izocyjanianem (100:110). Jako napełniacza użyto bentonitu (B), grafitu o budowie lamelarnej (G), miedzi o strukturze dendrytycznej (Cu), tlenku glinu (Al2O3) i węglika krzemu (SiC) oraz mieszaninę Al2O3/SiC (1:1). Do oceny struktury stosowano mikroskopię stereoskopową. Właściwości użytkowe oceniano na podstawie gęstości, absorpcji wody i odporności na ogień. Przebieg reakcji spieniania zależy od zawartości, rodzaju i właściwości fizykochemicznych napełniacza. Dodatek bentonitu zwiększa absorpcję wody, a Al2O3 zmniejsza palność pianki.

2

Studying the influence of selected controlled factors on the coefficient of sliding friction through experimental planning metho

Ahmedov Beyali, Aslanov Zabit

Nafta-Gaz

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2024

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R. 80, nr 1

30--38

EN

The article presents the use of mathematical statistics to determine controllable factors that influence the coefficient of friction in a dual-flow three-stage spur gear transmission of a newly designed sucker rod pumping unit. The load acting on the bearing units, the rotational speed of the main and auxiliary shafts, and the diametrical gap between the shaft and the bushing were assessed through tests. The tests were carried out in random order. The multivariate testing was used to determine the number of tests to be performed as well as the test conditions in order to achieve the required accuracy bushing. In the statistical analysis of the results, the Cochrane criterion was applied to verify the homogeneity of the variance values. Student's t-test was used to verify the significance of the coefficients included in the regression equation, Fisher’s F-test was used to determine the suitability of the adopted output function for describing the real object of study, i.e., the adequacy of the model, and sensitivity coefficients were used to assess the influence of the corresponding parameters on the optimization parameter. The analysis also considered the dispersion of optimization parameters, measurement repeatability, and errors in the model coefficients. Experimental values of the criteria, along with the dispersion of the adequacy and repeatability of the mathematical model, were evaluated to determine whether the model is fully suitable for the object of study. The impact of significant factors and their combinations, as well as their critical values, were assessed by comparing calculated values of the criteria. The significance or insignificance of the corresponding coefficients of the regression equation was determined. To investigate the impact of these controlled factors — load, rotational speed of the main and auxiliary shafts, and the diametrical gap between the auxiliary shaft and the bushing — on the sliding friction coefficient, a modernized device was developed. This device simulates the operating conditions of a double friction sliding bearing in a dual-flow, three-stage spur gearbox bushing. The experiments were conducted using I-40A industrial oil at room temperature. It has been determined that these factors significantly impact the coefficient of friction in a double friction bearing. Consequently, it is necessary to calculate their limit values to ensure the bearing assembly operates without failure during the required service life. Compared to other examined parameters, the optimization parameter, i.e., the coefficient of friction, is most significantly influenced by the diametrical gap between the auxiliary shaft and the bushing, and least affected by the magnitude of the load acting on the bearing assembly. The overall impact of controlled factors on the coefficient of friction is minimal. Employing the test planning method, a mathematical formula was derived, enabling the determination of the coefficient of friction in a double sliding friction bearing without additional tests within the range of limit bushing values of contact parameters.

PL

W artykule przedstawiono zastosowanie statystyki matematycznej do określenia sterowalnych czynników wpływających na współczynnik tarcia w podwójnej, trójstopniowej przekładni zębatej czołowej nowo zaprojektowanej pompy żerdziowej. Za pomocą badań oceniono obciążenie działające na zespoły łożyskowe, prędkość obrotową wału głównego i pomocniczego oraz średnicę szczeliny między wałem a tuleją. Badania przeprowadzono w losowej kolejności. Badania wielowariantowe wykorzystano do określenia liczby badań, które należy wykonać, a także warunków badawczych w celu osiągnięcia wymaganej dokładności. W analizie statystycznej wyników zastosowano kryterium Cochrane'a w celu weryfikacji jednorodności wartości wariancji. Test t-Studenta posłużył do weryfikacji istotności współczynników zawartych w równaniu regresji, test F-Fishera wykorzystano do określenia przydatności przyjętej funkcji wyjściowej do opisania rzeczywistego obiektu badań, tj. adekwatności modelu, a współczynniki wrażliwości wykorzystano do oceny wpływu odpowiednich parametrów na parametr optymalizacyjny. W analizie uwzględniono również rozrzut parametrów optymalizacyjnych, powtarzalność pomiarów oraz błędy we współczynnikach modelu. Eksperymentalne wartości kryteriów, wraz z rozproszeniem adekwatności i powtarzalności modelu matematycznego, zostały ocenione w celu ustalenia czy model w pełni spełnia wymagania stawiane obiektowi badań. Wpływ istotnych czynników i ich kombinacji, a także ich wartości krytyczne, oceniono poprzez porównanie obliczonych wartości kryteriów. Określono istotność lub nieistotność odpowiednich współczynników równania regresji. W celu zbadania wpływu tych kontrolowanych czynników – obciążenia, prędkości obrotowej wału głównego i pomocniczego oraz szczeliny średnicowej pomiędzy wałem pomocniczym a tuleją – na współczynnik tarcia ślizgowego, opracowano zmodernizowane urządzenie. Urządzenie to symuluje warunki pracy podwójnego łożyska ślizgowego w podwójnej, trzystopniowej przekładni czołowej. Eksperymenty przeprowadzono przy użyciu oleju przemysłowego I-40A w temperaturze pokojowej. Ustalono, że czynniki te mają znaczący wpływ na współczynnik tarcia w podwójnym łożysku ślizgowym. W związku z tym konieczne jest obliczenie ich wartości granicznych, aby zapewnić bezawaryjną pracę zespołu łożyskowego w wymaganym okresie eksploatacji. W porównaniu z innymi badanymi parametrami, na parametr optymalizacyjny, tj. współczynnik tarcia, największy wpływ ma szczelina średnicowa między wałem pomocniczym a tuleją, a najmniejszy wpływ ma wielkość obciążenia działającego na zespół łożysk. Ogólny wpływ kontrolowanych czynników na współczynnik tarcia jest minimalny. Wykorzystując metodę planowania badań, wyprowadzono wzór matematyczny umożliwiający wyznaczenie współczynnika tarcia w podwójnym ślizgowym łożysku bez dodatkowych badań w zakresie granicznych wartości parametrów styku.

3

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.

4

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

|

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.

5

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.

6

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.

7

Contaminant transport in the surf zone

Chin David A.

Oceanologia

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2022

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No. 64 (4)

651--664

EN

Dispersion of dissolved contaminants introduced at various locations within and just outside the surf zone are investigated. It is shown that the Longuet-Higgins model of surf-zone hydrodynamics adequately describes the distribution of longshore currents measured at the laboratory scale. Relations are derived between the longitudinal and transverse dispersion coefficients and the influencing parameters. The maximum longitudinal dispersion coefficients are associated with tracer releases near the breaker line, and longitudinal dispersion coefficients generally increase with travel time for distances up to at least 10 surf-zone widths. In contrast, transverse dispersion coefficients remain relatively constant for increasing travel time. The longitudinal and transverse dispersion coefficients can be significantly influenced by assumed values of local turbulent diffusion and cross-shore shear dispersion.

8

Influence of the numerical modelling methods on dispersions and errors of analysis results of ship hull and deckhouse vibrations

Murawski Lech

Journal of KONBiN

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2022

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Vol. 52, iss. 4

207--222

EN

Ships' (especially containers) vibrations significantly impact navigation safety. The presented analyses aims to identify the main forces exciting the ship's superstructure and hull vibrations, test their influence on vibration levels, and verify the assumptions of the computational methodology. Two container ships were analysed. The influence of different modeling methods on the obtained calculation results was investigated. The impact of various operating parameters on the vibration level was also analysed. The numerical analyses results are compared with some empirical formulas. As a result, the calculation confidence level was estimated. The calculation results have been verified by comparison with measurement tests carried out on the real ship.

PL

Drgania statków (zwłaszcza kontenerowców) mają duży wpływ na bezpieczeństwo żeglugi. Celem przedstawionych analiz jest identyfikacja głównych sił wymuszających drgania nadbudówki i kadłuba statku, zbadanie ich wpływu na poziom drgań oraz weryfikacja założeń metodyki obliczeniowej. Przeanalizowano dwa kontenerowce. Zbadano wpływ różnych metod modelowania na wyniki obliczeń. Przeanalizowano również wpływ różnych parametrów eksploatacyjnych na poziom drgań. Wyniki analiz numerycznych porównano z niektórymi wzorami empirycznymi. W rezultacie oszacowano poziom ufności obliczeń. Wyniki obliczeń zostały zweryfikowane poprzez porównanie z badaniami pomiarowymi wykonanymi na rzeczywistym statku.

9

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.

10

An introduction of the planetary roller extruder technology on the example of the wood-plastic composites production

Sąsiedzki Tad

Modelowanie Inżynierskie

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2021

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T. 42, nr 73

42--47

EN

Planetary roller extruder with his excellent mass temperature control, homogenization and dispersion is used not only in the plastics industry, but in a wide range of physical processes like continuous mixing, reactive chemical processes as polymerization and decomposition, for example in the process of recycling. ENTEX developed in last few years new improved technical solutions for example for better degassing, higher torque transmission, laboratory applications and direct extrusion. With these new solutions we create significant cost savings due to reduction of energy consumption and reduction of production costs by simplifying production process. We can also improve final product quality by reducing the thermal and mechanical load on the material on the example of WPC composite (Wood-Plastic-Composites).

PL

Rynek kompozytów WPC stale rośnie i otwiera potencjał dla nowych producentów i nowych technologii. Również firma ENTEX Rust & Mitschke GmbH podjęła wyzwanie i oferuje swoją technologię mieszalnika planetarnego do wyżej wymienionych zastosowań. Ze względu na dużą powierzchnię styku, wysoce wydajne i precyzyjne możliwości ogrzewania lub chłodzenia przetwarzanego materiału oraz modułową budowę wytłaczarka planetarna jest w stanie uzyskać do 78% wypełnienia wiórkami drzewnymi w polimerze przy zachowaniu najwyższej jakości produktu końcowego.

11

Simulation of photovoltaic panel cooling beneath a single nozzle based on a configurations framework

Mzad Hocine, Otmani Abdessalam

Archives of Thermodynamics

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2021

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Vol. 42, no 1

115--128

EN

Solar cell performance decreases with increasing temperature, heat can reduce output efficiency by 10–25%. The operating temperature plays a key role in the photovoltaic conversion process. Increase in electrical efficiency depends on cooling techniques, in particular photovoltaic modules installed in the high temperature regions. A cooling process using a single nozzle of photovoltaic panel operating under different configurations was simulated. The simulation contains two parts: the first is a thermodynamic investigation of fluid impingement upon the sensor front face. The second is a performance comparison between two types of glass cover. The major result that emerges from this simulation is the effect of a single nozzle arrangement to enhance the cooling process, under a low cadence of impinging droplets in the range 0.1–1.7 m/s.

12

A quadrature-free Legendre polynomial approach for the fast modelling guided circumferential wave in anisotropic fractional order viscoelastic hollow cylinders

Zhang X., Liang S., Shao S., Yu J.

Archives of Mechanics

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2021

|

Vol. 73, nr 2

121--152

EN

Compared to the traditional integer order viscoelastic model, a fractional order derivative viscoelastic model is shown to be advantageous. The characteristics of guided circumferential waves in an anisotropic fractional order Kelvin–Voigt viscoelastic hollow cylinder are investigated by a quadrature-free Legendre polynomial approach combining the Weyl definition of fractional order derivatives. The presented approach can obtain dispersion solutions in a stable manner from an eigenvalue/eigenvector problem for the calculation of wavenumbers and displacement profiles of viscoelastic guided wave, which avoids a lot of numerical integration calculation in a traditional polynomial method and greatly improves the computational efficiency. Comparisons with the related studies are conducted to validate the correctness of the presented approach. The full three dimensional spectrum of an anisotropic fractional Kelvin–Voigt hollow cylinder is plotted. The influence of fractional order and material parameters on the phase velocity dispersion and attenuation curves of guided circumferential wave is discussed in detail. Moreover, the difference of the phase velocity dispersion and attenuation characteristics between the Kelvin–Voigt and hysteretic viscoelastic models is also illustrated. The presented approach along with the observed wave features should be particularly useful in non-destructive evaluations using waves in viscoelastic waveguides.

13

An influence of the covariance between single orbit parameters on the accuracy of observations of the pseudo-ranges and phase differences

Skeivalas Jonas, Paršeliūnas Eimuntas, Putrimas Raimundas, Šlikas Dominykas

Metrology and Measurement Systems

|

2020

|

Vol. 27, nr 1

131--140

EN

The possibilities to improve values of the satellite orbit elements by employing the pseudo-ranges and differences of carrier phase frequencies measured at many reference GPS stations are analysed. An improvement of orbit ephemeris is achieved by solving an equation system of corrections of the pseudo-ranges and phase differences with the least-squares method. Also, equations of space coordinates of satellite orbit points expressed by ephemeris at fixed moments are used. The relation between the accuracy of the pseudo-ranges and phase differences and the accuracy of the satellite ephemeris is analysed. Formulae for estimation of the influence of the ephemeris on the measured pseudo-ranges and phase differences and for prediction of the accuracy of the pseudo-ranges and phase differences were obtained. An influence of the covariance between single orbit parameters on the accuracy of the pseudo-ranges and phase differences is detected.

14

Investigating Sintering Behavior of the Graphene Nanoplatelets (GNPs) Reinforced Aluminum Nanocomposites Via Low Energy Solution Ball Milling

Baig Zeeshan, Mamat Othman, Mustapha Mazli, Ali Sadaqat

Archives of Metallurgy and Materials

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2020

|

Vol. 65, iss. 2

755--759

EN

Owing to the excellent properties, graphene nanoplatelets (GNPs) show great reinforcing ability to improve the mechanical and tribological properties of Al nanocomposites for many automotive applications. In this work, the GNPs dispersion and reinforcing effect in Al nanocomposite was tested. Solvent dispersion via tip sonication and facile low energy ball milling (tumbling milling) using two milling speeds 200 and 300 rpm were employed to develop GNPs/Al powders. Sintering response of the GNPs/Al sintered samples wasgauged at two temperatures (550°C and 620°C). The effects of GNPs content, milling rotation speed and sintering temperature on the density, hardness and wear properties of the nanocomposite were examined. The results indicate that relative density % decreases with increasing GNPs content due to possible reagglomeration. The highest hardness of 35.6% and wear rate of 76.68% is achieved in 0.3 wt.% GNPs/Al nanocomposite processed at 300 rpm and 620°C as compared to pure Al due to uniform dispersion, higher diffusion rate at a higher temperature and effective lubrication effect.

15

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.

16

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.

17

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

Kowalik Joanna

Przemysł Chemiczny

|

2019

|

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.

18

Pseudostabilny lot naddźwiękowego pocisku moździerzowego

Merda Tomasz

Problemy Techniki Uzbrojenia

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2019

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R. 48, z. 149

23--46

PL

W trakcie prac nad opracowywaniem naddźwiękowych pocisków moździerzowych, podczas strzelań jednym z typów pocisku, zaobserwowano bardzo duży rozrzut. Wykorzystując model balistyki zewnętrznej traktujący pocisk jako bryłę sztywną wyznaczono tory lotu badanych pocisków oraz określono ich parametry i przyczyny rozrzutu ich punktów upadku. Analiza uzyskanych wyników wykazała, że przyczyną powstałego rozrzutu nie był podrzut aerodynamiczny tylko inne, nie opisane dotąd w literaturze, zjawisko, które w niniejszej pracy zostało nazwane „pseudostabilnym lotem pocisku”. W pracy przedstawiono opis, określono przyczyny i czynniki mające wpływ na jego występowanie oraz przedstawiono metodę wyznaczania kąta nutacji równowagi, który jest kluczowy dla tego zjawiska.

EN

Significantly large dispersion of projectiles was observed at firing a specific type of a supersonic mortar projectile being developed. The flying paths, parameters and reasons of falling points dispersion were determined for tested projectiles with a model of external ballistics describing the projectile as a rigid body. Analysis of received results has indicated that the dispersion was not caused by an aerodynamic jump but by an effect which has not been described yet in the literature and is named here as “projectile’s semi stable flight”. The paper includes a description of the effect with reasons and parameters affecting its occurrence, and a method for determination of the equilibrium nutation angle which plays a key role in this effect.

19

Dispersion Analysis of Rounds Fired from a Glauberyt Machine Pistol

Dziopa Zbigniew, Zdeb Krzysztof

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2019

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Vol. 10, Nr 1 (35)

121--134

EN

Within an enclosed shooting range of the EMJOT company, the process of firing one hundred single bullets from a Glauberyt machine pistol was recorded. The empirical test used 9x19 mm FMJ Luger (Parabellum) ammunition manufactured in the Czech Republic in 2017. As the weapon is dedicated to special forces, the shots were fired by an anti-terrorist operative, at a target located 25 m away. In order to determine bullet dispersion, the results of the experiment were subjected to statistical processing. Mean displacement and mean square displacement relative to the mean hit point, histograms, normal distribution, as well as statistical tests and hypotheses were used for estimation. The shots were recorded with a high speed digital camera Phantom v 9.1. The videos recorded were used to determine the initial kinematic parameters of the bullet trajectory.

PL

Na zamkniętej strzelnicy firmy EMJOT przeprowadzono rejestrację procesu wystrzelenia z pistoletu maszynowego Glauberyt ogniem pojedynczym stu pocisków. Do badań empirycznych użyto amunicję 9x19 mm FMJ Luger (Parabellum) produkcji czeskiej z 2017 roku. Ze względu na dedykowanie broni dla oddziałów specjalnych strzały oddane zostały przez antyterrorystę, do tarczy znajdującej się w odległości 25 m. W celu określenia rozrzutu pocisków wyniki eksperymentu poddano obróbce statystycznej. Do estymacji zastosowano uchylenie średnie i uchylenie średnio-kwadratowe względem średniego punktu trafień, histogramy, rozkład normalny, oraz testy i hipotezy statystyczne. Przy wykorzystaniu szybkiej kamery cyfrowej Phantom v.9.1 przeprowadzono rejestrację wykonanych strzelań. Zarejestrowane filmy posłużyły do określenia początkowych kinematycznych parametrów lotu pocisku.

20

Numerical analysis of an impact of planned location of sewage discharge on Natura 2000 areas – the dead Vistula region case study

Zima Piotr

Polish Maritime Research

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2019

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nr 2

76--84

EN

This article presents results of an analysis of impact of a designed discharge of contaminated water into the Dead Vistula (Wisła Martwa) in the region of the Isthmus (Przesmyk) with the aim of determination of a possible effect of the pollution onto protected areas of Natura 2000 (bird habitats and sites, especially the Bird Paradise – Ptasi Raj) nature reserve. The analysis was conducted on the basis of the two-dimensional modelling of unsteady transport of non-degradable dissolved matter. To this end, a numerical model of a section of the Dead Vistula was worked out. Four scenarios of hydro-dynamical conditions (2 – for average weather conditions and 2 – for stormy weather conditions) were selected. To solving the equation of pollution migration the finite volumes method (MOS) was applied. Two localizations of contaminated water discharge outlet were considered, namely: the first from the side of Siennicki Bridge before the Isthmus and the other in the section of the Brave Vistula (Wisła Śmiała) downstream the Isthmus. The obtained results made it possible to assess positively the first localization of the designed discharge outlet. In the other case there is a fear that at unfavourable hydro-meteorological conditions a water pollution may happen over Natura 2000 protected areas.