Wyniki wyszukiwania - BazTech

1

Machinability analysis of thin-walled carbon fiber reinforced ceramic composites based on wire electrical discharge machining

Poroś Dariusz, Wiśniewska Magdalena

Zeszyty Naukowe Politechniki Morskiej w Szczecinie

|

2024

|

nr 77 (149)

5--13

EN

We propose employing wire electrical discharge machining (WEDM) for shaping thin-walled, multidirectional, carbon fiber reinforced silicon carbide (Cf-SiC) composite parts. Ceramic matrix composite Cf-SiC combines the outstanding mechanical properties of the carbon fiber with oxidation, abrasive wear, corrosion resistance, and high strength at the high temperature of the silicon carbide matrix. The impact of time-related electrical discharge machining parameters (pulse ON-time and break OFF-time) on the material removal rate and surface roughness are analyzed. The material removal rate of the Cf-SiC is proved to be 36% lower than that for machined steel grade 55. The high thermal stresses and interaction of the composite accompanying WEDM are also discussed. Furthermore, an alternative mechanism to the WEDM of metals has been investigated and confirmed by a scanning electron microscopy (SEM) analysis. The morphology of the machined Cf-SiC surface demonstrates the dominance of the carbon fibers’ fracture mechanism, both the transverse and longitudinal forms, with interphase detachment over craters and micro-cracks, pitting, and spalling on the SiC matrix. Satisfactory roughness indicators (Sa = 2 µm) are obtained in 3D topography measurements of the Cf-SiC surfaces. Concluding, the WEDM should be considered a good alternative to Cf-SiC abrasive machining when cutting holes, grooves, keyways, splines, and other complex shapes.

2

Application properties and microscopic analysis of elastomer samples cross-linked by gamma radiation

Bonato Jasminka

Zeszyty Naukowe Politechniki Morskiej w Szczecinie

|

2024

|

nr 78 (150)

15--21

EN

Natural rubber is an important industrial material derived from caoutchouc trees (Hevea Brasiliensis). By chemical composition, it is a polymer material that is mostly cis-1,4-polyisoprene. It falls into the category of elastomers, which enables its wide usage due to its specific characteristics. Polymer materials include plastic, rubber, and glue and are the most important technical materials. Rubbers are used in the production of conveyor belts, shock absorbers, coatings, fenders, engines, and device parts. They are also used in composite materials such as threads, particles, and matrix materials. By analyzing the properties of natural rubber, the subject of the research is defined, i.e., the characterization of natural rubber samples and their connection with macroscopic properties. In accordance with the subject of the research, in this paper, tests are carried out on samples of natural rubber, which are obtained in the form of thin films from latex and cross-linked by gamma radiation. A total dose of 300 kGy is applied to the samples in the state of uniaxial deformation. In this sense, a hypothesis is put forward that involves examining the influence of radiation dose on the morphology of natural rubber samples using scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDX). The investigation aims to emphasize the importance of the method in acquiring a comprehensive characterization of the material samples, which are used both in maritime areas and in other fields of application.

3

Wykorzystanie tomografii komputerowej oraz SEM w ocenie morfologii przekrojów próbek azotanu(V) amonu

Biessikirski Andrzej, Kuterasiński Łukasz, Dworzak Michał, Kolano Malwina, Ruggiero-Mikołajczyk Małgorzata

Przemysł Chemiczny

|

2024

|

T. 103, nr 7

805--810

PL

Przedstawiono wyniki badań doświadczalnych związanych z analizą powierzchni morfologicznej w przekrojach granul porowaconego i rolniczego azotanu(V) amonu. Ocenę morfologii przeprowadzono z wykorzystaniem SEM oraz tomografii komputerowej. Przekroje próbek azotanu(V) amonu charakteryzowały się strukturą przypomi nająca pumeks. Wykazały występowanie niewielkiej liczby kanałów oraz brak chropowatości powierzchni krystalicznej. W przypadku porowaconego azotanu(V) amonu próbki charakteryzowały się zróżnicowaną budową wynikającą z różnych procesów produkcyjnych. Obie próbki wykazywały dużą liczbę porów, m.in. obecność porów kulistych i wydłużonych. Ponadto w przypadku AN-PP-2 w przekroju próbki widoczna była centralna pustka powietrzna, która nie znajdowała się na żadnym ze skanów dla AN-PP-1. Porowacony azotan(V) amonu charakteryzował się dużą porowatością, rzędu 60-70%, w po równaniu z porowatością rolniczego azotanu(V) amonu (ok. 49%). Przeprowadzone badania BET wykazały, że AN-PP-2 charakteryzował się największą powierzchnią właściwą, ok. 0,5 m²/g, co przy uwzględnieniu mocno rozwiniętej budowy morfologicznej potwierdza wysokie określane przez producenta współczynniki absorpcji.

EN

The morphology of cross sections of porous and agricultural NH₄NO₃ granules was analyzed by scanning electron microscopy (SEM), computed tomography and low-temperature nitrogen sorption. Agricultural NH₄NO₃ showed a pumice-like structure, characterized by a small number of channels and a smooth crystalline surface but samples of prilled NH₄NO₃ showed a significant presence of pores, including spherical and elongated pores. The porosity of prilled and agricultural NH₄NO₃ was 70 and 49%, resp. and BET surface area of both materials was 0.5 m²/g and 0.01 m²/g resp.

4

Effect of low-temperature plasma treatment on rubber properties

Ďurišová Silvia, Pajtášová Mariana, Ondrušová Darina, Janík Róbert, Mičicová Zuzana, Dubec Andrej, Pagáčová Jana, Šulcová Jana, Božeková Slavomíra, Vavro Jan, Klepka Tomasz

Polimery

|

2024

|

Vol. 69, nr 4

245--253

EN

The effect of the distance (0.5 and 5 mm) and exposure time (10 and 30 s) of the atmospheric plasma on the structure and surface properties (contact angle, adhesion) of unvulcanized rubber was examined. FT-IR and SEM were used to assess the structure. After plasma treatment, a higher intensity of the OH and COO- bands was observed, while the intensity of the bands from methylene groups decreased. SEM showed that plasma significantly reduces the size and number of agglomerates, resulting in a more uniform structure. The plasma distance has a significant effect on the surface properties of the rubber, with a better effect achieved at a smaller distance (0.5 mm). In this case, the rubber character changed from hydrophobic to hydrophilic, which is related to the introduction of oxygen species. A greater plasma distance (5 mm), regardless of the exposure time, resulted in a lower adhesion force. The exposure time had no significant effect on the tested rubber properties.

PL

Zbadano wpływ odległości (0,5 i 5 mm) oraz czasu ekspozycji (10 i 30 s) plazmy atmosferycznej na strukturę i właściwości powierzchniowe (kąt zwilżania, adhezja) niewulkanizowanej gumy. Do oceny struktury stosowano FT-IR i SEM. Po obróbce plazmą zaobserwowano większą intensywność pasm pochodzących od grup OH i COO-, natomiast intensywność pasm pochodzących od grup metylenowych zmniejszyła się. Metodą SEM wykazano, że plazma znacząco zmniejsza wielkość i liczbę aglomeratów, czego efektem jest bardziej jednorodna struktura. Odległość plazmy ma istotny wpływ na właściwości powierzchniowe gumy, przy czym lepszy efekt uzyskano przy mniejszej odległości (0,5 mm). W tym przypadku charakter gumy zmienił się z hydrofobowego na hydrofilowy, co jest związane z wprowadzeniem ugrupowań tlenowych. Większa odległość próbki od plazmy (5 mm), niezależnie od czasu ekspozycji, skutkowała mniejszą siłą adhezji. Czas ekspozycji nie miał istotnego wpływu na badane właściwości gumy.

5

Stabilization of Expansive Soil Mixture Using Human Hair Fibre (Biopolymer)

Idoui Imane, Bekkouche Souhila Rehab, Benzaid Riad, Berdi Inas

Civil and Environmental Engineering Reports

|

2024

|

Vol. 34, no. 2

63--75

EN

Expansive soils sensitivity to volumetric change is one of the well-known challenges in the field of geotechnical engineering. Various attempts have been made by researchers to solve this problem. Current research presents the effect of human hair fibers on the behavior of expensive soils. A reconstituted soil of 80% kaolin as raw material and 20% bentonite with different percentages of human hair (0%, 0.5%, 1%, 1.5% and 2%) was used. The microstructure of the formulations was characterized by studying the interactions between soil and human hair using scanning electron microscopy (SEM). The microstructure of the formulations was characterized by studying the interactions between soil and human hair using scanning electron microscopy (SEM). Atterberg limits, compaction characteristics, swelling parameters, compressibility and shear strength were also examined. The results of this study indicate that the inclusion of human hair fibers significantly improves the properties of the expansive soil mixture. These results open up new prospects for the stabilization of expansive soils.

6

The influence of travel mode choice on subjective well-being - a case study

Ali Mujahid, Macioszek Elżbieta

Transport Problems

|

2023

|

T. 18, z. 4

5--17

EN

The correlation between mobility and subjective well-being (SWB) has received much attention lately. Previous researchers have studied the effect of health parameters or SWB on transport mode; however, there is a lack of study on the influence of travel mode choice (TMC) for daily activities on SWB. Besides, the prediction of TMC is critical for transport planning. Therefore, the current study aims to study the TMC and its influence on overall SWB. Data from 732 individuals and 191 households are collected using random sampling techniques, which represents 0.029% of the total population. Statistical Package for Social Sciences (SPSS) was used for descriptive statistics, whereas R software was used for the multilevel linear regression analysis. The model estimation results show a significant correlation among the variables (p < 0.05, R2 > 0.20). Besides, those who are exposed to public transport and tend to use non- motorized transport modes engage in more physical activities than those who use a private vehicle, which has a negative impact on SWB. The outcome of current research helps policymakers build policies to achieve a sustainable transportation system.

7

Mechanical mixing and deaeration station for adhesive compositions

Miturska-Barańska Izabela

Technologia i Automatyzacja Montażu

|

2023

|

nr 4

38--47

EN

This paper presents the design of a specialised mixing and deaeration station for adhesive compositions. The aim of the work was to present a device for simultaneous mixing and gas bubble removal, as well as to verify the correctness of the practical application of the station by conducting experimental tests. In the experimental research, the subject of the study was an adhesive composition of the Epidian 5 epoxy resin with the PAC curing agent, which was prepared using four mixing methods carried out with the use of the station for simultaneous mixing and deaeration. The first mixing variant (V1) consisted of mixing the adhesive composition with a paddle mixer at 1170 rpm for 3 minutes, while in the second variant (V2) mixing was carried out with a dispersing disc mixer at 1170 rpm for 3 minutes. The third variant (V3) of mixing was carried out as variant 2, except that the adhesive composition was subjected to deaeration during mixing, while variant 4 (V4) additionally used deaeration of the composition after the mixing process for 2 minutes. The tested adhesive composition was physically modified by adding particles of calcium carbonate CaCO3 to verify the correct mixing of the composition components. The prepared samples were subjected to tensile and compressive strength tests. The structure of the prepared samples was also analysed using scanning electron microscopy (SEM). The tests carried out showed that the stand for simultaneous mixing and deaeration of adhesive compositions meets the expectations set for it. Mixing variant 4, in which mixing was realised using a dispersing disc mixer, proved to be the most favourable mixing method. Mixing was carried out at a speed of 1170 rpm for 3 minutes. In addition, during the mixing process, a deaeration process of the mixed composition was carried out, as well as deaeration was realised after the mixing process in a time of 2 minutes. Changing the mixing parameters contributed to an increase in both the tensile strength and compressive strength of the tested compositions. SEM analysis of the observed samples showed that changing the mixing parameters reduced the amount of air bubbles in the adhesive structure and, in the case of modified compositions, resulted in a better distribution of the filler in the structure of the mixed compositions.

PL

W niniejszej pracy przedstawiono projekt specjalizowanego stanowiska do mieszania i odpowietrzania kompozycji klejowych. Celem pracy była prezentacja urządzenia do jednoczesnego mieszania i usuwania pęcherzy gazowych, a także sprawdzenie prawidłowości praktycznego zastosowania stanowiska przez przeprowadzenie badań doświadczalnych. W badaniach doświadczalnych przedmiotem badań była kompozycja klejowa żywicy epoksydowej Epidian 5 z utwardzaczem PAC, którą przygotowano z zastosowaniem 4 sposobów mieszania realizowanych z użyciem stanowiska do jednoczesnego mieszania i odpowietrzania. Pierwszy wariant mieszania (V1) polegał na mieszaniu kompozycji klejowej mieszadłem łopatkowym z prędkością 1170 obr/min w czasie 3 minut, w drugim wariancie (V2) mieszanie realizowano z zastosowaniem mieszadła tarczowego dyspergującego z prędkością 1170 obr/min w czasie 3 minut. Trzeci wariant (V3) mieszania był realizowany tak jak wariant 2, z tym że kompozycję klejową poddano odpowietrzaniu w trakcie mieszania, natomiast w wariancie 4 (V4) zastosowano dodatkowo odpowietrzanie kompozycji po procesie mieszania w czasie 2 minut. Badaną kompozycję klejową poddano fizycznej modyfikacji poprzez dodanie cząsteczek węglanu wapnia CaCO3 celem weryfikacji poprawności zmieszania składników kompozycji. Wykonane próbki poddano badaniom wytrzymałości na rozciąganie i ściskanie. Analizowano również strukturę wykonanych próbek z zastosowaniem skaningowej mikroskopii elektronowej. Przeprowadzone badania wykazały, że stanowisko do jednoczesnego mieszania i odpowietrzania kompozycji klejowych spełnia stawiane mu oczekiwania. Najkorzystniejszym sposobem mieszania okazał się 4 wariant mieszania, w którym mieszanie zrealizowano z użyciem mieszadła tarczowego dyspergującego. Mieszanie realizowano z prędkością 1170 obr/min w czasie 3 minut. Dodatkowo w trakcie mieszania przeprowadzano process odpowietrzania mieszanej kompozycji, jak również odpowietrzanie realizowano po procesie mieszania w czasie 2 minut. Zmiana parametrów mieszania przyczyniła się do wzrostu wytrzymałości zarówno na rozciąganie, jak i wytrzymałości na ściskanie badanych kompozycji. Analiza SEM obserwowanych próbek wykazała, że zmiana parametrów mieszania pozwala zmniejszyć ilość pęcherzy powietrza w strukturze kleju, a w przypadku kompozycji modyfikowanych spowodowała lepsze rozprowadzenie napełniacza w strukturze mieszanych kompozycji.

8

Mycoremediation of Heavy Metals Contaminated Soil by Using Indigenous Metallotolerant Fungi

Akram Muhammad Bilal, Khan Ibrar, Ur Rehman Mujaddad, Sarwar Abid, Ullah Najeeb, ur Rahman Shafiq, Aziz Tariq, Alharbi Metab, Alshammari Abdulrahman, Alasmari Abdullah F.

Polish Journal of Chemical Technology

|

2023

|

Vol. 25, nr 3

1--13

EN

The present study was aimed to identify the indigenous fungal strains which could possibly be applied to the bioremediation of heavy metal-contaminated soil. The contaminated soil samples of Korangi Industrial Estate Karachi were found to have total concentration of Cu 1.044 mgL1 , and Pb 0.631 mgL–1. A total of eight indigenous strains of the fungus were isolated and screened for bioremediation capacity from heavy metals-contaminated soil. For the bioremediation of Lead (Pb) these same indigenous eight fungal strains were used for biological remediation. All the fungal isolated with enhanced bioremediation capability were through phenotypic and genotypical characterization. The topology of the phylograms established that the fungal isolates used in this study were allocated to: K1 (Penicillium notatum), K2 (Aspergillus parasiticus), K3 (Aspergillus fumigatus), K4 (Aspergillus flavus), K5 (Aspergillus terries), K6 (Fusarium solani), K7 (Penicillium chrysogenum), K8 (Aspergillus niger), K9 (Penicillium piceum) and K10 (Penicillium restrictum). Thus, K8 fungal isolate was found to be more efficient with maximum bioremediation capacity, for copper and lead removal efficiency, and selected for FTIR and SEM to find out the uptake of Cu and Pb which of the functional groups are involved, and further to detect the effects of bioleaching of both heavy metals on to the surface of K8 fungus biomass. The current study indicates that indigenous fungal isolates could be used with high potency to remediate or clean up the heavy metals-contaminated soil either by the technique of in situ or ex-situ bioremediation.

9

Preliminary studies on electrodeposition of Zn-Fe-W alloy coatings from citrate-sulphate baths

Shoaib Hafiz Muhammad, Winiarska Katarzyna, Winiarski Juliusz

Ochrona przed Korozją

|

2023

|

nr 2

44--47

EN

Exploratory studies of the electrodeposition process of zinc coatings containing iron and tungsten were carried out using SEM/EDS and XRD techniques. It was shown that from a citrate-sulphate plating bath composed of (mol dm−3): ZnSO4 – 0.2, FeSO4 – 0.2, Na3Cit (tri-sodium citrate salt) – 0.4, (NH4)2SO4 – 0.1 and Na2WO4 – 0.01 Zn-Fe-W alloys can be obtained on a rotating disc electrode. It was noted that the induced co-deposition of tungsten with iron only occurred at pH > 6.0. Below this value, a Zn-Fe alloy coating was obtained. In the pH range from 5.0 to 9.0, the maximum contents of tungsten (15.96 wt. %) and iron (29.36 wt. %) were shown by the coatings deposited at pH 7.0. The increase in the bath pH from 5.0 to 9.0 resulted in clear changes in the phase composition of the deposited coatings. According to the results of XRD analyzes, the following can be indicated as probable: Fe22Zn78 and Fe7W6. However, the recorded diffractograms are difficult to interpret and it was very difficult to clearly define the type of phases present in the coating without additional tests.

PL

Stosując techniki SEM/EDS i XRD, przeprowadzono rozpoznawcze badania procesu elektroosadzania powłok cynkowych zawierających żelazo i wolfram. Wykazano, że z cytrynianowo-siarczanowej kąpieli galwanicznej o składzie (mol dm−3): ZnSO4 – 0,2, FeSO4 – 0,2, Na3Cit (cytrynian tri-sodu) – 0,4, (NH4)2SO4 – 0,1 i Na2WO4 – 0,01 można otrzymać na wirującej elektrodzie dyskowej powłoki stopowe Zn-Fe-W. Zauważono, że indukowane współosadzanie wolframu z żelazem zachodziło dopiero przy pH > 6,0. Poniżej tej wartości otrzymywało się powłokę stopową Zn-Fe. W zakresie pH od 5,0 do 9,0 maksymalną zawartość wolframu (15,96% mas.) i żelaza (29,36% mas.) wykazały powłoki osadzone przy pH 7,0. Wzrost pH kąpieli od 4,5 do 9,0 powodował wyraźne zmiany w składzie fazowym osadzanych powłok. Zgodnie z wynikami analiz XRD można wskazać jako prawdopodobne występowanie: Fe22Zn78 oraz Fe7W6. Zarejestrowane dyfraktogramy są jednak trudne w interpretacji i jednoznaczne określenie rodzaju faz obecnych w powłoce bez wykonania dodatkowych badań było mocno utrudnione.

10

The influence of selected transition elements on cell metabolism

Terpiłowska Sylwia, Rafińska Katarzyna, Gołębiowski Adrian, Kowalkowski Tomasz, Buszewski Bogusław

Ecological Chemistry and Engineering. S

|

2023

|

Vol. 30, nr 4

471--488

EN

The elements are present in the environment. Moreover, they are used in pharmacy and the production of new materials used in medical applications. They are often as environmental pollutants. They can accumulate in organisms and induce toxic effects on the cellular level. HepG2, L929 and Caco-2 cell lines were exposed to known concentrations of chromium chloride, iron chloride, nickel chloride, molybdenum trioxide and cobalt chloride (200 or 1000 μ M used alone and in combinations). Concentrations of chromium, iron, nickel, molybdenum and cobalt in the cell lysate and the culture medium were determined by ICP-MS. Moreover, sodium, potassium, calcium and magnesium concentrations were also measured. What is more, cells were observed under light and scanning electron microscope. The dose-dependent increase in the concentration of chromium, iron, nickel, molybdenum and cobalt in all cell lines after incubation with elements was observed. Potassium concentration decreases while sodium calcium and magnesium increase after incubation of cells with of mentioned elements. The incubation of cells with microelements induces cell morphology changes. The presented study shows the crucial role of tested microelements in the induction of cell death as a result of an imbalance of sodium, potassium, calcium and magnesium concentration inside the cell.

11

Study of mechanical and morphological properties of CCTO-BT/epoxy composite

Mishra Swagatika, Mishra Punyapriya, Mishra Punyatoya, Mohapatra Deepak Kumar, Mishra Dinesh Kumar, Shadangi Krushna Prasad

Composites Theory and Practice

|

2023

|

R. 23, nr 3

123--128

EN

The demand for environment-friendly ceramic reinforced polymer matrix composite (CRPMC) fabrication leads to the development of lead-free CRPMC. Calcium copper titanate (CCTO) and barium titanate (BT) are two of the most widely used lead-free ceramics for embedded capacitor applications. In the present study, the mechanical and morphological properties of both single and hybrid ceramic (CCTO and BT) filled epoxy composites were evaluated and compared with the unfilled pure epoxy resin. Hand lay-up followed by the compression molding technique were used to synthesize the CRPMC samples. Among the single filler CRPMCs, the BT/epoxy composite exhibited better mechanical properties and density values than the CCTO/epoxy composite. The 60:40 ratio hybrid CCTO-BT/epoxy composite possessed the highest mechanical properties and density values in contrast to the other composite specimens. The SEM micrographs of the fractured surfaces of the BT and CCTO CRPMC specimens were found to have a rougher and wavier appearance than the unfilled epoxy.

12

Effect of MHA on tribo-behaviour of Al-MHA-Si3N4 hybrid composites

Faris Mohammad, Suhaib Mohd, Ahmed Mumtaz

Composites Theory and Practice

|

2023

|

R. 23, nr 1

37--43

EN

In the contemporary research community, hybrid composites with improved performance are emerging as a trend, overcoming the drawbacks of conventional composites and satisfying needs in tribological applications. In this work, Al-MHA-Si3N4 hybrid composites reinforced with various weight percentages of mustard husk ash (MHA), 0, 2.5, 5, 7.5% and 10%, produced by powder metallurgy techniques at 300, 400, 500, 600 and 700 MPa compaction pressure were analysed. The microstructural characterization of the metal matrix hybrid composites, followed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) investigations show the homogeneous distribution of the reinforcement in the metal matrix. A sliding wear study without lubrication was performed on a pin-on-disc wear testing machine under the following sliding conditions: sliding velocity (SV) of 1.5 m/s, sliding distance (SD) of 300 m and applied loads of 25 N and 35 N. The deformation of the worn surfaces was also investigated. It was found that the tribological characteristics of the composites were enhanced by increasing the weight percentage of MHA and the compaction pressure.

13

Przegląd nowoczesnych metod nieniszczących wykorzystywanych do badania płyt włóknisto-cementowych

Gorzelańczyk Tomasz, Schabowicz Krzysztof

Badania Nieniszczące i Diagnostyka

|

2023

|

nr 1-4

30--36

PL

W artykule przedstawiono i omówiono wybrane nowoczesne metody nieniszczące wykorzystywane do badania materiałów kompozytowych jakim są płyty włóknisto-cementowe. Omówiono metodę ultradźwiękową, w tym również z wykorzystaniem fal Lamba, metodę emisji akustycznej, metodę terahercową i metodę optyczną z wykorzystaniem elektronowego mikroskopu skaningowego SEM. Wszystkie te metody zostały z powodzeniem wykorzystane w badaniach, w tym również w badaniach własnych autorów, co jednoznacznie potwierdza ich przydatność w badaniu płyt włóknisto-cementowych.

EN

The article presents and discusses selected modern non-destructive methods used to test composite materials such as fiber-cement boards. The ultrasonic method, including the Lamb wave method, the acoustic emission method, the terahertz method and the optical method using the scanning electron microscope (SEM) are discussed. All these methods have been successfully used in research, including the authors' own research, which clearly confirms their usefulness in the study of fiber-cement boards.

14

Distortion Analysis of Thin-Walled Investment Castings

Mandal R., Roy Soumyajit, Sarkar Subhajit, Mandal T., Pramanick A. K., Majumdar G.

Archives of Foundry Engineering

|

2023

|

Vol. 23, iss. 3

59--60

EN

Dokra casting is famous for its Artistic value to the world but it is also sophisticated engineering. The technique is almost 4500 years old. It is practiced by the tribal artisans of India. It is a clay moulded wax-based thin-walled investment casting technique where liquid metal was poured into the red hot mould. Dimensional accuracy is always preferable for consumers of any product. Distortion is one of the barriers to achieving the accurate dimension for this type of casting especially for the bending parts. The cause and nature of the distortion for this type of casting must be analyzed to design a product with nominal tolerance and dimensional accuracy.

15

Evolution of zinc coatings during drawing process of steel wires

Suliga Maciej, Wartacz Radosław, Hawryluk Marek

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 2

art. no. e120, 2023

EN

The paper shows a significant influence of the multi-stage wire drawing technology on deformability and phase transformations in the zinc coating. SEM tests proved that the coating after hot-dip galvanizing consists of a number of thin layers, ranging from 1 to 5 μm, and differing in thickness, chemical composition and properties. When pulled through the drawing die the zinc coating heats up (as a result of friction between the material and the tool) and its dynamic plastic deformation. It resulted in the fracture and partial crushing of the hard-intermetallic phases. It has been proven that as the wire passes through successive drawing dies, the coating is thinned and diffusion as well as phase remodelling of individual structural components occurs; in the place of phase ζ, the intermetallic phase δ1 develops, increasing its share in the diffusion layer. The crystals of intermetallic phases located on the border of the diffusion and outer layers break up and remain dispersed in the zinc. An analysis of the microhardness of the coating has proven that the level of the increase in the microhardness of the zinc coating is contingent on percentage of iron in particular layers of coating.

16

Effect of alkaline treatment on mechanical properties of palmyra and S-glass fiber reinforced epoxy nanocomposites

Sravya Navuluri Padma, Sivaganesan S., Venkatesh R., Manikandan R.

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 2

art. no. e116, 2023

EN

Although epoxy resins have many advantages, their use needs to be expanded by improving their mechanical properties, including a wide variety of material quality, easy processing, negligible shrinkage due to curing, and good adhesiveness to many forms of fiber materials. The research focuses cost-effective utilization of palmyra fiber treated with 5% alkali solution and different volume percentages of S-glass fiberglass incorporated by epoxy resin developed by hand layup technique. The final epoxy hybrid composite consists of different weight ratios of palmyra/S-glass fiberglass as 25:75, 50:50, and 75:25. Influences of palmyra (treated) fiber dispersion quality on density, voids, mechanical and moisture absorption performance of the epoxy hybrid composite is studied by ASTM rule. The elevated output characteristics performance is compared with untreated fiber composite. Based on the rule of mixture, composite density is varied and Archimedes’ principle measures voids. The alkali treated composite samples showed good tensile stress, flexural and impact strength. While compared to untreated fiber composite, the tensile, flexural, and compressive strength of TPF/GF(25:75) composite was improved by 19.58%, 29%, and 14.3%, respectively. The reduced water absorption behaviour was observed on the treated composites. The effect of fiber dispersion on the mechanical failure of hybrid composite is studied by SEM analysis.

17

Comparison of mechanical properties and structure of Haynes 282 consolidated via two different powder metallurgy methods: laser powder bed fusion and hot pressing

Maj P., Bochenek K., Sitek R., Koralnik M., Jonak K., Wieczorek M., Pakieła Z., Mizera J.

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 2

art. no. e130, 2023

EN

The development of powder metallurgy methods in recent years has caused traditional casting methods to be replaced in many industrial applications. Using such methods, it is possible to obtain parts having the required geometry after a process that saves both manufacturing costs and time. However, there are many material issues that decrease the functionality of these methods, including mechanical properties anisotropy and greater susceptibility to cracking due to chemical segregation. The main aim of the current article is to analyze these issues in depth for two powder metallurgy manufacturing processes: laser powder bed fusion (LPBF) and hot-pressing (HP) methods-selected for the experiment because they are in widespread use. Microstructure and mechanical tests were performed in the main manufacturing directions, X and Z. The results show that in both powder metallurgy methods, anisotropy was an issue, although it seems that the problem was more significant for the samples produced via LPBF SLM technique, which displayed only half the elongation in the building direction (18%) compared with the perpendicular direction (almost 38%). However, it should be noted that the fracture toughness of LPBF shows high values in the main directions, higher even than those of the HP and wrought samples. Additionally, the highest level of homogeneity even in comparison with wrought sample, was observed for the HP sintered samples with equiaxed grains with visible twin boundaries. The tensile properties, mainly strength and elongation, were the highest for HP material. Overall, from a practical standpoint, the results showed that HP sintering is the best method in terms of homogeneity based on microstructural and mechanical properties.

18

Do telematics technologies help to manage road transport enterprises? Evidence from SME in Poland

Zalewski Wojciech, Osińska Magdalena, Żurek Mirosława

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

|

2022

|

z. 157

723--740

EN

Purpose: This study evaluates the acceptance of GPS/GPRS-based telematics technology in freight road transport companies registered in Poland. Design/methodology/approach: The evaluation is based on a survey of 500 representative road transport companies carried out in 2020. The Technology Acceptance Model was estimated, and its results were checked for robustness. The scope of the information collected in telematics systems is defined in terms of its perceived utility and perceived ease of use at the operational management level. The latent factors affecting technology use are defined and implemented. Findings: Most respondents (80%) claimed that telematics systems had a considerable influence on the effectiveness and efficiency of the whole company's operation. It contributed to a higher number of orders executed per time unit, more effective use of the driver's working time, and increased the entrepreneurs' trust in the company. The companies employing more workers recognize the higher usefulness of telematics systems and are motivated to use the technology more widely than smaller enterprises. TAMs estimated separately for small and medium-sized enterprises did not significantly differ among the parameter estimates. Research limitations/implications: The Technology Acceptance Model is a useful analytical tool for evaluating telematics technology acceptance by the road transport sector. The study is based on a random sample of enterprises observed once in 2020. It is recommended to monitor them in two or three waves to compare the dynamics of the telematics usage process. It is planned to continue the study in that direction. Practical implications: The outcomes are valuable in practice twofold. Firstly, the extension of telematics systems use is interesting for final users, i.e., road transport companies that will find scope for their application. Secondly, the results are helpful for system providers who get knowledge on telematics perception from enterprise management. Originality/value: Although widely applied to other IT systems, the TAM model has not been used to evaluate the use of telematics in road transport companies. The paper justifies TAM's categories at the operational management level in road transport enterprises, contributing to understanding managers' behavioral aspects of decision-making.

19

Determinants of participation in collaborative fashion consumption - provider perspectives

Michalak Szymon, Bartkowiak Paweł, Ankiel Magdalena, Olejniczak Tomasz, Stachwiak-Krzyżan Magda

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

|

2022

|

z. 158

413--442

EN

Purpose: The development of digital technology is one of the most important factors driving changes in consumer behavior in the 21st century. Today, the sharing economy covers more and more areas of consumers' daily lives. Using online apps to exchange, sell, buy or rent clothes has become one of the most popular ways of consuming fashion around the world. The main objective of this paper is to assess the importance and estimate the impact of the determinants (motives and unpleasant user experience) of providers' engagement in collaborative fashion consumption (CFC). Design/methodology/approach: The study was conducted using an online survey with 420 respondents in Poland - users (providers) of CFC platforms. A confirmatory factor analysis (CFA) and structural equation model (SEM) was performed using AMOS 21.0 version. The conducted research allowed to identify the importance and to determine the influence of examined factors on attitudes toward CFCs and willingness to use CFC apps in the future. Findings: Economic motives did not outperform non-economic motives to participate as a provider in CFC. Pragmatic motives were by far the most important determinants of fashion sharing. Environmental factors are an important reason for providers to participate in CFC but they may not be a direct motivation for CC participation. Social motives recorded the lowest average importance rating in the context of participation in CFC. Unpleasant user experience negatively influence both the attitudes toward using CFC apps and the willingness to use them in the future Research limitations/implications: The research was conducted only on Polish users, so due to cultural differences, the meaning and impact of the motives of using these apps may be different in other countries. Due to the method of sampling and sample size, the results cannot be treated as representative for the population of Polish users of CFC platforms. Future research could include conducting cross-country research and one may attempt to broaden the scope to include other categories of motives. Future research could also extend the scope of unpleasant user experience with other factors. Practical implications: The results of research on the motives of users' use of CFC apps should be useful for enterprises in the context of designing activities in the field of marketing communication. Originality/value: The paper fills a research gap in the field of research on the determinants of polish providers' engagement in collaborative fashion consumption (CFC).

20

Ocena jakości metalicznego proszku kobaltowego wykorzystywanego w stomatologii za pomocą mikroskopii optycznej i analizy charakterystyki ziarnowej

Turlej Tymoteusz, Augustyn-Nadzieja Joanna

Przemysł Chemiczny

|

2022

|

T. 101, nr 11

1014--1018

PL

Przedstawiono wyniki badań uziarnienia metalicznego proszku dentystycznego. Badania obejmowały pomiar rozkładu wielkości cząstek z wykorzystaniem zautomatyzowanej mikroskopii optycznej, a następnie porównanie uzyskanych wyników z badaniami uziarnienia przeprowadzonymi za pomocą SEM. Określono również możliwość oceny jakości proszku metalicznego za pomocą mikroskopii optycznej i analizy charakterystyki ziarnowej.

EN

The particle size distribution of metallic dental powder (Co-Cr powder with micro-additives of W and Mo) was detd. by automated optical microscopy and then compared with particle size anal. by SEM. The possibility of assessing the quality of metallic Co-Cr powder by means of optical microscopy and anal. of grain characteristics was also discussed.