Ograniczanie wyników
Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 459

Liczba wyników na stronie
first rewind previous Strona / 23 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  SEM
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 23 next fast forward last
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.
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.
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.
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.
5
Content available remote The influence of selected transition elements on cell metabolism
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.
6
Content available remote Study of mechanical and morphological properties of CCTO-BT/epoxy composite
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.
7
Content available remote Effect of MHA on tribo-behaviour of Al-MHA-Si3N4 hybrid composites
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.
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.
9
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.
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.
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.
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).
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.
EN
One of the great achievements of the last 50 years is the development of high-quality composite materials. By definition, classic composites are materials that are a combination of at least two components (phases), e.g. embedded particles, fibers, fabrics in a polymer, metal or ceramic matrix. Composites exhibit many unique properties if compared with solid metal and ceramic materials, as well as pure polymers and copolymers. This is typical to their stiffness and strength to weight ratios (strength and relative stiffness). The properties of composites depend to a large extent on the size, shape and form of the filling fibers and particles, in particular with their large share in the volume of the composite. This also applies to composite materials manufactured for the electronics and electrotechnical industries, where apart from appropriate mechanical properties, appropriate electrical properties are required, e.g. high ability to shielding of electromagnetic field in a wide frequency range.
PL
Znaczącym osiągnięciem ostatnich 50 lat jest rozwój badań nad wytwarzaniem wysokiej jakości materiałów kompozytowych. Z definicji klasyczne kompozyty to materiały będące kombinacją co najmniej dwóch składników (faz), np. cząstki, włókna, tkaniny w matrycy polimerowej, metalowej lub ceramicznej. Kompozyty wykazują wiele unikatowych właściwości w porównaniu z litymi materiałami metalowymi i ceramicznymi, a także czystymi polimerami i kopolimerami. Dotyczy to zwłaszcza stosunku ich sztywności i wytrzymałości do masy (wytrzymałość i sztywność właściwa). Właściwości kompozytów zależą w dużej mierze od wielkości, kształtu i postaci włókien i cząstek je wypełniających, w szczególności w przypadku ich dużego udziału w objętości kompozytu. Dotyczy to również materiałów kompozytowych wytwarzanych dla przemysłu elektronicznego i elektrotechnicznego, gdzie oprócz odpowiednich właściwości mechanicznych wymagane są odpowiednie właściwości elektryczne, m.in. wysoka zdolność ekranowania pola elektromagnetycznego w szerokim zakresie częstotliwości.
EN
The effect of nonwoven Abutilon Indicum fiber content (20, 25, 30, 35, and 40 wt%) on the structure (FTIR, SEM) and selected mechanical and thermal (TGA) properties of epoxy resin was investigated. The best mechanical properties were obtained with a fiber content of 35 wt%. The tensile strength of the composite was about 40 MPa, the flexural strength over 60 MPa, and the compressive strength about 48 MPa. Moreover, the composite showed the fracture energy about 0.44 J.
PL
Zbadano wpływ zawartości włókna Abutilon Indicum (20, 25, 30, 35 i 40% mas.) na strukturę (FTIR, SEM) oraz wybrane właściwości mechaniczne i termiczne (TGA) żywicy epoksydowej. Najlepsze właściwości mechaniczne uzyskano przy zawartości włókna 35% mas. Wytrzymałość na rozciąganie tego kompozytu wynosiła ok. 40 MPa, wytrzymałość na zginanie powyżej 60 MPa, a na ściskanie ok. 48 MPa. Natomiast energia pęknięcia wynosiła ok. 0,44 J.
EN
Bikes are becoming an increasingly popular and reliable mode of transportation in developing countries because of their efficiency and ability to navigate through rough terrain and narrow roadways. Bikes are more vulnerable to road accidents and their riders’ safety is the main concern at present days. Hence, it is essential to reduce the possibility of accidents caused by bike riders. The main reason for bike accidents is bike rider behaviours in the form of traffic rules violations. The paper’s main aim is to categorize the importance of seven attributes on traffic rules violations, including bike rider behaviours, road features, ambient conditions, driving skills, type of license, bike age/tenure and riding without a safety device (helmet). Bike riders’ violations that can lead to an accident and the impact of attributes have been analyzed using the structural equation modelling (SEM) technique. To analyze these attributes, 450 bike riders have been interviewed in Bhubaneswar, India. It has been concluded that bike rider behaviours are the most significant attribute of violations. Since most bike riders are young, with low income and education, paying more attention to their training and education before issuing a driving license is necessary. In addition, those who do not use safety devices (helmets) are more susceptible to committing violations. This relates to the lack of enough control and enforcement in developing cities. Also, it shows that the current traffic fines for not using safety devices (helmets) are not enforced enough. Finally, considering this research’s outcomes can help minimize traffic rules violations among bike riders, which is a step towards safer roads.
EN
5005A series aluminum samples were passivated to obtain a conversion coating based on Cr(III) compounds. It was shown that the corrosion resistance of galvanized aluminum in a bath containing both zirconium and cobalt compounds, measured in a 0.05 M NaCl solution, slightly increased compared to the corrosion resistance of aluminum as delivered, i.e. without conversion coating. In the case of galvanic treatment of aluminum in baths containing separately cobalt or zirconium compounds, a significant increase in corrosion resistance was achieved in relation to aluminum in the delivered condition. SEM analysis showed that in the presence of the simultaneous addition of zirconium and cobalt compounds, the most developed surface was created compared to the addition of only zirconium, where bright spheroidal precipitates occur locally. EDS analysis showed the presence of : C, O, Mg, Al and Si, small amounts of Cr, Zr, F on the surface of the aluminum covered with the Cr + Zr + HF conversion coating. During measurements with the use of the linear polarization resistance (LPR) technique, the best anti-corrosion properties were demonstrated by the samples that were passivated in a Cr(III) solution with the addition of Zr compound and HF and in a Cr(III) solution with the addition of Co compound and HF.
PL
Próbki aluminium serii 5005A poddano procesowi pasywacji z wytworzeniem powłoki konwersyjnej na bazie związków Cr(III). Wykazano, że odporność korozyjna aluminium poddanego obróbce galwanicznej w kąpieli zawierającej jednocześnie związki cyrkonu i kobaltu, mierzona w 0,05 M roztworze NaCl, nieznacznie wzrosła w stosunku do odporności korozyjnej aluminium w stanie dostarczenia, tzn. bez powłoki konwersyjnej. W przypadku obróbki galwanicznej aluminium w kąpielach, które zawierały osobno związki kobaltu lub cyrkonu, uzyskano wyraźny wzrost odporności korozyjnej w stosunku do aluminium w stanie dostarczenia. Analiza SEM wykazała, że w obecności jednocześnie dodatku cyrkonu i kobaltu powstała najbardziej rozwinięta powierzchnia. W przypadku zastosowania tylko dodatku cyrkonu jasne wytrącenia sferoidalne występują lokalnie. Analiza EDS wykazała obecność C, O, Mg, Al i Si, niewielkich ilości Cr, Zr, F na powierzchni aluminium pokrytego powłoką konwersyjną Cr + Zr + HF. Podczas pomiarów techniką liniowego oporu polaryzacji (LPR) najlepsze właściwości antykorozyjne wykazały próbki poddane pasywacji w roztworze Cr(III) z dodatkiem związków Zr i HF oraz w roztworze Cr(III) z dodatkiem związków Co i HF.
EN
Lanthanum-doped nickel coatings were obtained from the bath based on a deep eutectic solvent: choline chloride and propylene glycol, mixed in a molar ratio of 1 : 2, and 0.2 mol dm−3 NiCl2 ∙ 6H2O and 0.5 mol dm−3 LaCl2 ∙ xH2O. The morphology, topography and chemical composition were examined. The lanthanum content in the coating was determined to be 1.7 wt. % using the ICP-MS method. Lanthanum on the surface was mainly in the form of lanthanum carbonate. The obtained coating was exposed to a 7-day exposure in 0.05 mol dm−3 NaCl solution. The coating showed the highest corrosion resistance (Rp ~ 30 kΩ cm2) after 15 hours of exposure to the NaCl solution.
PL
Powłoki niklowe domieszkowane lantanem zostały otrzymane z kąpieli na bazie rozpuszczalnika eutektycznego chlorku choliny i glikolu propylenowego zmieszanych w proporcjach molowych 1 : 2 oraz 0,2 mol dm−3 NiCl2 ∙ 6H2O i 0,5 mol dm−3 LaCl2 ∙ xH2O. Zbadano morfologię, topografię oraz skład chemiczny. Zawartość lantanu w powłoce została określona na 1,7% mas. techniką ICP-MS. Na powierzchni powłoki lantan występował głównie w postaci węglanu lantanu. Otrzymana powłoka została poddana 7-dniowej ekspozycji w 0,05 mol dm−3 roztworze NaCl. Największą odporność na korozję powłoki stwierdzono po 15-godzinnej ekspozycji w roztworze NaCl.
EN
Formamidinium lead tribromide (FAPbBr3) perovskite quantum dot (PQ-Dot) solution was incorporated in a polymer sol, which was used to fabricate solid nanocomposite rods and disks. The solid nanocomposite samples were studied by different characterization techniques. The absorption, emission, and excitation spectra of the PQ-Dot in the solid rods/disks were quite significant as compared to the spectra of the PQ-Dot solution. Scanning electron microscopy (SEM) was used to inspect the structural morphology of the PQ-Dot in the solid environment. The PQ-Dot particles were evidently present in the solid matrix and were confirmed by the SEM images and energy dispersive X-ray spectroscopy (EDX) spectra. The size of the PQ-Dots was examined by transmission electron microscopy (TEM). The majority of the particles were about 3–8 nm in size. The spontaneous and stimulated emission profiles of the solid composite rods/disks were studied using pumping energy ranging from 2 μJ to 18 μJ from a high-power picosecond neodymium-doped yttrium aluminum garnet (Nd:YAG) tunable laser system. The observed emission signal was quite significant. The emission peak of the PQ-Dot solution had a slight change when it was included in the solid matrix. Amplified spontaneous emission (ASE) behavior was obtained from the PQ-Dot composite rod. The ASE peaks were quite steady at different levels of excitation energy. ASE was achieved at low threshold energy. The composite rod with ASE behavior indicates that it is a promising composite material that can be used to achieve lasing in the future. The ASE obtained from the composite rods/disks may improve to achieve lasing if a high concentration of PQ-Dot solution is used in the matrix.
EN
PAN-based carbon fiber was surface-modified with silane coating, and a composite material was prepared using a PI resin as a matrix. The structure and surface properties of carbon fibers were studied by means of X-ray photoelectron spectroscopy (XPS) and SEM. The tensile strength of the composite was measured by a tensile tester, and the friction properties of the composite were measured by a micro-nano mechanics comprehensive test system. The results show that treatment with silane coating can improve the surface roughness and chemical activity of carbon fiber, improve the interface between carbon fiber and PI resin matrix, and improve the tensile strength and wear rate of the composite.
first rewind previous Strona / 23 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.