Wyniki wyszukiwania - BazTech

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Wielofunkcyjne warstwowe materiały kompozytowe na kadłuby wybranych jednostek eksploatowanych w warunkach żeglugi śródlądowej

Grabian J., Ślączka W., Przetakiewicz W.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2018

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z. 90 [298], nr 3

297--308

PL

Artykuł przedstawia badania wstępne dotyczące wielowarstwowego materiału kompozytowego spełniającego postawione wymagania dotyczące budowy kadłubów wybranych jednostek pływających, przeznaczonych do żeglugi śródlądowej. Dokonano analizy i opisano warunki eksploatacyjne jednostek pływających śródlądowych, ze szczególnym naciskiem na bezpieczeństwo i koszty obsługi eksploatacyjnej jednostek. Zaproponowano sposób zwiększenia bezpieczeństwa użytkowania jednostki przez wprowadzenie wielowarstwowego materiału ograniczającego możliwości rozszczelnienia kadłuba w przypadku uderzenia o obiekty znajdujące się pod wodą. W celu badań porównawczych określono warunki przyjętej technologicznej próby zginania oraz wymagania dotyczące wielowarstwowych płyt próbnych. Wytworzono trój- i czterowarstwowe płyty próbne o grubości 14-30 mm, wykorzystując: kompozyty zawiesinowe na bazie żywicy epoksydowej zbrojone cząstkami ceramicznymi, kompozyty na bazie żywicy poliestrowej zbrojone uporządkowanym włóknem szklanym oraz piany metalowe na bazie aluminium oraz kompozytu aluminiowo-ceramicznego. Przedstawiono wyniki wstępnych badań dotyczących odporności płyt próbnych na zginanie w warunkach przyjętej próby technologicznej, a także odporności na ścieranie. Odniesiono się do możliwości wytwarzania tak skomponowanych materiałów warstwowych w warunkach znanej, szeroko stosowanej technologii formowania elementów kształtowych z kompozytów polimerowo-szklanych w formach negatywowych. Doprecyzowano typ śródlądowych obiektów pływających, wykazując zalety i celowość stosowania tych materiałów.

EN

The article presents the preliminary tests of a multilayer composite material that meets design requirements for hulls of some vessels intended for inland navigation. In the analysis and description of operating conditions of inland vessels a particular focus was put on the safety and operational costs of the vessels. The solution proposed to increase operational safety consists in introducing a multilayer material that limits the loss of hull integrity in the case a vessel hits an underwater object. For comparative studies, the conditions of the adopted technological bending test were defined along with requirements for multilayer test plates. Plates produced for the tests were three- and four-layered 14-30 mm thick plates made of three materials: epoxy resin-based suspension composites reinforced with ceramic particles, polyester resin-based composites reinforced with ordered fiberglass and metal foams based on aluminium and aluminium-ceramic epoxy. The preliminary research results include the resistanceof test plates to bending in the adopted technological test conditions and abrasive resistance. Particular reference was made to the manufacturing of so composed layered materials applying a known and widely used process of forming profiled elements of polymer-glass composites in negative moulds. The type of inland vessel was more precisely indicated, along with advantages and purpose of using the materials under consideration.

2

Strategies for the viability of rechargeable lithium-sulfur batteries

Manthiram A., Chung S. H., Chang C. H.

Archives of Materials Science and Engineering

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2015

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Vol. 75, nr 2

70--81

EN

Purpose: Lithium-sulfur (Li-S) batteries are considered as one of the most promising next-generation rechargeable batteries for electrical energy storage because of their high theoretical specific energy of ~ 2500 Wh kg-1, low production cost, and high abundance of sulfur. However, the high charge-storage capacity of sulfur cannot be effectively utilized due to the insulating nature of the active material and the easy migration of polysulfide intermediates from the cathode to the anode. In this research article, we describe a concise summary of two successful methods for solving the scientific problems and improving the Li-S cell performances. Design/methodology/approach: Successful strategies in addressing the scientific and engineering issues of Li-S cells can be divided into two major categories: (i) sulfur-based nanocomposites that improve the Li-S cell performance based on the cathode active material and (ii) cell configuration modifications that enhance the Li-S cell performance by adopting the materials nature of sulfur. Findings: Current technologies including nanocomposite development and cell configuration design have greatly ameliorated the overall electrochemical performance of Li-S batteries by improving the electrochemical utilization of sulfur and the retention rate of polysulfides. Research limitations/implications: The overcome the challenges of Li-S batteries, a fair balance has to be taken between (i) sulfur loading/content and cell performances, (ii) amount of active material and porosity of the matrix, and (iii) added weight from the modified cell components and energy density of the custom Li-S cells. Practical implications: The next step for the reality of commercial Li-S batteries might be (i) development of high-loading sulfur cathodes, (ii) anode configuration modification, and (iii) design of electrochemically stable electrolytes. Originality/value: A concise introduction of the development of the sulfur core in Li-S cells is provided.

3

Thermoelectric properties of expanded graphite as filler of multifunctional cement composites

Pichór W., Frąc M.

Composites Theory and Practice

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2012

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R. 12, nr 3

205-209

EN

This paper presents the results of investigations on the thermoelectric properties of expanded graphite obtained by different methods. The expanded graphite was subjected to thermal treatment by two different ways: by rapid heating in a furnace and by irradiated microwave. For each of the methods, graphite was expanded in different conditions for the purpose of investigating the influence of thermal treatment on their thermoelectric properties. The bulk density and thermoelectric properties (Seebeck coefficient) of expanded graphite were measured. The results of the investigations show that the method and time of thermal treatment have a major influence on the thermoelectric properties of expanded graphite.

PL

W pracy przedstawiono wyniki badań właściwości termoelektrycznych grafitu ekspandowanego otrzymanego różnymi metodami. Wykorzystano dwie metody ekspandacji: przez gwałtowne podgrzanie w piecu laboratoryjnym oraz przez poddanie działaniu promieniowania mikrofalowego. W przypadku metody bezpośredniego ogrzewania proces prowadzono w różnej temperaturze w zakresie 500÷1000°C i przy różnym czasie ogrzewania, natomiast w metodzie mikrofalowej zmienną poza czasem procesu była moc dostarczona do próbki. Wyniki pomiaru współczynnika Seebecka pokazały, że metoda ekspandacji oraz czas procesu mają duży wpływ na otrzymane właściwości termoelektryczne grafitu ekspandowanego.

4

Research of electrical conductivity of synthetic powders

Sorek A., Popielska-Ostrowska A., Niesler M.

Archives of Materials Science and Engineering

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2012

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Vol. 57, nr 2

53-56

EN

Purpose: This paper describes the electrical conductivity of liquid phase powders and laboratory research of electrical conductivity of synthetic powders. Design/methodology/approach: Research of electrical conductivity of liquid synthetic slag was performed using voltmeter-ammeter method on the specially designed research stand. Findings: The electrical conductivity of slag depends on the chemical composition of the liquid slag, which is related to their ionic structure. The electrical conductivity is determined by the dimensions of the ions, their number and mobility as a function of the viscosity of the liquid in which they are. Research limitations/implications: Laboratory studies of electrical conductivity of liquid powders should be the basis for further studies crystallizer powders used in continuous casting conditions. Practical implications: The chemical composition of powders (ion) can cause changes in the lubrication conditions in the near-meniscus zone in continuous casting mold and can influence on the surface quality on the continuous casting ingots. Originality/value: This paper presents the result of research of electrical conductivity CaO-SiO2-Al2O2-FeO-MgO-K2O powders.

5

Microstructure stability of the PtRh alloys used for catalytic ammonia oxidation

Rdzawski Z. M., Stobrawa J. P., Szynowski J.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 1

106-114

EN

Purpose: The aim of this work was to investigate the possibility of increasing performance of the PtRh alloys used in industrial processes of catalytic ammonia oxidation. Design/methodology/approach: In order to reach this objective, the extensive studies have been carried out, which were aimed at better understanding of the phenomena taking place on a surface and inside the wires of catalytic gauzes during the process. The electron microscopy methods (SEM, TEM, HRTEM), optical microscopy and microanalysis were used to examine the alloys under investigation. Findings: It was found that the performance and lifetime of the catalytic gauzes is closely related with structural stability of the alloys and with the stability of parameters of the ammonia oxidation process. Practical implications: The PtRh1O-based alloys modified with boron and yttrium have been developed, which are characterised by more stable structure than the classical PtRh1O alloy and enable significant reduction of the grain growth effect during the use of the gauzes. This should contribute to the improvement of the process efficiency and selectivity, and increase the lifetime of the catalytic gauzes. Originality/value: The developed alloys are new and original.

6

Development of ecomaterials and materials technologies

Nowosielski R., Kania A., Spilka M.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 21, nr 1

27-30

EN

Purpose: This paper presents a development of ecomaterials particularly in materials technology. Using this materials make possible minimize the environmental load in a whole "life". The design criteria for ecomaterials include compatibility with humans and the environment in addition to the traditional physical, mechanical and chemical properties. Design/methodology/approach: Using ecomaterials would help the manufacturers as well as consumers in material and product selection in the aim of achieving sustainable development (SD). Findings: The concept of "ecomaterials" shows the necessary directions of materials development what allows protection the environment from resource depletion, global warming, ozone depletion and dioxin contamination, etc. Research limitations/implications: More fundamental research and new ideas are needed in order for these materials (ecomaterials) to receive widespread use in the near future. Practical implications: The most important thing is that all materials and their properties should be reconsidered from the ecomaterials viewpoint. It is necessary to demand materials (products) with less environmental load, improved recyclability and achieved maximum performance with the least material consumption. In order to establish the fundamental design and assessment techniques for ecomaterials, a research projects should be still organized. Originality/value: In the paper ecomaterials as a key conception for materials technology what will help reduce the environmental impact of product produced and consumed and promote the emergence of a high-recycling-rate society.

7

Characterisation of TiCxOy thin films produced by PVD techniques

Cunha L., Fernandes A. C., Vaz F., Parreira N. M. G., Goudeau P., Le Bourhis E., Riviere J. P., Munteanu D., Borza F.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 21, nr 1

35-38

EN

Purpose: The purpose of this work consists in the characterisation of TiCxOy thin films produced by dc reactive magnetron sputtering. The main goal consists in studying the influence of the reactive gas flow in the atomic composition, structure, colour and electrical and mechanical properties of the films. Design/methodology/approach: All the deposition parameters were maintained constant except the reactive gas flow. After deposition, the properties of the coatings were measured and were related with variation of reactive gas flow. Findings: The results show that the films properties subsist into 3 different regimes - i) carbide, ii) a transition zone and iii) an oxide one. The colour results indicate a strong dependence on the O/Ti ratio. A progressive reduction of hardness and residual stresses with increasing of the O/Ti ratio was observed. The residual stresses, as well as the film structure, seem to play an important role on the adhesion of the coatings. Research limitations/implications: The main limitation of this work is linked to the deposition technique itself. It is difficult to avoid surface defects and pinholes that strongly influence the tribological results. Practical implications: TiCxOy thin films are multifunctional due to present good electrical and optical properties but also good mechanical properties which allow them to be used in several applications; from decorative to electronic applications. Originality/value: There is a new class of coatings where the research of TiCxOy thin films is included: the multifunctional coatings. This class of coatings should be easy to prepare and to tune the properties as function of particular applications. This characteristic may be extremly important to advanced coatings industry.