Wyniki wyszukiwania - Biblioteka Nauki

1

Nanopores with controlled profiles in track - etched membranes

100%

Sartowska B. A.

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tom Vol. 57, No. 4

575-579

EN

Track-etched membranes are porous systems consisting of a polymer foil with thin channels-pores - from surface to surface. The increasing interest in this kind of material is connected with the development of nanoporous materials with unique properties such as diode-like effects in membranes with highly asymmetrical nanopores. The materials can be used for molecular sensors and atom beam optics, development of nanocapillary bodies for modelling the transport of molecules and ions in constrained volumes. Control over pore geometry opens the way to a number of new applications of track-etch membranes (TMs). The nanopores were obtained by the ion-track etching method using surfactant-doped alkaline solutions. Control over the pore profile and dimensions was achieved by varying the alkali concentration in the etchant and the etching time. The pore geometry was characterized in detail using field-emission scanning electron microscopy (SEM). SEM images of the surfaces and cleavages of TMs with different pore morphology are shown.

2

Synthesis, chemical characterization and antifungal activity of thin layers prepared by sol-gel method

100%

Nocun M. , Zontek J. , Kwasny S.

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tom Vol. 42, nr 2

315-322

EN

Sol-gel method was used to prepare SiO2-TiO2 thin layers on the microscope slide glasses with additions of Cu, Ag, Au compounds. The films were calcimined at 150 °C for 1 hour. We studied the morphology of the following samples by scanning electron microscopy (SEM with EDS analysis), and the X-ray photoelectron spectroscopy (XPS). Antifungal properties of the layers were tested with the use of fungi Penicyllium. The results have shown that the best antifungal effect among the examined layers has got the sample with Au ions addition.

3

Study of the electrical properties of polystyrene-foliated graphite composite

100%

Srivastava N. K. , Mehra R. M.

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tom Vol. 27, No. 1

109--122

EN

The present paper reports the development of polystyrene-foliated graphite composites via a hot compression moulding technique. Foliated graphite, as obtained by the sonication of expanded graphite, was used as a filler. A distinct percolative behaviour was observed in the variation of conductivity of the composites as a function of graphite concentration. At the percolation concentration of graphite content (0.02 vol. fraction), the conductivity is found to be ca. 10-5 S/cm. The percolation behaviour was analyzed using the generalized effective media equation. An estimation of the interparticle distance between the filler particles/clusters in the composites was made. The analysis of current-voltage characteristics revealed that near the percolation threshold the electrical transport is due to tunnelling of charge carriers, while above the threshold it is ohmic in nature.

4

Environmental degradation of advanced fibre hybrid composites

100%

Imielińska K.

Advances in Materials Science

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2007

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tom Vol. 7, nr 2(12)

115-120

EN

Water absorption, water-induced degradation of flexural properties and failure mechanisms were investigated in hybrid aramid-glass fibre-reinforced/epoxy 4 ply laminates. After extended periods of service, significant water absorbtion (ca. 3,5 wt%) resulted in deterioration of flexural strength by ca 20% and of the interlaminar shear strength by ca. 30%. Following water immersion, under flexural loading aramid-glass fibre reinforced/epoxy composites failed by aramid fibre buckling and fibre/matrix interfacial damage propagation, whereas the principal failure mechanisms in glass fibre composites are single or multiple ply and fibre fractures. Plots showing changes in stress regimes responsible for damage development in dry/wet specimens, failure maps of stress versus % water/failure mechanism, are presented.

5

Mechanical properties of Ni-Fe-Cu-P-B alloy produced by two component melt spinning (TCMS)

88%

Wojciechowska M. , Ziewiec K. , Kąc S. , Prusik K.

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tom Vol. 62, iss. 1

137--140

EN

The aim of this work was to investigate the microstructure and mechanical properties of the two-component melt-spun (TCMS) alloy produced from Ni40Fe40B20 and Ni70Cu10P20 melts. The Ni40Fe40B20, Ni70Cu10P20, Ni55 Fe20 Cu5 P10 B10 alloys were arc-melted. Then the alloys were melt-spun in the two different ways i.e.: by casting from a single-chamber crucible and from the two-chamber crucible. All of the above mentioned alloys were processed in the first way and the Ni40Fe40B20 and Ni70Cu10P20 were simultaneously cast on the copper roller from the two-chamber crucible. The microstructure of the alloy was studied using transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS) and light microscopy. The mechanical properties were investigated using tensile testing and nanoindentation. The two-component melt-spun (TCMS) amorphous Ni55 Fe20 Cu5 P10 B10 alloy present hardness, tensile strength and Young modulus on the significantly higher level than for a single phase amorphous Ni55 Fe20 Cu5 P10 B10 alloy and slightly below the corresponding values for the Ni40Fe40B20.

6

Low velocity impact damage in glass / polyester composite sandwich panels

88%

Lendze T. , Wojtyra R. , Guillaumat L. , Biateau C. , Imielińska K.

Advances in Materials Science

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2006

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tom Vol. 6, nr 1

26-34

EN

Impact resistance of glass/polyester facesheets/PVC foam core sandwich structures was primarily assessed in terms of skin-/core bonding efficiency using two types of adhesives and bonding with uncured resin. Also, the air-coupled ultrasonic C-scan technique was estimated as a means of characterizing impact damage size in sandwich structures. The following observations were made. The impact damage size estimated by visual inspection was much more extensive in all samples, which is due to the C-scan images showing only the overlapping delaminations area directly under the impact site, whereas the visual inspection of the laminate surface and macroscopic observations of the sample section show the extent of the largest, single delamination. The least extensive damage size was found in the two-phase high-density adhesive samples showing also the highest tendency for core cracking. In contrast, the “pinkglue” adhesive, which is low-density due to the presence of the microspheres provides greater local flexibility which prevented core craking.

7

Diatomaceous rocks of the Jawornik deposit (the Polish Outer Carpathians): petrophysical and petrographical evaluation

75%

Figarska-Warchoł B. , Stańczak G. , Rembiś M. , Toboła T.

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tom Vol. 41, no. 4

311--331

EN

Diatomites belonging to a list of raw materials used in the EU criticality assessment are essential to many industrial applications due to a unique combination of their physical properties, i.e. porous and permeable structure, high specific surface area and adsorption capacity, low density and thermal conductivity, and chemical inertness. The present study was undertaken to analyse the relationships between the pore network characteristics, petrophysical parameters, and mineralogical variability of the Lower Miocene diatomites from the Jawornik deposit (Skole Unit, the Polish Outer Carpathians, SE Poland). Five varieties of the diatomites, distinguished on the basis of the macroscopic features, i.e., colour and fracturing effects, have been investigated by SEM, chemical and XRD analysis, mercury intrusion porosimetry, helium pycnometry, and the Vickers hardness tests. Significantly differing are two varieties. The light-coloured, massive and block-forming diatomites (variety BL) consist mainly of poorly cemented siliceous skeletal remains of diatoms, and represent the rocks with high total porosity (38–43%), low bulk density (1.28–1.38 g/cm3) and low microhardness (10.7 HV0.3). The dark-gray silicified diatomites with a platy or prismatic splitting (variety PD) reveal obscured microfossils of diatoms and are the most compact and hard rocks (80.8 HV0.3), with poor total porosity (17–24%) and higher bulk density (1.70–1.78 g/cm3). The spatial distribution of the field identifiable rock varieties allows selective exploitation of the diatomites with the predictable petrophysical characteristics that define their future use.

8

Shield Effect Of Functional Interlining Fabric

63%

Šaravanja B. , Malarić K. , Pušić T. , Ujević D.

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2015

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tom Vol. 15, no. 2

93--98

EN

Electromagnetic interference (EMI) have become very serious in a variety of different electronic equipments, such as personal computers (frequency at several GHz), mobile devices (0.9 – 2.4 GHz) and similar. This imposes the need for setting boundaries for EM emission of electric and electronic devices in order to minimize the possibility of interference with radio and wireless communications. Functional textiles can offer protective properties against EM radiation. The aim of this study is to investigate the degree of protection against EM radiation provided by polyamide copper-coated interlining fabric before and after dry cleaning treatment. EM protection efficiency of the interlining functional fabric is explored on both sides at the frequencies of 0.9; 1.8; 2.1 and 2.4 GHz. The results obtained have shown that the interlining fabric has good protective properties against EM radiation, but after dry cleaning, treatment reduction is observed. Scanning electron microscopy micrographs of the interlining surface confirms shield effect decline due to degradation and firing of the copper layers during the process of dry cleaning.

9

Structure and chemical composition of anodic oxide layers obtained on aluminium alloys

63%

Skoneczny W.

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tom nr 3

175-184

EN

The bases for shaping the properties of aluminium alloys' upper layer by electrolytic method are presented in the paper. The structure of the oxide layer of aluminium and its alloys obtained by means of hard anodic coating has been determined. The structure of Al2O3 layers is the basic factor deciding about its functional properties. The structure of oxide layers depends, to a large degree, on the type and concentration of electrolyte as well as on the conditions in which the hard anodizing process is conducted. The anodic density of current applied during the electrolytic process has a significant influence on the structure of anodic oxide coatings. It influences the process speed, which is strictly correlated with the growth and size of crystals in the coating. Also, the temperature of electrolyte, with other parameters of the electrolytic process being constant, affects the formation of coatings of a different grain size, which results from changes in the conditions of secondary oxide dissolution. An analysis of the chemical composition of an oxide layer obtained on the AlMg2 aluminium alloy in a three-component electrolyte SAS, on a transverse microsection, in the middle of its thickness (Fig. 4) has shown that the obtained layer contains: 54.47% Al. and 45.53% of oxygen. According to stechiometric calculations of Al2O3 (oxide layer), its chemical composition should include: 52.92% Al. and 47.08% of oxygen. As results from the investigations carried out, the oxide layers obtained on aluminium alloys have fibrous structures and a developed surface morphology. The obtained oxide layers have a columnar (fibrous) structure oriented under the influence of electric field.

PL

W pracy przedstawiono podstawy kształtowania właściwości warstwy wierzchniej stopów aluminium metodą elektrolityczną. Określono strukturę warstwy tlenkowej aluminium i jego stopów otrzymanej metodą anodowania twardego. Struktura warstw Al2O3 jest podstawowym czynnikiem decydującym o jej właściwościach użytkowych. Struktura warstw tlenkowych w dużym stopniu zależy od rodzaju i stężenia elektrolitu oraz od warunków prowadzenia procesu anodowania twardego. Duży wpływ na strukturę anodowych powłok tlenkowych ma gęstość anodowa prądu, jaka jest stosowana w trakcie procesu elektrolitycznego. Wpływa ona na szybkość procesu, co jest ściśle współzależne ze wzrostem i rozmiarami kryształów w powłoce. Również temperatura elektrolitu, przy stałych pozostałych warunkach procesu elektrolitycznego, wpływa na powstawanie powłok o różnej ziarnistości, co wynika ze zmian warunków rozpuszczania wtórnego tlenku. Dokonana analiza składu chemicznego warstwy tlenkowej otrzymanej na stopie aluminium AlMg2 w elektrolicie trójskładnikowym SAS, na zgładzie poprzecznym w środkowej części według grubości (rysunek 4) wykazała, że uzyskana warstwa zawiera: 54,47% Al oraz 45,53% tlenu. Według obliczeń stechiometrycznych Al2O3 (warstwa tlenkowa) skład chemiczny warstwy powinien zawierać: 52,92% Al oraz 47,08% tlenu. Z przeprowadzonych badań wynika, że otrzymywane warstwy tlenkowe na stopach aluminium posiadają struktury włókniste oraz rozwiniętą morfologię powierzchni. Otrzymywane warstwy tlenkowe posiadają strukturę kolumnową (włóknistą), zorientowaną wskutek wpływu pola elektrycznego.