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1

Fabrication of Cu2O nanostructured thin film by anodizing

Voon C. H., Lim B. Y., Gopinath S. C. B., Al-Douri Y., Foo K. L., Md Arshad M. K., Ten S. T., Ruslinda A. R., Hashim U., Tony V. C. S.

Materials Science Poland

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2018

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Vol. 36, No. 2

209--216

EN

Cuprous oxide, a narrow bandgap p-type semiconductor, has been known as a potential material for applications in supercapacitors, hydrogen production, sensors, and energy conversion due to its properties such as non-toxicity, easy availability, cost effectiveness, high absorption coefficient in the visible region and large minority carriers diffusion length. In this study, Cu2O nanostructured thin film was fabricated by anodizing of Cu plates in ethylene glycol containing 0.15 M KOH, 0.1 M NH4F and 3 wt.% deionized water. The effects of anodizing voltage and temperature of electrolyte were investigated and reported. It was found that nanoporous Cu2O thin film was formed when anodizing voltages of 50 V and 70 V were used while a dense Cu2O thin film was formed due to the aggregation of smaller nanoparticles when 30 V anodizing voltage was used. Nanoplatelets thin film was formed when the temperature of electrolyte was reduced to 15 °C and 5 °C. X-ray diffraction confirmed the presence of Cu2O phase in thin film formed during anodizing of Cu plates, regardless of the anodizing voltage and temperature of electrolyte. Photoluminescence spectroscopy showed the presence of Cu2O peak at 630 nm corresponding to band gap of 1.97 eV. A mechanism of the formation of Cu2O thin film was proposed. This study reported the ease of tailoring Cu2O nanostructures of different morphologies using anodizing that may help widen the applications of this material.

2

Fabrication and geometric characterization of highly-ordered hexagonally arranged arrays of nanoporous anodic alumina

Stępniowski W. J., Nowak-Stępniowska A., Michalska-Domańska M., Norek M., Czujko T., Bojar Z.

Polish Journal of Chemical Technology

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2014

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Vol. 16, nr 1

63-69

EN

Anodic aluminum oxide (AAO) has been fabricated in the 0.3 M oxalic acid at voltage range 20-60 V and temperature range of 35-50oC. The resulting nanoporous alumina surfaces were characterized by high resolution scanning electron microscopy, and the images were quantitatively analysed by means of an innovative approach based on fast Fourier transform. The influence of operating anodization voltage and electrolyte temperature on nanopores geometry (pore diameter, interpore distance, porosity, pores density) and arrangement has been studied in details and compared to literature data and theoretical calculations. It was found that independently from the temperature, the best arrangement of the nanopores is for anodic aluminum oxide formed at voltages ranging from 40 to 50 V. Moreover, it was found that pore diameter and interpore distance increase linearly with voltage, what is in line with the literature data.

3

Przepływy gazu przez nanopory – próba oceny

Such P.

Nafta-Gaz

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2014

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R. 70, nr 10

671--675

PL

Przeanalizowano teorie dotyczące przepływów gazu w formacjach łupkowych. Podstawowym parametrem charakteryzującym przepływy jest przepuszczalność urealniona (w literaturze apparent permeability). Zdefiniowano ten parametr, uwzględniając wszystkie procesy zachodzące w nanoporach. Dodatkowo przedyskutowano wielkość przepływu w nanoprzestrzeni porowej. Przeanalizowano czynniki, od których zależą te wielkości, oraz przebadano ich przebieg zmienności w typowych warunkach polskich złóż w formacjach łupkowych w funkcji promieni porów.

EN

The flow of gas in shale gas rocks was analyzed. The key parameter characterizing the flow is apparent permeability. This parameter was defined for nanopore space. Additionally total flux of gas was discussed. Variability of apparent permeability as well as total flux were analyzed for typical p, V conditions in the Polish shale reservoirs in a function of pore radius.

4

Optimising sulfuric acid hard coat anodising for an Al-Mg-Si wrought aluminium alloy

Bartolo N, Sinagra E, Mallia B

Materials Science Poland

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2014

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Vol. 32, No. 2

136--144

EN

This research evaluates the effects of sulfuric acid hard coat anodising parameters, such as acid concentration, electrolyte temperature, current density and time, on the hardness and thickness of the resultant anodised layers. A small scale anodising facility was designed and set up to enable experimental investigation of the anodising parameters. An experimental design using the Taguchi method to optimise the parameters within an established operating window was performed. Qualitative and quantitative methods of characterisation of the resultant anodised layers were carried out. The anodised layer’s thickness, and morphology were determined using a light optical microscope (LOM) and field emission gun scanning electron microscope (FEG-SEM). Hardness measurements were carried out using a nano hardness tester. Correlations between the various anodising parameters and their effect on the hardness and thickness of the anodised layers were established. Careful evaluation of these effects enabled optimum parameters to be determined using the Taguchi method, which were verified experimentally. Anodised layers having hardness varying between 2.4 – 5.2 GPa and a thickness of between 20 – 80 μm were produced. The Taguchi method was shown to be applicable to anodising. This finding could facilitate on-going and future research and development of anodising, which is attracting remarkable academic and industrial interest.

5

Confined phase envelope of gas-condensate systems in shale rocks

Nagy S., Siemek J.

Archives of Mining Sciences

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2014

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Vol. 59, no. 4

1005--1022

EN

Natural gas from shales (NGS) and from tight rocks are one of the most important fossil energy resource in this and next decade. Significant increase in gas consumption, in all world regions, will be marked in the energy sector. The exploration of unconventional natural gas & oil reservoirs has been discussed recently in many conferences. This paper describes the complex phenomena related to the impact of adsorption and capillary condensation of gas-condensate systems in nanopores. New two phase saturation model and new algorithm for search capillary condensation area is discussed. The algorithm is based on the Modified Tangent Plane Criterion for Capillary Condensation (MTPCCC) is presented. The examples of shift of phase envelopes are presented for selected composition of gas-condensate systems.

PL

Gaz ziemny z łupków (NGS) oraz z ze złóż niskoprzepuszczalnych (typu ‘tight’) staje się jednym z najważniejszych zasobów paliw kopalnych, w tym i następnym dziesięcioleciu. Znaczący wzrost zużycia gazu we wszystkich regionach świata zaznacza się głównie w sektorze energetycznym. Rozpoznawanie niekonwencjonalnych złóż gazu ziemnego i ropy naftowej w ostatnim czasie jest omawiane w wielu konferencjach. Niniejszy artykuł opisuje złożone zjawiska związane z wpływem adsorpcji i kapilarnej kondensacji w nanoporach w złożach gazowo-kondensatowych. Pokazano nowy dwufazowy model równowagowy dwufazowy i nowy algorytm wyznaczania krzywej nasycenia w obszarze kondensacji kapilarnej. Algorytm bazuje na kryterium zmodyfikowanym płaszczyzny stycznej dla kapilarnej kondensacji (MTPCCC). Przykłady zmiany krzywych nasycenia są przedstawiane w wybranym składzie systemów gazowo- kondensatowych.

6

Well testing in shale gas reservoir - new idea

Rybicki C.

AGH Drilling, Oil, Gas

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2014

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Vol. 31, no. 3

441--453

EN

Generally hydrocarbons reservoirs can be divided into conventional reservoirs and unconventional reservoirs. Conventional reservoirs belong these reservoirs which can be used directly after the discovering process. Unconventional reservoirs - reservoirs which after the discovery process have to be prepared to be effective. Unconventional gas resources are targets for development in order to contribute to a national energy mix. Better recognition of the unconventional gas reservoirs allow us to obtain good results after discovering them. The main subject of this paper is giving some details about the testing methods of unconventional reservoirs and their properties and characteristics.

7

Nanopory : budowa, właściwości, modele, zastosowania

Stachiewicz A., Molski A.

Wiadomości Chemiczne

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2013

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[Z] 67, 3-4

277--302

EN

Nanopores are small (1–100 nm diameter) holes/channels formed in biological membranes (Fig. 1) or fabricated in synthetic materials (Fig. 2). Permeation of ions and small molecules through nanopores is common in biological systems. The first experiments where nanopores were used as single-molecule sensors were performed in the 90s [1, 2]. The detection principle is based on a monitoring of an ionic current passing through a nanopore as an electric field is applied across the membrane. Electrically charged particles (e.g. DNA ) move in the electric field and block the ionic current as they pass through the nanopore. A sudden drop of the ionic current signals a single-molecule translocation event (Fig. 3–5). Nanopore sensors can give an information about the analyte: its size, structure and bonds stability. Today, a major topic of interest is the possibility of nanopore DNA sequencing. In this work we present an introduction to nanopore technology and to current research related to potential nanopore applications. First, we describe biological and synthetic nanopores: their structure and methods of fabrication. Next, different modes of nanopore experiments are presented. In the third section, we focus on theoretical models and simulations of nanopores. Finally, we present future perspectives for applications with particular reference to DNA sequencing.

8

Analitical criteria of homogeneous and heterogeneous detonation of liquid energetic materials

Kaim S.

Materiały Wysokoenergetyczne

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2013

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T. 5

5--13

EN

Statistical theory of liquids is used to investigate mechanism of detonation initiation on fronts of flat shock waves in homogeneous liquid and in liquid containing spherical nanopores. We calculated thermodynamic parameters of liquid methane sufficient for shock dissociation of molecules at a front of a shock wave. Calculations of the average single-particle force potential show that at high pressures and temperatures atoms and molecules get emitted from the surface into a nanopore with hyper-thermal speeds. Implosion of spherically symmetric stream of molecules may lead to destruction of the molecules at impact. We explained existence of top and bottom bounds for pressure during detonation initiation in heterogeneous energetic materials. In terms of pair interaction potentials and correlation functions there are formulated criteria for boundary values of thermodynamic parameters which are required for initiation of homogeneous and heterogeneous detonations based on the "hot spot"’ mechanism.

9

Mechanism of adsorption in cylindrical nanopores. The roles of adsorbate-adsorbate interactions in stabilizing the adsorbed phase

Kuchta B., Firlej L.

Materials Science Poland

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2006

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Vol. 24, No. 2/2

432--442

EN

Mechanism of adsorption in nanometric cylindrical pores has been analysed. Grand canonical Monte Carlo simulations were performed for two model systems: krypton and argon, adsorbed in an ideal (smooth) cylindrical silica pore of diameter 2R = 4 nm. The role of interatomic (adsorbate-adsorbate) interactions and atom-wall (adsorbate-adsorbent) forces in the mechanism of adsorption has been discussed. It has been shown that the correlation between these two energy components plays a crucial role in layering and capillary condensation transitions. The stability of different stages of adsorption has been analysed and discussed taking into consideration fluctuations of energy and number of adsorbed atoms during simulations.

10

Formation of the tribological properties of oxide layers.

Kmita T., Skoneczny W.

Advances in Manufacturing Science and Technology

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2006

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Vol. 30, nr 2

47-54

EN

The paper presents the problem of the influence of the structure of oxide layers obtained in an electrolytic process on tribological cooperation with constructional materials. Microhardness and abrasion resistance of oxide layers obtained on aluminium alloys by means of hard anodizing depend mainly on their porosity, morphology, surface roughness and layers' thickness. Utilitarian properties of alumina can be controlled to a rarge degree by changing the current and temperature conditions of the process as well as the composition of electrolyte or of the aluminium substrate. A porous oxide layer characterizes with a columnar structure with numerous micro-, macro- and nanopores formed at the contact point of Al203 fibres. Numerous structural and morphological studies conducted by AFM (atom-force microscopy) and SEM (scanning electron microscopy) have shown that it is possible to effectively control the number and size of alumina as well as micro- and nanopores. Any changes in the structure translate directly into changes of nanoroughness and porosity of the obtained oxide layers. Micro- and macropores on surfaces can be used as lubrication dispensers at sliding cooperation with modern constructional materials, e.g. TG15 or PEEK/BC. Tribological investigations have shown a dependence of wear intensity and friction factor of the couple: anodic oxide layer/plastic, on the internal structure of the cooperating triboelements.

PL

W pracy omówiono zagadnienie wpływu budowy warstw tlenkowych uzyskiwanych metodą elektrolityczną na procesy współpracy tribologicznej z tworzywami konstrukcyjnymi. Twardość i odporność na ścieranie warstw tlenkowych wytwarzanych na stopach aluminium metodą anodowania twardego zależą od ich porowatości, morfologii i chropowatości powierzchni oraz głębokości tych warstw. Właściwości użytkowe warstw tlenku glinu można kształtować w szerokim zakresie przez zmianę warunków prądowych i temperaturowych procesu anodowania oraz składu chemicznego elektrolitu i podłoża. Porowata warstwa tlenkowa odznacza się kolumnową mikrostrukturą z licznymi mikro-, makro- i nanoporami powstającymi na styku włókien AI2O3. Przeprowadzone badania mikrostruktury z użyciem mikroskopii sił atomowych AFM oraz elektronowej mikroskopii skaningowej SEM wykazały, że można skutecznie kształtować objętość względną i wymiary włókien tlenku glinu oraz mikro- i nanopor. Zmiany morfologiczne mikrostruktury oddziaływają bezpośrednio na zmiany nanochropowatości oraz porowatości uzyskiwanych warstw tlenkowych. Mikro- i makropory na powierzchni mogą pełnić funkcję zasobników smarnych przy współpracy ślizgowej z nowoczesnymi tworzywami konstrukcyjnymi, na przykład TC15 czy PEEK/BC. Badania tribologiczne wykazały zależność intensywności zużywania oraz współczynnika tarcia pary: anodowa warstwa tlenkowa - tworzywo sztuczne od struktury wewnętrznej współpracujących triboelementów.