Wyniki wyszukiwania - Biblioteka Nauki

1

Energy saving using heat exchangers covered with porous coatings

100%

Wójcik T. M.

Structure and Environment

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2010

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tom Vol. 2. no. 3

35-39

EN

Exploitation of technical devices is always related to the energy consumption. Thus, if more efficient heat exchangers are used as part of mechanical systems, it is possible to save energy. The paper presents possible ways of producing more efficient heat transfer surfaces working under the nucleate boiling mode. When porous coverings are used, significant reduction of temperature differences is noticed at the same heat flux. It leads to higher energy efficiency.

2

Badania mikrostruktury porowatych pokryć modelowych implantów dokostnych

75%

Uklejewski R. , Winiecki M. , Rogala P.

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2009

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tom Vol. 12, no. 89-91

112--114

3

Charakterystyka porowatych powłok otrzymanych na niobie i stopie Ti-Nb-Zr (TNZ) w procesie elektrolitycznego utleniania plazmowego (PEO)

63%

Rokosz K. , Hryniewicz T.

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tom R. 88, nr 12CD1

15--18

PL

Elektrolityczne utlenianie plazmowe (POE) zastosowano do biomateriałów metalowych, takich jak niob i stop Ti-Nb-Zr (TNZ). Obróbkę prowadzono w elektrolicie kwasu H3PO4 z dodatkiem azotanu miedzi. Otrzymane porowate powłoki badano z użyciem SEM/EDX. Badania uzyskanych powłok wykazały, że są one wzbogacone w jony miedzi (ponad 3,5 %mas.), podczas gdy Cu/P oraz Cu/(P+osnowa) wynosiły odpowiednio 0,2 i 0,07. Taka charakterystyka sprzyja poprawie biokompatybilności badanego biomateriału.

EN

The Niobium and Titanium-Niobium-Zirconium (TNZ) alloy biomaterials were treated by Plasma Electrolytic Oxidation (PEO) in view of getting porous surface layers. For the PEO process, a special set up was built to perform the experiments in the electrolyte composed of concentrated H3PO4, with an addition of copper II nitrate. The surface layers were studied by means of SEM and EDS methods to reveal the effects of porosity and compositions. It was found one may create porous coatings on niobium and on TNZ alloy, enriched with copper ions. Over 3.5 wt% content of copper, with Cu/P and Cu/(P+Matrix) ratios equaling to 0.2 and 0.07, respectively, may assure a better biocompatibility of the biomaterials.

4

Graphene based porous coatings with antibacterial and antithrombogenous function - Materials and design

63%

Major R. , Sanak M. , Mzyk A. , Lipinska L. , Kot M. , Lacki P. , Bruckert F. , Major B.

Archives of Civil and Mechanical Engineering

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2014

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tom Vol. 14, no. 4

540--549

EN

The studies considered graphene-based biomaterials dedicated for cardiovascular therapy. Reduced graphene oxide flakes were introduced into the porous structure of the polyelectrolyte based coatings. TEM analysis showed the presence of graphene flakes arranged parallel to the substrate surface, firmly connected to the porous coating. Biomaterials were subjected to a comprehensive diagnosis of the biological and material properties. The material behavior was simulated using finite element method. The coatings were deposited using layer by layer method. Mechanical analysis was done using Berkovich indenter geometry. They confirmed theoretical FEA based calculations, it was observed the coating stiffness incensement under the influence of introduced particles of graphene. The endanger of the bacteriology film formation was verified based on the E-coli and Staphylo coccus bacteria. Blood–material interaction was examined in the dynamic flow conditions. Bacteriological analysis showed reduced presence of bacteria after contact with the surface with introduced graphene flakes. Dynamic analyzes on blood showed high activation of the coagulation, strong platelets consumption and a strong immune response. It is caused by sharp edge of the single plane of the graphene flake.

5

Experimental Investigations on the Structural-Osteoinductive Properties of Porous Coatings on Orthopaedic Implants

51%

Uklejewski R. , Winiecki M. , Mielniczuk J. , Auguściński A. , Rogala P.

Machine Dynamics Problems

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2006

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tom Vol. 30, No. 4

171-180

EN

The adaptive bone tissue ingrowth into the pore space of a porous coating on orthopaedic implants is influenced by the structural-osteoinductive properties of this coating. The effective bone tissue ingrowth determines the proper fixation of the porous implant in its bony surroundings. The adequate evaluation of the structural-adaptive compatibility of bone-implant interface can be performed on the basis of the two-phase poroelastic biomechanical model of bone tissue and of implant porous coatings with the set of original parameters characterizing the poroaccessibility of implant porous coatings: the effective volumetric porosity φVef, the index of the porous coating space capacity VPM, the effective pore depth ρdef, the representative surface porosity φSrep, the representative pore size ρSrep, the representative angle of the poroaccessibility Ωrep, the index of the enlargement of the adhesive surface of bone-implant interface Ψ, which is proposed in (Mielniczuk et al., 2006; Winiecki et al., 2006; Uklejewski et al., 2005a and 2005b; Winiecki, 2006) to the biostructural evaluation of the porous coated orthopedic implants. This paper presents the results of experimental investigations of the microgeometrical properties of implants porous coatings made with contact profile measurement on the representative examples of endoprostheses stems.

6

SEM and EDS Characterization of Porous Coatings Obtained On Titaniumby Plasma Electrolytic Oxidation in Electrolyte Containing Concentrated Phosphoric Acid with Zinc Nitrate

51%

Rokosz K. , Hryniewicz T. , Pietrzak K. , Malorny W.

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tom Vol. 17, nr 2(52)

41--54

EN

The SEM and EDS results of porous coatings formed on pure titanium by Plasma Electrolytic Oxidation (Micro Arc Oxidation) under DC regime of voltage in the electrolytes containing of 500 g zinc nitrate Zn(NO3)2·6H2O in 1000 mL of concentrated phosphoric acid H3PO4 at three voltages, i.e. 450 V, 550 V, 650 V for 3 minutes, are presented. The PEO coatings with pores, which have different shapes and the diameters, consist mainly of phosphorus, titanium and zinc. The maximum of zinc-to-phosphorus (Zn/P) ratio was found for treatment at 650 V and it equals 0.43 (wt%) | 0.20 (at%), while the minimum of that coefficient was recorded for the voltage of 450 V and equaling 0.26 (wt%) | 0.12 (at%). Performed studies have shown a possible way to form the porous coatings enriched with zinc by Plasma Electrolytic Oxidation in electrolyte containing concentrated phosphoric acid H3PO4 with zinc nitrate Zn(NO3)2·6H2O.