Wyniki wyszukiwania - Biblioteka Nauki

1

The methods of modifications of turboprop and turboshaft civil and military engines

100%

Antas S.

Prace Instytutu Lotnictwa

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2001

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tom Nr 2-3 (165-166)

43-54

EN

This paper presents shortly reasons of improving designs and describes general methods of making modifications of turboprop and turboshaft engines. The theoretical analysis of methods of modifying, concerning general changes of efficiency, flow, and rating. So, the influence of the following factors on engine performance was presented: change of quality unit functioning factors, increase of compression and flow rate by using a compressor zero-stage; changes of gas temperature keeping the gasgenerator rotational speed by adjusting the minimal throat area of turbine nozzle guide vanes; modelling; changes of rotational speeds of operational ratings; and change of exhaust gas temperature. The theoretical analysis is illustrated by examples of usage.

PL

W pracy przedstawiono skrótowo przesłanki doskonalenia konstrukcji oraz omówiono zagadnienia termodynamiczne i przepływowe zasadniczych sposobów tworzenia modyfikacji turbinowych silników śmigłowych oraz śmigłowcowych. Badania teoretyczne poszczególnych sposobów modyfikacji obejmują ogólnie zmiany wydajności, przepływu oraz zakresu roboczego. Przedstawiono zatem kolejno następujące metody zmian osiągów silnika: zmiana wartości wspołczynników jakości działania (sprawności) zespołów; wzrost sprężu i strumienia masy powietrza przepływającego przez sprężarkę poprzez zastosowanie stopnia zerowego; zmiana sprężu sprężarki przy zachowaniu strumienia masy powietrza przeplywającego przez silnik; zmiana prędkości obrotowej roboczych zakresów pracy; zmiana temperatury spiętrzenia spalin przed turbiną sprężarki przy utrzymaniu prędkości obrotowej pędni, poprzez regulację pola powierzchni przekroju minimalnego wieńca dyszowego; modelowanie oraz zmiana temperatury gazów wylotowych. Analizę teoretyczną przedstawionych sposobów modyfikacji zilustrowano przykładami zastosowań.

2

W kierunku modyfikacji współczesnego systemu handlu międzynarodowego

85%

Puślecki Z. W.

Przegląd Politologiczny

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2013

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nr 4

59-84

EN

The primary goal of this analysis is to present the necessity for the improvement of the system of international commerce and its reform. Detailed goals involve the presentation of the opportunities for a new model ofthe WTO’s functioning to emerge, curbing of EU agricultural neoprotectionism, the necessity of changing the system of direct payments following from the EU’s Common Agricultural Policy towards the WTO, the issues of food security, improvement of the food supply chain, and the increased importance of bilateral agreements and normative solutions, the increased role and significance ofthe G-20 as an important and influential global institution, and the necessity of increasing the integrity and transparency of derivatives on commodity markets. The failure of the WTO Doha round of negotiations resulted from the determined standpoint taken by the developing states on the issue of developed countries decreasing agricultural subsidies, and the difference of opinions between the US and EU on the issue of the level to which agricultural subsidies should be reduced. Given the perspective of the WTO, it is crucial to reduce the EU’s agricultural neoprotectionism and to continue the alignment of this policy’s mechanisms to the new conditions posed by the developing global economy and the principles of the WTO. Ensuring global food security is a particular challenge. The EU should also contribute to the improved functioning of the food market on a global and regional level, ensuring also more market transparency. In the modern multipolar world, regional agreements and relations are becoming increasingly important, and following the failure of the Doha round - bilateral ones as well. Also significant from the theoretical point of view, the practical reasons are becoming less significant in favor of normative solutions, in particular in the case of developing states. In future, the essential reforms of the WTO should allow it to continue to stimulate the liberalization of global commerce and, to a larger extent, support progress in developing countries, mainly owing to aid fo r trade. The role and significance of the G-20 has clearly increased, as concems financial issues and international commerce. Both the WTO and G20 should jointly take steps to coordinate their efforts to promote the principles of open international commerce and increase the access of developing countries to the global market. Supporting open commercial principles in the global system will contribute to the legitimization of the G-20.

PL

Celem głównym opracowania było przedstawienie konieczności doskonalenia systemu i reform handlu międzynarodowego. Celami szczegółowymi natomiast było ukazanie możliwości powstania nowego modelu funkcjonowania WTO, ograniczania neoprotekcjonizmu rolnego UE, konieczności zmian systemu płatności bezpośrednich wynikających ze zobowiązań Wspólnej Polityki Rolnej UE wobec WTO, zagadnień bezpieczeństwa żywnościowego, doskonalenia łańcucha dostaw żywności oraz wzrostu znaczenia porozumień bilateralnych i rozwiązań normatywnych, wzrostu roli i znaczenia grupy G-20 jako ważnej i wpływowej instytucji globalnej, a także konieczności zwiększania integralności i przejrzystości instrumentów pochodnych na rynkach towarowych. Podłożem niepowodzeń Rundy Doha WTO, było zdecydowane stanowisko krajów rozwijających się dotyczące zmniejszenia subsydiowania rolnictwa przez państwa wysoko rozwinięte oraz różnice zdań między USA i UE w kwestii poziomu ograniczenia subsydiów rolnych. W perspektywie funkcjonowania WTO istotna jest potrzeba osłabienia neoprotekcjonizmu rolnego Unii Europejskiej i dalsze dostosowywanie mechanizmów tej polityki do nowych uwarunkowań rozwoju gospodarki światowej i reguł WTO. Szczególnym wyzwaniem jest również zapewnienie globalnego bezpieczeństwa żywności. UE powinna przyczynić się do poprawy funkcjonowania rynku żywności na poziomie światowym, regionalnym i globalnym, zapewniając także większą przejrzystość rynkową. We współczesnym wielobiegunowym świecie, coraz większego znaczenia nabierają porozumienia i więzi regionalne, a po fiasku Rundy Doha także bilateralne. Ponadto, co jest istotne z punktu widzenia teoretycznego, szczególnie w przypadku państw rozwijających się, osłabieniu ulegają uzasadnienia względów praktycznych, a zwiększa się znaczenie rozwiązań normatywnych. W przyszłości, w wyniku niezbędnych reform, WTO powinna nadal stymulować liberalizację handlu międzynarodowego, a także, bardziej niż dotychczas, wspierać rozwój państw rozwijających się, głównie poprzez aid fo r trade. W kwestiach finansowych i handlu międzynarodowego wyraźnie wzrosła rola i znaczenie grupy G-20. Zarówno WTO, jak i grupa G-20 powinny wspólnie podejmować i koordynować wysiłki na rzecz zasad promujących otwarty handel międzynarodowy, rozszerzający dostęp do rynku światowego państw rozwijających się. Poprzez wspieranie otwartych zasad handlowych w systemie globalnym wzmacniać się będzie równocześnie legitymizacja funkcjonowania grupy G-20.

3

Self-sensitizable Characteristics of Modified Ammonium Nitrate

80%

Ye Z. , Qian H. , Lu C. , Liu Z.

Central European Journal of Energetic Materials

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2005

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tom Vol. 2, nr 4

55-62

EN

Ammonium nitrate has been modified by evaporative recrystallization from its mixture solution with hexadecyl trimethyl ammonium bromide and sodium dodecyl sulfate. The physical property of the modified compound has been nwestigated by SEM, DSC, specific surface area and particle size measurements. The results show that in comparation with common ammonium nitrate, the modified ammonium nitrate has an irregular crystal shape, greater specific surface area, better particle size distribution, lower heat of crystal pattern transition and higher transition temperaturę. These indicate the modified ammonium nitrate has a mesoporous structure with good self-sensitizable, anti-hygroscopic and anticaking performances as an oxidizer of industrial explosive.

4

Wyznaczanie parametrów i osiągów silników śmigłowych oraz śmigłowcowych w przypadku modyfikacji przez zmianę temperatury spalin

80%

Antas S.

Silniki Spalinowe

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2006

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tom R. 45, nr 4

34-43

PL

W artykule zaprezentowano kompleksową analizę powszechnie stosowanej metody zmiany osiągów lotniczych silników śmigłowych i śmigłowcowych z wolną turbiną napędową. Przedstawiono opisy metody analitycznej oraz numerycznej oceny parametrów i geometrii zespołów turbin. Podano zasadnicze sposoby zmiany przepustowości wieńców dyszowych turbin oraz ich wpływ na osiągi silników. Metody obliczeń zweryfikowano rezultatami badań eksperymentalnych przeprowadzonych w WSK "PZL-Rzeszów" S.A.

EN

The article presents the analysis of a commonly used performance modification method for turboprop and turboshaft engines with a free power turbine. The description of analytical and numerical methods of evaluation for a change of parameters and geometry of turbine assemblies are presented. There are also given the basic methods of changing throat area of turbine nozzle guide vanes and its influence on engine performance. The calculation methods are verified by experimental tests run by WSK "PZL-Rzeszów" S.A.

5

The modification process of AlSi21CuNi silumin and its effect on change of mechanical properties of the alloy

80%

Pezda J.

Archives of Foundry Engineering

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2011

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tom Vol. 11, iss. 2

101-104

EN

Due to difficulties present during machining operations and with segregation of crystals of primary silicon, hypereutectic silumins can be used after modification only. It is why elaboration of effective modification methods is necessary for complete utilization of such alloys for machinery parts made from castings. In the paper are presented test results concerning an effect of modification with phosphor copper and strontium of AlSi21CuNi silumin on change of its mechanical properties [...] and its structure. Investigated alloy was melted in electric resistance furnace. All smelting processes were performed in temperature of 800 - 820oC. Obtained results concern light microscopy and strength tests of the investigated alloy. Performed tests have shown that application of phosphorus in form of CuP10 and AlSr10 master alloy as an inoculant gives positive results in form of refinement of primary crystals of silicon. Modification with phosphorus has enabled obtainment of clearly visible growth of tensile strength, [...].

6

Surface modification of metalic biomaterials with antibacterial coatings

80%

Basiaga M. , Walke W. , Paszenda Z.

Engineering of Biomaterials

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2018

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tom Vol. 21, no. 148

111

7

Kinetic research of quinoline, pyridine and phenol adsorption on modified coking coal

80%

Sun X. , Xu H. , Wang J. , Ning K. , Huang G. , Yu Y. , Ma L.

Physicochemical Problems of Mineral Processing

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2018

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tom Vol. 54, iss. 3

965--974

EN

Adsorption is widely used in wastewater treatment. In this work, the removal of quinoline, pyridine and phenol from coking wastewater by using modified coking coal, which was treated by four different modification methods i.e. acidification sodium hydroxide (5 mol/dm3), hydrochloric acid (5 mol/dm3) and acetic acid (5 mol/dm3) and low-temperature (105 oC) oxidation, was investigated. The modified coal was characterized by the surface area analysis, SEM, total acidity and basicity and FT-IR. The results showed that the surface area from high to low follows the order: modification with acetic acid, modification with hydrochloric acid, raw coal, modification with sodium hydroxide and modification with low-temperature. Experimental data were fitted to pseudo-first-order, pseudo-second-order and intra-particle diffusion. The adsorption of all followed pseudo-second-order kinetics. The result showed that the removal efficiency of coal modified by hydrochloric acid and acetic acid are higher than raw coal, while modified by sodium hydroxide and low-temperature are lower than raw coal., The coal modified by hydroxide acid had the best adsorption capacity.

8

Modification of silicone resins with epoxy resins

80%

Leśniak E.

Polish Journal of Chemical Technology

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2003

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tom Vol. 5, nr 3

109-111

EN

The modification of silicone resins with epoxy resins in order to obtain coating materials with good adhesion to copper and aluminium surfaces has been caried out. Curing times for several mixtures of silicone resins (Silak 31, Silak 32 and silicone - dianol resins Ph 1, PhM 1) with epoxy resin (Epidian 5) and with addition of curing agents (aliphatic or aromatic amines, Y-aminopropyltrimethoxysilane) have been determined. Coatings for adhesion studies have been prepared on copper and aluminium panels. The adherence of tested coatings to copper and aluminium surfaces, detrmined by the method of incisions net, has been very good regardless of a kind of applied modification. Films obtained from pure silicone resins type Silak get autonomously detached from copper supports.

9

Fading mechanism on grain refinement and modification with Al-B-Sr master alloys in an aluminium-silicon cast alloy

80%

Muangnoy P. , Eidhed K.

Archives of Metallurgy and Materials

|

2022

|

tom Vol. 67, iss. 3

1137--1144

EN

A fading mechanism during casting of treated Al-B-Sr master alloys in an aluminium-silicon cast alloy was investigated. Two different master alloys, the Al-3%B-3%Sr and Al-4%B-1%Sr were demonstrated for the efficiency test both grain refinement and modification microstructure. From experimental result, the addition of Al-3%B-3%Sr master alloy led to a refined grain size and fully modified eutectic Si. However, smaller grain sizes were found with Al-4%B-1%Sr master alloy addition while eutectic Si had coarser acicular morphology. The formation of high amounts of SrB6 compound in the Al-3%B-3%Sr master alloy resulted to increase of grain size and eutectic Si. In fading mechanism test when holding the melt for prolong time, the agglomeration of the SrB6 and AlSiSr compounds at the bottom of the casting specimen was important factors that decreased both grain refinement and modification efficiency. The stirring of the melt before pouring was found that the grain size and Si morphology were improved.

10

Plasma modification of nanodiamond particles

80%

Mitura K. , Ceynowa P. , Mitura S.

Engineering of Biomaterials

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2016

|

tom Vol. 19, no. 138 spec. iss.

123

11

Antibacterial activity assessment of bioactive modifiers for bone cements

80%

Wekwejt M. , Pałubicka A. , Świeczko-Żurek B.

Engineering of Biomaterials

|

2018

|

tom Vol. 21, no. 148

58

12

Development of a Manufacturing Technology of Compacted Graphite Iron Castings from a Cupola Furnace

80%

Bouska O. , Heunisch J. , Zadera A. , Nedelova K. , Kobersky F.

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nr 1

13

Modyfication of electric properties of hydroxyapatite with magnetite - preliminary research

80%

Gryń K. , Grzegorczyk M.

Engineering of Biomaterials

|

2018

|

tom Vol. 21, no. 148

118

14

Molybdates and tungstates sorption on organo-smectites as a process controlled by the type and amount of surfactant

80%

Muir B. , Andrunik D. , Bajda T.

Geology, Geophysics and Environment

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2016

|

tom Vol. 42, no. 1

102--103

EN

Modification of a smectite with organic surfactants leads to the formation of an organo-mineral complex characterized by a positive charged (Baj da et al. 2015). The process involves the exchange of naturally occurring cations, e.g. Ca 2+, Mg 2+, Na +, K + by large organic cations of surfactants. This alteration makes it possible to use organo-smectites as sorbents to remove anionic forms of Mo(VI) and W(VI) from aqueous solutions. The concentration of molybdenum in the environment is significantly enhanced by anthropogenic inputs from coal-resource development, fly ash, sewage sludge and hard-rock mining activity (Kalembkiewicz & Sočo 2009). W(VI) is released to the environment through its use in winter tires or by its applications in industry e.g. enriches alloys or electrotechnics (Gustafsson 2003). The environmental behavior of molybdenum and tungsten becomes very complex once they dissolve as Mo(VI) and W(VI) anions occur as a monomer only in alkaline or neutral solutions. Bentonite from the Jelšovy Potok in Slovakia, rich in montmorillonite phase, was used in the sorption experiments (Bajda et al. 2015). Through the preparation of a series of experiments it was possible to define the impact of various surfactants, their amount and organo-smectites’ properties order on the sorption capacity and pH effect. Smectite has been modified with dodecyltrimethylammonium bromide (DDTMA), didodecyldimethylammonium bromide (DDDDMA), hexadecyltrimethylammonium bromide (HDTMA) and dihexadecyldimethylammonium bromide (DHDDMA) in amounts of: 0.5, 1.0 and 2.0 of cation exchange capacity (CEC). Experiments of Mo(VI) and W(VI) sorption on organo-smectites were conducted under various concentrations of Mo(VI) and W(VI) (0–20 mM) and in wide range of pH’s (1–13). The effectiveness of modifications follows the order DDTMA-smectite > HDTMA-smectite > DDDDMA-smectite > DHDDMA-smectite. The unmodified smectite did not remove Mo(VI) and W(VI) anions from the aqueous solution at all. In the removal of Mo(VI), sorption efficiency follows the order: DDTMA-smectite > DDDDMA-smectite > HDTMA-smectite > DHDDMA-smectite. In case of W(VI) the efficiency of the removal can be place: DDDDMA-smectite > DDTMA- -smectite > HDTMA-smectite > DHDDMA- -smectite. With an increasing concentration of Mo(VI) or W(VI) in the solutions, the sorption increases. The maximum sorption capacity in the removal of Mo(VI) was 1710 mmol Mo(VI)/kg in case of smectite modified with DDTMA at 0.5 CEC. The best result of tungsten sorption was 5882 mmol W(VI)/kg and it was obtained for DDDDMA-smectite (0.5 CEC). Results showed that the sorption is more effective at a lower pH, in both Mo(VI) and W(VI) removal. The smectite modified with surfactant with double carbon chain (DDDDMA, DHDDMA) proved to be a better sorbent. With an increasing amount of surfactant attached to the smectite, the sorption efficiency increases.

15

Effect of surface titanum modification on interaction with graphene oxide coatings

80%

Frączek-Szczypta A. , Kluska S. , Młynarska P.

Engineering of Biomaterials

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2017

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tom Vol. 20, no. 143 spec. iss.

70

16

Using Deep Etching in the Study of Eutectic Silicon 3D-Morphology in AlSi7MgTi Cast Alloy

80%

Kuchariková L. , Tillová E. , Bonek M. S. , Chalupová M.

Archives of Metallurgy and Materials

|

2018

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tom Vol. 63, iss. 4

2017--2022

EN

The effect of combination grain refinement with AlTi5B1 master (55 ppm) and Sr-modification with AlSr5 master (20, 30, 40, 50 and 60 ppm) on the microstructure, tensile and hardness properties of AlSi7MgTi cast alloy were systematically investigated. Eutectic silicon was studied by optical and scanning electron microscopy after standard (0.5% HF) and deep etching (HCl). Morphology of eutectic Si changes from compact plate-like (as-cast state) to fibbers (after modification). Si-fibbers in samples with 50 and 60 ppm Sr coarsen probably as a result of over-modification. The optimum mechanical properties has the experimental material which was grain refined and modified with 40 ppm of Sr (UTS = 220.6 MPa; ductility = 6.1%, and 82.3 HBW 5/250/15).

17

Plasma surface modifications of polymeric substrate for applications in biomedicine

80%

Kyzioł A. , Szczerba A. , Klich M. , Kaczmarek Ł. , Kyzioł K.

Engineering of Biomaterials

|

2016

|

tom Vol. 19, no. 138 spec. iss.

107

18

Prace rozpoznawcze nad technologią ciągłej modyfikacji sodem stopów Al-Si

80%

Białobrzeski A. , Dudek P. , Fajkiel A. , Leśniewski W.

Archiwum Odlewnictwa

|

2006

|

tom R. 6, nr 18/1

97--102

PL

Jednym z możliwych sposobów ciągłej modyfikacji stopów około eutektycznych sodem, może być ciągła elektroliza związków (soli) sodowych, odbywających się bezpośrednio w kąpieli metalowej (w tyglu). Do takiego procesu niezbędne jest zastosowanie stałego elektrolitu - przewodzącego jony sodu. Sól sodowa umieszczona np. w retorcie, wykonanej ze stałego elektrolitu, w wyniku przyłożonego napięcia prądu stałego ulega dysocjacji, a następnie elektrolizie. Retorta jest zanurzona w ciekłym metalu. Anodą jest ciekła w tej temperaturze sól sodowa, połączona ze źródłem prądu stałego np. przez elektrodę grafitową, a katodą jest ciekły metal. Jony sodu powstające z dysocjacji soli sodu i elektrolizy są transportowane przez ściankę stałego elektrolitu (materiał retorty), a w zetknięciu z ciekłym stopem jako katodą, jony sodu przechodząc w stan atomowy modyfikują kąpiel metalową.

EN

One of the validated methods of continuous sodium modification of around-eutectic alloys can be continuous electrolysis of sodium compounds (salts), conducted directly in metal bath (in crucible). To carry out this process it is necessary to have a solid electrolyte conducting sodium ions. The sodium salt placed in e.g. a retort made from the solid electrolyte undergoes, due to the application of direct current, the process of dissociation, first, and of electrolysis next. The retort is immersed in liquid metal. The anode is sodium salt, liquid at this temperature and connected to the source of direct current through e.g. a graphite electrode, while cathode is liquid metal. Sodium ions formed by dissociation of sodium salt and electrolysis are trasported through the wall of solid electrolyte (the material of retort), and in contact with liquid alloys acting as a cathode, they are passing into atomic state and modify the metal bath.

19

Modifikacija polimierov v sozdanii materialov mediko-biologičeskogo naznačenija

80%

Shtilman M. I.

Prace Naukowe Instytutu Technologii Organicznej i Tworzyw Sztucznych Politechniki Wrocławskiej. Konferencje

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2001

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tom Vol. 50, nr 23

82-82

20

The Study of the Tensile Strength of AlSi21CuNiMg Silumin in the Final Stage of Solidification and the Initial Stage of Cooling

80%

Romankiewicz R.

Journal of Casting & Materials Engineering

|

2019

|

tom Vol. 3, no. 3

57--61

EN

The paper presents the results of tensile strength tests of AlSi21CuNiMg silumin made on a test stand. Silumin was under examination in an unmodified state and after modification with AlCu19P1.4 master alloy in quantity of 0.2% in relation to the mass of the alloy. Using a scanning microscope, the surface fractures obtained from tensile tests were tested. The structure and profiles of fractures were examined using an optical microscope. Modification of the tested silumin resulted in a favorable fragmentation and regular distribution of the crystals of the primary silicon in the alloy structure, which led to an almost twofold increase in the strength of the silumin samples at the final solidification stage from 3.5 to 6.6 MPa. As a result of these changes, the resistance of silumin to hot cracks should increase, which is of great importance when casting hypereutectic silumin in a metal mould that strongly inhibits the shrinkage of the castings.