Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "korozja" wg kryterium: Wszystkie pola

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 17
Tytuł:
Korozja metali
Corrosion of metals
Autorzy:
Levchenko, Rostyslav
Powiązania:
https://bibliotekanauki.pl/articles/2200310.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
korozja
rodzaj korozji
szybkość korozji
ochrona przed korozją
corrosion
corrosion type
corrosion rate
corrosion protection
Opis:
Korozja jest zjawiskiem szkodliwym dla wyrobów metalowych. Procesy stopniowego niszczenia struktury metalu następują wskutek jego chemicznych reakcji ze składnikami otoczenia lub procesów elektrochemicznych. Krótko scharakteryzowano te procesy. Przedstawiono w skali sześciostopniowej odporności metali w zależności od średniej szybkości korozyjnej Vc, Vp. Przedstawiono metody przeciwdziałania korozji metali na przykładach – modyfikacji składu chemicznego stali, ochronie elektrochemicznej, zastosowanie powłok ochronnych oraz inhibitorów korozji. Wskazano, iż korozja jest ważnym problemem gospodarczym, ponieważ straty powodowane przez nią w krajach rozwiniętych szacuje się na 3 do 5% produktu krajowego brutto.
Corrosion is a harmful phenomenon for metal products. The processes of gradual destruction of the structure of a metal occur due to its chemical reactions with environmental components or electrochemical processes. These processes are briefly characterized. The six-stage scale of resistance of metals depending on the average corrosion rate Vc, Vp is presented. Methods of counteracting the corrosion of metals are presented with examples - modification of the chemical composition of steel, electrochemical protection, the use of protective coatings and corrosion inhibitors. It was pointed out that corrosion is an important economic problem, since losses caused by it in developed countries are estimated at 3 to 5% of gross domestic product.
Źródło:
Archiwum Wiedzy Inżynierskiej; 2022, 7, 1; 13--16
2544-2449
Pojawia się w:
Archiwum Wiedzy Inżynierskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrosion of RC beams during time
Autorzy:
Blikharskyy, Yaroslav
Khmil, Roman
Blikharskyy, Zinoviy
Powiązania:
https://bibliotekanauki.pl/articles/103955.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
corrosion
aggressive environment
reinforced concrete beam
korozja
agresywne środowisko
wzmacnianie belki betonowej
Opis:
This article presented results of impact corrosion on reinforce concrete beams during time with previous loading. Before testing the RC beams were loaded by 37% and 75% from bearing-capacity load of undamaged corrosion beams. There were tested two types of beams. First type beams were tested under force loading action and second type beams were tested under force loading and corrosion action. As an aggressive environment were used the 10% solution of sulfuric acid H2SO4. Such environment takes place in separate chemical manufactures, galvanic workshops, flue pipes of thermal power plants. The results of experimental studies have established that the effect of the aggressive environment with simultaneous loading significantly impairs the stress-strain state of reinforced concrete beams. Bearing capacity due to the yielding of reinforcement bars for specimens with the simultaneous action of aggressive environment and previous loading of 37% and 75% takes place on 51…53 and 58…60 days. The destruction of these specimens, by crushing compressive concrete, at previous loading 37% occurred after 75…79 and at previous loading 75% - after 79…88 days. The history loading does not impact significantly on beams failure, on finite deflections and timing exhaustion bearing capacity since the start of the simultaneous action of aggressive environment and loading.
Źródło:
Quality Production Improvement - QPI; 2019, 1, 1; 311-318
2657-8603
Pojawia się w:
Quality Production Improvement - QPI
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrosion of reinforce bars in RC constructions
Autorzy:
Blikharskyy, Zinoviy
Selejdak, Jacek
Blikharskyy, Yaroslav
Khmil, Roman
Powiązania:
https://bibliotekanauki.pl/articles/973032.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
steel bars
corrosion
aggressive environment
pręty stalowe
korozja
środowisko agresywne
Opis:
In this article presented results of researching corrosion of steel bars in aggressive environment in time under loading. For researching were used special equipment. The experience and research works shown that steel bars in the crack cross-section area can be corrode. With increasing width of crack in re-bars and power of aggressive of environment increased the level of corrosion and decreased time of progress. The level of danger of corrosion in the crack in depend of specialty of steel bars. It is geometry parameters of steel bars and characteristic of corrosive behaviour. The general tendency of the influence of various defects on the strength of steels is widely studied experimentally and theoretically only for geometrically correct stress concentrators. For damages that are irregular in shape, such as corrosion ulcers, significantly less researching in each case must experiment to find their effect on the mechanical properties of steels. In this work the influence of simultaneous action of the aggressive environment and loading on strength of steel rebars has been described.
Źródło:
System Safety : Human - Technical Facility - Environment; 2019, 1, 1; 277-283
2657-5450
Pojawia się w:
System Safety : Human - Technical Facility - Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Roughness of 1.0721 steel after corrosion tests in 20% NaCl
Autorzy:
Lipiński, T.
Powiązania:
https://bibliotekanauki.pl/articles/111793.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
steel
corrosion
corrosion rare
roughness
NaCl solution
korozja stali
roztwór NaCl
chropowatość stali
zużycie korozyjne
Opis:
Non-alloy quality case-hardening steels are used for low-load components made on automatic machining centers (automatic lines). Because of the widespread use of these steel in open constructions, they are exposed to atmospheric corrosion. The study attempted to analyze the effect of 20% aqueous NaCl solution on the roughness of the steel as a result of corrosion. The steel roughness and corrosion wear were determined according to corrosion time.
Źródło:
Production Engineering Archives; 2017, 15; 27-30
2353-5156
2353-7779
Pojawia się w:
Production Engineering Archives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of corrosion effect on the quality and safety of refractory materials
Autorzy:
Šolc, Marek
Kotus, Martin
Grambalová, Eva
Kliment, Juraj
Palfy, Pavol
Powiązania:
https://bibliotekanauki.pl/articles/88547.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
refractory material
process
corrosion
requirements
materiał ogniotrwały
jakość
korozja
Opis:
The quality of refractory materials plays an important role especially in high temperature processes. In case of violation of qualitative properties of refractory materials, the safety of the use of the technological equipment in which these materials are used is compromised. The requirements on the quality of refractories and their properties are now high, as their operating life should be as long as possible. The aim of the article is to point out the quality of refractory material in contact with corrosive media, to analyze the technological factors that affect the quality and safety of technological equipment. An analysis of the refractory material, as well as the analysis of the melt was performed. Subsequently, an experiment was realized, which was evaluated by macroscopic analysis and chemical analysis. After the experiments, we found that the melt had penetrated the masonry and consequently created corrosion layers in the masonry. These layers have affected the life of the material and reduced the safety of the technological equipment in which they were used.
Źródło:
System Safety : Human - Technical Facility - Environment; 2019, 1, 1; 760-767
2657-5450
Pojawia się w:
System Safety : Human - Technical Facility - Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrosion effect of 65% Nitrate acid on X4CrNi1812 at 333 K
Autorzy:
Lipiński, Tomasz
Karpisz, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/104158.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
steel
stainless steel
corrosion
corrosion rate
roughness
stal
stal nierdzewna
korozja
szybkość korozji
chropowatość
Opis:
Austenitic stainless steels are often used for a materials in the construction of machines and equipment for agricultural and for industrial construction. One of the most important factors constructional material is corrosion resistance. Equipment with austenitic stainless steel can be easy join by quickly welding at a not to high construction price, but one with the serious problem in aggressive environment is their corrosion resistance. A few corrosion processes in crevices and awkward corners can be avoided at the design stage (low roughness parameters, round-section and other). But still the construction material is exposed to corrosion. These steels often come into contact with an aggressive environment based on nitric acid. The main aim of this research is to investigate corrosion resistance in different time (48, 96, 144, 192, 240, 288, 336 hours). For this used weight loss of test samples and its profile roughness. The research was conducted on austenitic stainless steel in grade in Nitrate acid at 333 K. Corrosion tests confirmed that the research this steel in 65% nitrate acid as a corrosive environments is characterized through proportionate to time corrosion process whose measure may be surface roughness. In industrial practice roughness parameters for all the research times can be used for determine the stage and size of steel corrosion.
Źródło:
Quality Production Improvement - QPI; 2019, 1, 1; 425-432
2657-8603
Pojawia się w:
Quality Production Improvement - QPI
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of temperature on corrosion resistance of austenitic stainless steel in cl¯ containing solutions
Autorzy:
Zatkalíková, Viera
Markovičová, Lenka
Powiązania:
https://bibliotekanauki.pl/articles/111992.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
pitting corrosion
temperature
cyclic potentiodynamic test
immersion test
pitting potential
korozja wżerowa
temperatura
test potencjodynamiczny
Opis:
Temperature is considered a complicated external factor of the susceptibility of stainless steels to the pitting. This paper deals with the corrosion behaviour of AISI 316Ti stainless steel in temperature range 22 - 80°C in aggressive chloride environments (3 and 5% FeCl3 solutions). The corrosion resistance of tested steel is evaluated on the base of results of exposure immersion tests and cyclic potentiodynamic tests. According to the obtained results the resistance of AISI 316Ti to the pitting is markedly affected by temperature changes in the range 22 - 80°C. Intensity of corrosion attack increases with the rise of Cl¯ concentration. Gentle changes of temperature and Cl¯ concentration cause significant differences in character of local damage. The appearance of pitted surfaces changes with the rise of the temperature (a density of pitting increases, a size of pits decreases). The strongest change in appearance is observed between 40 and 50ºC.
Źródło:
Production Engineering Archives; 2019, 25; 43-46
2353-5156
2353-7779
Pojawia się w:
Production Engineering Archives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-uniform corrosion of steel rebar and its influence on reinforced concrete elements` reliability
Autorzy:
Blikharskyy, Yaroslav
Kopiika, Nadiia
Selejdak, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/1839520.pdf
Data publikacji:
2020
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
corrosion
steel rebar
material anisotropy
mathematical modeling
korozja
stalowy pręt zbrojeniowy
anizotropia materiałowa
modelowanie matematyczne
Opis:
Remarkable place of reinforced concrete structures in construction field has been noted in wide number of recent researches. Subsequently, their degradation due to aggressive environment has become the topical problem nowadays. Therefore, the formulation of reliable technique for corroded element strength decrement is of great importance, and could be achieved only with the use of complex experimental and theoretical analysis. In this article an attempt is made to propose the mathematical approach to corrosive process modelling, taking into consideration the specifics of its development. According to thorough literature review on existing studies, main specifics of the process were indicated for further suppositions and assumptions formulation. Accordingly, the complex theoretical investigation with corresponding mathematical computations was conducted and results of analytical modelling were discussed. As the initial data for analytical modelling results of previously conducted experiments were used. Analysis of the obtained results shows rather high correspondence with the real conditions of structural element exploitation, taking into consideration material anisotropy and complexity of the corroded zone spread along the rebar cross-section. Proposed methodology for limit force decrease evaluation in general demonstrates reliable results and could be used for further evaluation of corrosion impacts on reinforced concrete elements bearing capacity.
Źródło:
Production Engineering Archives; 2020, 26, 2; 67-72
2353-5156
2353-7779
Pojawia się w:
Production Engineering Archives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrosion of RC elements` reinforcement and its influence on the stress-strain state
Autorzy:
Blikharskyy, Yaroslav
Kopiika, Nadiia
Blikharskyy, Zinoviy
Powiązania:
https://bibliotekanauki.pl/articles/103969.pdf
Data publikacji:
2020
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
corrosion
reinforced concrete elements
steel bars
stress-strain state
korozja
elementy żelbetowe
pręty stalowe
stan naprężenie-odkształcenie
Opis:
The stress-strain state of reinforced concrete elements is rather complicated issue of scientific research, which integrates different factors, such as the load type, atmospheric conditions, various defects, damages, geometric deviations. It is commonly known that corrosion of reinforced concrete elements affects both the strength and deformation parameters of the structure significantly; thus, internal stresses` parameters are also influenced. Therefore, detailed theoretical investigation of this issue is the main goal of this article. The detailed literature review and thorough analysis was conducted concerning previous experimental and theoretical studies of the corrosion defects` influence on the reinforced concrete elements` stress-strain state. Existing data and results were systematized and analyzed. On the basis of provided research it could be concluded that the reinforced concrete elements` stressstrain state greatly depends on existing damages and impurities. The stress-strain state could be complicated on micro-scale due to material chemical and mechanical peculiarities; simultaneously on macro-scale the bearing capacity is of the structure could be reduced in general. In the articles existing methods for this issue simulation and evaluation are described and perspective fields for further research are identified. The practical significance of the article is due to complex approach to the research and multilateral identification of the main issue key points.
Źródło:
Quality Production Improvement - QPI; 2020, 2, 1; 214-220
2657-8603
Pojawia się w:
Quality Production Improvement - QPI
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of corrosion rate of X55CrMo14 stainless steel at 65% nitrate acid at 348 K
Autorzy:
Lipiński, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/1839535.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
stal
stal nierdzewna
korozja
szybkość korozji
profil chropowatości
steel
stainless steel
corrosion
corrosion rate
profile roughness
Opis:
A number of factors determine the mechanical, but also physical and chemical properties. One of the most important are the steel microstructure and its working conditions. A few corrosion processes in crevices and awkward corners can be avoided at the design stage (low roughness parameters, roundsection and other). But still the construction material is exposed to corrosion. These steels often come into contact with an aggressive environment based on nitric acid. Stainless steel is more and more often used in many sectors of industry. The purpose of this article is to investigate corrosion resistance in different time (48, 96, 144, 192, 240, 288, 336, 384 and 432 hours) using weight loss and profile roughness parameters of martensitic steel in grade X55CrMo14 in nitric acid 65% pure-basic at temperature 348 K. Corrosion tests show that the tested steel in nitric acid as a corrosive environments is characterized through continuous corrosion process whose measure may be surface roughness.
Źródło:
Production Engineering Archives; 2021, 27, 2; 108-111
2353-5156
2353-7779
Pojawia się w:
Production Engineering Archives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The impact of the agressive acid environment on RC constructions
Autorzy:
Blikharskyy, Yaroslav
Khmil, Roman
Blikharskyy, Zinoviy
Shnal, Taras
Powiązania:
https://bibliotekanauki.pl/articles/88692.pdf
Data publikacji:
2020
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
aggressive environment
reinforce concrete
beams
corrosion
damaged constructions
środowisko agresywne
środowisko kwaśne
konstrukcja żelbetowa
belka
beton zbrojony
korozja
Opis:
The main issue of the article is the corrosion of the reinforced concrete elements by the co-influence of the aggressive and power factors. The problem of corrosion is extremely actual one. Therefore the tests were carried out upon the specimens considering the corrosion in the acid environment, namely 10 % HSO4. The acid environment H2SO4 was taken as a model of the aggressive environment. Conclusions concerning the corrosion model of the cross section and investigation of stress-strain state have been made. That material concerns the problem of the reinforced concrete corrosion as a whole construction. Reinforced concrete beams were tested with and without the co-action of the aggressive environment and power factor.
Źródło:
System Safety : Human - Technical Facility - Environment; 2020, 2, 1; 223-229
2657-5450
Pojawia się w:
System Safety : Human - Technical Facility - Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stress-strain state of damaged reinforced concrete bended elements at operational load level
Autorzy:
Kopiika, Nadiia
Vegera, Pavlo
Vashkevych, Rostyslav
Blikharskyy, Zinoviy
Powiązania:
https://bibliotekanauki.pl/articles/23967534.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
korozja
pręt stalowy
belki o rzeczywistych wymiarach
uszkodzone belki
corrosion
steel rebar
real size beams
damaged beams
Opis:
Each structure is exposed to different influences during operation. As a result, there are various defects and damages of these elements that affect their safe operation. The article presents the results of experimental studies of reinforced concrete beams with damages to stretched reinforcement made with and without initial load application. As the damages were accepted one or five Ø5.6 mm holes. In one case, the damage was made until the beam destruction (up to the 8.4 mm opening) Control samples of both series were destroyed due to crushing of the compressed zone of concrete. Samples that were damaged without initial loading collapsed due to rupture of the stretched reinforcement. The same type of failure was identified for damages at the operational load level.
Źródło:
Production Engineering Archives; 2021, 27, 4; 242--247
2353-5156
2353-7779
Pojawia się w:
Production Engineering Archives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrosion resistance of SiMo- and SiCu-types of nodular cast iron in NaCl solution
Autorzy:
Vaško, Alan
Zatkalíková, Viera
Kaňa, Václav
Powiązania:
https://bibliotekanauki.pl/articles/88510.pdf
Data publikacji:
2020
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
nodular cast iron
corrosion
exposure immersion test
NaCl solution
żeliwo sferoidalne
korozja
roztwór NaCl
właściwości mechaniczne
właściwości zmęczeniowe
Opis:
Nodular cast irons are used in a wide range of industrial applications, especially in the automotive industry. SiMo-type of nodular cast iron is suitable for high-temperature applications, for example the exhaust manifolds of the combustion engines; SiCu-type of nodular cast iron is used in various components of tribotechnical units. These automotive components often work in a corrosive environment. Therefore, the aim of this paper is to compare the corrosion resistance of two types of the nodular cast irons (SiMo-type and SiCu-type). Corrosion resistance was determined by the exposure immersion test at ambient temperature. Specimens of both types of nodular cast iron were immersed in 3.5 % NaCl solution (to simulate sea water) and gradually removed from the solution after 1, 2, 4 and 8 weeks. Subsequently, the weight loss (g) and the average corrosion rate (g m-2 day-1) were calculated. Experimental results show that nodular cast iron alloyed by Si and Mo has higher corrosion resistance than the nodular cast iron alloyed with Si and Cu. Moreover, the mechanical properties (evaluated by tensile test, impact bending test and hardness test) and fatigue properties of both types of nodular cast iron has been compared in the paper.
Źródło:
System Safety : Human - Technical Facility - Environment; 2020, 2, 1; 191-198
2657-5450
Pojawia się w:
System Safety : Human - Technical Facility - Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Odporność korozyjna utlenianego anodowo stopu tytanu Ti6Al4V
Corrosion resistance of anodically oxidated titanium Ti6Al4V alloy
Autorzy:
Sitkowska, Nikoletta
Jagielska-Wiaderek, Karina
Powiązania:
https://bibliotekanauki.pl/articles/1818923.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
tytan
Ti6Al4V
korozja
anodowanie
implanty
titanium
corrosion
anodizing
implants
Opis:
Celem pracy było zbadanie wpływu parametrów anodowania stopu tytanu na jego odporność korozyjną w roztworze sztucznej śliny. Stwierdzono, że w środowisku kwasu fosforowego, narastanie warstw tlenowych zależało od czasu i gęstości prądu anodowania. Zaobserwowano, że warstwy pasywne pełnią funkcje ochronne i zwiększają odporność na korozję stopu tytanu. Odporność korozyjna materiału wzrastała wraz ze wzrostem grubości tworzonych warstw.
The objective of the work was to investigate the effect of anodizing parameters of titanium alloy on its corrosion resistance in artificial saliva solution. It was found that in the environment of phosphoric acid, the growth of oxygen layers depended on the time and density of the anodizing current. It has been observed that the passive layers perform a protective function and increase the corrosion resistance of the titanium alloy. The corrosion resistance of the material increased with the thickness of the created layers.
Źródło:
Archiwum Wiedzy Inżynierskiej; 2021, 6, 1; 9-12
2544-2449
Pojawia się w:
Archiwum Wiedzy Inżynierskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Local corrosion of AISI 304 stainless steel in acidic chloride solution
Autorzy:
Zatkalíková, Viera
Markovičová, Lenka
Hanusová, Patrícia
Powiązania:
https://bibliotekanauki.pl/articles/104041.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
austenitic stainless steel
pitting corrosion
exposure test
cyclic potentiodynamic test
direction of rolling
austenityczna stal nierdzewna
korozja wżerowa
próba narażenia
cykliczna próba potencjodynamiczna
kierunek walcowania
Opis:
AISI 304 austenitic stainless steel is recommended and used for various applications in industry, architecture and medicine. Presence of halides in environment evokes a possibility of the local corrosion which limits seriously exploitation of this material in aggressive conditions. The presented paper is focused on the pitting corrosion resistance (“as received” steel surface) in 1M chloride solution (pH=1.2) at a common (20 °C) and an elevated (50 °C) ambient temperatures. 24-hours exposure immersion test (ASTM G48) and cyclic potentiodynamic test (ASTM G61) are used as the independent test methods. The exposure immersion test is carried out with cross-rolled and longitudinally rolled specimens and the effect of direction of rolling on the resistance to pitting is studied.
Źródło:
Quality Production Improvement - QPI; 2019, 1, 1; 268-275
2657-8603
Pojawia się w:
Quality Production Improvement - QPI
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 17

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies