Informacja

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

Wyszukujesz frazę "liquid scintillation" wg kryterium: Wszystkie pola


Tytuł:
Differentiation between fossil and biofuels by liquid scintillation beta spectrometry - direct method
Autorzy:
Edler, R.
Kaihola, L.
Powiązania:
https://bibliotekanauki.pl/articles/148479.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
biocarbon
liquid scintillation
biofuel
14C
Quantulus
PerkinElmer
Opis:
Liquid scintillation spectrometry of 14C in gasoline/ethanol and diesel oil was carried out using QuantulusŽ and straight mixtures of fuel and an organic scintillation cocktail. A linear correlation was found between the concentration of carbon that originates from the bioethanol (biocarbon) and the fuel mixture’s 14C activity in the range 0–100% (m/m) bioethanol content. Because of these good linear correlations, quantitative determination of a fuel’s biocarbon content can be made by 14C analysis. The direct method is also applicable to analysis of the bio-based materials dissolvable in solvents, which can be mixed with scintillation cocktails.
Źródło:
Nukleonika; 2010, 55, 1; 127-131
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of plutonium extraction with methyltrioctylammonium chloride preceding its determination by liquid scintillation spectrometry
Autorzy:
Komosa, A.
Piekarz, M.
Powiązania:
https://bibliotekanauki.pl/articles/148483.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Pu
LSC spectrometry
methyltrioctylammonium chloride
extraction
Opis:
Optimization of selective extraction conditions for separating plutonium from uranium and thorium standard solutions using methytrioctylammonium chloride (Aliquat 336) as extracting agent is presented. Influence of such parameters as concentration of extracting agent and nitric acid, and kind of reducing agent on the efficiency of extraction were studied. The method was developed for standard solutions of Pu, Th and U. A Quantulus liquid scintillation spectrometer was used for determination of alpha activity of these isotopes. It was found that using HDEHP in the first stage of the elaborated procedure and Aliquat 336 in the next, it is possible to separate Pu from the mixture of U and Th. Optimal values of measuring parameters such as a PSA value and a scintillation cocktail volume were established as well.
Źródło:
Nukleonika; 2010, 55, 2; 137-141
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of exhalation rates through measurements of alpha and beta radiation with the aid of liquid scintillation counter
Autorzy:
Chau, N.
Chruściel, E.
Powiązania:
https://bibliotekanauki.pl/articles/148422.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radon
exhalation rate
iquid scintillation counter
Opis:
In this paper, a method for the determination of the relative and mass exhalation rates is presented. For the measurement of radon content in an emanation chamber, an ?/ß liquid scintillation counter was applied. The method was preliminarily tested on the following samples: (1) samples of uranium tailing piles in the Kowary region, (2) samples obtained by mixing of the mentioned waste with various materials such as cement, gypsum and anhydrite and (3) samples of some building materials.
Źródło:
Nukleonika; 2003, 48, 3; 133-136
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radon in drinking water in the Białystok region of Poland
Autorzy:
Karpińska, M.
Kapała, J.
Mnich, Z.
Szpak, A.
Powiązania:
https://bibliotekanauki.pl/articles/148370.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radon in water
Białystok region
liquid scintillation
Opis:
Water is one of the indoor sources of 222Rn. As radon is soluble in water, it is carried indoor by water supply and there it is released. The presence of radon in groundwaters is caused by direct migration of 222Rn from rocks and soil to waters as well as by radium content in water. Radon inflow indoor is possible in the areas where drinking water shows high radon concentration. Radon concentration changes significantly from low in natural surface water to relatively high from water in drilled wells. It is estimated that out of 10,000 Bq·m–3 of radon contained in water supply we can obtain radon concentration increase by 1 Bq·m–3 indoor. The aim of the study was to measure radon in water supply in the Białystok region and also estimation of doses and investigation how the treatment influenced radon concentration in water. Water was collected from rural and municipal waterworks as well as from home wells. Measurements of radon concentration in particular stages of drawing and treatment of water in Białystok waterworks were also conducted. A liquid scintillation method was used in the study. The arithmetic mean of radon concentrations in the samples was equal to 5800 Bq·m–3, median – 4800 Bq·m–3, and geometric mean – 4600 Bq·m–3. The lowest values of radon concentration were observed in surface waters (from surface intake). Radon concentrations in waters from drilled wells, shallow home wells and surface intake were compared and statistically significant differences were obtained at p < 0.05. The results of radon concentrations in drinking water in the Białystok area revealed radon-poor waters (88%) and low-radon waters (12%).
Źródło:
Nukleonika; 2010, 55, 2; 177-180
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Realisation of radionuclides activity unit using the liquid scintillation counting (LSC)
Odtwarzanie jednostki aktywności radionuklidów za pomocą techniki ciekłych scyntylatorów (LSC)
Autorzy:
Broda, R.
Dziel, T.
Ziemek, T.
Listkowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/408183.pdf
Data publikacji:
2016
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
radionuclide activity
liquid scintillators
LSC technique
aktywność radionuklidu
ciekłe scyntylatory
technika LSC
Opis:
Registration of the effects of interaction of the radiation emitted after radioactive decay enables determination of activity of a given material expressed in becquerels (Bq). Measurements in a frame of international comparisons of 14 C activity using the triple-to-double coincidence ratio (TDCR) method and of 177 Lu activity using the 4π(LS)-γ coincidence and anticoincidence method, where the liquid scintillation technique (LSC) was used, were described. Specificity of short-lived radionuclides activity determination was discussed.
Rejestracja oddziaływania z materią promieniowania emitowanego w czasie rozpadów promieniotwórczych umożliwia określenie aktywności danego materiału w bekerelach (Bq). Omówiono wykonane w trakcie międzynarodowych porównań pomiary aktywności 14 C metodą potrójno-podwójnych koincydencji (TDCR) oraz 177 Lu metodą 4π(LS)-γ koincydencji i antykoincydencji, w których zastosowana jest technika ciekłych scyntylatorów (LSC). Omówiono specyfikę pomiaru aktywności radionuklidów krótkożyciowych.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2016, 3; 28-31
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radon levels in household waters in southern Poland
Autorzy:
Kusyk, M.
Mamont-Ciesla, K.
Powiązania:
https://bibliotekanauki.pl/articles/147159.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
dose assessment
household water
limits
liquid scintillation
radon
Opis:
Determination of radon concentrations in household waters were performed in 1997 in three regions of south-western Poland which are considered to have an enhanced natural radioactivity level: in the Jelenia Gora and Walbrzych regions (both in south-western Sudety Mountains) and in the Upper Silesian Coal Basin. Water samples were collected from taps, wells and springs and were analyzed in a liquid scintillation counter. In the Upper Silesian Coal Basin all values are below 50 Bq/dm3 with a maximum of 32 Bq/dm3 and in the Sudety Mts. the radon concentration in water exceed this level in 68% of houses, reaching a maximum value of ca. 1400 Bq/dm3 in drilled well water in the Jelenia Gora region. The annual ingestion dose calculated for this value equals to ca. 0.5 mSv for infants, 0.4 mSv for children and 0.3 mSv for adults. The average annual effective whole body doses calculated for tap water samples for a representative population in the investigated regions range from about 0.02 mSv to 0.32 mSv and the maximum value reaches 1.39 mSv. The inhalation doses corresponding to the unit of water-borne radon concentration are about one order higher than the ingestion ones for tap water supplies.
Źródło:
Nukleonika; 2002, 47, 2; 65-68
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of radon concentration in the air by PicoRad detectors
Autorzy:
Chau, N. D.
Powiązania:
https://bibliotekanauki.pl/articles/146088.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radon
PicoRad detectors
charcoal
adsorption
desorption
liquid scintillation
Opis:
The paper presents the theory and methodology of radon concentration measurement in the air by PicoRad detector, which consists of a porous canister held securely near the top of a plastic vial. The porous canister contains a bed of a controlled mass of charcoal (1.3 g) and silica desiccant (0.9 g). To measure the radon concentration, the vial detector is exposed in the radon laden air for a certain interval of time (24, 48 or 72 h or longer), then the liquid scintillation cocktail is added into the vial and measured by the help of a liquid scintillation counter. In this paper both radon adsorption by the charcoal detector, while it is being exposed in the radon laden air, and desorption of radon from the charcoal into the liquid scintillation cocktail were investigated. As a result, some conclusions concerning the methodology of radon measurement by PicoRad detectors have been done. The desorption factor of radon from the charcoal into the liquid scintillation cocktail was determined. The radon concentration values in the air measured by PicoRad detectors were in good agreement with those obtained by an AlphaGuard radon monitor.
Źródło:
Nukleonika; 2008, 53, suppl. 2; 21-24
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rapid 90Sr quantification method based on the Bateman equation for routine laboratory work
Autorzy:
Wiatr, Karol
Rubel, Barbara
Kardaś, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/2173387.pdf
Data publikacji:
2022
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Bateman equation
liquid scintillation
Strontium-90
Yttrium-90
Opis:
Artificially introduced into the environment 90Sr is highly radiotoxic, so its content levels in foodstuff and biota require constant monitoring for radiological protection. Most analytical procedures used for 90Sr determination are time-consuming, and therefore, a faster approach is needed. Employing the Bateman equation enables more effi cient exploitation of the secular equilibrium between 90Sr and its daughter radionuclide 90Y in the calculations. This article describes a method for computing the 90Sr activity concentration, while accounting for 90Y activity. The developed approach was tested and validated in terms of its applicability in everyday analysis.
Źródło:
Nukleonika; 2022, 67, 4; 67--72
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
NORM in drinking water - measurements using ultra low-level liquid scintillation spectrometry and consideration for compliance with the EU Drinking Water Directive
Autorzy:
Schonhofer, F.
Maringer, F.
Powiązania:
https://bibliotekanauki.pl/articles/340851.pdf
Data publikacji:
2004
Wydawca:
Główny Instytut Górnictwa
Tematy:
radioaktywne skażenie wody
NORM w wodzie pitnej
dyrektywa EU w sprawie jakości wody pitnej
radioactive water contamination
NORM in drinking water
EU drinking water directive
Źródło:
Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa; 2004, 1; 139-139
1643-7608
Pojawia się w:
Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Concentration of selected natural radionuclides in the thermal groundwater of Uniejów, Poland
Autorzy:
Bem, H.
Olszewski, M.
Kaczmarek, A.
Powiązania:
https://bibliotekanauki.pl/articles/147969.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
natural radionuclides
alfa/beta liquid scintillation counting
thermal groundwater
Opis:
Activities of the main radionuclides from the 238U and 232Th series in the Uniejów geothermal water were determined by combining liquid scintillation counting with a/b separation and g-spectrometry methods. The 222Rn and 226Ra activities were measured after extraction of radon from 10 ml water samples to 10 ml of an Ultima Gold F scintillation cocktail directly in 22 ml scintillation vials. The samples were counted in a new generation portable liquid scintillation counter, Betascout, without separation of the phases over the period of 30 days after extraction. The average values of the specific activities were equal to 2.95 and 0.64 Bq/dm3 for 222Rn and 226Ra, respectively. The 210Po radionuclide before counting was preconcentrated from 1 dm3 water samples on hydrated manganese oxide and deposited on silver discs. The discs were immersed in 10 ml of the scintillator and their activity was measured also by the same method. The average 210Po concentration was 0.052 Bq/dm3. Activity of the remaining radionuclides was determined by g-spectrometry after their preconcentration on hydrated manganese oxides from 10 dm3 samples. The activities of two radium radionuclides, 224Ra and 226Ra, can be calculated from their basic gamma-lines, whereas 228Ra can be determined from its decay product - 228Ac, and were equal to 0.40, 0.65 and 0.58 Bq/dm3, respectively. The activities of 210Pb and 238U (234Th) were below the detection limit of the method equal to 0.03 Bq/dm3. Based upon the obtained results, it can be concluded that there are not any radiological restrictions for using this water as a heat source or for balneological purposes. However, it cannot be used as drinking water, because the calculated committed effective dose from its one year consumption exceeds the WHO recommended value of 0.1 mSv.
Źródło:
Nukleonika; 2004, 49, 1; 1-5
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The applicability of C-14 measurements in the soil gas for the assessment of leakage out of underground carbon dioxide reservoirs
Autorzy:
Chałupnik, S.
Wysocka, M.
Powiązania:
https://bibliotekanauki.pl/articles/148781.pdf
Data publikacji:
2014
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
greenhouse gases
carbon dioxide sequestration
radiocarbon
liquid scintillation spectrometry
Opis:
Poland, due to the ratification of the Kioto Protocol, is obliged to diminish the emission of greenhouse gases. One of the possible solutions of this problem is CO2 sequestration (CCS – carbon capture and storage). Such an option is a priority in the European Union. On the other hand, CO2 sequestration may be potentially risky in the case of gas leakage from underground reservoirs. The most dangerous event may be a sudden release of the gas onto the surface. Therefore, it is very important to know if there is any escape of CO2 from underground gas reservoirs, created as a result of sequestration. Such information is crucial to ensure safety of the population in areas located above geological reservoirs. It is possible to assess the origin of carbon dioxide, if the measurement of radiocarbon 14C concentration in this gas is done. If CO2 contains no 14C, it means, that the origin of the gas is either geological or the gas has been produced as a result of combustion of fossil fuels, like coal. A lot of efforts are focused on the development of monitoring methods to ensure safety of CO2 sequestration in geological formations. A radiometric method has been tested for such a purpose. The main goal of the investigations was to check the application possibility of such a method. The technique is based on the liquid scintillation counting of samples. The gas sample is at first bubbled through the carbon dioxide adsorbent, afterwards the adsorbent is mixed with a dedicated cocktail and measured in a low-background liquid scintillation spectrometer Quantulus. The described method enables measurements of 14C in mine and soil gas samples.
Źródło:
Nukleonika; 2014, 59, 1; 3-7
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of natural radium contamination of barium chloride on the determination of radium isotopes in the water samples using α/β liquid scintillation spectrometry
Autorzy:
Dinh, C. N.
Czechowska, M.
Nowak, J.
Jodłowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/147718.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
α/β liquid scintillation spectrometry
barium chloride
radium isotopes
detection limit
Opis:
The determination of radium isotopes in drinking water by liquid scintillation technique requires some reagents that are used for separating radium from water samples. One of the main reagents is BaCl2·H2O. This paper presents the study of this compound and shows that barium chloride reagent is naturally contaminated with 226Ra. The 226Ra activity concentration in BaCl2·H2O reagent produced by chemical companies from Poland and other countries is equal to a few dozen Bq/kg. Furthermore, 14 mL of 0.10 M BaCl2·H2O solution is the optimum amount which should be used for the chemical procedure. At the optimum amount of barium chloride and 2-hour measurement, the detection limit of 226Ra and 228Ra of the liquid scintillation counting method is equal to 5 and 30 mBq per sample, respectively.
Źródło:
Nukleonika; 2016, 61, 4; 467-471
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of radioactivity in air filters by alpha and gamma spectrometry
Autorzy:
Bem, H.
Bem, E.
Krzemińska, M.
Ostrowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/147178.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
aerosol activity determination
aerosol residence times
liquid scintillation counting
radon daughters
Opis:
Combination of alpha and gamma spectrometry for air filters measurement allows a simple determination of all short-lived 222Rn and 220Rn daughters as well as cosmogenic 7Be and anthropogenic 137Cs in the air. Solid radionuclides in the atmosphere, attached to aerosol particles, were collected on filters of High Volume Air Sampler. After the desired collection period, the activity of deposited radionuclides was measured by ă-spectrometry for 7Be, 212Pb, 212Bi, 214Pb, 214Bi and by á-spectrometry for 212Po, 214Po and 218Po. Spectrometric methods do not require additional sample preparation and allow one to find aerosol activity by a simple filter measurement. A special measurement and calculation procedure was applied in the case of radionuclides from the uranium and thorium series. A technique of liquid scintillation counting (LSC) was used to determine the activity of the long-lived radon daughters 210Pb, 210Bi, 210Po after leaching into HCl solution and a two-step pre-concentration. Simultaneous determination of 210Pb and 210Bi enables one to find aerosol residence times.
Źródło:
Nukleonika; 2002, 47, 2; 87-91
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Możliwości zastosowania metody ciekłoscyntylacyjnej oraz ICP-MS w kontroli jakości opakowań ekologicznych
The applicability of the method of liquid scintillation and ICP-MS in the quality control of ecological packaging
Autorzy:
Lenkiewicz, M.
Paprotny, W.
Ślęzak, E.
Powiązania:
https://bibliotekanauki.pl/articles/392137.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Ceramiki i Materiałów Budowlanych
Tematy:
opakowanie ekologiczne
biopolimer
węgiel pochodzenia biologicznego
zawartość metali ciężkich
kontrola jakości
spektrometria ciekłoscyntylacyjna
spektrometria mas ze wzbudzeniem w plazmie indukcyjnie sprzężonej
ICP-MS
ecological packaging
biopolymer
biobased carbon
heavy metals content
quality control
liquid scintillation spectrometry
inductively coupled plasma mass spectrometry
Opis:
Coraz więcej produktów na rynku jest znakowanych określeniami, takimi jak: „biodegradowalne”, „nadające się do kompostowania” lub „pochodzenia naturalnego”. Wiele z nich jest przeznaczonych do przechowywania żywności, występując w postaci tzw. opakowań ekologicznych. W ostatniej dekadzie nastąpił gwałtowny wzrost zainteresowania tymi produktami na rynku. Niektóre z przyczyn leżą po stronie konsumenckiej świadomości i przeświadczeniu o pochodzeniu produktów. Toteż niezbędna jest kontrola jakości takich opakowań. W pracy przedstawiono wyniki badań półproduktów i produktów pod kątem zawartości surowców odnawialnych oraz metali ciężkich. Dokonano również porównania uzyskanych wyników z danymi deklarowanymi przez producentów oraz określono zgodność z obowiązującymi danymi normatywnymi.
More and more products in the market is labeled terms such as „biodegradable”, „compostable”, or „natural”. Many of them intended to hold the food appearing in the form of the ecological packaging. In the last decades there has been a sharp rise in interest in the products on the market. Some of the causes lie with the consumer awareness and belief about the origin of the products, in relation to the depletion of fossil resources and climate change. Therefore, it is necessary to control the quality of packaging. This paper presents the results of research semi-finished products and product, in terms of the content of biobased carbon and heavy metals. Also a comparison with the data declared by the manufacturers and determined compliance with the normative data was made.
Źródło:
Prace Instytutu Ceramiki i Materiałów Budowlanych; 2016, R. 9, nr 25, 25; 27-34
1899-3230
Pojawia się w:
Prace Instytutu Ceramiki i Materiałów Budowlanych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An application of LSC method for the measurement of gross alpha and beta activities in spiked water and drinking water samples
Autorzy:
Çakal, G. Ö.
Güven, R.
Yücel, H.
Powiązania:
https://bibliotekanauki.pl/articles/146427.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
alpha activity
beta activity
drinking water
liquid scintillation counting (LSC)
pulse shape analysis (PSA) calibration
quench
Opis:
In this study, after the pulse shape calibration of a liquid scintillation counting (LSC) spectrometer (Quantulus 1220), the efficiency was determined depending on sample quenching parameters. Then, gross alpha and beta activities in two spiked water samples obtained from International Atomic Energy Agency (IAEA) were used for the validation of the ASTM D7283-06 method, which is a standard test method for alpha and beta activity in water by LSC. Later, the drinking water samples (35 tap water and 9 bottled water) obtained from different districts of Ankara, Turkey, were measured. The maximum gross alpha activities are measured to be 0.08 Bq/L for tap waters and 0.13 Bq/L for bottled waters, whereas the maximum gross beta activities are found to be 0.18 Bq/L for tap waters and 0.16 Bq/L for bottled waters. These results indicate that these drinking water samples are below the required limits, which are 0.1 Bq/L for alpha emitting radionuclides and 1 Bq/L for beta emitting radionuclides. As a result, gross alpha and beta activities in drinking water of Ankara were determined accurately by this validated LSC method. It is also worth noting that LSC is a rapid and accurate method for the determination of gross alpha and beta activities without requiring a tedious sample preparation.
Źródło:
Nukleonika; 2015, 60, No. 3, part 2; 637-642
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł

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