TY  - JOUR
AU  - Morosh, Viacheslav
AU  - Röttger, Annette
AU  - Neumaier, Stefan
AU  - Krasniqi, Faton S.
AU  - Živanović, Miloš Z.
AU  - Kržanović, Nikola
AU  - Pantelić, Gordana K.
AU  - Iurlaro, Giorgia
AU  - Mariotti, Francesca
AU  - Sperandio, Luciano
AU  - Bell, Stephen James
AU  - Ioannidis, Sotiris
AU  - Kelly, Martin
AU  - Sangiorgi, Marco
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9807
AB  - In the aftermath of a nuclear or radiological accident, an extended mapping of reliable dose rate values is of key importance for any governmental decision and countermeasures. Presently, numerous dosimetry network stations, operated by the national governments of the member states in Europe, provide such dose rate data on an hourly basis. Nevertheless, there are large areas in Europe that are not covered at all by these early warning networks and other areas that show only a low density of governmental network stations. Hence, there may be a significant lack of information in case of a nuclear or radiological emergency. As a consequence of the Fukushima Daiichi nuclear power plant accidents in 2011, a number of non-governmental radiation monitoring networks (NRMN) appeared on the internet, providing dose rate data based on stationary as well as on mobile measurements of ionizing radiation by laypersons. Especially the mobile detectors are able to cover large areas in short time. Therefore, it is of considerable importance to investigate the feasibility of using dose rate data from non-governmental networks as a complementary input to the European Radiological Data Exchange Platform (EURDEP). Within the European Metrology Program for Innovation and Research (EMPIR), the project 16ENV04 “Preparedness” has studied the metrological relevance of such non-governmental dose rate data (also called crowd-sourced radiological monitoring) in the most comprehensive way so far. Sixteen different dose rate detector systems (in general 4 of each type, plus 2 types with 2 detectors, i.e. 68 detectors in total) used in NRMN have been investigated for the reliability of their data and the corresponding networks, and their data provision to the public were analyzed. The most relevant performance parameters of dosimetry systems (detector's inherent background, energy dependence and linearity of the response as well as the response to secondary cosmic radiation, the sensitivity to small increases of the dose rate and finally the stability of the detector's indication at various climatic conditions - temperature and humidity) have been investigated for fourteen representative types of non-governmental dose rate measuring instruments. Results of this comprehensive performance study of the simple, light-weighted and cheap dose rate meters used in NRMN, and conclusions on the feasibility of using their data for governmental monitoring in case of a nuclear or radiological emergency are presented. © 2021 The Authors
T2  - Radiation Measurements
T1  - Investigation into the performance of dose rate measurement instruments used in non-governmental networks
VL  - 143
DO  - 10.1016/j.radmeas.2021.106580
ER  - 

@article{
author = "Morosh, Viacheslav and Röttger, Annette and Neumaier, Stefan and Krasniqi, Faton S. and Živanović, Miloš Z. and Kržanović, Nikola and Pantelić, Gordana K. and Iurlaro, Giorgia and Mariotti, Francesca and Sperandio, Luciano and Bell, Stephen James and Ioannidis, Sotiris and Kelly, Martin and Sangiorgi, Marco",
year = "2021",
abstract = "In the aftermath of a nuclear or radiological accident, an extended mapping of reliable dose rate values is of key importance for any governmental decision and countermeasures. Presently, numerous dosimetry network stations, operated by the national governments of the member states in Europe, provide such dose rate data on an hourly basis. Nevertheless, there are large areas in Europe that are not covered at all by these early warning networks and other areas that show only a low density of governmental network stations. Hence, there may be a significant lack of information in case of a nuclear or radiological emergency. As a consequence of the Fukushima Daiichi nuclear power plant accidents in 2011, a number of non-governmental radiation monitoring networks (NRMN) appeared on the internet, providing dose rate data based on stationary as well as on mobile measurements of ionizing radiation by laypersons. Especially the mobile detectors are able to cover large areas in short time. Therefore, it is of considerable importance to investigate the feasibility of using dose rate data from non-governmental networks as a complementary input to the European Radiological Data Exchange Platform (EURDEP). Within the European Metrology Program for Innovation and Research (EMPIR), the project 16ENV04 “Preparedness” has studied the metrological relevance of such non-governmental dose rate data (also called crowd-sourced radiological monitoring) in the most comprehensive way so far. Sixteen different dose rate detector systems (in general 4 of each type, plus 2 types with 2 detectors, i.e. 68 detectors in total) used in NRMN have been investigated for the reliability of their data and the corresponding networks, and their data provision to the public were analyzed. The most relevant performance parameters of dosimetry systems (detector's inherent background, energy dependence and linearity of the response as well as the response to secondary cosmic radiation, the sensitivity to small increases of the dose rate and finally the stability of the detector's indication at various climatic conditions - temperature and humidity) have been investigated for fourteen representative types of non-governmental dose rate measuring instruments. Results of this comprehensive performance study of the simple, light-weighted and cheap dose rate meters used in NRMN, and conclusions on the feasibility of using their data for governmental monitoring in case of a nuclear or radiological emergency are presented. © 2021 The Authors",
journal = "Radiation Measurements",
title = "Investigation into the performance of dose rate measurement instruments used in non-governmental networks",
volume = "143",
doi = "10.1016/j.radmeas.2021.106580"
}

Morosh, V., Röttger, A., Neumaier, S., Krasniqi, F. S., Živanović, M. Z., Kržanović, N., Pantelić, G. K., Iurlaro, G., Mariotti, F., Sperandio, L., Bell, S. J., Ioannidis, S., Kelly, M.,& Sangiorgi, M.. (2021). Investigation into the performance of dose rate measurement instruments used in non-governmental networks. in Radiation Measurements, 143.
https://doi.org/10.1016/j.radmeas.2021.106580

Morosh V, Röttger A, Neumaier S, Krasniqi FS, Živanović MZ, Kržanović N, Pantelić GK, Iurlaro G, Mariotti F, Sperandio L, Bell SJ, Ioannidis S, Kelly M, Sangiorgi M. Investigation into the performance of dose rate measurement instruments used in non-governmental networks. in Radiation Measurements. 2021;143.
doi:10.1016/j.radmeas.2021.106580 .

Morosh, Viacheslav, Röttger, Annette, Neumaier, Stefan, Krasniqi, Faton S., Živanović, Miloš Z., Kržanović, Nikola, Pantelić, Gordana K., Iurlaro, Giorgia, Mariotti, Francesca, Sperandio, Luciano, Bell, Stephen James, Ioannidis, Sotiris, Kelly, Martin, Sangiorgi, Marco, "Investigation into the performance of dose rate measurement instruments used in non-governmental networks" in Radiation Measurements, 143 (2021),
https://doi.org/10.1016/j.radmeas.2021.106580 . .

TY  - CONF
AU  - Živanović, Miloš
AU  - Morosh, Viacheslav
AU  - Kržanović, Nikola
AU  - Iurlaro, Giorgia
AU  - Bell, Steven
AU  - Sangiorgi, Marco
AU  - Pantelić, Gordana K.
AU  - Ciraj-Bjelac, Olivera
AU  - Đaletić, Miloš
AU  - Sperandio, Luciano
AU  - Ioannidis, Sotiris
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11138
PB  - RAD Centre, Niš, Serbia
C3  - RAD 2020 : 8th International Conference on Radiation in Various Fields of Research : book of abstracts; Virtual Conference
T1  - Testing of low-cost dosimeters used in non-governmental networks within 16ENV04 Preparedness project
SP  - 93
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11138
ER  - 

@conference{
author = "Živanović, Miloš and Morosh, Viacheslav and Kržanović, Nikola and Iurlaro, Giorgia and Bell, Steven and Sangiorgi, Marco and Pantelić, Gordana K. and Ciraj-Bjelac, Olivera and Đaletić, Miloš and Sperandio, Luciano and Ioannidis, Sotiris",
year = "2020",
publisher = "RAD Centre, Niš, Serbia",
journal = "RAD 2020 : 8th International Conference on Radiation in Various Fields of Research : book of abstracts; Virtual Conference",
title = "Testing of low-cost dosimeters used in non-governmental networks within 16ENV04 Preparedness project",
pages = "93",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11138"
}

Živanović, M., Morosh, V., Kržanović, N., Iurlaro, G., Bell, S., Sangiorgi, M., Pantelić, G. K., Ciraj-Bjelac, O., Đaletić, M., Sperandio, L.,& Ioannidis, S.. (2020). Testing of low-cost dosimeters used in non-governmental networks within 16ENV04 Preparedness project. in RAD 2020 : 8th International Conference on Radiation in Various Fields of Research : book of abstracts; Virtual Conference
RAD Centre, Niš, Serbia., 93.
https://hdl.handle.net/21.15107/rcub_vinar_11138

Živanović M, Morosh V, Kržanović N, Iurlaro G, Bell S, Sangiorgi M, Pantelić GK, Ciraj-Bjelac O, Đaletić M, Sperandio L, Ioannidis S. Testing of low-cost dosimeters used in non-governmental networks within 16ENV04 Preparedness project. in RAD 2020 : 8th International Conference on Radiation in Various Fields of Research : book of abstracts; Virtual Conference. 2020;:93.
https://hdl.handle.net/21.15107/rcub_vinar_11138 .

Živanović, Miloš, Morosh, Viacheslav, Kržanović, Nikola, Iurlaro, Giorgia, Bell, Steven, Sangiorgi, Marco, Pantelić, Gordana K., Ciraj-Bjelac, Olivera, Đaletić, Miloš, Sperandio, Luciano, Ioannidis, Sotiris, "Testing of low-cost dosimeters used in non-governmental networks within 16ENV04 Preparedness project" in RAD 2020 : 8th International Conference on Radiation in Various Fields of Research : book of abstracts; Virtual Conference (2020):93,
https://hdl.handle.net/21.15107/rcub_vinar_11138 .

TY  - CONF
AU  - Kržanović, Nikola
AU  - Živanović, Miloš
AU  - Morosh, Viacheslav
AU  - Neumaier, Stefan
AU  - Röttger, Annette
AU  - Iurlaro, Giorgia
AU  - Bell, Stevan
AU  - Sangiorgi, Marco
AU  - Ciraj-Bjelac, Olivera
AU  - Pantelić, Gordana
AU  - Đaletić, Miloš
AU  - Sperandio, Luciano
AU  - Ioannidis, Sotiris
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11905
AB  - Non-governmental networks for environmental monitoring employ a wide range of radiation protection instruments from different manufacturers, which provide the public with often unreliable dosimetric data. These Measuring Instruments in Non-governmental Networks (MINN) are mostly based on Geiger-Muller tube gas detectors, which represent low-cost easily operated instruments. An extensive testing of these devices was performed in order to validate the data acquired with MINN within the 16ENV04 Preparedness EMPIR project. In total, 16 different dosemter types were selected, with a sample size of four dosemeters per dosemeter type. Performance testing included the energy dependence and the linearity tests of the dosemeter response. Additionally, during the Researcher Mobility Grant associated with the 16ENV04 project, two Geiger-Muller based dosemeter types, with a sample size of two dosemeters per type were included in the testing. These instruments were subjected to the angular dependence testing in both horizontal and vertical planes, besides the energy dependence and linearity tests in the reference Cs-137 field at Physikalisch-Technische Bundesanstalt (PTB). For all the dosemeter types, inherent background, response to secondary cosmic radiation and the response to small changes of dose rate were determined at the metrological facilities of PTB. The sensitivity of the measuring instruments used in non-governmental networks to small variations of the ambient dose equivalent rate was examined by exposing the dosemeters to low dose rate Cs-137, Co-60 and Ra-226 radiation sources, in order to estimate the effect of environmental radioactive contamination with artificially produced radionuclides. For the comparison purposes, besides the measuring instruments used in non-governmental networks, a previously characterized CdZnTe-based spectrodosemeter was irradiated with the aforementioned radiation fields. The measured values were compared with a reference Reuter-Stokes ionisation chamber used for low-dose rate level measurements.
PB  - Niš : Sievert Association
C3  - RAP 2020 : International conference on radiation applications; Book of abstracts
T1  - Testing of the measuring instruments in non-governmental networks for the purpose of environmental monitoring of ionising radiation
SP  - 11
EP  - 11
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11905
ER  - 

@conference{
author = "Kržanović, Nikola and Živanović, Miloš and Morosh, Viacheslav and Neumaier, Stefan and Röttger, Annette and Iurlaro, Giorgia and Bell, Stevan and Sangiorgi, Marco and Ciraj-Bjelac, Olivera and Pantelić, Gordana and Đaletić, Miloš and Sperandio, Luciano and Ioannidis, Sotiris",
year = "2020",
abstract = "Non-governmental networks for environmental monitoring employ a wide range of radiation protection instruments from different manufacturers, which provide the public with often unreliable dosimetric data. These Measuring Instruments in Non-governmental Networks (MINN) are mostly based on Geiger-Muller tube gas detectors, which represent low-cost easily operated instruments. An extensive testing of these devices was performed in order to validate the data acquired with MINN within the 16ENV04 Preparedness EMPIR project. In total, 16 different dosemter types were selected, with a sample size of four dosemeters per dosemeter type. Performance testing included the energy dependence and the linearity tests of the dosemeter response. Additionally, during the Researcher Mobility Grant associated with the 16ENV04 project, two Geiger-Muller based dosemeter types, with a sample size of two dosemeters per type were included in the testing. These instruments were subjected to the angular dependence testing in both horizontal and vertical planes, besides the energy dependence and linearity tests in the reference Cs-137 field at Physikalisch-Technische Bundesanstalt (PTB). For all the dosemeter types, inherent background, response to secondary cosmic radiation and the response to small changes of dose rate were determined at the metrological facilities of PTB. The sensitivity of the measuring instruments used in non-governmental networks to small variations of the ambient dose equivalent rate was examined by exposing the dosemeters to low dose rate Cs-137, Co-60 and Ra-226 radiation sources, in order to estimate the effect of environmental radioactive contamination with artificially produced radionuclides. For the comparison purposes, besides the measuring instruments used in non-governmental networks, a previously characterized CdZnTe-based spectrodosemeter was irradiated with the aforementioned radiation fields. The measured values were compared with a reference Reuter-Stokes ionisation chamber used for low-dose rate level measurements.",
publisher = "Niš : Sievert Association",
journal = "RAP 2020 : International conference on radiation applications; Book of abstracts",
title = "Testing of the measuring instruments in non-governmental networks for the purpose of environmental monitoring of ionising radiation",
pages = "11-11",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11905"
}

Kržanović, N., Živanović, M., Morosh, V., Neumaier, S., Röttger, A., Iurlaro, G., Bell, S., Sangiorgi, M., Ciraj-Bjelac, O., Pantelić, G., Đaletić, M., Sperandio, L.,& Ioannidis, S.. (2020). Testing of the measuring instruments in non-governmental networks for the purpose of environmental monitoring of ionising radiation. in RAP 2020 : International conference on radiation applications; Book of abstracts
Niš : Sievert Association., 11-11.
https://hdl.handle.net/21.15107/rcub_vinar_11905

Kržanović N, Živanović M, Morosh V, Neumaier S, Röttger A, Iurlaro G, Bell S, Sangiorgi M, Ciraj-Bjelac O, Pantelić G, Đaletić M, Sperandio L, Ioannidis S. Testing of the measuring instruments in non-governmental networks for the purpose of environmental monitoring of ionising radiation. in RAP 2020 : International conference on radiation applications; Book of abstracts. 2020;:11-11.
https://hdl.handle.net/21.15107/rcub_vinar_11905 .

Kržanović, Nikola, Živanović, Miloš, Morosh, Viacheslav, Neumaier, Stefan, Röttger, Annette, Iurlaro, Giorgia, Bell, Stevan, Sangiorgi, Marco, Ciraj-Bjelac, Olivera, Pantelić, Gordana, Đaletić, Miloš, Sperandio, Luciano, Ioannidis, Sotiris, "Testing of the measuring instruments in non-governmental networks for the purpose of environmental monitoring of ionising radiation" in RAP 2020 : International conference on radiation applications; Book of abstracts (2020):11-11,
https://hdl.handle.net/21.15107/rcub_vinar_11905 .

TY  - CONF
AU  - Živanović, Miloš
AU  - Kržanović, Nikola
AU  - Iurlaro, Giorgia
AU  - Bell, Steven
AU  - Morosh, Viacheslav
AU  - Đaletić, Miloš
AU  - Pantelić, Gordana
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11922
AB  - In recent years, the number of non-governmental networks providing quasi real time dose rates is growing. This data is available to the general public via open access based platforms on the internet. The research on the non-governmental networks is scarce and the measurements represented there are mostly carried out using broadly available commercial simple hand-held devices. Without proper testing of these devices in metrological laboratories, there is a significant possibility for discrepancies between the official and non-governmental data, which may have wider implications. Within project 16ENV04 Preparedness, a systematic study of non-governmental networks produced a list of 16 types of dosimeters that are commonly used. Four dosimeters of each type were sourced and commissioned by project partners and are currently undergoing the testing. Test procedures are shortly described in this paper and preliminary results for 2 types of dosimeters are presented.
PB  - Београд : Институт за нуклеарне науке "Винча" : Друштво за заштиту од зрачења Србије и Црне Горе
C3  - 30. симпозијум ДЗЗСЦГ : зборник радова
T1  - Evaluaton of dose rate data provided by non-governmental networks
SP  - 297
EP  - 302
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11922
ER  - 

@conference{
author = "Živanović, Miloš and Kržanović, Nikola and Iurlaro, Giorgia and Bell, Steven and Morosh, Viacheslav and Đaletić, Miloš and Pantelić, Gordana",
year = "2019",
abstract = "In recent years, the number of non-governmental networks providing quasi real time dose rates is growing. This data is available to the general public via open access based platforms on the internet. The research on the non-governmental networks is scarce and the measurements represented there are mostly carried out using broadly available commercial simple hand-held devices. Without proper testing of these devices in metrological laboratories, there is a significant possibility for discrepancies between the official and non-governmental data, which may have wider implications. Within project 16ENV04 Preparedness, a systematic study of non-governmental networks produced a list of 16 types of dosimeters that are commonly used. Four dosimeters of each type were sourced and commissioned by project partners and are currently undergoing the testing. Test procedures are shortly described in this paper and preliminary results for 2 types of dosimeters are presented.",
publisher = "Београд : Институт за нуклеарне науке "Винча" : Друштво за заштиту од зрачења Србије и Црне Горе",
journal = "30. симпозијум ДЗЗСЦГ : зборник радова",
title = "Evaluaton of dose rate data provided by non-governmental networks",
pages = "297-302",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11922"
}

Živanović, M., Kržanović, N., Iurlaro, G., Bell, S., Morosh, V., Đaletić, M.,& Pantelić, G.. (2019). Evaluaton of dose rate data provided by non-governmental networks. in 30. симпозијум ДЗЗСЦГ : зборник радова
Београд : Институт за нуклеарне науке "Винча" : Друштво за заштиту од зрачења Србије и Црне Горе., 297-302.
https://hdl.handle.net/21.15107/rcub_vinar_11922

Živanović M, Kržanović N, Iurlaro G, Bell S, Morosh V, Đaletić M, Pantelić G. Evaluaton of dose rate data provided by non-governmental networks. in 30. симпозијум ДЗЗСЦГ : зборник радова. 2019;:297-302.
https://hdl.handle.net/21.15107/rcub_vinar_11922 .

Živanović, Miloš, Kržanović, Nikola, Iurlaro, Giorgia, Bell, Steven, Morosh, Viacheslav, Đaletić, Miloš, Pantelić, Gordana, "Evaluaton of dose rate data provided by non-governmental networks" in 30. симпозијум ДЗЗСЦГ : зборник радова (2019):297-302,
https://hdl.handle.net/21.15107/rcub_vinar_11922 .

TY  - CONF
AU  - Kržanović, Nikola
AU  - Röttger, Annette
AU  - Morosh, Viacheslav
AU  - Luchkov, Maksym
AU  - Neumaier, Stefan
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11919
AB  - Concerning ionising radiation monitoring in the environment in areas which, by normal means, are inaccessible, e.g. in contaminated areas after a nuclear or radiological incident, the use of highly mobile systems, comprising of unmanned airborne vehicles equipped with ionising radiation detector, is advised in order to protect the health and the life of first responders. As a promising candidate, the compact solid-state spectrometer based on CdZnTe is characterised by performing irradiations in the reference radionuclide radiation fields of PTB. The energydependent conversion coefficients are derived from recorded pulse-height spectra, and they enable calculation of the operational radiation protection quantity, ambient dose equivalent rate, directly from the spectrum without deconvolution. The validity of the conversion coefficients was evaluated by determining the deviation of the calculated dose rate from the reference ambient dose equivalent rate for the 226Ra radionuclide, available at the Underground Dosimetry Laboratory (UDO II) of PTB. By employing the derived conversion coefficients, the detector “linearity” (dose rate dependence of the response) was checked in the 137Cs reference fields of different ambient dose equivalent rates ranging from 25 nSv/h up to 1 μSv/h. The deviation of the calculated 226Ra dose rate from the achieved reference value was +2%.
PB  - Niš : Sievert Association
C3  - RAP 2019 : International conference on radiation applications; Proceedings book
T1  - Cadmium Zinc Telluride solid-state detector characterisation for its use as a spectro-dosemeter
SP  - 148
EP  - 151
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11919
ER  - 

@conference{
author = "Kržanović, Nikola and Röttger, Annette and Morosh, Viacheslav and Luchkov, Maksym and Neumaier, Stefan",
year = "2019",
abstract = "Concerning ionising radiation monitoring in the environment in areas which, by normal means, are inaccessible, e.g. in contaminated areas after a nuclear or radiological incident, the use of highly mobile systems, comprising of unmanned airborne vehicles equipped with ionising radiation detector, is advised in order to protect the health and the life of first responders. As a promising candidate, the compact solid-state spectrometer based on CdZnTe is characterised by performing irradiations in the reference radionuclide radiation fields of PTB. The energydependent conversion coefficients are derived from recorded pulse-height spectra, and they enable calculation of the operational radiation protection quantity, ambient dose equivalent rate, directly from the spectrum without deconvolution. The validity of the conversion coefficients was evaluated by determining the deviation of the calculated dose rate from the reference ambient dose equivalent rate for the 226Ra radionuclide, available at the Underground Dosimetry Laboratory (UDO II) of PTB. By employing the derived conversion coefficients, the detector “linearity” (dose rate dependence of the response) was checked in the 137Cs reference fields of different ambient dose equivalent rates ranging from 25 nSv/h up to 1 μSv/h. The deviation of the calculated 226Ra dose rate from the achieved reference value was +2%.",
publisher = "Niš : Sievert Association",
journal = "RAP 2019 : International conference on radiation applications; Proceedings book",
title = "Cadmium Zinc Telluride solid-state detector characterisation for its use as a spectro-dosemeter",
pages = "148-151",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11919"
}

Kržanović, N., Röttger, A., Morosh, V., Luchkov, M.,& Neumaier, S.. (2019). Cadmium Zinc Telluride solid-state detector characterisation for its use as a spectro-dosemeter. in RAP 2019 : International conference on radiation applications; Proceedings book
Niš : Sievert Association., 148-151.
https://hdl.handle.net/21.15107/rcub_vinar_11919

Kržanović N, Röttger A, Morosh V, Luchkov M, Neumaier S. Cadmium Zinc Telluride solid-state detector characterisation for its use as a spectro-dosemeter. in RAP 2019 : International conference on radiation applications; Proceedings book. 2019;:148-151.
https://hdl.handle.net/21.15107/rcub_vinar_11919 .

Kržanović, Nikola, Röttger, Annette, Morosh, Viacheslav, Luchkov, Maksym, Neumaier, Stefan, "Cadmium Zinc Telluride solid-state detector characterisation for its use as a spectro-dosemeter" in RAP 2019 : International conference on radiation applications; Proceedings book (2019):148-151,
https://hdl.handle.net/21.15107/rcub_vinar_11919 .