Mathematical Modeling of Optical Radiation Emission as a Function of Welding Power during Gas Shielded Metal Arc Welding
Abstract Arc welding is accompanied by intense optical radiation emission that can be detrimental not only for the welder himself but also for people working nearby or for passersby. Technological progress advances continuously in the field of joining, so an up-to-date radiation database is necessary. Additionally, many literature irradiance data have been measured for a few welding currents or for parts of the optical spectral region only. Within this paper, a comprehensive study of contemporary metal active gas, metal inert gas, and cold metal transfer welding is presented covering optical radiation emission from 200 up to 2,700 nm by means of (spectro-) radiometric measurements. The investigated welding currents range from 70 to 350 A, reflecting values usually applied in industry. Based upon these new irradiance data, three mathematical models were derived in order to describe optical radiation emission as a function of welding power. The linear, exponential, and sigmoidal emission models depend on the process variant (standard or pulsed) as well as on the welding material (mild and stainless steel, aluminum). In conjunction with the corresponding exposure limit values for incoherent optical radiation maximum permissible exposure durations were calculated as a function of welding power. Typical times are shorter than 1 s for the ultraviolet spectral region and range from 1 to 10 s for visible radiation. For the infrared regime, exposure durations are of the order of minutes to hours. Finally, a validation of the metal active gas emission models was carried out with manual arc welding.
THE DETERMINATION OF HEALTH SERVICES VOCATIONAL SCHOOL STUDENTS’ KNOWLEDGE LEVELS ABOUT THE EFFECTS OF RADIATION ON HEALTH
Radyasyon, surekli duruma gecerken atom cekirdeginden yayilan enerjidir. Insanlar bircok farkli kaynaktan radyasyona maruz kalmaktadir. Bu arastirma, radyasyonun saglik uzerindeki etkileri konusunda ogrencilerin bilgi duzeylerini belirlemek amaciyla yapilmistir. Bu tanimlayici arastirma, 351 Saglik Hizmetleri Meslek Yuksekokulu ogrencisi ile “anket basvuru yontemi” ile gerceklestirilmistir. Verilerin istatistiksel analizi betimleyici istatistikler ve ki-kare analizi kullanilarak yapilmistir. Tibbi Goruntuleme Programi ogrencilerinin; ‘Radyasyon beyin hucrelerine zarar vererek bas agrisina yol acar’ (% 86.0), ‘Radyasyon yayan cihazlar insanlarin psikolojisini bozar’ (% 75.0) ve ‘Cep telefonlarinin saglik uzerinde ciddi olumsuz etkileri vardir’ (% 68.0)  ifadelerini 'evet' olarak yanitlama oranlari diger ogrencilerden istatistiksel olarak farkliydi. Radyasyona karsi gerekli onlemleri aldigini belirten ogrencilerin daha yuksek oranlarda; cep telefonunu yatak odasina getirmedikleri (% 81.1), radyasyon yayan cihazlari uykuda iken baslarindan uzak tuttuklari (% 61.1), sarj edilirken cep telefonunu kullanmadiklari (% 55.2), dizustu bilgisayarlari vucuttan uzak tuttuklari (% 58.3) belirlendi. Saglik egitimi alan ogrencilerin radyasyon bilgisi duzeyinin yeterli olmadigi belirlenmistir. Bu bakimdan, mufredatlarinda  duzenlemelerin  yapilmasi yararli olacaktir.
Chromatographic analysis of elastomer antidegradants and accelerators
Summary The use of various chromatographic methods in the analysis of all classes of elastomer antidegradants and accelerators is reviewed. The review of extraction methods is also included.