Mercury Oxidation by UV Irradiation: Effect of Contact Time, UV Wavelength, and Moisture Content

2017 ◽  
Vol 56 (21) ◽  
pp. 6131-6135 ◽  
Author(s):  
Alexander F. Gruss ◽  
Regina Rodriguez ◽  
David W. Mazyck
Keyword(s):  
Moisture Content ◽  
Uv Irradiation ◽  
Contact Time ◽  
Irradiation Effect ◽  
Mercury Oxidation

scholarly journals Effect of UV Ageing on the fatigue life of bulk polyethylene

2018 ◽  
Vol 165 ◽  
pp. 08002 ◽  
Author(s):  
Hamza Lamnii ◽  
Moussa Nait-Abdelaziz ◽  
Georges Ayoub ◽  
Jean-Michel Gloaguen ◽  
Ulrich Maschke ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Uv Irradiation ◽  
Chemical Structure ◽  
Fatigue Behavior ◽  
Crystalline Polymer ◽  
Fatigue Loading ◽  
Chain Scission ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Irradiation Effect

Polymers operating in various weathering conditions must be assessed for lifetime performance. Particularly, ultraviolet (UV) radiations alters the chemical structure and therefore affect the mechanical and fatigue properties. The UV irradiation alters the polymer chemical structure, which results into a degradation of the mechanical and fatigue behavior of the polymer. The polymer properties degradation due to UV irradiation is the result of a competitive process of chain scission versus post-crosslinking. Although few studied investigated the effect of UV irradiation on the mechanical behaviour of thermoplastics, fewer examined the UV irradiation effect on the fatigue life of polymers. This study focuses on investigating the effect of UV irradiation on the fatigue properties of bulk semi-crystalline polymer; the low density Polyethylene (LDPE). Tensile specimens were exposed to different dose values of UV irradiation then subjected to fatigue loading. The fatigue tests were achieved under constant stress amplitude at a frequency of 1Hz. The results show an important decrease of the fatigue limit with increasing absorbed UV irradiation dose.

scholarly journals ESR Study on the UV-Irradiation Effect of Higher PolyolhydrogenPeroxide Systems

1962 ◽  
Vol 83 (6) ◽  
pp. 652-655 ◽  
Author(s):  
Keiji KUWATA ◽  
Takahisa ICHIKAWA ◽  
Kozo HIROTA
Keyword(s):  
Uv Irradiation ◽  
Irradiation Effect

scholarly journals Development of a Test System To Evaluate Procedures for Decontamination of Respirators Containing Viral Droplets

2009 ◽  
Vol 75 (23) ◽  
pp. 7303-7309 ◽  
Author(s):  
Evanly Vo ◽  
Samy Rengasamy ◽  
Ronald Shaffer
Keyword(s):  
Uv Irradiation ◽  
Sodium Hypochlorite ◽  
Standard Method ◽  
Contact Time ◽  
Test System ◽  
Log Reduction ◽  
Pathogenic Viruses ◽  
Particle Counts ◽  
Particle Sizer ◽  
Higher Doses

ABSTRACT The aim of this study was to develop a test system to evaluate the effectiveness of procedures for decontamination of respirators contaminated with viral droplets. MS2 coliphage was used as a surrogate for pathogenic viruses. A viral droplet test system was constructed, and the size distribution of viral droplets loaded directly onto respirators was characterized using an aerodynamic particle sizer. The sizes ranged from 0.5 to 15 μm, and the sizes of the majority of the droplets were the range from 0.74 to 3.5 μm. The results also showed that the droplet test system generated similar droplet concentrations (particle counts) at different respirator locations. The test system was validated by studying the relative efficiencies of decontamination of sodium hypochlorite (bleach) and UV irradiation with droplets containing MS2 virus on filtering facepiece respirators. It was hypothesized that more potent decontamination treatments would result in corresponding larger decreases in the number of viable viruses recovered from the respirators. Sodium hypochlorite doses of 2.75 to 5.50 mg/liter with a 10-min decontamination period resulted in approximately 3- to 4-log reductions in the level of MS2 coliphage. When higher sodium hypochlorite doses (≥8.25 mg/liter) were used with the same contact time that was used for the dilute solutions containing 2.75 to 5.50 mg/liter, all MS2 was inactivated. For UV decontamination at a wavelength of 254 nm, an approximately 3-log reduction in the level of MS2 virus was achieved with dose of 4.32 J/cm2 (3 h of contact time with a UV intensity of 0.4 mW/cm2), while with higher doses of UV irradiation (≥7.20 J/cm2; UV intensity, 0.4 mW/cm2; contact times, ≥5 h), all MS2 was inactivated. These findings may lead to development of a standard method to test decontamination of respirators challenged by viral droplets.

scholarly journals Ozone inactivation of fungi associated with barley grain

2021 ◽  
Author(s):  
Brent Allen
Keyword(s):  
Moisture Content ◽  
Aspergillus Flavus ◽  
Contact Time ◽  
Vegetative State ◽  
Barley Grain ◽  
High Moisture Content ◽  
Penicillium Verrucosum ◽  
High Moisture ◽  
Ozone Dose

The use of ozone as a fungicide for barley storage was studied. The effects of ozone on the inactivation of natural and inoculated fungi on barley were evaluated at different water activities and temperatures. Results indicated that higher ozone doses were better at inactivating the natural fungi on barley than lower ozone doses. An ozone dose of 0.98mg/g • min was able to reduce the natural fungi counts on the barley at 0.98aw by over 97% after 45 minutes of ozone contact time. The inactivation of the natural fungi and Aspergillus flavus on the barley was favoured by higher temperatures. Ozone consumption of the barley was higher at higher temperatures. Tests on A. flavus spores inoculated on barley indicated that they were resistant to ozone doses up to 4.90mg/g while Penicillium, verrucosum spores showed no resistance to any ozone doses that were tested. Inactivation of A. flavus (vegetative state) and P. verrucosum spores were favoured by higher water activities. The effect of ozone on barley germination was also examined. By 15 minutes of treatment at an ozone dose of 0.98mg/g • min, all the fungi tested were inactivated by over 90%, while germination was only reduced by 6%. Different water activities had no effect on the germination of barley. The findings show that ozone may be applied as a fumigant against fungi attacking high moisture content barley and provide the possibility of using it as an alternative to current chemicals for preserving stored barley.

scholarly journals Biosorpsi Ion Logam Tembaga (Cu2+) Pada Biosorben Rumput Laut Coklat (Padina australis)

2018 ◽  
Vol 6 (1) ◽  
pp. 26-37
Author(s):  
Catherina M. Bijang ◽  
Jolantje Latupeirissa ◽  
Marike Ratuhanrasa
Keyword(s):  
Moisture Content ◽  
Metal Ions ◽  
Atomic Absorption ◽  
Contact Time ◽  
Brown Seaweed ◽  
Ash Content ◽  
Atomic Absorption Spectrophotometer ◽  
Batch Method ◽  
Optimum Ph ◽  
Determine Moisture Content

The research on the biosorption of Cu2+ metal ions in brown seaweed biosorbent (Padina australis) has been done. This study aims to determine moisture content, ash content, biomass content, pH and optimum contact time of Cu2+  metal ions absorption pH and optimum contact time of Cu2+  metal ions absorption. The method used is batch method. The adsorption result of Cu2+ metal ions was analyzed  by  using  atomic  absorption  spectrophotometer  (AAS).  The  results showed that the optimum pH was 7 with 99.8308 % absorption ability of biosorbent and the optimum contact time was 5 hours with 99.5570 % biosorbent absorbency.

scholarly journals UV irradiation effect on the electrical properties of Pb2MoO5 single crystal

2018 ◽  
Vol 26 (2) ◽  
pp. 63-66
Author(s):  
I. P. Volnyanskaya ◽  
M. P. Trubitsyn ◽  
D. M. Volnianskii ◽  
D. S. Bondar
Keyword(s):  
Electrical Properties ◽  
Single Crystal ◽  
Uv Irradiation ◽  
Room Temperature ◽  
Uv Light ◽  
Dipole Moments ◽  
Irradiation Effect ◽  
Deep Traps ◽  
Temperature Dependences ◽  
Ac Field

Electrical properties of Pb2MoO5 single crystal were studied in AC field (f=1 kHz) after irradiation with UV light (290 K). It was found that UV irradiation caused appearance of maximums on permittivity ε and conductivity σ temperature dependences, which were observed around 530 K. The anomalies of ε and σ vanished after annealing at 700 K and could be restored by subsequent UV irradiation performed at room temperature. The magnitude of ε and σ peaks increased for higher exposition time. Above 600 K conductivity σ was practically independent on irradiation. It is proposed that photoelectrons induced by UV light, are trapped by Mo located -within the oxygen tetrahedrons with vacancy VO in one of the vertexes. The dipole moments of (MoO3) groups reorient at VO hopping through the tetrahedron vertexes. Annealing at 700 K thermally decomposes (MoO3)- complexes. For T>600 K behavior of σ(T) is determined by conduction currents and nearly insensitive to UV irradiation. At high temperatures the photoelectrons do not contribute to conductivity since they are bound in (MoO3)- centers, recombine with holes or re-captured by more deep traps.

scholarly journals Comparison of Reactive Blue 203 Dye Removal Using Ultraviolet Irradiation, Ferrate (VI) Oxidation Process and MgO Nanoparticles

2018 ◽  
Vol 5 (2) ◽  
pp. 78-90 ◽  
Author(s):  
Amirreza Talaiekhozani ◽  
Nilofar Torkan ◽  
Fahad Banisharif ◽  
Zeinab Eskandari ◽  
Shahabaldin Rezania ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Uv Radiation ◽  
Uv Irradiation ◽  
Ultraviolet Irradiation ◽  
Contact Time ◽  
Dye Removal ◽  
Oxidation Process ◽  
Batch Mode ◽  
Mgo Nanoparticles ◽  
Ph Values

This study investigated the effect of various parameters on the removal of Reactive Blue 203 dye from wastewater using ferrate(VI) oxidation process, ultraviolet radiation (UV) radiation and MgO nanoparticles under batch mode. Although several studies have been carried out on dye removal, there is no study on the removal of Reactive Blue 203 dye using ferrate(VI) oxidation process, UV radiation, and MgO nanoparticles. Therefore, the aim of this study is to investigate the effect of different factors including pH, temperature, contact time, the intensity of UV radiation and the concentration of MgO nanoparticles on Reactive Blue 203 dye removal using the above-mentioned methods. The results showed that the best pH values for dye removal using UV radiation, ferrate(VI), and MgO nanoparticles were 13, 1 and 13, respectively. The best temperature for Reactive Blue 203 dye removal using ferrate(VI) was 50°C. Hence, temperature variation had no significant effect on Reactive Blue 203 dye removal using UV irradiation and absorption by MgO nanoparticles. Based on the results, the best contact time was 15 minutes using UV radiation. The removal of Reactive Blue 203 dye using ferrate(VI) oxidation process was a quick reaction, and in a fraction of a second, the reactions were completed. The results showed that dye removal using MgO nanoparticles could be described by the Temkin isotherm. Therefore, the contact time was not considered as an effective parameter. In addition, the maximum dye removals were 95, 85 and 94% using UV irradiation, ferrate(VI) and MgO nanoparticles.

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