scholarly journals A standardized method to measure the longitudinal UV emittance of low-pressure-lamps in dependence of water temperature

2021 ◽  
Author(s):  
Alois W. Schmalwieser ◽  
Georg Hirschmann ◽  
Jutta Eggers ◽  
Regina Sommer
Keyword(s):  
Water Temperature ◽  
Low Pressure ◽  
Water Disinfection ◽  
Uv Disinfection ◽  
The Past ◽  
Different Types ◽  
Drinking Water Disinfection ◽  
Standardized Method ◽  
High Level ◽  
Uv Lamps

Abstract The high level of acceptance of ultraviolet (UV) irradiation for water disinfection in the past decade is due to the development of quality standards, especially for drinking water disinfection in Europe (Austrian Standards Institute, German Standards Institute). The central parts of a UV-disinfection device are the UV lamps. Despite their importance, their characterisation and quality assurance is far from being a matter of course and had not been regulated so far. This holds especially with regard to their temperature behaviour. The UV radiation (UVR) emittance of Mercury-Low-Pressure- and Amalgam-Low-Pressure-lamps (LP-lamps) depends on temperature. Each lamp type has its own optimal temperature where UVR emittance is highest. At lower or higher temperatures, UVR emittance is reduced. Additionally LP-lamps do not emit homogeneous along their length and this emission profile can change with temperature. In this paper, we present a standardized method to measure the UVR emittance of LP-lamps along the length in water in dependence of water temperature. This method has been included in the updated Austrian standard ÖNORM M 5873-1 (2020) and in the new release DIN 19294-1 (2020). With this method, the UVR emittance of LP-lamps can be characterized and different types of lamps can be compared.

Fifteen years of experience with standardized reference radiometers for controlling low-pressure UV disinfection plants for drinking water

2016 ◽  
Vol 17 (4) ◽  
pp. 975-984
Author(s):  
A. W. Schmalwieser
Keyword(s):  
Drinking Water ◽  
Environmental Conditions ◽  
Quality Criteria ◽  
Low Pressure ◽  
Test Methods ◽  
Radiation Monitoring ◽  
Uv Disinfection ◽  
Test Results ◽  
High Quality ◽  
The Past

The only practicable way to control the disinfection capability of a UV disinfection plant for drinking water all the time is to use a UV radiometer. According to the Austrian Standard M5873, this plant radiometer is a standardized part of each plant. The standard defines a so-called reference radiometer (RRM) as well. This is necessary because a plant radiometer has to be controlled periodically. A RRM is a hand-held device which has to fulfil high-quality criteria and must be almost insensitive to environmental conditions. In this paper the principles of the concept behind the RRM are explained together with the requirements of such a device. Further on, the test methods are presented as well as a summary of test results from all RRMs developed during the past 15 years. It is shown that the radiation monitoring concept of the Austrian Standard has been successfully practicable and that the international acceptance of the Austrian Standard is justified.

scholarly journals Effects of UV Radiation on Photolyase and Implications with Regards to Photoreactivation following Low- and Medium-Pressure UV Disinfection

2007 ◽  
Vol 74 (1) ◽  
pp. 327-328 ◽  
Author(s):  
Jiangyong Hu ◽  
Puay Hoon Quek
Keyword(s):  
Uv Radiation ◽  
Uv Irradiation ◽  
Flavin Adenine Dinucleotide ◽  
Low Pressure ◽  
Uv Disinfection ◽  
Medium Pressure ◽  
Uv Lamps

ABSTRACT Photolyase activity following exposure to low-pressure (LP) and medium-pressure (MP) UV lamps was evaluated. MP UV irradiation resulted in a greater reduction in photolyase activity than LP UV radiation. The results suggest that oxidation of the flavin adenine dinucleotide in photolyase may have caused the decrease in activity.

Inactivation differences of microorganisms by low pressure UV and pulsed xenon lamps

2003 ◽  
Vol 47 (3) ◽  
pp. 185-190 ◽  
Author(s):  
M. Otaki ◽  
A. Okuda ◽  
K. Tajima ◽  
T. Iwasaki ◽  
S. Kinoshita ◽  
...  
Keyword(s):  
Low Pressure ◽  
High Energy ◽  
Suppressive Effect ◽  
Uv Disinfection ◽  
Xenon Lamp ◽  
Survival Ratio ◽  
E Coli ◽  
High Turbidity ◽  
The Difference ◽  
Uv Lamps

UV disinfection has been applied to water treatment in recent years with low-pressure and medium-pressure UV lamps mainly used as the light source. In general, UV disinfection is considered to be inefficient with water of high turbidity because of inhibition of light penetration. Additionally, photoreactivation may be a problem that should be considered in case a disinfected water is discharged to the environment where sunlight causes reactivation. Recently, other types of lamps have been proposed including a flush-type lamp (such as a pulsed-xenon lamp) that emits high energy and wide wavelength intermittently. In this study, the difference between inactivation efficiencies by low-pressure UV (LPUV) and pulsed-xenon (PXe) lamps was investigated using two coliphage types and three strains of Escherichia coli. PXe had a suppressive effect on photoreactivation rate of the E. coli strains even though there was no significant effect on inactivation rate and maximum survival ratio after photoreactivation. PXe also had a benefit when applied to high turbidity waters as no tailing phenomena were observed in the low survival ratio area although it was observed in LPUV inactivation. This efficiency difference was considered to be due to the difference in irradiated wavelength of both lamps.

scholarly journals Demonstration and evaluation of germicidal UV-LEDs for point-of-use water disinfection

2010 ◽  
Vol 8 (3) ◽  
pp. 479-486 ◽  
Author(s):  
Christie Chatterley ◽  
Karl Linden
Keyword(s):  
Uv Irradiation ◽  
Uv Light ◽  
Low Pressure ◽  
Water Disinfection ◽  
Light Emitting ◽  
E Coli ◽  
Point Of Use ◽  
One Year ◽  
Uv Lamps ◽  
Uv Leds

Ultraviolet (UV) irradiation is a common disinfection option for water treatment in the developed world. There are a few systems installed in developing countries for point-of-use treatment, but the low-pressure mercury lamps currently used as the UV irradiation source have a number of sustainability issues including a fragile envelope, a lifetime of approximately one year, and they contain mercury. UV light emitting diodes (LEDs) may offer solutions to many of the sustainability issues presented by current UV systems. LEDs are small, efficient, have long lifetimes, and do not contain mercury. Germicidal UV LEDs emitting at 265 nm were evaluated for inactivation of E. coli in water and compared to conventional low-pressure UV lamps. Both systems provided an equivalent level of treatment. A UV-LED prototype was developed and evaluated as a proof-of-concept of this technology for a point-of-use disinfection option, and the economics of UV-LEDs were evaluated.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

Using Histological and Chemical Methods for Detection of Unauthorized Tissues Addition in Emulsion Type Meat Product

2020 ◽  
Keyword(s):  
Vascular Tissue ◽  
Meat Product ◽  
Calcium Content ◽  
Processed Meat ◽  
Low Protein ◽  
Significant Difference ◽  
Different Types ◽  
Plant Stem ◽  
High Level ◽  
Reliable Methods

Total twenty different processed meat plant producing emulsion type sausage were histologically and chemically examined for detection of adulteration with unauthorized tissues. Results revealed that samples were adulterated with different types of animal tissues included; hyaline cartilage, tendon, spongy bone, peripheral nerve trunk, basophilic matrix, lymphatic tissue, fascia, fibrocartilage and vascular tissue. Moreover, these samples were adulterated Also, adulterated with plant tissue included; plant stem, leaves and root. Chemical analysis showed a significant difference in their chemical composition (moisture, fat, protein, ash and calcium) content. Moisture and fat content varied around the permissible limit of E.S.S. while low protein, high ash and calcium content was detected in the examined samples. Therefore, Histological and chemical examinations can be used as reliable methods to detect adultration using unauthorized addition of both animal and plant tissues in processed meat product samples which revealed a high level of falsification.

Impact of Particulate Matter on Distribution System Disinfection Efficacy

2008 ◽  
Vol 43 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Linda Wojcicka ◽  
Carole Baxter ◽  
Ron Hofmann
Keyword(s):  
Helicobacter Pylori ◽  
Particulate Matter ◽  
Distribution System ◽  
Contact Time ◽  
Water Disinfection ◽  
Sphingomonas Paucimobilis ◽  
Soil Corrosion ◽  
Log Reduction ◽  
Drinking Water Disinfection ◽  
The Impact

Abstract Microorganisms have been shown to survive drinking water disinfection and remain viable in disinfected waters despite the presence of disinfectant residuals. This may be partially attributed to protection by particulate matter. The aim of this study was to determine the effects of the presence of particulate matter on disinfection kinetics. Sphingomonas paucimobilis ATCC 10829 and Helicobacter pylori ATCC 43504 were used in inactivation experiments in the presence and absence of soil, corrosion, and wastewater particles. The results showed that the presence of such particles tended to inhibit chlorine and monochloramine inactivation, although the magnitude of the impact under the conditions tested was small (e.g., 1-log reduction in inactivation for several minutes of contact time in the presence of less than 1 mg/L of disinfectant).

Is Healthcare Special?

2018 ◽  
Author(s):  
Gordon Moore ◽  
John A. Quelch ◽  
Emily Boudreau
Keyword(s):  
Consumer Choice ◽  
Special Relationship ◽  
Individual Choice ◽  
Health Consequences ◽  
Critical Question ◽  
The Past ◽  
Different Types ◽  
Collective Benefit ◽  
Patient Ethics

Chapter 2 asks the critical question of whether healthcare is different from other consumer-driven markets. In the past, many pushed back on the notion that healthcare could be a consumer-driven industry, arguing that it is fundamentally different from other markets. This chapter acknowledges and reviews these critiques, highlighting four areas that might present challenges to increasing consumer choice in healthcare: the special relationship between doctor and patient, ethics and morality, individual choice versus collective benefit, and the health consequences of consumer choice. In doing so, this chapter also presents a schematic for thinking about the different types of healthcare choices, arguing that not all choices are equal and consumers may be more prepared to make decisions in some areas as opposed to others. In presenting the counterargument to consumer choice, this chapter asks the reader to consider the drawbacks and potential limitations of consumer choice in healthcare.

Vietnamese Historical Writing

2018 ◽  
Author(s):  
Patricia Pelley
Keyword(s):  
Cold War ◽  
East Asian ◽  
History Writing ◽  
Southern State ◽  
The Past ◽  
South Vietnam ◽  
Political Function ◽  
Different Types ◽  
The Cold War ◽  
North Vietnam

This chapter demonstrates how the process of decolonization and the ensuing separation of Vietnam into a northern and southern state as part of the Cold War in Asia led to different types of history-writing. In both Vietnamese regimes, the writing of history had to serve the state, and in both countries historians emphasized its political function. Whereas North Vietnam located itself in an East Asian and Marxist context, historians of South Vietnam positioned it within a Southeast Asian setting and took a determinedly anti-communist position. After 1986—over a decade after reunification—with past tensions now relaxed, the past could be revaluated more openly under a reformist Vietnamese government that now also permitted much greater interaction with foreign historians.

Different Types of Auricular Keloids and Treatment by Intralesional Cryosurgery: Best Practice for Obtaining Long-Lasting Clinical Results

Dermatology ◽  
2021 ◽  
pp. 1-10
Author(s):  
Yaron Har-Shai ◽  
Lior Har-Shai ◽  
Viktor A. Zouboulis ◽  
Christos C. Zouboulis
Keyword(s):  
Quality Of Life ◽  
Body Image ◽  
Recurrence Rate ◽  
Best Practice ◽  
Clinical Results ◽  
Psychosocial Impact ◽  
Aesthetic Outcome ◽  
The Past ◽  
Different Types

<b><i>Background:</i></b> Auricular keloids belong to the most perplexing medical conditions, which have significant psychosocial impact on the patient’s body image and quality of life. <b><i>Summary:</i></b> The article is purposed to provide dermatologists and plastic surgeons with the best proven practice using intralesional cryosurgery for the treatment of the different auricular keloid types in order to obtain superior clinical results by minimizing the probability of recurrence. In the past 20 years, the authors have developed novel procedures in order to increase the effectiveness of intralesional cryosurgery on auricular keloids, including hydrodissection, warm gauze technique, and excision of dangling skin. Long-lasting clinical results with a low recurrence rate and a satisfactory aesthetic outcome are achieved with no deformation of the ear framework.

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