METROLOGICAL SUPPORT FOR THE VERIFICATION OF MEDICAL INFRARED THERMOMETERS

The paper analyzes two methods of checking medical infrared thermometers – using the black body model and using the gray body model. The use of black body models provides the highest accuracy of temperature reproduction. Direct verification of infrared thermometers is not possible due to the discrepancy between the emissivity value entered in the infrared thermometer and the emissivity value of the black body. In this paper, we propose an algorithm for calculating corrections to the value of the temperature reproduced by the black body. The values of the corrections for different temperatures and emissivity introduced in infrared thermometers are given. Using the gray body model does not require any additional calculations. A model of a gray body with an emissivity from 0.94 to 0.99 has been developed and studied. The advantage of the proposed design is low cost, ease of practical application, and the possibility of simultaneous verification of infrared thermometers with different set emissivity values. For each of the methods, an algorithm for estimating the measurement uncertainty during verification is proposed. The results of the research can be used in testing medical infrared thermometers for type approval and the development of verification methods.

Ultraviolet C lamps for disinfection of surfaces potentially contaminated with SARS-CoV-2 in critical hospital settings: examples of their use and some practical advice

Background UltraViolet-C (UV-C) lamps may be used to supplement current hospital cleaning and disinfection of surfaces contaminated by SARS-CoV-2. Our aim is to provide some practical indications for the correct use of UV-C lamps. Methods We studied three UV-C lamps, measuring their spatial irradiance and emission over time. We quantify the error that is committed by calculating the irradiation time based exclusively on the technical data of the lamps or by making direct irradiance measurements. Finally, we tested specific dosimeters for UV-C. Results Our results show that the spatial emission of UV-C lamps is strongly dependent on the power of the lamps and on the design of their reflectors. Only by optimizing the positioning and calculating the exposure time correctly, is it possible to dispense the dose necessary to obtain SARS-CoV-2 inactivation. In the absence of suitable equipment for measuring irradiance, the calculated irradiation time can be underestimated. We therefore consider it precautionary to increase the calculated times by at least 20%. Conclusion To use UV-C lamps effectively, it is necessary to follow a few simple precepts when choosing, positioning and verifying the lamps. In the absence of instruments dedicated to direct verification of irradiance, photochromic UV-C dosimeters may represent a useful tool for easily verifying that a proper UV-C dose has been delivered.

The Inactivation of SARS-CoV-2 in Critical Hospital Settings by Means of Ultraviolet C Lamps: Examples of Their Use and Some Practical Advice

Background UltraViolet-C (UV-C) lamps may be used to supplement current hospital cleaning and disinfection of surfaces contaminated by SARS-CoV-2. Our aim is to provide some practical indications for the correct use of UV-C lamps. Methods We studied three UV-C lamps, measuring their spatial irradiance and emission over time. We quantify the error that is committed by calculating the irradiation time based exclusively on the technical data of the lamps or by making direct irradiance measurements. Finally, we tested specific dosimeters for UV-C. Results Our results show that the spatial emission of UV-C lamps is strongly dependent on the power of the lamps and on the design of their reflectors. Only by optimizing the positioning and calculating the exposure time correctly, is it possible to dispense the dose necessary to obtain SARS-CoV-2 inactivation. In the absence of suitable equipment for measuring irradiance, the calculated irradiation time can be underestimated. We therefore consider it precautionary to increase the calculated times by at least 20%. Conclusion To use UV-C lamps effectively, it is necessary to follow a few simple precepts when choosing, positioning and verifying the lamps. In the absence of instruments dedicated to direct verification of irradiance, photochromic UV-C dosimeters may represent a useful tool for easily verifying that a proper UV-C dose has been delivered.

Parallelohedrons and Stereohedrons of Delaunay

The works of Delaunay and the followers of his ideas about the geometry of n-dimensional parallelohedrons and stereohedrons are considered. It is proved that these representations do not take into account the conditions for the existence of polytopes of higher dimension and the properties characteristic of figures of higher dimension. They are an attempt to extend the properties of three-dimensional figures to figures of higher dimension. A direct verification of the parallelohedrons from the Delaunay classification taking into account the Shtogrin parallelohedron showed that these figures do not satisfy the Euler-Poincaré equation and therefore the assertion that they are parallelohedrons with dimension 4 is erroneous.

Experimental Investigation of the Maximum Punching Resistance of Slab-Column Connections

Flat slabs represent a structural system with a typical concentration of shear forces near the vicinity of its local supports. A possible failure from punching is a dangerous phenomenon due to the brittleness and possible progressive collapse of a whole structure. An improvement in the structural behaviour of a slab-column connection provides transverse reinforcement. The amount of this reinforcement and thus its contribution to the resistance against punching has a limit, which is represented by the maximum punching capacity. This capacity can be assessed using the kmax factor or by direct verification of the strut capacity. The article deals with the results of a test campaign carried out on flat slab specimens with their transverse reinforcements designed in such a way that the crushing of the struts is the governing mode of any failure. The test results obtained allowed for an evaluation of the kmax factors and provide an answer as to whether it is possible to cover failures due to the crushing of struts by this factor.

The development of waste assay monitors based on the HPGe detectors

The results from the development and the evaluation of radioactive waste monitors for small, medium, and large volumes of those wastes are presented. The efficiency calibration of monitors was made using the standard sources in point geometry as well as by using the complex calculation of the efficiency curves using the Monte Carlo simulation method. The volumetric activity sources were manufactured in the form of real 200, 400, and 700 litre barrels with matrix-fillers in order to calibrate the monitors using the direct verification method. The peculiarities of the software that controls the monitors are presented.