Engineering Method for Calculating the Temperature on the Inner Surface of the Outer Corner of a Building

Постановка задачи. Температура на внутренней поверхности наружного угла всегда меньше, чем по глади наружной стены, что при низких температурах наружного воздуха может приводить к образованию конденсата на внутренней поверхности стены. В связи с этим актуальным является проблема разработки инженерного метода расчета температуры в наружном углу для исключения возможности конденсатообразования на внутренней поверхности угла на стадии проектирования стеновых конструкций. Результаты. Для решения этой задачи на основе решения уравнения теплового баланса, учета амплитуды колебания температуры воздуха в помещении и теплопоглощения внутренних поверхностей стен, междуэтажных перекрытий (поверхности потолка и пола), перегородок, окон получена формула для вычисления температуры на внутренней поверхности наружного угла. Также в ходе исследования проведены натурные испытания стеновой конструкции с наружным углом и получены значения температур на внутренней и наружной поверхностях. Выводы. Сопоставление результатов расчетов по разработанной методике и экспериментальных данных показало, что значения температур на внутренней поверхности наружного угла практически совпадают. Это дает основание использовать предложенный инженерный метод расчета температуры на внутренней поверхности угла наружной стены при проектировании ограждающих конструкций зданий для создания благоприятных комфортных и санитарно-гигиенических условий в помещении. Statement of the problem. The temperature on the inner surface of the outer corner is always lower than on the inner surface of the outer wall. This temperature difference might lead to the formation of condensation on the inner surface of the wall at low outdoor temperatures. Therefore the problem of developing an engineering method for calculating the temperature in the outer corner to exclude the possibility of condensation on the inner surface in the design process of the outer wall structures is extremely relevant. Results. To address this problem, based on solving the heat balance equation, taking into account the amplitude of air temperature fluctuations in the room and heat absorption of the inner surfaces of walls, intermediate bottoms (ceiling and floor surfaces), parting walls, a formula was obtained to calculate the temperature on the inner surface of the outer corner. Also, through the course of the study, natural tests of the wall structure with an outer corner were carried out and the temperatures on the inner and outer surfaces were obtained. Conclusions. Comparison of the calculation results using the developed engineering calculation method and experimental data showed that the temperatures on the inner surface of the outer corner almost coincided. This makes it possible to use the suggested engineering method for calculating the temperature on the inner surface of the outer wall corner in the design of enclosing structures to exclude condensation.

ENGINEERING METHOD FOR CALCULATING THE TEMPERATURE ON THE INNER SURFACE OF THE OUTER CORNER OF A BUILDING

Statement of the problem. The temperature on the inner surface of the outer corner is always lower than on the inner surface of the outer wall. This temperature difference might lead to the formation of condensation on the inner surface of the wall at low outdoor temperatures. Therefore the problem of developing an engineering method for calculating the temperature in the outer corner to exclude the possibility of condensation on the inner surface in the design process of the outer wall structures is extremely relevant. Results. To address this problem, based on solving the heat balance equation, taking into account the amplitude of air temperature fluctuations in the room and heat absorption of the inner surfaces of walls, intermediate bottoms (ceiling and floor surfaces), parting walls, a formula was obtained to calculate the temperature on the inner surface of the outer corner. Also, during the study, natural tests of the wall structure with an outer corner were carried out and the temperatures on the inner and outer surfaces were obtained.Conclusions. Comparison of the calculation results using the developed engineering calculation method and experimental data showed that the temperatures on the inner surface of the outer corner almost coincided. This makes it possible to use the suggested engineering method for calculating the temperature on the inner surface of the outer wall corner in the design of enclosing structures to exclude the appearance of condensation.

Aspergillus Section Fumigati in Firefighter Headquarters

Background: Aspergillus section Fumigati is one of the Aspergillus sections more frequently related to respiratory symptoms and by other health outcomes. This study aimed to characterize Aspergillus section Fumigati distribution in eleven firefighter headquarters (FFHs) to obtain an accurate occupational exposure assessment. Methods: A sampling approach protocol was performed using active (impaction method) and passive sampling methods (floor surfaces swabs, electrostatic dust collectors (EDCs), and settled dust). All samples were analysed by culture-based methods and passive sampling was used for molecular detection of Aspergillus section Fumigati. Results: Of all the matrices, the highest counts of Aspergillus sp. were obtained on settled dust filters (3.37% malt extract agar—MEA, 19.09% dichloran glycerol—DG18) followed by cleaning cloths (1.67% MEA; 7.07% DG18). Among the Aspergillus genus, the Fumigati section was predominant in Millipore and EDC samples in MEA (79.77% and 28.57%, respectively), and in swabs and settled dust filters in DG18 (44.76% and 30%, respectively). The Fumigati section was detected more frequently in DG18 (33.01%) compared to MEA (0.33%). The Fumigati section was observed in azole supplemented media (itraconazole and voriconazole) in several passive sampling methods employed and detected by qPCR in almost all passive samples, with EDCs being the matrix with the highest prevalence (n = 61; 67.8%). Conclusion: This study confirms that Aspergillus sp. is widespread and the Fumigati section is present in all FFHs. The presence of fungi potentially resistant to azoles in the FFHs was also observed. Further studies are needed to identify the best corrective and preventive measures to avoid this section contamination in this specific occupational environment.

A study of ladder-like silk foothold for the locomotion of bagworms

While walking on horizontal substrates, caterpillars skilfully engage all their legs, including three pairs of thoracic legs and a maximum of five pairs of prolegs, to move in a flexible wave-like motion. Such locomotory behaviours, represented by ‘crawling’ and ‘inching’ motions, have widely inspired the development of locomotion systems in soft robotics. However, bagworms are unable to use their prolegs for walking because these are always accommodated in a portable bag; thus, they are unable to walk using such general locomotory behaviours. Indeed, how they walk with only three pairs of thoracic legs is unknown at present. In this study, we show that bagworms construct a ladder-like foothold using their silk to walk without using prolegs. This enables them to walk not only on horizontal floor surfaces but also on wall and ceiling surfaces, even those with slippery or smooth surfaces. They construct the foothold by spinning a continuous silk thread in a zigzag manner and controlling the discharge of adhesive to attach the folded parts of the silk to a substrate. Discovery of this elaborate silk utilisation technique offers fresh insights into the diversity of silk use in lepidopteran larvae and provides potential designs for robot locomotion systems.

Exposure to cisplatin in the operating room during hyperthermic intrathoracic chemotherapy

Purpose Hyperthermic intrathoracic chemotherapy (HITOC) is an additive, intraoperative treatment for selected malignant pleural tumors. To improve local tumor control, the thoracic cavity is perfused with a cisplatin-containing solution after surgical cytoreduction. Since cisplatin is probably carcinogenic to humans, potential contamination of surfaces and pathways of exposure should be systematically investigated to enable risk assessments for medical staff and thus derive specific recommendations for occupational safety. Methods Wipe sampling was performed at pre-selected locations during and after ten HITOC procedures, including on the surgeon's gloves, for the quantitation of surface contaminations with cisplatin. After extraction of the samples with hydrochloric acid, platinum was determined as a marker for cisplatin by voltammetry. Results High median concentrations of cytostatic drugs were detected on the surgeons’ (1.73 pg Cis-Pt/cm2, IQR: 9.36 pg Cis-Pt/cm2) and perfusionists’ (0.69 pg Cis-Pt/cm2, IQR: 1.73 pg Cis-Pt/cm2) gloves. The display of the perfusion device showed partially elevated levels of cisplatin up to 4.92 pg Cis-Pt/cm2 and thus could represent an origin of cross-contamination. In contrast, cisplatin levels on the floor surfaces in the area of the surgeon and the perfusion device or in the endobronchial tube were relatively low. Conclusion With a correct use of personal protective equipment and careful handling, intraoperative HITOC appears to be safe to perform with a low risk of occupational exposure to cisplatin.

Salmonella in Captive Reptiles and Their Environment—Can We Tame the Dragon?

Reptiles are considered a reservoir of a variety of Salmonella (S.) serovars. Nevertheless, due to a lack of large-scale research, the importance of Reptilia as a Salmonella vector still remains not completely recognized. A total of 731 samples collected from reptiles and their environment were tested. The aim of the study was to assess the prevalence of Salmonella in exotic reptiles kept in Poland and to confirm Salmonella contamination of the environment after reptile exhibitions. The study included Salmonella isolation and identification, followed by epidemiological analysis of the antimicrobial resistance of the isolates. Implementation of a pathway additional to the standard Salmonella isolation protocol led to a 21% increase in the Salmonella serovars detection rate. The study showed a high occurrence of Salmonella, being the highest at 92.2% in snakes, followed by lizards (83.7%) and turtles (60.0%). The pathogen was also found in 81.2% of swabs taken from table and floor surfaces after reptile exhibitions and in two out of three egg samples. A total of 918 Salmonella strains belonging to 207 serovars and serological variants were obtained. We have noted the serovars considered important with respect to public health, i.e., S. Enteritidis, S. Typhimurium, and S. Kentucky. The study proves that exotic reptiles in Poland are a relevant reservoir of Salmonella.

Tribological approach for the safety assessment of flooring/walkway surfaces: Application for the prevention of pedestrian fall incidence

This study investigated the role of surface finishes from different material types of floors/walkways on traction properties and identified their effects on slipperiness controls under diverse walking environments to prevent fall incidence. Measurements and analyses of surface textures and traction properties of floors/walkways and interpretations were based on a tribological concept. Dynamic friction tests were conducted amongst nine indoor and outdoor floor specimens and three shoes under four different risk levels of environments. Test results showed that traction performances were considerably influenced by surface finishes of the floor specimens under the moderately (soapy) and highly (oily) risky conditions. This study also uncovered that rough floors did not mechanically ensure higher slip resistance whilst some smooth floors exhibited better slip resistance than the rougher ones. Nevertheless, outcomes from this study provided fundamental, but important information on the walkway traction properties that showed multifaceted features of tribological phenomena. Based on the overall findings, this study proposed an insight to identify the impact of floor/walkway textures on traction performances and consequently exploit sensible design concepts for the floor surfaces to prevent fall incidents.

Determining the potential food safety risks associated with dropped produce on floor surfaces in grocery stores

Grocery stores handle fresh produce in large quantities daily. According to the Food and Drug Administration Food Code, food is to be stored at least 15 cm above the floor, and all foods shall be protected from any source of contamination or otherwise discarded. It is reported in the literature that dropped produce could be a potential source of microbial contamination. Both consumers and employees often drop produce on the floor and place it back into a display case or bin, which could potentially serve as a source of contamination. This study aims to determine the bacterial transfer rate on different produce types when dropped onto Listeria monocytogenes contaminated floor surfaces for various contact times. Apples, peaches, and romaine lettuce were dropped separately onto carpet and tile surfaces from a distance of 1 m and held for 5s, 1min, 10min, 1h, and 4h. Results showed that transfer from all produce types occurred from both the carpet (10.56%) and tile (3.65%) surfaces. Still, percent transfer was not statistically significant among different times used in this study (p>0.05). Dropped romaine lettuce had the most transfer (28.97%) from both the surfaces combined, followed by apple(s) (8.80%) and peach(es) (7.32%) with minimal transfer. Even with a low transfer level, grocery stores should include signage to alert consumers not to pick up dropped produce, and train their employees accordingly.