Experimental Investigation of the Effect of Fire Protection Lobby on Stair Pressurization System in a High-Rise Building

In this study, the stair pressurization system in a 40-storey high office building in Istanbul is investigated through field tests, in order to understand the effect of the presence of a non-pressurized vestibule (fire protection lobby, FPL) before entering the stair at each floor. The building without FPL is simulated by keeping only one of the two doors (of the stair and FPL) open at each floor. This method gave an opportunity to fix other parameters affecting the stair pressurization system and check solely the effect of FPL. Two different cases are taken into account, where the first one (all doors closed) analyses the condition that all stair doors are kept closed and the second one (critical doors are open) is conducted when the stairwell is opened to the floor on a given level (fire floor) and the stair termination door at the discharge floor is kept open. For both cases, the availability of the FPL is investigated by using the aforementioned arrangement. Under the conditions with approximately the same pressurized air flow rate at all doors closed condition, it is found that the availability of FPL increases the pressure difference between the stairwell and the corridor by a factor of approximately 2.2. This is also justified by using empirical formulations available in literature, where this ratio is calculated as 2.0. The results of this study showed that the FPL arrangement improves the effectiveness of pressurization system in a very high-rise building, despite some tolerable drawbacks.     

Comparison of microwave and conventionally heated reactor performances in catalytic dehydrogenation of ethane

In the present study, non-oxidative dehydrogenation of ethane was carried out by using conventional heated (CHRS) and microwave heated (MWHRS) reactor systems. Reactions were conducted in the presence of SBA-15 supported Cr or Mo catalysts, and the activity of the catalysts were evaluated in terms of ethane conversion and C₂H₄/H₂ ratio. The physicochemical properties of synthesized catalysts were determined by XRD, N₂ adsorption/desorption, ICP-OES, TPR, SEM, and EDS analysis. XRD pattern of reduced catalysts revealed the formation of metallic Mo and Eskolaite Cr₂O₃ over the catalysts. The mesoporous structure of SBA-15 was confirmed using N₂ adsorption/desorption analysis. Activity test results showed higher ethane conversion in the presence of Mo than Cr in both reactor systems. However, more side reaction took place over Mo than Cr based catalysts. Cr based catalyst showed better activity in terms of ethylene formation and C₂H₄/H₂ ratio. Results proved the superior performance of microwave heated reactor over the conventionally heated reactor. Significantly higher conversion was obtained over Cr based catalysts in MWHRS than CHRS due to the occurrence of micro-plasmas (hot spots) in the catalyst bed. The performance of 5Cr@SBA-15 in CHRS was poor due to negligible ethane conversion below 650 °C, while almost complete conversion could be achieved in MWHRS with this catalyst at identical conditions. The ethane conversion values obtained at 650 °C in CHRS were achieved at 450 °C, in MWHRS.     

Design of wideband microstrip power divider/combiner with input and output impedance matching for RF energy harvesting applications

Lately, it has been seen that wireless communication systems have been more developed and there has been a huge demand for multi‐spectral transactions. Using circuits for more than one function is a serious requirement in communication technology. Especially, it expected from RF output stages to show the same performance on more than one frequency. To that end, it is required to produce a solution with wideband designs. In this study, a novel power divider/combiner design with a layered conic line has been investigated for the RF energy harvesting applications. The center frequency was set at 2 GHz and concluded with three different designs. In each design, bandwidth and S parameter characteristics were compared according to the number of layers of the transmission, and it was observed that as the number of layers increases, the bandwidth also increases. According to the design result, triple layer Wilkinson power divider was selected to connect to Villard voltage doubler circuit. The Wilkinson power combiner circuit inputs were given between ?10 dBm and 5 dBm input power. As a result, when low input power was given, efficiency was observed about 70%.     

Bacterial and fungal microbiota of mould-ripened cheese produced in Konya

Bacterial and fungal diversities of 24 mould-ripened cheeses originating from Konya-Türkiye were examined by metagenomic analysis. Firmicutes phylum, Enterococcus, Clostridium sensu stricto and Lactobacillus (Levilactobacillus) genera were the dominant bacteria. Ascomycota phylum and Penicillium and Pichia genera and Penicillium roqueforti and Pichia membranifaciens species were dominant fungi. Enterococcus faecium (n = 30) and Enterococcus faecalis (n = 6) were identified, and all strains were susceptible to penicillin, ampicillin, vancomycin, teicoplanin, chloramphenicol and linezolid. The highest resistance (n = 14) was against rifampin. Tetracycline resistance was determined in two strains. Biofilm-forming ability was found in nine E. faecium and 1 E. faecalis. E. faecium strains revealed 40–88.9%, and E. faecalis showed 59.2–100% homology by pulsed field gel electrophoresis.     

Role of rheology on the formation of Nanofibers from pectin and polyethylene oxide blends

Characterizing the parameters critical to the prediction of a successful electrospinning process from solution properties is essential, yet, not easy in the case of biopolymers. In this study, we attempted to present a broad perspective by simultaneously evaluating the effect of eight different parameters, namely zero shear viscosity, tip viscosity, elastic modulus, phase angle, cohesive energy, pH, conductivity, and surface tension, on the formation of smooth pectin nanofibers. Our results showed that (1) the viscosity of the solution is not an indication of jet formation, but once the jet is formed, high zero shear viscosity and high tip viscosity are required to maintain a dominant whipping instability for smooth nanofiber formation and (2) while evaluating the elasticity of the spinning solutions, comparing only the elastic modulus values would be misleading, since low phase angle values are also necessary for pectin solutions to be electrospun into nonbeaded fibers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48294.