There exists a problem with an in situ diagnostics of contamination of ethyl alcohol in a human being exhaled air. When ethyl alcohol in a mouth blowing (in a gaseous state) exists, the characteristic C–H stretch absorption bands in –CH3 and –CH2 – functional groups in ethanol (CH3–CH2–OH) appear at a wavelength of λ = 3.42 μm. To investigate the presence of ethyl alcohol in exhaled human air, the light beam of λ = 3.42 μm is passing through an air sample. If one alternately measures the intensity of the investigated beam and the reference, a percentage of ethanol in the air sample can be estimated using a sensitive nondispersive infrared (NDIR) system with a stable operating flow mass detector. To eliminate a mechanical chopper and noise generating stepper motors, a photonic chopper as a liquid crystal shutter for λ = 3.42 μm has been designed. For this purpose, an innovative infrared nematic liquid crystal mixture was intentionally prepared. The working mixture was obtained by a selective removal of CH bonds and its exchange by heavier polar substituents, what ensures a lack of absorption band of C–H bonds. The paper presents theory, concept and final experimental results of the infrared nematic liquid crystals mixture and the liquid crystal shutter for breathalyzer applications.
This paper reports the species of macromycetes collected on King George Island and Livingstone Island (South Shetlands). Brief notes on taxonomy and distribution of the species are added.
From Hedera helix and Epipremnum aureum showing necrosis of shoot base spread upwards and on leaves Phytophthora tropicalil was isolated. The species was obtained from ⅞of Hedera and ¾ of Epipremnum diseased shoot and root parts. Additionally, Botrytis cinerea, Fusarium avenaceum and Rhizoctonia solani was recovered from some of affected plants. The chosen 2 isolates colonised petioles and leaf blades of both host plants. P. tropicalis caused necrosis of leaves of 11 tested cultivars of H. helix and 13 other pot plant species and seedlings of tomato. The fastest spread of necrosis was observed on leaves of Peperomia magnoliaefolia, Pelargonium zonale and Phalaenopsis x hybridum. The development of disease was observed at temperatures ranged from 10 to 32.5°C with optimum 30°C.
A novel non-orthogonal multiple access (NOMA) scheme is proposed to improve the throughput and the outage probability of the cognitive radio (CR) inspired system which has been implemented to adapt multiple services in the nextgeneration network (5G). In the proposed scheme, the primary source (PS) had sent a superposition code symbol with a predefined power allocation to relays, it decoded and forwarded (DF) a new superposition coded symbol to the destination with the other power allocation. By using a dual antenna at relays, it will be improved the bandwidth efficiency in such CR NOMA scheme. The performance of the system is evaluated based on the outage probability and the throughput with the assumption of the Rayleigh fading channels. According to the results obtained, it is shown that the outage probability and throughput of the proposed full-duplex (FD) in CR-NOMA with reasonable parameters can be able deploy in practical design as illustration in numerical results section.
Silicon – molybdenum cast iron commonly called SiMo due to its unique properties has becoming more and more interesting engineering material. The history and development of this alloy is relatively long but, due to the significant difficulties during the manufacturing process resulting in the lower final quality than expected, it has not been applied to often in practice. The biggest challenge is its brittleness as a result of the carbides precipitations. During last few years, thanks to the many important researches made and the general foundry technology development, the interest in SiMo iron has been rapidly growing, especially for the castings for heavy duty applications like corrosion, high temperature and wear abrasion resistant parts. In the article the heat treatment attempts to improve the microstructure of SiMo castings has been presented. The goal was to destroy or at least to refine and uniformly distribute the carbides precipitations to improve mechanical properties of the exhaust manifold castings for the cars. The experiments were carried out for the alloy contains approx. 4% Si, 1% Mo and 3.2%C. The range of the research included: hardness measuring, standard mechanical properties and microstructure for as-cast state and after that the subsequent heat treatment process with another properties check. The result of the heat treatment was the elimination of pearlite from the metal matrix. Moreover, the changes of the carbide molybdenum – rich phase morphology were observed. The dispersion of the carbides precipitations in the carbides area was observed. The experiments proved the possibility to control the microstructure and the mechanical properties of the SiMo castings by means of heat treatment but only to some extent.
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