Prof. Przemysław Perlikowski, a mechanical engineer, and his wife Asst. Prof. Renata Perlikowska, who studies opioid peptides used in medicine, discuss the challenges of research work and life.
The most important feature of bells is their sound. Their clarity and beauty depend, first of all, on the bell’s geometry - particularly the shape of its profile and the mechanical properties of alloy. Bells are the castings that work by emitting sound in as-cast state. Therefore all features that are created during melting, pouring, solidification and cooling processes will influence the bell's sound. The mechanical properties of bronze depend on the quality of alloy and microstructure which is created during solidification and depend on its kinetics. Hence, if the solidification parameters influence the alloy’s properties, how could they influence the frequencies of bell`s tone? Taking into account alterable thickness of bell's wall and differences in microstructure, the alloy's properties in bell could be important. In the article authors present the investigations conducted to determine the influence of cooling kinetics on microstructure of bronze with 20 weight % tin contents.
The most important feature of bells is their sound. Its clarity and beauty depend, first of all, on the bell’s geometry - particularly the shape
of its profile, but also on the quality of alloy used to its cast. Hence, if the melting and pouring parameters could influence the alloy’s
properties, what influence they would have on the frequencies of bell’s tone. In the article authors present their own approaches to find
answers on that and more questions.
This paper introduces security assessment methodology for isolated single-workstation multilayer systems processing sensitive or classified data according with a corresponding security model for such system. The document provides a high-level tool for systematizing certain-class-systems security models development. The models based on the introduced methodology cover data confidentiality and availability attributes protection on a sufficient level.
Underwater Acoustic Communications (UWAC) is an emerging technology in the field of underwater communications, and it is challenging because of the signal attenuation of the sound waves. Multiple Input and Multiple- Output (MIMO) is introduced in UWAC because of its support in enhancing the data throughput even under the conditions of interference, signal fading, and multipath. The paper presents the concept and analysis of 2× 2 MIMO UWAC systems that uses a 4- QAM spatial modulation scheme thus minimizing the decoding complexity and overcoming the Inter Channel Interference (IChI). Bit Error Rate (BER) investigation is carried out over different link distances under acoustic Line of Sight (LOS). The utilization of Zero Forcing (ZF) and Vertical-Bell Laboratories Layered Space-Time (VBLAST) equalizers, which estimates the transmitted data proves a success of removing Inter Symbol Interference (ISI). The ISI caused due to multipath effect and scattering in UWAC can be reduced by iterative process considered in VBLAST. A study is made on how the distance between the transmitter and the receiver and the Doppler Effect has its impact on the performance of the system.