Search Results (3)

To examine how reaction media influence the copolymerization processes of acrylamide-based copolymers, [BMIM]Oac and water were utilized as the reaction media. Four copolymers P(AM-SSS) (H₂O), P(AM-UA) (H₂O), P(AM-SSS) (ILs), and P(AM-UA) (ILs) were synthesized using the soluble monomer sodium p-styrene sulfonate (SSS), the insoluble monomer 10-undecylenoic acid (UA), and acrylamide (AM). The properties of the copolymers were characterized using infrared spectroscopy and ¹H NMR, and the copolymerization rates of the monomers and the segment sequences of the copolymers were calculated. The results indicated that copolymerization of SSS in ionic liquids could reduce the length of the continuous units of AM in the copolymer’s molecular chain from 231.2866 to 91.1179, with a more uniform distribution within the molecular chain. The thermal stability and micro-morphology of the copolymers were tested using a synchronous thermal analyzer and scanning electron microscopy, and the resistance of the copolymer solutions to temperature, salt, and shear were evaluated. Comparisons revealed that the three-dimensional spatial structure formed by the copolymers in ionic liquids is robust and loose. When AM and SSS polymerize in [BMIM]Oac, the resulting copolymer exhibits a higher viscosity retention rate in temperature and shear resistance tests, with a thermal decomposition temperature reaching 260 °C. Conversely, when AM and UA polymerize in [BMIM]Oac, the copolymer demonstrates good salt resistance, maintaining a viscosity retention rate of 259.04% at a Na⁺ concentration of 200,000 mg/L. Therefore, the ionic liquid [BMIM]Oac can enhance the various application performances of copolymers formed by monomers with different solubilities and AM. Full article

Today, multispectral optical sensors are extensively studied in non-contact and remote imaging systems. However, our previous experimental studies have shown that the changes in the reflective properties of chicken eggshells allow for the classification of their origin as either healthy or Mycoplasma synoviae (MS)-infected hens. MS is a pathogen affecting poultry that may have a significant economic impacts on poultry breeding. In this work, we present the portable optical fiber reflectometer, which can be used for early MS detection in a flock by the measurement of back-reflected light in a multispectral system. The designed reflectometer consists of control and optical modules. The control module is responsible for the light source and photodetector modulation, the synchronization and the power supply, as well as data recording. The main part of this module is a microcontroller used to ensure flexibility in creating the research sequence during operation. The optical module is based on a fiber bundle with six light outputs and a single detection line. The loose end of the fiber bundle is integrated with an optical head, which shapes the illuminating beam to obtain measurement conditions. The same optical head collects a back-reflected beam that propagates through the detection line to the detector. The application of the optical fiber decreases the weight of the whole system and enables the flexible operation of the optical head, making this system portable. In order to classify the test objects, the collected data were subjected to numerical analysis by means of machine learning. Full article

This work analyses the effect of the receiver movement on the detection by pulse compression of different families of codes characterizing the emissions of an Ultrasonic Local Positioning System. Three families of codes have been compared: Kasami, Complementary Sets of Sequences and Loosely Synchronous, considering in all cases three different lengths close to 64, 256 and 1,024 bits. This comparison is first carried out by using a system model in order to obtain a set of results that are then experimentally validated with the help of an electric slider that provides radial speeds up to 2 m/s. The performance of the codes under analysis has been characterized by means of the auto-correlation and cross-correlation bounds. The results derived from this study should be of interest to anyone performing matched filtering of ultrasonic signals with a moving emitter/receiver. Full article