The phenomenon of adsorption known since ancient times is now widely used to convert low-temperature heat. This short review addresses recent results and current tendencies in adsorption heat ...conversion/storage in closed systems, which are the most important according to the author's opinion. The survey is based on literature data, reported mainly in the second decade of this century, and concerns the development of new adsorbents and cycles, improvement of adsorption dynamics, and some other topical issues. The paper aims at highlighting the current progress, research trends and existing gaps of the technology involved.
•The review addresses adsorption heat conversion/storage (AHCS) in closed systems.•It surveys results and tendencies reported mainly in the second decade of the century.•New adsorbents, cycles, heat exchangers, dynamic issues and other topics are involved.•The review aims at highlighting the AHCS current progress, trends and existing gaps.
The review is dedicated to characteristics of the mechanical behavior of various materials at submicro- and nanoscale levels. To a large extent, progress in this area is determined by the development ...of a large family of methods for precision force nanotesting, which have been referred to as “nanoindentation”. However, nanomechanical properties are studied to date not only and not so much by nanoindentation methods in narrow sense, i.e., the methods of local deformation of macro-, micro-, and nanoscale objects. Force nanomechanical testing is interpreted more broadly and includes the application of small forces to the test object and the precise measurements of deformation with nanometer resolution under uniaxial compression, tension, bending, shear, and torsion by various methods with simultaneous in situ registration of their microstructural parameters by electron microscopy and X-ray diffraction methods. The main research directions developed in the last decade to improve experimental approaches and the results on single-, micro-, and nanocrystalline materials, composites, films, and coatings obtained by means of these approaches in amorphous solids and biomaterials (tissues, living cells, and macromolecules) are described. Particular attention is paid to size effects and atomic deformation/fracture mechanisms at the nanoscale. This review is a natural continuation and development of the author’s review published in Phys. Solid State, vol. 50, issue 12, p. 2113 (2008), in which the specifics of the nanomechanical properties of solids are analyzed, and describes both the basic concepts of nanomechanical testing of materials and the latest advances in this area.
The reduction of energy costs in the production of livestock products by maintaining the required illumination parameters is an important task. The results of studies on the development of a program ...for automatic control and maintenance of lighting parameters in premises for keeping birds, depending on the cross, technologies of keeping and the age of birds, using programmable logic controllers (PLC) are presented. The use of a dimming system will reduce the energy consumption of lighting equipment and increase the efficiency of electrical energy use.
We studied the formation of Y junctions for transonic elastic strings. In particular, using the general solution for these strings, which is described by left- and right-moving modes, we obtained the ...dynamics of kinks and Y junctions. Considering the linearized ansatz for straight strings, we constructed the parameter region space for which the formation of Y junctions due to strings collisions is allowed.
Recently, there has been a rapid progress in the development of techniques for isothermal amplification of nucleic acids as an alternative to polymerase chain reaction (PCR). The advantage of these ...methods is that the nucleic acids amplification can be carried out at constant temperature, unlike PCR, which requires cyclic temperature changes. Moreover, isothermal amplification can be conducted directly in living cells. This review describes the principles of isothermal amplification techniques and demonstrates their high efficiency in designing new highly sensitive detection methods of nucleic acids and enzymes involved in their modifications. The data on successful application of isothermal amplification methods for the analysis of cells and biomolecules with the use of DNA/RNA aptamers are presented.
Adsorptive heat transformation is an emerging technology that can store heat, convert it to heat with another temperature potential, and generate cold. Progress in this field is determined by the ...development of new advanced adsorbents, implementing efficient cycles, and harmonizing the adsorbent with the cycle. The article examines how the fundamental potential theory of adsorption is used to reach these applied goals and highlights the progress resulted from its application to adsorptive heat transformation.
A complete and exact solution of the ground-state problem for the Ising model on the Shastry-Sutherland lattice in an applied magnetic field is found. The magnetization plateau at one third of the ...saturation value is shown to be the only possible fractional plateau in this model. However, stripe magnetic structures with 1/2 and 1/n (n>3) magnetization, observed in the rare-earth-metal tetraborides RB(4), occur at the boundaries of the three-dimensional regions of the ground-state phase diagram. These structures give rise to new magnetization plateaus if interactions of longer range are taken into account. For instance, an additional third-neighbor interaction is shown to produce a 1/2 plateau. The results obtained significantly refine the understanding of the magnetization process in RB(4) compounds, especially in TmB(4) and ErB(4), which are strong Ising magnets.
We investigate the contribution of cosmic string loops to the cosmic microwave background (CMB) anisotropies. This is done by extending the unconnected segment model (USM) to include the contribution ...of the cosmic string loops created throughout the cosmological evolution of a cosmic string network to the stress-energy tensor. We then implement this extended USM in the publicly available CMBACT code and obtain the linear cold dark matter power spectrum and the CMB angular power spectra generated by cosmic string loops. We find that the shape of the angular power spectra generated by loops is, in general, similar to that of long strings. However, there is generally an enhancement of the anisotropies on small angular scales. Vector modes produced by loops dominate over those produced by long strings for large multipole moments ℓ . The contribution of loops to the CMB anisotropies generated by cosmic string networks may reach a level of 10% for large loops but decreases as the size of loops decreases. This contribution may then be significant and, thus, this extension provides a more accurate prediction of the CMB anisotropies generated by cosmic string networks.
Our study focused on the preparation and characterization of biocomposite films consisting of poly(vinyl alcohol) (PVA) and green tea extract (GTE) with a small amount of glycerol as a plasticizer. ...Scanning electron microscopy (SEM) showed that both the surface and cross-section of the GTE-PVA biocomposite films were smooth and uniform. Incorporation of GTE could considerably alter the optical and mechanical properties of the pure PVA film. Notably, the GTE-PVA biocomposite films presented better water vapor and UV–vis light barrier properties and higher mechanical strength than the pure PVA film. The antioxidant ability of the biocomposite films was evaluated by measuring the 2,2-diphenyl-1-picrylhydrazyl radical scavenging and ferric reducing power in terms of the total phenolic content. The GTE-PVA biocomposite films showed higher antioxidant activity than the pure PVA film, and the antioxidant activity increased with increasing GTE concentration. The color of the GTE-PVA biocomposite films became yellow when the pH was lower than 6 and became dark red when the pH was higher than 6. Moreover, color variations were observed in the GTE-PVA biocomposite films by changing the pH. These results suggest that GTE-PVA composite films may be used as a promising antioxidant and visible pH-sensing food packaging materials.
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•Active food packaging film was developed by GTE biomass compounded with PVA.•GTE-PVA films have better water vapor and UV barrier properties than pure PVA.•Mechanical properties of GTE-PVA films were improved with the content of GTE increased.•GTE-PVA films show antioxidant activity and pH-sensitive color change.
Developing superior-performance marine-biodegradable plastics remains a critical challenge in mitigating marine plastic pollution. Commercially available biodegradable polymers, such as ...poly(L-lactide) (PLA), undergo slow degradation in complex marine environments. This study introduces an innovative bioplastic design that employs a facile ring-opening and coupling reaction to incorporate hydrophilic polyethylene glycol (PEG) into PLA, yielding PEG-PLA copolymers with either sequence-controlled alternating or random structures. These materials exhibit exceptional toughness in both wet and dry states, with an elongation at break of 1446.8% in the wet state. Specifically, PEG4kPLA2k copolymer biodegraded rapidly in proteinase K enzymatic solutions and had a significant weight loss of 71.5% after 28 d in seawater. The degradation primarily affects the PLA segments within the PEG-PLA copolymer, as evidenced by structural changes confirmed through comprehensive characterization techniques. The seawater biodegradability, in line with the Organization for Economic Cooperation and Development 306 Marine biodegradation test guideline, reached 72.63%, verified by quantitative biochemical oxygen demand analysis, demonstrating rapid chain scission in marine environments. The capacity of PEG-PLA bioplastic to withstand DI water and rapidly biodegrade in seawater makes it a promising candidate for preventing marine plastic pollution.
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•PLA-based bioplastic with tunable marine biodegradability.•Exploring PEG-PLA with alternating or random structures impacts its performance.•Alternating PEG-PLA showed superior mechanical properties in dry and wet states.•The introduction of PEG promoted PLA biodegradation in proteinase K and seawater.•PEG-PLA exhibited the fastest degradability in reported marine-degradable polymers.
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