63 research outputs found
Correction: Pogorelsky, I.V.; Polyanskiy, M.N. Harnessing Ultra-Intense Long-Wave Infrared Lasers: New Frontiers in Fundamental and Applied Research. <i>Photonics</i> 2025, <i>12</i>, 221
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Grain size distribution of aggregates of crushed concrete
No full textThe results of studies of recycling aggregates obtained by crushing concrete scrap are presented. The heterogeneity of the material received as a result of crushing concrete scrap, complicates the task of selecting the fractional composition of aggregates. The presence of the mortar component in recycled aggregates significantly increases their water demand. This indicates the expediency of their use in a mixture with natural ones. This work aimed at optimizing the granulometry of recycling rubble and sand. Concrete scrap was used for the research. It was represented by destroyed samples of heavy concrete cubes. Standard methods for determining the grain composition and properties of aggregates of concrete, manufacturing and testing mortar mixes were used. It has been shown that recycling rubble of the 5-20 mm fraction has a minimum voidness when it contains 35% of the 5-10 mm grains and 65% of the 10-20 mm grains, which is close to the ratio of these fractions in the initial crushing product. Therefore, it is advisable to use recycling rubble fractions of 5-20 mm without separation into fractions. The rather high content in the recycling sand of grains with a particle size of more than 0.63 mm indicates the feasibility of using it in a mixture with natural fine and very fine sand. A grain-optimized mixture of natural very fine sand (46% of the total mass of mixed sand) and coarse fractions (0.63–5 mm) of recycled sand (54%) is proposed. Should be considered that recycled sand has increased water demand
Changes in the composition and structure at PET-waste processing into building materials
No full textThe results of studies of the composition and structure of polyethylene terephthalate in the process of thermomechanical processing of polymeric wastes as well as properties of waste products obtained on the basis of waste are presented. Methods of infrared spectroscopy, differential thermal analysis and thermogravimetry, as well as standard methods for manufacturing and testing the technical properties of samples of structural building products were used. As a result of thermomechanical processes during re-melting of polyethylene terephthalate waste, the number of hydroxyl groups in the polymer composition decreases, due to the possible cross-linking and polycondensation of macromolecules through terminal hydroxyl and unactivated carboxyl groups. In this case, conformational rearrangements take place in the structure of polyethylene terephthalate. When thermomechanical processing of secondary PET with rapid cooling of the melt, the temperature of the onset of subsequent melting decreases, which allows to reduce power consumption in melting-mixing units during the process of manufacturing construction products. Construction and technical properties of secondary PET as binder composite building materials allow to obtain potentially durable products with structural strength and high decorative
Harnessing Ultra-Intense Long-Wave Infrared Lasers: New Frontiers in Fundamental and Applied Research
No full textThis review explores two main topics: the state-of-the-art and emerging capabilities of high-peak-power, ultrafast (picosecond and femtosecond) long-wave infrared (LWIR) laser technology based on CO2 gas laser amplifiers, and the current and advanced scientific applications of this laser class. The discussion is grounded in expertise gained at the Accelerator Test Facility (ATF) of Brookhaven National Laboratory (BNL), a leading center for ultrafast, high-power CO2 laser development and a National User Facility with a strong track record in high-intensity physics experiments. We begin by reviewing the status of 9–10 μm CO2 laser technology and its applications, before exploring potential breakthroughs, including the realization of 100 terawatt femtosecond pulses. These advancements will drive ongoing research in electron and ion acceleration in plasma, along with applications in secondary radiation sources and atmospheric energy transport. Throughout the review, we highlight how wavelength scaling of physical effects enhances the capabilities of ultra-intense lasers in the LWIR spectrum, expanding the frontiers of both fundamental and applied science
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