Effect of calcination temperature and Ti substitution on optical properties of (Fe,Cr)2O3 cool black pigment prepared by spray pyrolysis

Ti-Dispersed (Fe,Cr)2O3 cool black pigment particles synthesized by a spray pyrolysis process showed improvement in NIR reflectance by about 10.0% and heat-shielding performance.

USE OF DIGITALIZATION MEANS IN THE FORMATION OF THE MICROCLIMATE OF ANIMAL PREMISES

The study of information systems and technologies, specialized software products aimed at solving the problems of animal husbandry management and determining the prospects for their use by specialists is relevant. The main factor determining the life of animals is the environment. One of the ways to intensify livestock (pigs, cattle, poultry, etc.) is a comprehensive automation of labor-intensive technological processes, including the formation of the microclimate of livestock facilities, which would have a positive impact on animal health, productivity and product quality. However, animals are also affected by certain methods and methods of feeding, man-made content, zonal climate, heat-shielding properties of enclosing structures, air exchange rate, ventilation efficiency, sewage condition, manure removal and removal methods, lighting. The impact of microclimate on animals consists of a set of environmental factors: temperature, humidity, air velocity, chemical composition, microbial and dust pollution, lighting, etc. The main parameter of the air environment is temperature. This has the greatest impact on animal health and productivity. The hygienic value of temperature is that it affects the thermoregulation of the body, which is divided into the processes of chemical thermoregulation - the reaction of heat generation and the processes of physical thermoregulation - the regulation of heat transfer. The study of the technology of improving the efficiency of microclimate regulation in livestock premises based on the use of an automated control system is promising. Thus, changing the composition and properties of the environment, you can affect the body of animals, achieving high productivity.

Influence of washing on textile material thermal properties under exposure of an open flame and heating ele-ment heat flow

Elevated temperatures are factors causing harm to human health and life. To ensure protection, various personal protective equipment is used, which includes special protective clothing. The article discusses the heat-shielding indicators of the safety of textile material. In order to determine the heat-shielding properties of the material, various types of exposure are used – convective heat from a heating element and an open flame. Fabrics of various raw materials and surface density are used for sewing special protective clothing. Five clothes were selected for the research. The research was held under the exposure of an open flame and convective heat of heating element with a comparable heat flux density equal to 80 kW/m². Also, research was held under influence of multiple wash cycles on radiant heat transfer index and heat transfer index.

AUTOMATION OF CALCULATION OF HEAT-SHIELDING CHARACTERISTICS OF WINDOWS

The use of information modeling tools at all stages of the life cycle of a capital construction object allows you to analyze design information in order to make the most correct decision, while significantly reducing the uncertainty of processes by increasing the amount of data available for analysis. One of the labor-intensive processes at the design stage is the selection of the most suitable structural elements, including translucent structures. As part of the work, the normative and reference information related to the calculation of the heat-shielding characteristics of building structures has been analyzed, scientific developments and publications devoted to the automation of the implementation of heat engineering calculations using various software tools are considered. For the purpose of the study, two indicators were calculated: the normalized value of the reduced heat transfer resistance and the reduced heat transfer resistance of the window. To solve the problem, such automation tools as the Dynamo visual programming tool and the Python programming language were used, with the help of which a script was developed for calculating the thermal performance of windows for use in Autodesk Revit (Autodesk, Inc., USA). As part of the study, it was determined that the combined use of the Dynamo visual programming tool and the Python text programming tool, expanding the functionality of Autodesk Revit, made it possible to automate the task of calculating the reduced heat transfer resistance of a window and the normalized heat transfer resistance, taking into account conditions of a specific construction region.

Residual stresses in surface layers and coatings

Methods of measurement and mechanisms of formation of residual stresses in the surface layers of metal alloys after ion nitriding, as well as in heat-shielding and refractory coatings are considered. Examples of the application of a technique based on the peculiarities of elastic anisotropy for measuring residual stresses in heterogeneous surface layers, for which the standard technique of diffraction tensometry “sin2Ψ” is not applicable, are given.

These boots are made for burnin’: Inferring the position of the corpse and the presence of leather footwears during cremation through isotope (δ13C, δ18O) and infrared (FTIR) analyses of experimentally burnt skeletal remains

Cremation is a complex mortuary practice, involving a number of activities of the living towards the dead before, during, and after the destruction of the bodily soft tissues by fire. The limiting information concerning these behavioral patterns obtained from the pyre remains and/or cremation deposits prevents the reconstruction of the handling of the corpse during the burning process. This pioneering study tries to determine the initial positioning of the corpse in the pyre and assess whether the deceased was wearing closed leather shoes during cremation through isotopic (δ13C, δ18O) and infrared (ATR-FTIR) analyses of experimentally burnt pig remains, used as a proxy for humans. The results obtained show that both the position of feet on or within the pyre and the presence of footwears may moderately-to-highly influence the oxygen isotope ratios of bone apatite carbonates and the cyanamide content of calcined bone in certain situations. By forming a protective layer, shoes appear to temporarily delay the burning of the underlying pig tissues and to increase the heat-shielding effect of the soft tissues protecting the bone mineral fraction. In such case, bioapatite bone carbonates exchange oxygen with a relatively more 18O-depleted atmosphere (due to the influence of lignin-derived oxygen rather than cellulose-derived oxygen), resulting in more pronounced decrease in the δ18Ocarb values during burning of the shoed feet vs. unshoed feet. The shift observed here was as high as 2.5‰. A concomitant isotopic effect of the initial location of the feet in the pyres was also observed, resulting in a top-to-bottom decrease difference in the δ18Ocarb values of shoed feet of about 1.4‰ between each deposition level tested. Finally, the presence of cyanamide (CN/P ≥ 0.02) seems to be indicative of closed footwear since the latter creates favorable conditions for its incorporation into bone apatite.

Study on the thermal insulation performance of the core–shell skeleton graphene oxide/carbon composite aerogel

Phenolic resin (PR) was grafted onto the surface of graphene oxide (GO) through π–π conjugation and chemical bonding. After carbonization, organic compounds turned into carbon layers with a thickness of about 10 nm and coated on the surface of GO formed a core–shell structure. Besides, the adiabatic interface formed during organic carbonization can effectively connect the aerogels into a three-dimensional network. The optimum mass ratio of GO was determined to be 10 wt% in the preparation of the precursor aerogel. The adiabatic interfaces (carbon) between GO lamellae could effectively reduce the solid phase heat transfer in aerogels (thermal conductivity is 0.0457 W m−1 K−1). At the same time, the existence of GO also ensured better mechanical properties of GO/carbon composite aerogel (compressive strength is 2.43 MPa) compared with the pure carbon aerogel (1.52 MPa), demonstrating the excellent heat-shielding performance and mechanical property of GO/carbon aerogel.

About the possibility of application of laser vacuum welding for the integration of elements of heat-protective structures from powder materials

The results of studying the process of laser vacuum welding of elements of heat-shielding panels made of heat-resistant dispersion-strengthened powder materials Ni-20Cr-6Al-Ti-Y2O3 of increased strength are presented. Such materials can be used to create ultralight heat-shielding panels, which are systems integrated on the surface of aircraft from typical modules of a cellular structure. Technical solutions of heat-insulating modules are considered, which are a cellular (honeycomb) structure consisting of two plates with a thickness of 0.1 to 0.14 mm, inside which there is a thin honeycomb filler. It is shown that the small thickness of the plates and the complexity of integrating the elements into a single system significantly impair the formation of a strong connection of such elements and do not allow the direct use of the known methods of diffusion welding or vacuum brazing. It has been established that laser welding of elements of heat-shielding structures in vacuum provides satisfactory strength of the structure of the heat-shielding element as a whole. Local heating at certain points prevents deformation of the parts to be joined during the welding process. The use of a pulsed Nd:Yag laser with a power of 400–500 W, operating in the frequency range of 50–200 Hz, allows welding with or without a filler powder. It was found that the use of filler additives practically does not affect the mechanical properties of the welded joint, however, it reduces the melt zone, while increasing the density of the welded joint. Based on the results obtained, it was concluded that it is possible to use laser vacuum welding for the integration of thin elements of heat-shielding modules. It is shown that a satisfactory joint strength is achieved by ensuring high cleanliness of the surfaces of elements before welding, maintaining a high vacuum (less than 10–2 Pa) and rational thermal loading of the surfaces of the elements to be integrated. The use of the proposed process makes it possible to obtain a stronger and denser seam in comparison with the known methods of soldering multicomponent powder dispersion-strengthened materials