Nanotechnologies in agricultural production as a factor of transition to a new level of technological design

The article discusses one of the directions of the transition of agricultural production in Russia to the sixth technological order based on the introduction of nanotechnology in the field of hygrothermal effects on grain crops. The features of hygrothermal action on grain under vacuum conditions are presented. The distinctive features of such processing as nanotechnology are substantiated. Based on the method of similarity in the functioning of technical systems for vacuum-capillary processes of humidification, drying, and wet-heat treatment, generalized similarity criteria are obtained, their numerical values are determined, and generalized criterion dependences of the intensity of the processes under consideration on the processing parameters are obtained. The implementation of this method made it possible to quantitatively describe the processes of vacuum capillary hygrothermal treatment of grain, to assign processing parameters and control them.

Research of processes of the heatmass transfer in the porous environments having stochastic characteristics on the basis of methods of applied synergetic

On the basis of a synergetic approach, mathematical models of the stochastic similarity of the functioning of heat and mass transfer processes in porous media (grain materials) have been developed. In these models, the indicators of the stochastic characteristics of these media are combined with the parameters of the processes of hygrothermal treatment under vacuum conditions: residual pressure - P, temperature - T, time-τ, with a density of couple - ρ. The resulting models can be used to control hygrothermal processes in the processing of natural tanning and grain materials that have a stochastic character of the building. A method for the formation of mathematical models of stochastic similarity has been developed, including functional dependences of indicators of stochastic characteristics of materials subjected to hygrothermal treatment on parameters characterizing its state: input, setting, disturbing influences and internal (structural) system.

Impact of hygrothermal treatment on the physical properties and chemical composition of Moso bamboo (Phyllostachys edulis)

Natural bamboo is rapidly replacing wood, but it is highly hygroscopic and has poor dimensional stability. Herein, Moso bamboo was subjected to hygrothermal treatment at different temperatures. The hydrophobicity and dimensional stability of bamboo increased, as indicated by the 16.5% decrease in volumetric swelling and three-fold increase in the contact angle at 220 °C. The fibers and parenchyma cells delaminated, and pores appeared after treatment at 200 °C. These changes were attributed to the significant degradation of hemicelluloses. The acetyl groups of hemicelluloses decomposed into acetic acid. The apparent crystallinity of cellulose increased mainly due to the reduced hemicellulose content. Furthermore, a breakage of xylan and β-O-4 bonds was observed, and S units were condensed after treatment at 220 °C. In addition, the syringyl/guaiacyl ratio showed more than a five-fold increase, while associated ferulic acid decreased after hygrothermal treatment, indicating that the dense structure of the cell walls was broken. These data were used to propose a mechanism for changes in the bamboo cell walls during hygrothermal treatment. This simple and environmentally-friendly approach holds great potential for use in high-humidity environments.

Author Correction: Effect of Hygrothermal Treatment on the Porous Structure and Nanomechanics of Moso Bamboo

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Hygrothermal recovery of compression wood in relation to DMSO swelling and drying shrinkage

To understand the irreversible dimensional changes caused by hygrothermal treatment of green wood, i.e. hygrothermal recovery (HTR), green hinoki compression wood (CW) and normal wood (NW) were hygrothermally (HT) treated in water at 100°C for 120 min and their HTR strains were determined. The specimens were then swollen using dimethyl sulfoxide (DMSO) and then completely dried after solvent exchange with water at room temperature. Their HTR strains were then compared with their DMSO swelling and drying shrinkage strains. The volumetric HTR strains in the CW were about twice as large as those in the NW. Moreover, the microfibril angle (MFA) was found to be an important factor for controlling the HTR intensity. A clear commonality between the HTR behavior and both DMSO swelling and drying shrinkage behavior was identified, which indicates that HTR is caused by volumetric changes in the matrix substances. HTR has been defined as a phenomenon due to the release of locked-in growth stress when a wood specimen is HT treated. To determine whether DMSO treatment has a similar effect as hygrothermal treatment, both HT-untreated and HT-treated specimens were swollen using DMSO, and their dimensional changes during and after DMSO treatment were compared. The results showed that DMSO treatment is a possible alternative for releasing the locked-in growth stress.

Effect of Hygrothermal Treatment on the Porous Structure and Nanomechanics of Moso Bamboo

Hygrothermal treatment is an environmentally friendly and efficient modification method. In this study, Moso bamboo was modified with hygrothermal treatments, and the results of nitrogen adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM) and nano indentation (NI) were then examined. Interestingly, the samples that underwent hygrothermal treatment at 180 °C and 100% RH (relative humidity) had the highest crystallinity (36.92%), which was 11.07% statistically larger than that of the control samples. Simultaneously, the total pore volume and average pore diameter (2.72 nm) dramatically decreased by 38.2% and 43.7%, respectively. The NI elasticity and hardness of the samples also reached the highest values under this condition; both increased by nearly 21% as compared with the control samples. Therefore, 180 °C is a favorable hygrothermal treatment temperature for Moso bamboo modification due to the porosity changes and the improvement of the nanomechanics of the cell walls.

Hygrothermal Treatment of Tepa (Laureliopsis philippiana Looser) Fibers

The present study consisted in determining the effects of a hygrothermal treatment on wood fibers from the Laureliopsis philippiana Looser species. The fibers were treated in autoclave at 150 °C for 90 minutes at a pressure of 430 kPa, which was generated during the evaporation process of the water in autoclave. Physical properties, color, and water retention capacity of hygrothermically treated and untreated fibers were analyzed. The chemical properties determined were the extractable amount in sodium hydroxide, toluene ethanol, hot and cold water, the cellulose, holocellulose and lignin contents, the pH value, the percentage of volatile and washable acids, and the buffer capacity. In hygrothermically treated fibers, a change of color was detected as well as a reduction in the water retention capacity and an increase in the percentage of extractable, cellulose, lignin and a decrease of holocellulose. Also an increase in acidity, amount of volatile and washable acids and buffer capacity were determined. Due to the chemical changes observed in the treated fibers, these would present advantages in the manufacture of fiberboards, facilitating the setting of the amino resins.