Effect of conditions and parameters of drawing on strength and surface condition of basalt continuous fibers

Basalt continuous fibers are used in the development of new composite materials. The influence of various factors on the strength and formation of the surface microstructure of basalt continuous fibers is considered. An experimental determination of tensile strength was performed and the surface condition of continuous andesite-basalt fibers with a diameter of 8 to 10 μm fibers was investigated. It is established that the strength of fibers, among other factors, is influenced by the conditions of their production, which are determined by the drawing parameters: the production temperature, the level of melt in the feeder and the winding speed. The effect of production temperature on the strength of the fibers was the greatest. It was found that the fibers obtained at a production temperature of 1450 °C had a strength of 24—28% greater than that of the fibers obtained at a production temperature of 1400 °C. The separate influence of other parameters of drawing, the level of melt in the feeder and the winding speed on the strength of the fibers is less significant. A qualitative relationship between the state of the surface of the fibers and the conditions of their production at different parameters of formation. The greatest influence on the change in the state of the surface of the fibers has the temperature of fiber production. It is established that the surface of the fibers obtained at a production temperature of 1450 °C is more homogeneous with a small number of visible defects. On the other hand, on the surface of the fibers, which are obtained at a production temperature of 1400 ºC, there is a large number of defects. There is also an increase in the defect of the surface of the fibers, which are obtained at low levels of melt in the feeder and the winding speed. Keywords: continuous fibre, surface structure, strength, cooling rate, production temperature, winding speed, melt level in the feeder.

The non-random structure of multi-trophic ecological interactions maximizes species coexistence within ecologically realistic constraints

Theory posits that the persistence of species in ecological communities is shaped by their interactions within and across trophic levels. However, we lack empirical evaluations of how the structure, strength and sign of these interactions drive the potential to coexist in diverse multi-trophic communities. Here we model community feasibility domains, a theoretically-informed measure of coexistence probability, from empirical data on communities comprising more than 50 species for three trophic guilds (plants, pollinators, and herbivores). Although feasibility domains vary depending on the number of trophic guilds considered, we show that higher network connectance leads to lower coexistence opportunities. Moreover, empirical estimations of the feasibility domains were higher with respect to random network structures but lower than a mean-field approach, suggesting that observed interaction structures tend to maximize coexistence within its imposed limits. Our results stress the importance of incorporating empirically-informed interaction structures within and across guilds to better understand how species coexist in diverse multi-trophic communities.

Application of topology optimization method for the gothic greenhouse design

Purpose This research presents a design method for designing greenhouse structures based on topology optimization. Moreover, the structural design of a gothic greenhouse is proposed in which its structural strength has been improved by using this proposed method. In this method, the design of the structure is done mathematically; therefore, in the design process, more attention can be focused on the constraint space and boundary conditions. It was also shown how the static reliability and fatigue coefficients will change as a result of the design of the greenhouse structure with this method. Another purpose of this study is to find the weakest part of the greenhouse structure against lateral winds and other general loads on the greenhouse structure. Design/methodology/approach In the proposed method, the outer surface and the allowable volume as a constraint domain were considered. The desired loads can be located on the constraint domain. The topology optimization was used to minimize the mass and structural compliance as the objective function. The obtained volume was modified for simplifying the construction. The changes in the shape of the greenhouse structure were investigated by choosing three different penalty numbers for the topology optimization algorithm. The final design of the proposed structure was performed based on the total simultaneous critical loads on the structure. The results of the proposed method were compared in the order of different volume fractions. This showed that the volume fraction approach can significantly reduce the weight of the structure while maintaining its strength and stability. Findings Topology optimization results showed different strut and chords composition because of the changes in maximum mass limit and volume fraction. The results showed that the fatigue was more hazardous, and it decreased the strength of structure nearly three times more than a static analysis. Further, it was noticed that how the penalty numbers can affect topology optimization results. An optimal design based on topology optimization results was presented to improve the proposed greenhouse design against destruction and demolition. Furthermore, this study shows the most sensitive part of the greenhouse against the standard loads of wind, snow, and crop. Originality/value The obtained designs were compared with a conventional arch greenhouse, and then the structural performances were shown based on standard loads. The results showed that in designing the proposed structure, the optimized changes increased the structure strength against the standard loads compared to a simple arch greenhouse. Moreover, the stress safety factor and fatigue safety factor because of different designs of this structure were also compared with each other.

Design and formulation of microbially induced self-healing concrete for building structure strength enhancement

Self-healing concrete is described as the capability of material to repair their cracks independently. Cracks in concrete are well-known circumstance because of their short tensile strength. Many researchers carried out their research on self-healing concrete using different classification and clustering methods. But the temperature variation and pH variation were not minimized. In order to address these problems, a Multivariate Logistic Regressed Chi-Square Deep Recurrent Neural Network based Self-Healing (MLRCSDRNN-SH) Method is introduced. The main aim of MLRCSDRNN-SH method is to improve building structures strength through inducing the micro-bacteria in concrete. Multiple Logistic Regressed Chi-Square Deep Recurrent Neural Network (MLRCSDRNN) is used to revise bacteria’s stress-strain behaviour towards enhanced material strength in the MLRCSDRNN-SH approach. Initially, the bacteria selection is carried out in alkaline environment like Bacillus subtilis, E. coli and Pseudomonas sps. The data sample is given to the input layer. The input layer transmits sample to the hidden layer 1. The regression analysis is carried out between the multiple independent variables (i.e., parameters) using multivariate logistic function for improving the building structure strength. The regressed value is transmitted to the hidden layer 2. The pearson chi-squared independence hypothesis is performed to identify the probability of crack self-healing property for increasing the building structure strength. When probability value is higher, then the building structure strength is high. Otherwise, the output of second hidden layer is feedback to the input of hidden layer 1. The mixture with higher strength of building structure is sent to the output layer. Several specimens have different sizes used by various researchers for bacterial material study in comparison with the concrete. Depending on experimental results, compressive strength restoration proved higher self-healing ability of the concrete.