A Semi-Theoretical Model for Water Condensation: Dew Used in Conservation of Earthen Heritage Sites

Dew is a common but important phenomenon. Though water is previously considered to be a threat to earthen heritage sites, artificial dew is showing potential in relic preservation. A model of dew prediction on earthen sites will be essential for developing preventive protection methods, but studies of dew formation processes on relics are limited. In this study, a two parameter model is proposed. It makes approximations according to the features of earthen heritage sites, assuming that a thin and steady air layer exists close to the air–solid interface. This semi-theoretical model was based on calculations of the mass transfer process in the air layer, and was validated by simulations of laboratory experiments (R > 0.9) as well as field experiments. Additionally, a numerical simulation, performed by the commercial software COMSOL, confirmed that the difference between fitting parameter δ and the thickness of assumed mass transfer field was not significant. This model will be helpful in developing automatic environmental control systems for stabilizing water and soluble salts, thus enhancing preventive protection of earthen heritage sites

Distribution and Diversity of Bacteria and Fungi Colonization in Stone Monuments Analyzed by High-Throughput Sequencing - Fig 5

<p>Principal component analyses of the (A) bacterial and (B) fungal communities in the six samples.</p

Poly(Butylene Adipate/Terephthalate-Co-Glycolate) Copolyester Synthesis Based on Methyl Glycolate with Improved Barrier Properties: From Synthesis to Structure-Property

The main problem of manufacturing with traditional biodegradable plastics is that it is more expensive than manufacturing with polymers derived from petroleum, and the application scope is currently limited due to poor comprehensive performance. In this study, a novel biodegradable poly(butylene adipic acid/terephthalate-co-glycolic acid) (PBATGA) copolyester with 25–60% glycolic acid units was successfully synthesized by esterification and polycondensation using cheap coal chemical byproduct methyl glycolate instead of expensive glycolic acid. The structure of the copolyester was characterized by ATR-FTIR, 1H NMR, DSC, and XRD; and its barrier property, water contact angle, heat resistance, and mechanical properties were tested. According to the experiment result, the PBATGA copolyesters showed improved oxygen (O2) and water vapor barrier character, and better hydrophilicity when compared with PBAT. The crystallization peaks of PBATGAs were elevated from 64 °C to 77 °C when the content of the GA unit was 25 mol %, meanwhile, the elongation at the break of PBATGA25 was more than 1300%. These results indicate that PBATGA copolyesters have good potentiality in high O2 and water vapor barrier and degradable packaging material

Investigation of the ionic curing effect and performance of modified nano-montmorillonite on river sludge pastes: Influence of sludge substitution and MNMt dosage

The effect of replacing cementitious materials with different dosages of river sludge on the properties of the cement-slag binary-based geopolymer composites was investigated. The application of this research is the possibility of reusing river sludge into environment-friendly unburned bricks. The influence of nano-montmorillonite on the solidification of heavy metals in the matrix was also explored. Samples containing sludge were characterized by lower fluidity and compressive strength, but prolonged hardening time; at 60% replacement, the strength was equal to 8 MPa and the final setting time was 4.5 h. The sample including 0.4% NMt helps to improve strength thanks to its ability to partially fill the capillary pores and promote the degree of hydration. The pastes containing NMt have less dangerous heavy metals like Cu (II) and Cr (VI). The reaction products and the microstructure of the mixes with modified-NMt are exploited to understand the mechanisms at the basis of the findings

Sampling site locations.

<p>Sampling site locations.</p

Accelerating heat exchanger design by combining physics-informed deep learning and transfer learning

Recently developed physics-informed deep learning is regarded as a transformative learning philosophy that has been applied in many scientific domains, but such applications are often limited to simulating relatively simple equations and well-defined physics. Here, we propose a systematic framework that can leverage the capabilities of space decomposition, physics-informed deep learning, and transfer learning to accelerate the multi-objective stochastic optimization of a heat exchanger system. In particular, this method seamlessly integrates the strengths of the modified Fourier network for capturing steep gradient variation, the point density adjustment strategy to identify the appropriate size of residual points, as well as the accelerated linear algebra to allow for kernel fusion and just-in-time compilation that enables an acceptable computational expense. The performance is verified by discovering the best-performing geometric design and the corresponding optimal operating conditions of an air cooler system under uncertainty.</p

Multi-objective inverse design of finned heat sink system with physics-informed neural networks

This study proposes a new inverse design method that utilizes a physics-informed neural network (PINN) to parameterize the geometric and operating inputs, enabling the identification of optimal heat sink designs by starting with the desired objectives and working backward. A specialized hybrid PINN is designed to accurately approximate the governing equations of the conjugate heat transfer processes. On this basis, a surrogate model derived from the hybrid PINN is constructed and integrated with multi-objective optimization and decision-making algorithms. The results of an example finned heat sink system are presented, showcasing the accelerated search for Pareto-optimal designs. The proposed method nearly halved the search time to approximately 113.9 h in comparison with the traditional methods. Moreover, three representative scenarios—high-performance design, equilibrium design, and low-cost design —were compared to visualize the real-time changes in the multiphysics field, facilitating improved physical inspection and understanding of the optimal designs.</p

16S rRNA sequencing reveals the relationship and membership of the colonies from the stone monuments.

<p>Weighted UniFrac UPGMA tree based on bacterial and archaeal V4 16S rRNA gene sequences obtained from the six stone monuments located in Hangzhou city, Zhejiang province. The heat map shows the relative abundance within each sample of the 24 bacterial classes that were most abundant in the entire dataset. The abundance data were normalized by range-scaling each class Log₁₀ (-3–1).</p

Study on the impact of HTPP fibers on the mechanical properties of ceramsite concrete

In this paper, the effect of High-Toughness Polypropylene (HTPP) fibers admixture (0, 0.3 %, 0.6 %, 0.9 %) on the mechanical properties of ceramsite concrete was investigated, and four kinds of ceramsite concrete specimens were prepared and tested for various kinds of ceramsite concrete compressive strength, flexural strength, and stress-strain curves, and the performance characteristics obtained include the strength-to-weight ratio, flexural-to-compressive ratio, tensile-to-compressive ratio, compressive toughness index, and failure morphology. Furthermore, combined with Scanning Electron Microscope (SEM) images, we analyzed the enhancement mechanism of basic mechanical properties of ceramic concrete by HTPP fibers. The results show that HTPP fibers can effectively improve the strength and toughness performance of ceramsite concrete, and the effect on improving toughness performance is more significant; After adding HTPP fibers, the compressive strength of ceramsite concrete increased by 26.3 %, the flexural strength increased by 29.7 %, the toughness index increased by 28.9 %, and the strength to weight ratio increased by 24.1 %; After adding HTPP fibers, the brittle failure characteristics of concrete are significantly weakened, and when it fails under load, it can still maintain good integrity, without scattering or continuous cracking. Based on the SEM test results, the mechanism of HTPP fibers reinforced ceramsite concrete was explained, mainly attributed to three aspects: fibers preventing ceramsite from floating, fiber surface maintaining good bonding with cement matrix, and effective synergistic bearing between fibers and ceramsite concrete. The research findings of this study can provide a theoretical foundation for the structural analysis and design of this type of concrete. It will be beneficial for the use of ceramsite concrete as a structural material and holds significant implications for the advancement of prefabricated lightweight wall panels