A radiative cooling structural material.

Reducing human reliance on energy-inefficient cooling methods such as air conditioning would have a large impact on the global energy landscape. By a process of complete delignification and densification of wood, we developed a structural material with a mechanical strength of 404.3 megapascals, more than eight times that of natural wood. The cellulose nanofibers in our engineered material backscatter solar radiation and emit strongly in mid-infrared wavelengths, resulting in continuous subambient cooling during both day and night. We model the potential impact of our cooling wood and find energy savings between 20 and 60%, which is most pronounced in hot and dry climates

Single-digit-micrometer thickness wood speaker

Partial funding for Open Access provided by the UMD Libraries' Open Access Publishing Fund.Thin films of several microns in thickness are ubiquitously used in packaging, electronics, and acoustic sensors. Here we demonstrate that natural wood can be directly converted into an ultrathin film with a record-small thickness of less than 10 μm through partial delignification followed by densification. Benefiting from this aligned and laminated structure, the ultrathin wood film exhibits excellent mechanical properties with a high tensile strength of 342 MPa and a Young’s modulus of 43.6 GPa, respectively. The material’s ultrathin thickness and exceptional mechanical strength enable excellent acoustic properties with a 1.83-times higher resonance frequency and a 1.25-times greater displacement amplitude than a commercial polypropylene diaphragm found in an audio speaker. As a proof-of-concept, we directly use the ultrathin wood film as a diaphragm in a real speaker that can output music. The ultrathin wood film with excellent mechanical property and acoustic performance is a promising candidate for next-generation acoustic speakers

A method for estimating yield of maize inbred lines by assimilating WOFOST model with Sentinel-2 satellite data

Maize is the most widely planted food crop in China, and maize inbred lines, as the basis of maize genetic breeding and seed breeding, have a significant impact on China’s seed security and food safety. Satellite remote sensing technology has been widely used for growth monitoring and yield estimation of various crops, but it is still doubtful whether the existing remote sensing monitoring means can distinguish the growth difference between maize inbred lines and hybrids and accurately estimate the yield of maize inbred lines. This paper explores a method for estimating the yield of maize inbred lines based on the assimilation of crop models and remote sensing data, initially solves the problem. At first, this paper analyzed the WOFOST(World Food Studies)model parameter sensitivity and used the MCMC(Markov Chain Monte Carlo) method to calibrate the sensitive parameters to obtain the parameter set of maize inbred lines differing from common hybrid maize; then the vegetation indices were selected to establish an empirical model with the measured LAI(Leaf Area Index) at three key development stages to obtain the remotely sensed estimated LAI; finally, the yield of maize inbred lines in the study area was estimated and mapped pixel by pixel using the EnKF(Ensemble Kalman Filter) data assimilation algorithm. Also, this paper compares a method of assimilation by setting a single parameter. Instead of the WOFOST parameter optimization process, a parameter representing the growth weakness of the inbred lines was set in WOFOST to distinguish the inbred lines from the hybrids. The results showed that the yield estimated by the two methods compared with the field measured yield data had R2: 0.56 and 0.18, and RMSE: 684.90 Kg/Ha and 949.95 Kg/Ha, respectively, which proved that the crop growth model of maize inbred lines established in this study combined with the data assimilation method could initially achieve the growth monitoring and yield estimation of maize inbred lines

Efficiency Enhancement of an Ammonia-Based Solar Thermochemical Energy Storage System Implemented with Hydrogen Permeation Membrane

The ammonia-based solar thermochemical energy storage (TCES) is one of the most promising solar TCESs. However, the solar-to-electric efficiency is still not high enough for further commercialization. The efficiency is limited by the high ammonia decomposition reaction temperature, which does not only increase the exergy loss through the heat recuperation but also causes a large re-radiation loss. Nonetheless, lowering the reaction temperature would impact the conversion and the energy storage capacity. Thanks to the recent development of the membrane technology, the hydrogen permeation membrane has the potential to enhance the conversion of ammonia decomposition under the moderate operating temperature. In this paper, an ammonia-based solar thermochemical energy storage system implemented with hydrogen permeation membrane is proposed for the first time. The system model has been developed using the Aspen Plus software implemented with user-defined Fortran subroutines. The model is validated by comparing model-generated reactor temperatures and conversions profiles with data from references. With the validated model, an exergy analysis is performed to investigate the main exergy losses of the system. Furthermore, the effects of the membrane on system efficiency improvement are studied. The results show that exergy loss in the charging loop is dominant, among which the exergy losses of Heat Exchanger Eh,A, together with that of the re-radiation Er, play important roles. Compared with the conventional system, i.e., the system without the membrane, the Eh,A and Er of the proposed system are more than 30% lower because the hydrogen permeation membrane can improve ammonia conversion at a lower endothermic reaction outlet temperature. Consequently, the proposed system, presumably realized by the parabolic trough collector at ~400 °C, has a theoretical solar-to-electric efficiency of ηste, which is 4.4% higher than the conventional ammonia-based solar thermochemical energy storage system. Last but not least, the efficiency is 3.7% higher than that of a typical parabolic trough solar power plant, which verifies the thermodynamic feasibility of further commercialization

Solar-assisted fabrication of large-scale, patternable transparent wood

Transparent wood is considered a promising structural and light management material for energy-efficient engineering applications. However, the solution-based delignification process that is used to fabricate transparent wood generally consumes large amounts of chemicals and energy. Here, we report a method to produce optically transparent wood by modifying the wood's lignin structure using a solar-assisted chemical brushing approach. This method preserves most of the lignin to act as a binder, providing a robust wood scaffold for polymer infiltration while greatly reducing the chemical and energy consumption as well as processing time. The obtained transparent wood (~1 mm in thickness) demonstrates a high transmittance (>90%), high haze (>60%), and excellent light-guiding effect over visible wavelength. Furthermore, we can achieve diverse patterns directly on wood surfaces using this approach, which endows transparent wood with excellent patternability. Combining its efficient, patternable, and scalable production, this transparent wood is a promising candidate for applications in energy-efficient buildings

Unique Microbial Diversity and Metabolic Pathway Features of Fermented Vegetables From Hainan, China

Fermented vegetables are typically traditional foods made of fresh vegetables and their juices, which are fermented by beneficial microorganisms. Herein, we applied high-throughput sequencing and culture-dependent technology to describe the diversities of microbiota and identify core microbiota in fermented vegetables from different areas of Hainan Province, and abundant metabolic pathways in the fermented vegetables were simultaneously predicted. At the genus level, Lactobacillus bacteria were the most abundant. Lactobacillus plantarum was the most abundant species, followed by Lactobacillus fermentum, Lactobacillus pentosaceus, and Weissella cibaria. These species were present in each sample with average absolute content values greater than 1% and were thus defined as core microbiota. Analysis results based on the alpha and beta diversities of the microbial communities showed that the microbial profiles of the fermented vegetables differed significantly based on the regions and raw materials used, and the species of the vegetables had a greater effect on the microbial community structure than the region from where they were harvested. Regarding microbial functional metabolism, we observed an enrichment of metabolic pathways, including membrane transport, replication and repair and translation, which implied that the microbial metabolism in the fermented vegetables tended to be vigorous. In addition, Lactobacillus plantarum and Lactobacillus fermentum were calculated to be major metabolic pathway contributors. Finally, we constructed a network to better explain correlations among the core microbiota and metabolic pathways. This study facilitates an understanding of the differences in microbial profiles and fermentation pathways involved in the production of fermented vegetables, establishes a basis for optimally selecting microorganisms to manufacture high-quality fermented vegetable products, and lays the foundation for better utilizing tropical microbial resources

Presentation1.pdf

<p>Fermented vegetables are typically traditional foods made of fresh vegetables and their juices, which are fermented by beneficial microorganisms. Herein, we applied high-throughput sequencing and culture-dependent technology to describe the diversities of microbiota and identify core microbiota in fermented vegetables from different areas of Hainan Province, and abundant metabolic pathways in the fermented vegetables were simultaneously predicted. At the genus level, Lactobacillus bacteria were the most abundant. Lactobacillus plantarum was the most abundant species, followed by Lactobacillus fermentum, Lactobacillus pentosaceus, and Weissella cibaria. These species were present in each sample with average absolute content values greater than 1% and were thus defined as core microbiota. Analysis results based on the alpha and beta diversities of the microbial communities showed that the microbial profiles of the fermented vegetables differed significantly based on the regions and raw materials used, and the species of the vegetables had a greater effect on the microbial community structure than the region from where they were harvested. Regarding microbial functional metabolism, we observed an enrichment of metabolic pathways, including membrane transport, replication and repair and translation, which implied that the microbial metabolism in the fermented vegetables tended to be vigorous. In addition, Lactobacillus plantarum and Lactobacillus fermentum were calculated to be major metabolic pathway contributors. Finally, we constructed a network to better explain correlations among the core microbiota and metabolic pathways. This study facilitates an understanding of the differences in microbial profiles and fermentation pathways involved in the production of fermented vegetables, establishes a basis for optimally selecting microorganisms to manufacture high-quality fermented vegetable products, and lays the foundation for better utilizing tropical microbial resources.</p

Scalable aesthetic transparent wood for energy efficient buildings

Transparent wood composites are promising engineered materials for green energy-efficient building. Here, authors demonstrate novel aesthetic wood with integrated functions of optical transparency, UV-blocking, thermal insulation, and mechanical strength for this sustainable application