Graphene Oxide Functionalized Cottonseed-Lignin Resin with Enhanced Wet Adhesion for Woody Composites Application

With rising interior air pollution, health, and food shortage concerns, wood adhesives derived from non-food sustainable materials have therefore attracted considerable attention. Here we developed an eco-friendly cottonseed-lignin adhesive consisting of non-food defatted cottonseed flour (DCF), alkali lignin (AL), and graphene oxide (GO). The cation-π interaction, and hydrogen and covalent bonds between AL@GO and DCF collectively enhanced the cross-linking structure of the cured cottonseed-lignin adhesive, based on the Fourier-transform infrared spectroscopy, thermogravimetric analyses, scanning electron microscopy, and sol-gel tests. The high performance of the developed cottonseed-lignin adhesive was evidenced by its increased wet/dry shear strength and decreased rheological properties before curing and improved thermal stability and decreased soluble substances after curing. Particularly, the highest wet shear strength of poplar plywood bonded with cottonseed-lignin adhesive was 1.08 MPa, which increased by 74.2 and 54.3% as compared to the control and requirement of the Chinese standard GB/T 9846-2015 for interior plywood (≥0.7 MPa), respectively. The technology and resultant adhesives showed great potential in the preparation of green woody composites for many applications.

Mercury Accumulation in Commercial Varieties of Oryza sativa L. Cultivated in Soils of La Mojana Region, Colombia

The Hg accumulation in different commercial varieties of Oryza sativa L. was evaluated in the region of La Mojana, Colombia, where rice cultivation has become the staple food of the population living in this area. The varieties studied were Fedearroz-473 (FA473), Fedearroz-2000 (FA2000), and Fedearroz-Mocari (FAM). Soil spiked at different Hg levels was evaluated, (130, 800, and 1500 µg kg−1) using a 32 factorial design that consisted of 3 (rice varieties) × 3 (Hg contents). The biomass, 1000-grain weight, and the accumulation of Hg in the roots, grains, and husks were determined. The highest biomass was found in the FA473 (308.76 ± 108.26 g), and the lowest was found in FAM (144.04 ± 26.45 g) in the 1500 µg kg−1 Hg soil in both cases. The weight per 1000-grains decreased significantly in the soil containing 800 µg of Hg kg−1. Hg accumulation in the organs of the evaluated varieties was higher in the roots, followed by in the husks and grains. The Hg in the rice grains of the evaluated varieties presented levels close to the permissible limit of the Chinese standard (20 μg Hg kg−1) in the evaluated soils and were only exceeded by FA473. Although in natural soil concentrations, the non-cancer health risk (HQ) from rice consumption was lower for FA473 and FAM; Hg enrichment in the soil of La Mojana region may endanger the health of future populations due to their high consumption of rice.

Research Status and Environmental Protection Disposal of Recycled Electrolytic Manganese Residue

Electrolytic manganese residue (EMR) is a common industrial solid waste. The ammonia and manganese components contained in it will pollute the soil environment and have potential risks to human health. Under the premise of investigating the production of electrolytic manganese slag and conventional processes, it is found that the traditional harmless treatment methods of electrolytic manganese slag are still mainly lime solidification, cement solidification, and fly ash solidification, and the resource utilization directions such as cement, concrete, non-sintered bricks, road bases, etc. are mainly used. But, EMR contains ammonia nitrogen, and manganese (prone to leaching) that difficult to meeting environmental protection requirements by using general cement cementitious material solidification. Therefore, this study focused on manufacturing new eco-friendly bricks with EMR using calcination process. Specifically, the physical performance and environmental characterization of the sintered bricks were investigated. Furthermore, the sintering behavior and crystallization of all bricks containing EMR were studied using XRD, FT-IR, and SEM. The results showed the EMR leaching solution contained 1256 mg/L and 8120 mg/L of ammonia nitrogen and manganese, respectively, both of them exceeds Chinese standards (GB 8978-1996). Because of EMR is rich in Fe2O3 and K2O, it greatly promotes particle rearrangement and transfer in the EMR system, reducing the sintering temperature. The compressive strength, leaching performance and radioactivity of sintered bricks with EMR all met the state standard requirement for "sintered common bricks" (GB/T 5101-2017) and (GB 8978). The product can be used as bricks of MU20 grade of Chinese standard. The study provides an effective method for the safe and environmentally friendly disposal of EMR.

Defining Uncertainty: Comparing Resource/Reserve Classification Systems for Coal and Coal Seam Gas

Transparent, objective, and repeatable resource assessments should be the goal of companies, investors, and regulators. Different types of resources, however, may require different approaches for their quantification. In particular, coal can be treated both as a solid resource (and thus be mined) as well as a reservoir for gas (which is extracted). In coal mining, investment decisions are made based on a high level of data and establishment of seam continuity and character. The Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the JORC Code) allows deposits to be characterised based on the level of geological and commercial certainty. Similarly, the guidelines of the Petroleum Resource Management System (PRMS) can be applied to coal seam gas (CSG) deposits to define the uncertainty and chance of commercialisation. Although coal and CSG represent two very different states of resources (i.e., solid vs. gaseous), their categorisation in the JORC Code and PRMS is remarkably similar at a high level. Both classifications have two major divisions: resource vs. reserve. Generally, in either system, resources are considered to have potential for eventual commercial production, but this has not yet been confirmed. Reserves in either system are considered commercial, but uncertainty is still denoted through different subdivisions. Other classification systems that can be applied to CSG also exist, for example the Canadian Oil and Gas Evaluation Handbook (COGEH) and the Chinese Standard (DZ/T 0216-2020) and both have similar high-level divisions to the JORC Code and PRMS. A hypothetical case study of a single area using the JORC Code to classify the coal and PRMS for the gas showed that the two methodologies will have overlapping, though not necessarily aligned, resource and reserve categories.

A Customized Mask Retainer and Its Effects on Improving the Fit Performance of Surgical Masks

Background: With the outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the effectiveness of providing mask protection is important for people. This article introduces a customized mask retainer to improve the fit performance of face masks.Methods: The participant’s 3D face scans with and without a surgical mask were taken by using a 3D face scanner. The fitter was designed on the 3D face scan data according to the facial anthropometric landmarks, and examined and adjusted on the face scan data with a mask. The fitter was 3D printed using a metal printer for Titanium. The effectiveness of the fitter on augmentation of fit of surgical mask was test according to the Chinese Standard. Tests were repeated three times per participant, and compare differences between groups by Wilcoxon Matched-Pairs Signed-Ranks Test using software (a=.05).Results: The effectiveness test of the retainer on augmentation of fit performance showed a result more than 25-fold increase of overall Fit Factor, which have met the fit requirement for KN95 respirators in China.Conclusions: Fit Factor results indicated that by using the retainer, the Fit Factors of overall and each exercise have significantly increased as compared to that of face mask alone group. It may provide a solution to the shortage of N95 respirators the world is now encountering as fighting against the COVID-19 epidemic.

Compressed Sensing-Based Range-Doppler Processing Method for Passive Radar

Passive radar (PR) systems use the existing transmitters of opportunity in the environment to perform tasks such as detection, tracking, and imaging. The classical cross-correlation based methods to obtain the range-Doppler map have the problems of high sidelobe and limited resolution due to the influence of signal bandwidth. In this paper, we propose a novel range-Doppler processing method based on compressed sensing (CS), which performs sparse reconstruction in range and Doppler dimensions to achieve high resolution and reduces sidelobe without excessive computational burden. Results from numerical simulations and experimental measurements recorded with the Chinese standard digital television terrestrial broadcasting (DTTB) based PR show that the proposed method successfully handles the range-Doppler map formatting problem for PR and outperforms the existing CS-based PR processing methods.

Research on Fire Test Method of High Pressure Hydrogen Storage Cylinders for Transportation

As important equipment in the entire hydrogen industry chain, composite hydrogen storage cylinders for transportation have developed rapidly in recent years. The fire test is used to verify the explosion resistance of gas cylinders under specified fire conditions. Compared to steel gas cylinder, composite gas cylinder is more dangerous in the fire condition. The wound layer, as the main pressure-bearing structure of the composite hydrogen storage cylinder, is inflammable. In the case of fire, the mechanical properties of the cylinder will degrade quickly due to the high temperature. If the gas inside the cylinder cannot be discharged in time, the cylinder explosion will occur. Currently, some relevant standards or standard drafts have been drawn up by the international organizations, which are useful for formulating Chinese standard for hydrogen storage cylinders for transportation. The applicable scope of the standards was discussed in this paper, such as composite cylinder type, working pressure, nominal volume and design life, etc. The fire test methods of composite gas cylinders in various standards were compared and analyzed, such as experiment method, cylinder placement method, cylinder filling requirements, fuel selection, fire source setting, temperature measurement requirements, and qualified indicators, etc. Finally, the challenges for development of composite hydrogen storage cylinders and compressed hydrogen storage systems in China were proposed.

Proposal to Refine Solar Radiation of Typical Meteorological Year Database and Evaluation on the Influence of Air-Conditioning Load

The Typical meteorological year (TMY) database is often used to calculate air-conditioning loads, and it directly affects the building energy savings design. Among four kinds of TMY databases in China—including Chinese Typical Year Weather (CTYW), International Weather for Energy Calculations (IWEC), Solar Wind Energy Resource Assessment (SWERA) and Chinese Standard Weather Data (CSWD)—only CSWD is measures solar radiation, and it is most used in China. However, the solar radiation of CSWD is a measured daily value, and its hourly value is separated by models. It is found that the cloud ratio (diffuse solar radiation divided by global solar radiation) of CSWD is not realistic in months of May, June and July while compared to the other sets of TMY databases. In order to obtain a more accurate cloud ratio of CSWD for air-conditioning load calculation, this study aims to propose a method of refining the cloud ratio of CSWD in Shanghai, China, using observed solar radiation and the Perez model which is a separation model of high accuracy. In addition, the impact of cloud ratio on air-conditioning load has also been discussed in this paper. It is shown that the cloud ratio can yield a significant impact on the air conditioning load.