In recent years, increasing attention has been given to the potential supply risks of critical battery materials, such as cobalt, for electric mobility transitions. While battery technology and ...recycling advancement are two widely acknowledged strategies for addressing such supply risks, the extent to which they will relieve global and regional cobalt demand-supply imbalance remains poorly understood. Here, we address this gap by simulating historical (1998-2019) and future (2020-2050) global cobalt cycles covering both traditional and emerging end uses with regional resolution (China, the U.S., Japan, the EU, and the rest of the world). We show that cobalt-free batteries and recycling progress can indeed significantly alleviate long-term cobalt supply risks. However, the cobalt supply shortage appears inevitable in the short- to medium-term (during 2028-2033), even under the most technologically optimistic scenario. Our results reveal varying cobalt supply security levels by region and indicate the urgency of boosting primary cobalt supply to ensure global e-mobility ambitions.
The crash of an aircraft with an almost vertical attitude in Wuzhou, Guangxi, China, on 21 March 2022, has caused a robust discussion in the civil aviation community. We propose an active disturbance ...rejection controller (ADRC) for suppressing aeroelastic vibrations of a flexible aircraft at the simulation level. The ADRC has a relatively simple structure and it has been proved in several fields to provide better control than the classical proportional-integral-derivative (PID) control theory and is easier to translate from theory to practice compared with other modern control theories. In this paper, the vibration model of the flexible aircraft was built, based on the first elastic vibration mode of the aircraft. In addition, the principle of ADRC is explained in detail, a second-order ADRC was designed to control the vibration model, and the system’s closed-loop frequency domain characteristics, tracking effect and sensitivity were comprehensively analyzed. The estimation error of the extended state observer (ESO) and the anti-disturbance effect were analyzed, while the robustness of the closed-loop system was verified using the Monte Carlo method, which was used for the first time in this field. Simulation results showed that the ADRC suppressed aircraft elastic vibration better than PID controllers and that the closed-loop system was robust in the face of dynamic parameters.
Previous studies have estimated emissions from China's cement industry for some specific periods, but a trend analysis of historical emissions has not yet been carried out. Based on changes in ...clinker quality and developments in energy-saving technologies of different clinker kilns, we calculated carbon dioxide (CO2) emissions due to cement production in China for the continuous period from 1980 to 2014. Our analysis showed that total CO2 emissions from cement production in China were 1270.55 Mt in 2014, which is 18 times higher than that in 1980. There was a slight reduction in the share of emissions from fuel consumption, while the percentage of process emissions rose at a stable rate. The cement emission factor fell sharply from 852.12kg/t in 1980 to 513.15kg/t in 2014. Two scenarios were considered to predict future emissions, namely a baseline scenario (BS) and a best practice scenario (BPS). We found that CO2 emissions could be reduced to 856.62–957.91 Mt in 2020, which corresponds to a cement output of 1.86 billion tons. This implies that, by 2020, clinker and cement emission factors will fall to 789.11–840.618kg/t and 460.55–513.15kg/t, respectively. By 2020, energy efficiency improvements will be the main driver of emission reductions. Our projections also indicated that emission reductions resulting from process improvements would only account for 1.48% of total direct emissions, even under the BPS scenario. Thus, we suggest that the development of alternative industrial byproducts and fuels, substituting for natural resources, should be a main focus of future innovation efforts toward a sustainable cement industry in China.
•Historical and future emission trends for China's cement industry are addressed.•Estimated emissions derive from the input method rather than default values.•The future energy intensity of the cement industry is analyzed.•Energy efficiency improvements will be the main driver of emission reductions.
Cement production, which is highly dependent on the availability of natural resources, will face severe resource constraints in the future. This is especially true for the cement industry in China. ...Thus, the industry is focusing on reducing the consumption of natural resources at both the manufacturing and operational stages. The aim of this article is to improve the management of resources used in the cement production process and mitigate their environmental effects. First, material flow routes for the cement manufacturing process are established, after which three mass balances are built during the three production stages using actual plant data received from an existing cement manufacturing facility. Finally, the material efficiency of the units and stages as well as the waste recycle rates during these stages is calculated. The results show that approximately 2.48 t, 4.69 t, and 3.41 t of materials are required to produce a ton of the product in raw material preparation, clinker production, and cement grinding stages, and their waste rates are 63.31%, 74.12%, and 78.89%, respectively. The recycling rate of wastes during clinker production is remarkably higher than those during other manufacturing stages, wherein waste gases are directly discharged into the atmosphere. The material efficiency values for a raw mill, pyro-processing tower, rotary kiln, clink cooler, and cement mill are determined to be 36.69%, 34.24%, 39.24%, 29.76%, and 25.88%, respectively, whereas the waste recycling rates for these units are found to be 16.33%, 81.98%, 100.00%, 99.53%, and 0.00% respectively. These results will provide researchers with knowledge regarding the effectiveness and efficient use of natural resources in the cement sector. These important findings can also be used to influence the development of national and industrial policies in relation to the goal of achieving sustainable development in the cement industry.
•The material flow route for a cement plant was obtained.•Three mass balances for three cement production stages were established.•Each ton of products requires 2.48, 4.69, and 3.41 t of materials in three stages.•Waste gas recycling rate in clinker production is higher than in other stages.•Recycling waste gas discharged from raw and cement mills should be the focus.
Critical metals are indispensable to a world seeking to transition away from carbon. Yet their extraction, processing, and application leave an unsustainable global environment and climate change ...footprint. To capture the development dynamics and research emphases of critical metals throughout their life cycle, this paper adopts bibliometrics to analyze the various stages of global critical metal flow in multiple dimensions to reveal the hot issues and future strategic trends. The research results indicate that the number of research papers on critical metals is annually rising, with remarkably rapid growth after 2010. Judging from the number of articles published by the authors and the citations, among the authors, Kawakita, Poettgen, Anwander, Inoue, and Dongmei Cui have a significant influence on critical metal research fields. The institutions with the most research on critical metals are universities, not research institutes. In addition, the focus has extended from a single discipline to the interdisciplinary development of multiple disciplines. Analysis of keywords shows that “rare metals” and “precious metals” are the most popular metals among the researched metals. The researched buzzwords of critical metals are disappearing, convergent, and merging over time. The research has focused on the mining and the whole life cycle process of extraction, treatment, and application. Based on the above characteristics, this paper tries to understand the dynamic development and evolution of global critical metals from multiple dimensions, resorting to giving a reference for follow-up-related research scholars.
In China, H9N2 avian influenza virus (AIV) has become widely prevalent in poultry, causing huge economic losses after secondary infection with other pathogens. Importantly, H9N2 AIV continuously ...infects humans, and its six internal genes frequently reassort with other influenza viruses to generate novel influenza viruses that infect humans, threatening public health. Inactivated whole-virus vaccines have been used to control H9N2 AIV in China for more than 20 years, and they can alleviate clinical symptoms after immunization, greatly reducing economic losses. However, H9N2 AIVs can still be isolated from immunized chickens and have recently become the main epidemic subtype. A more effective vaccine prevention strategy might be able to address the current situation. Herein, we analyze the current status and vaccination strategy against H9N2 AIV and summarize the progress in vaccine development to provide insight for better H9N2 prevention and control.
Abstract
The identification and characterization of new β-galactosidases will provide diverse candidate enzymes for use in food processing industry. In this study, two β-galactosidases, Nf-LacZ and ...WspA1, from the terrestrial cyanobacterium
Nostoc flagelliforme
were heterologously expressed in
Escherichia coli
, followed by purification and biochemical characterization. Nf-LacZ was characterized to have an optimum activity at 40 °C and pH 6.5, different from that (45 °C and pH 8.0) of WspA1. Two enzymes had a similar Michaelis constant (
Km
= 0.5 mmol/liter) against the substrate o-nitrophenyl-β-D-galactopyranoside. Their activities could be inhibited by galactostatin bisulfite, with IC50 values of 0.59 µM for Nf-LacZ and 1.18 µM for WspA1, respectively. Gel filtration analysis suggested that the active form of WspA1 was a dimer, while Nf-LacZ was functional as a larger multimer. WspA1 was further characterized by the truncation test, and its minimum central region was found to be from residues 188 to 301, having both the glycosyl hydrolytic and transgalactosylation activities. Finally, transgenic analysis with the GFP reporter protein found that the N-terminus of WspA1 (35 aa) might play a special role in the export of WspA1 from cells. In summary, this study characterized two cyanobacterial β-galactosidases for potential applications in food industry.
Urban agriculture has been proposed as an important urban element to deal with the challenges of food insecurity and environmental deterioration. In order to track current popular topics and global ...research trends in urban agriculture, we used bibliometric analysis and visualization mapping to evaluate and analyze the developments in the knowledge of urban agriculture based on 605 papers from the core collection database Web of Science from 2001–2021. The results were as follows. (1) The number of urban agriculture publications increased substantially year by year, indicating that the field is attracting increasing attention. The University of Kassel, Chinese Academy of Sciences, and University of Freiburg are the most productive research institutions in the field of urban agriculture. The top-five most influential countries are the Unites States, Germany, the United Kingdom, Italy, and China, of which the Unites States plays a central role in the cooperative linkage between countries. (2) Research on urban agriculture focuses not only on food production and different styles but also on how to realize the various functions of urban agriculture. In addition, UA-related sustainability and the water-energy-food nexus have become two emerging research topics. (3) Urban agriculture does not necessarily mean a resource-conserving and environmentally friendly food system. To achieve sustainable development, a transition based on technological innovation is needed. How to improve the sustainable development level of the food system while fully considering the resilience, sustainability, and versatility of urban agriculture is the main direction of future research.
Cement is a primary component of concrete and is consumed extensively for construction and transportation infrastructures worldwide. Cement is largely produced and consumed locally but has global ...impact in terms of both energy consumption and greenhouse gas emissions. China is both the largest producer of cement and the biggest emitter of CO2 emissions in the world. It has been widely recognized that uncertainties of China׳s CO2 emissions were poorly quantified and clear discrepancies can be identified among different sources. These discrepancies arise from many uncertainties, including system boundary and statistical standards, availability of production data (especially for the clinker and cement outputs), and emission factors. We argue that the emission factors (EFs, either default values or adjusted ones) are the most important here and highlight the importance of clearly defining the CO2 accounting and reporting boundaries for determining the emission factors. We therefore developed a factory-level measurement for different types of clinker and cement production, primarily using onsite surveys and sampling, with the objective of distinguishing process-, combustion- and electricity-related emission factors on a factory level. It is a bottom-up CO2 emission inventory for China using the uniform formula and calculators and the first time factory-level sampling method (BFSM) based on three tiers of production lines, provincial and national integrations. Our results indicate that China׳s carbon emissions from cement production might be overestimated in the previous estimates because they overlooked the technology transition from the wet process to the dry process, differences in lime content and clinker-to-cement ratios, raw materials and fuels substitutions, and usages of blend additives.
•CO2 emission factors are critical for estimating the emissions from China׳s cement production.•The importance of clearly defining the CO2 accounting and reporting boundaries and determining of emission factors is discussed.•A large amount of onsite factory-level samples are collected and measured.•Four different types of cement production cases in China are compared.•Discrepancies of CO2 emission factors between measured data and two widely used public data are analyzed.
In the present study, a multi-step (MS) cyclic rolling and intercritcal annealing process was proposed and applied for dual-phase (DP) steel. The MS process performed three times with 27% ...deformations and intercritical annealing, while the single-step (SS) process performed an 81% rolling, along with intercritical annealing. A microstructure with an average grain size of 3 μm and a martensite content of ~40% was obtained after MS treatment, which is similar to results obtained from the SS treatment. However, the distribution exhibits significant differences between the two different routes. A more homogenous distribution of ferrite–martensite was achieved after the multi-step compared with the single-step treatment. The yield strength of MS is slightly smaller than that of SS, while the ultimate tensile strength is better, which results in a decrease in yield ratio. Furthermore, the ductility was greatly improved after MS, which is mainly attributed to the uniform chain-like distribution of martensite.
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