Assessment of an Electrostatic Energy-Based Charge Model for Modeling the Electrostatic Interactions in Water Solvent.

The protein force field based on the restrained electrostatic potential (RESP) charges has limitations in accurately describing hydrogen bonding interactions in proteins. To address this issue, we propose an alternative approach called the electrostatic energy-based charges (EEC) model, which shows improved performance in describing electrostatic interactions (EIs) of hydrogen bonds in proteins. In this study, we further investigate the performance of the EEC model in modeling EIs in water solvent. Our findings demonstrate that the fixed EEC model can effectively reproduce the quantum mechanics/molecular mechanics (QM/MM)-calculated EIs between a water molecule and various water solvent environments. However, to achieve the same level of computational accuracy, the electrostatic potential (ESP) charge model needs to fluctuate according to the electrostatic environment. Our analysis indicates that the requirement for charge adjustments depends on the specific mathematical and physical representation of EIs as a function of the environment for deriving charges. By comparing with widely used empirical water models calibrated to reproduce experimental properties, we confirm that the performance of the EEC model in reproducing QM/MM EIs is similar to that of general purpose TIP4P-like water models such as TIP4P-Ew and TIP4P/2005. When comparing the computed 10,000 distinct EI values within the range of -40 to 0 kcal/mol with the QM/MM results calculated at the MP2/aug-cc-pVQZ/TIP3P level, we noticed that the mean unsigned error (MUE) for the EEC model is merely 0.487 kcal/mol, which is remarkably similar to the MUE values of the TIP4P-Ew (0.63 kcal/mol) and TIP4P/2005 (0.579 kcal/mol) models. However, both the RESP method and the TIP3P model exhibit a tendency to overestimate the EIs, as evidenced by their higher MUE values of 1.761 and 1.293 kcal/mol, respectively. EEC-based molecular dynamics simulations have demonstrated that, when combined with appropriate van der Waals parameters, the EEC model can closely reproduce oxygen-oxygen radial distribution function and density of water, showing a remarkable similarity to the well-established TIP4P-like empirical water models. Our results demonstrate that the EEC model has the potential to build force fields with comparable accuracy to more sophisticated empirical TIP4P-like water models.

Development of an extended STIRPAT model to assess the driving factors of household carbon dioxide emissions in China.

Although the past twenty years have witnessed China's remarkable economic development, the cost in terms of greenhouse gas emissions and a deteriorating environment has been enormous. Numerous studies have revealed the influence of household factors on household carbon dioxide emissions (HCEs) and called for a reduction of HCEs to mitigate climate change, but few have focused on assessing the most significant household driving factors of HCEs. Using statistical data between 2005 and 2019 in Jiangsu, China, this study developed an extended stochastic impact by regression on population, affluence, and technology (STIRPAT) model to assess the most significant driving factors of HCEs. The results show that the most significant driving factors are household size, total population, unemployment, and urbanisation rate. The study found that HCEs are positively impacted by household size while negatively impacted by the unemployment rate. Based on the study's findings, the following suggestions are proposed to lower HCEs: (i) establish an optimal consumption concept to guide residents towards consuming reasonably; (ii) cultivate a low-carbon concept among residents and promote low-carbon emissions living; and (iii) pay close attention to population structure factors and formulate effective measures accordingly. The study provides insightful information on the key driving factors of HCEs, which can facilitate achieving carbon emissions neutrality.

A life cycle assessment of an enterprise's low-carbon emissions model: The Xinjiang Shihezi pig farm faecal treatment biogas project as a case study.

The requirement of carbon emission reduction promotes the continuous implementation and development of low carbon emission mode in typical high-carbon industry aquaculture, especially in the resourceful treatment of terminal waste. However, the previous studies usually focus on a single process or chain, the difference between the long-chain (LC) and automated integration (AI) in the overall environmental impact needs to be quantified and standardised. This paper intends to make a comparative study on two waste treatment biogas projects of aquaculture, a typical industry with high resource consumption and pollution emission in industry and agriculture, and a typical production mode case of aquaculture. The life cycle assessment method is adopted to analyse the environmental impact intensity, identify key link materials, and put forward targeted improvement and optimization schemes. The study found the LC system's comprehensive environmental impact (CEI) is smaller, which is 59.73% less than the AI system. Biogas slurry returning to the field can effectively avoid inorganic fertilizer input. The pretreatment and storage of feces are the key stages. The key substances are NH3 and nitrogen oxides. Suggestions were put forward to optimize the manure management process. In practical pig farms, the process of dry-cleaning manure pre-treatment, automatic fermentation gas production and final biogas slurry filtration drip irrigation should be promoted.

Sustainability evaluation based on the Three-dimensional Ecological Footprint and Human Development Index: A case study on the four island regions in China.

Sustainable development emphasizes the sustainability of natural resources and the environment as well as the development of social welfare. Under the background of resource scarcity and environmental constraints, maximizing social welfare is an inevitable choice to achieve sustainable development. Ecological Wellbeing Performance (EWP) can comprehensively reflect the efficiency of natural capital conversion into social welfare, and improving EWP is a feasible measure to achieve sustainable development. Moreover, island areas are the extremely complicated ecological-social-economic systems due to the traits that are geographical isolation, scarce resources, and frequent natural disasters, so that emphasizing the sustainability of island systems is a key step for achieving sustainable development goals. This study developed the EWP model based on the improved Three-dimensional Ecological Footprint (EF) and urban-scale Human Development Index (HDI), to synthetically evaluate and analyze the sustainable development of four major island regions in China with the data in 2017. Results found that: (1) The four regions are all in ecological deficits, being in exchange for overdraft natural capital for economic development. The EFdepth is greater than the original length 1 indicating the excessive consumption of the natural capital stock. The EFsize reflects the abundance and liquidity of regional natural capital, all the four regions are with the generally low level of flow capital utilization. Hainan with highest EFsize 0.428 is due to its comparatively sparse population density, abundant resources, and strong ecological capacity, while the relatively large population density and more restricted natural capital flows make Taiwan in the lowest value. (2) Judging from the evaluation results of the HDI, Chongming (0.796) and Hainan (0.773) high development level are relatively behind Taiwan (0.912) and Zhoushan (0.827) very high development level, for the impact of income is greater, that is, economic development in Hainan and Chongming is slightly weak. (3) Taiwan, with the highest EWP 3.646, shows the excellent natural resource utilization efficiency and sustainability, followed by Zhoushan, Chongming, and Hainan. In general, increasing HDI while reducing EF can be an ideal way to improve the efficiency of ecological resources and achieve sustainable urban development.

On the Relationship between Economic Development, Environmental Integrity and Well-Being: The Point of View of Herdsmen in Northern China Grassland.

Inner Mongolia is among the most important regions in terms of contribution to the socio-economic development of China. Furthermore, its grassland is a major ecological barrier for Northern China. The present study evaluates the changes in ecosystem services availability and human wellbeing based on a survey on864 herdsmen of the grassland and 20 governmental officials. The survey provided the following results: (1) The supporting and provisioning services of the grassland have recently declined, thus affecting the herdsmen's wellbeing. The intensity of grazing, coal exploitation and tourism development heavily limits the availability of ecosystem services, among which provisioning ones are perceived as the most important. Below a certain threshold, grazing and mining are likely to promote the improvement of herdsmen's wellbeing, while trespassing that point, the enhancement of the herdsmen's living standards is curbed. (2) The herdsmen's cultural exchange, health conditions and social relations are better now than before; however, the threats on herdsmen's health and safety have increased. (3) A better income is among the most urgent herdsmen's needs. Livestock revenues did not increase at the same rate as the damage to the grassland and human risk exposure did. (4) The governmental ecological compensation policy did not entirely solve the problem of grassland desertification and environmental degradation, although it is also true that the degree of implementation and effectiveness of government policies is related to the still insufficient herdsmen's understanding and acceptance of these policies.

[National survey of urban sewage reuse in China].

On the basis of the national survey of the urban sewage treatment, the survey of 2007 national urban sewage reuse was conducted under the charge of the Ministry of Water Resources. The survey results indicated that the amount of urban sewage reuse was 17.9 x 10(8) m3 x a(-1), mainly used for industry, landscape, agriculture forestry, animal husbandry, urban non-potable water, and groundwater recharge. The urban sewage reuse rate was 5.23%. There were 127 sewage reclaiming plants in China, of which the production capacity of reclaimed water reached 347.75 x 10(4) m3 x d(-1), which produced 5.74 x 10(8) m3 reclaimed water in 2007. The total investment of sewage reclaiming plants was 56.44 x 10(8) Yuan, in which the central government investment, local fiscal investment and other investments accounted for 16%, 26% and 58%, respectively. The reclaimed water price varied greatly with the purposes or areas.