bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detectability of COVID-19 global emissions reductions in local CO2 concentration measurements
Authors: Dacre H F , Western L M , Say D , O’Doherty S , Arnold T , Rennick C , Hawkins E 
Published: August 2021

Abstract
It is estimated that global anthropogenic carbon dioxide (CO2) emissions reduced by up to 12% at the start of 2020 compared to recent years due to the COVID-19 related downturn in economic activity. Despite the large decrease in CO2 emissions, no reduction in the trend in background atmospheric CO2 concentrations has been detected. So, how long would it take for sustained COVID-19 CO2 emission reductions to be detected in daily and monthly averaged local CO2 concentration measurements? CO2 concentration measurements for five measurement sites in the UK and Ireland are combined with meteorological numerical weather prediction data to build statistical models that can predict future CO2 concentrations. It is found that

75
%

of the observed daily variability can be explained by these simple models. Emission reduction scenario experiments using these simple models illustrate that large daily and seasonal variability in local CO2 concentrations precludes the rapid emergence of a detectable signal. COVID-19 magnitude emissions reductions would only be detectable in the daily CO2 concentrations after at least 38 months and in monthly CO2 concentrations after 11 months of sustained reductions. For monthly CO2 concentrations the time of emergence is similar for all sites since the seasonal variability is largely driven by non-local fluxes of CO2 between the terrestrial biosphere and the atmosphere. The COVID-19 CO2 anthropogenic emissions reductions are similar in magnitude to those that are required to meet the Paris Agreement target of keeping global temperatures below

2
°

C. This study demonstrates that, using measurements alone, there will be a considerable lag between changes in global anthropogenic emissions and a detected signal in local CO2 concentration trends. Thus, there is likely to be a delay of several years between changes in policy designed to meet CO2 anthropogenic emissions targets and our ability to detect the impact of these policies on CO2 concentrations using atmospheric measurements alone.
Efficacy of face masks against respiratory infectious diseases: a systematic review and network analysis of randomized-controlled trials
Authors: Tran Thach Quang , Mostafa Esraa Mahmoud , Tawfik Gehad Mohamed , Soliman Mohammed , Mahabir Seshini , Mahabir Randi , Dong Vinh , Ravikulan Rohanti , Alhijazeen Suleiman , Farrag Doha Ahmed , Dumre Shyam Prakash , Huy Nguyen Tien , Hirayama Kenji 
Published: August 2021

Abstract
During the ongoing COVID-19 pandemic, face masks are among the most common and practical control measures used globally in reducing the risk of infection and disease transmission. Although several studies have investigated the efficacy of various face masks and respirators in preventing infection, the results have been inconsistent. Therefore, we performed a systematic review and network meta-analysis (NMA) of the randomized-controlled trials (RCTs) to assess the actual efficacy of face masks in preventing respiratory infections. We searched nine electronic databases up to July 2020 to find potential articles. We accepted trials reporting the protective efficacy of face masks against respiratory infections, of which the primary endpoint was the presence of respiratory infections. We used the ROB-2 Cochrane tool to grade the trial quality. We initially registered the protocol for this study in PROSPERO (CRD42020178516). Sixteen RCTs involving 17 048 individuals were included for NMA. Overall, evidence was weak, lacking statistical power due to the small number of participants, and there was substantial inconsistency in our findings. In comparison to those without face masks, participants with fit-tested N95 respirators were likely to have lesser infection risk (RR 0.67, 95% CI 0.38–1.19, P-score 0.80), followed by those with non-fit-tested N95 and non-fit-tested FFP2 respirators that shared the similar risk, (RR 0.73, 95% CI 0.12–4.36, P-score 0.63) and (RR 0.80, 95% CI 0.38–1.71, P-score 0.63), respectively. Next, participants who donned face masks with and without hand hygiene practices showed modest risk improvement alike (RR 0.89, 95% CI 0.67–1.17, P-score 0.55) and (RR 0.92, 95% CI 0.70–1.22, P-score 0.51). Otherwise, participants donning double-layered cloth masks were prone to infection (RR 4.80, 95% CI 1.42–16.27, P-score 0.01). Eleven out of 16 RCTs that underwent a pairwise meta-analysis revealed a substantially lower infection risk in those donning medical face masks (MFMs) than those without face masks (RR 0.83 95% CI 0.71–0.96). Given the body of evidence through a systematic review and meta-analyses, our findings supported the protective benefits of MFMs in reducing respiratory transmissions, and the universal mask-wearing should be applied—especially during the COVID-19 pandemic. More clinical data is required to conclude the efficiency of cloth masks; in the short term, users should not use cloth face masks in the outbreak hot spots and places where social distancing is impossible.
Exploring the potential greywater use in a typical microcosmic commercial area of South Africa
Authors: Kapata AK , Ngidi SD , Nkhonjera GK 
Published: August 2021

Abstract
With water scarcity looming, South Africa needs to be mindful of the way water is used, conserved, or disposed of. By investigating the biological and physical characteristics of grey water, this paper attempted to explore the potential use of grey water within a microcosmic commercial area. Through different methods, samples were tested for Conductivity, Temperature, pH, and Turbidity. Using IDEXX 2000 method, biological characteristics of the grey water (Total Coliform (TC) and E-coli) were tested. At a pH range of 5.8 to 9, Turbidity in the grey water was found to be between 20.1 and 814. The count for TC ranged between 6.83 ×105 – 3.255 ×109 MPN/100 ml, and that for E-coli ranged between 0.1046 ×104 and 0.7701 ×108 MPN/100 ml. The study found that high turbidity values may have serious implications on the perception of people on grey water use as a potential substitute for potable water. However, the low number of E-coli counts suggests that greywater in commercial areas of South Africa may not pose a major health risk to people compared to black water. This paper will contribute to the knowledge about grey water characteristics expected to be encountered when contemplating exploiting grey water in commercial areas around South Africa.
Genesis and petroleum geological significance of calcareous mudstone in Beier Sag
Authors: Chen Fangju 
Published: August 2021

Abstract
Beier sag is one of the most oil-rich sags in the south of Hailaer Basin in China. The purpose of the study is to clarify the identification characteristics and geological origin of calcareous mudstone strata in Nantun Formation of Beier sag, so as to provide new ideas for the identification and evaluation of high-quality source rocks, and to provide effective support for efficient exploration of oil and gas in the basin. The comparative analysis of logging curves and seismic reflection characteristics shows that the calcareous mudstone layer has the “three high and one low” logging response with high GR (Natural Gamma Ray), high LLD (Deep Investigate Induction Log), high AC (Acoustic) and low DEN (Rock Density), showing continuous and strong seismic reflection characteristics. Through the comparative analysis of experimental data of rock thin slice and microscopic image and organic geochemistry, the layer lithology is mainly gray-black mudstone, locally mixed with oil shale and marl, rich in calcium and algae. The layer has the high abundance of organic matter, good organic matter type ( II1-I ), high hydrocarbon-generating potential and high hydrocarbon-exhausting efficiency. It is the highest quality source rock found in Beier sag, and is the material base to form the large scale oil and gas accumulation. The formation of calcareous mudstone formed in the brackish water and wide lake basin by a wide range, represents the anoxic event early in Cretaceous period and is the significant stratigraphic correlation marker bed of the sag. In addition, this layer and the fan-delta front sand widely distributed in the lower part of Nantun Formation form the most favorable reservoir combination, which controls the plane distribution of oil and gas reservoirs. Above and below the calcareous mudstone strata, oil and gas are very rich.
Method of multi-objective optimal operation for combined cooling, heating, and power system
Authors: Sun Peiran , Hao Xuejun , Wang Jun 
Published: August 2021

Abstract
In order to give full play to the advantages of energy saving, high efficiency, economy, and low carbon of combined cooling, heating, and power (CCHP) system, it is necessary to seek an optimal operation mode. In this paper, a CCHP system model including energy storage equipment and ground source heat pump is established. To ensure the control accuracy, the unit commitment problem is considered in the programming. The optimal operation mode of CCHP system is obtained by taking the minimum annual operation cost, including pollutant treatment cost and the maximum primary energy utilization rate as the objective, and discussing the weight value of the above two purposes. Compared with the single objective optimization method, this optimal operation mode can provide more diversified and refined choices for the actual operation of CCHP system.
Photovoltaic grid-connected inverter based on super capacitor energy storage MMC
Authors: Sun Shuqin , Pang Xiaoyu , Zhang Xinhao , Li Gang 
Published: August 2021

Abstract
In order to improve the reliability of grid-connected operation of photovoltaic power generation systems, this paper proposes a photovoltaic grid-connected inverter based on supercapacitor energy storage MMC. Compared with traditional battery energy storage devices, the converter has the advantages of environmental friendliness, high energy storage efficiency, and long service life. The control strategy of the system is divided into three parts: carrier phase shift modulation strategy (CPS-SPWM), voltage balance control strategy and super capacitor charging control strategy. Finally, the feasibility of the proposed photovoltaic grid-connected inverter and its control strategy is verified in MATLAB/Simulink. The results show that the system can realize the photovoltaic grid-connected inverter process, realizes soft switching, and has high Energy storage efficiency.
Spectrophotometric determination of chlorophylls in different solvents related to the leaf traits of the main tree species in Northeast China
Authors: Sun Huizhen , Liu Shanshan , Chen Kangkang , Li Gaiyan 
Published: August 2021

Abstract
The accurate detection of the leaf chlorophyll (Chl) is of substantial importance for the immediate assessment of forest conditions to manage and conserve forest ecosystems. We compared 80% acetone, 95% ethanol, and dimethyl sulfoxide (DMSO) over a range of incubation times (2, 4, 6, 8, 18, 26, and 32 h) to determine the Chl contents of 12 tree species in northeast China. The results showed that to obtain the maximum Chl (a+b) contents for most tree species extracted by 80% acetone and 95% ethanol required a minimum of 18 h, while the incubation periods by DMSO were 2-6 h and 18-32 h to extract 90% of the Chl from the broadleaved and coniferous tree species, respectively. We observed that the amount of Chl extracted with DMSO was significantly higher than that extraction with 80% acetone and 95% ethanol, particularly for conifer species with the exception of Phellodendron amurense, Fraxinus mandshurica, and Tilia amurensis, in which the maximum amount of Chl was extracted with acetone. The DMSO extracted Chl in exhibited the lowest degree of variation among the three solvents. The leaf mass area (LMA), leaf thickness, and diameter of the primary leaf vein were significantly negatively correlated with the Chl a, Chl b, and Chl (a+b) content for the 12 tree species. There were non-significant different slopes or intercepts between the curves for LMA and Chl a, Chl b, or Chl (a+b) at the different incubation times for the same solvent or the different solvents at the certain incubation time (P > 0.05).
Design and realization of the supervision system for the harmless treatment of building waste based on LCA
Authors: Chen Lanyun , Wu Shuanglei , Zhao Quanwei 
Published: August 2021

Abstract
With the acceleration of our country’s urbanization and the continuous enrichment of people’s material life, it is necessary to improve the construction of urban functions. Therefore, it should demolish and rebuild existing buildings to improve the original scattered, chaotic, and poor environment, resulting in a large amount of construction waste. At present, most of the construction waste has not undergone any treatment and is disposed of in open-air storage or landfill. This treatment method not only takes up a lot of arable land and construction funds, but also increases environmental pollution, causing increasingly unbearable pressure on the social environment. For this reason, it is essential to design a monitoring system for the harmless treatment of building waste from the perspective of a long-term life cycle. The purpose of this article is to study the harmless treatment of building waste and the real-time supervision of waste. In this paper, the field survey method and questionnaire survey method are used to investigate and respond to on-site construction waste. Experimental research results show that the design of the supervision system for the harmless treatment of building waste is supported by the state, society, enterprises and citizens. Among them, the treatment of concrete in the waste is the first place, because its proportion in the waste reaches 47.8%. In order to protect the environment and follow the path of sustainable development, it is imperative to treat wastes in a harmless manner.
Sedimentary characteristics and geological significance of sublacustrine fan in the Houdomoer tectonic belt
Authors: Li Yue 
Published: August 2021

Abstract
At present, the sedimentary characteristics of the sublacustrine fans in the Houdomoer tectonic belt have not been clearly understood, which restricts further oil and gas exploration. In this research, the sedimentary characteristics of the sublacustrine fans and their oil and gas geological significance are studied based on the data of core, well logging, logging and earthquake. It is found that the sublacustrine fans in the study area can be divided into three types. The sublacustrine fan of the Houdomoer tectonic belt is located in the stratum next to the best source rock in Nantun Formation. Oil and gas are injected into the sublacustrine fan sand body from the bottom and side. Generally, oil and gas accumulation is mainly controlled by the physical characteristics of the reservoir. Experimental analysis shows that the reservoir capacity of different sedimentary microfacies is quite different. The braided channel microfacies of the middle fan is the most favorable type of reservoir facies belt, and the main channel microfacies of the inner fan is the second most favorable reservoir. The practice of oil and gas exploration also proves that the high-yield wells are mostly located in the braided channel microfacies of the middle fan. Therefore, this microfacies type has a broad exploration prospect.
Research on spatial ecological response mechanism of Hexi Corridor
Authors: Xie Xiaoling , Wei Yaqiang , Yan Xiangyu 
Published: August 2021

Abstract
This paper focuses on the ecological problems that hinder development, such as lack of water resources and desertification in the Hexi region. On the basis of the impact of urbanization in the Hexi region on the ecological environment, this paper focuses on the ecological environment response brought by the process of urbanization due to the change in the ecological land, living land and production land of Sansheng Space Structure through quantitative analysis, explores its underlying reasons and puts forward strategies to protect and upgrade the ecological environment in the process of urbanization in Hexi.
Changes of vegetation coverage in Beijing in the background of urbanization based on the data from 2000 to 2019
Authors: Zhao Linyi , Wang FanTianming , Dong Fan , Xiao Caixuan 
Published: August 2021

Abstract
With the rapid development of urbanization, high-intensity human activities in Beijing profoundly impact the changes of ecological environment, especially on vegetation coverage. Vegetation can provide a variety of ecological services for the city. Based on the data of NDVI (Normalized vegetation Index) from 2000 to 2019, the study analysed the Spatio-temporal changes of vegetation variation and land use pattern in Beijing by GIS analysis. The proportion of the significantly increased pixels of NDVI occupied 76.71% while that of the significantly decreased pixels only occupied 4.99% of the total. The significant positive trends of NDVI were concentrated in the urban core functional areas within the Fifth Ring Road and in the northern and western mountainous areas. The significant negative trends of NDVI were concentrated from the 5th Ring Road to the outside areas of the 6th Ring Road. And the gradual change of land use type is a prominent feature in significantly positive trend area. The reflection of the vegetation coverage and land use change on a large time scale in Beijing has a certain reference value for future land pattern planning and urban policy revision.
Characteristics of community domestic waste separation: separation amount, physical and chemical characteristics
Authors: Guo Hanwen , Tong Lin , Shu Tianchu , Li Xu , Bai Binjie , Nie Xiaoqin 
Published: August 2021

Abstract
With the improvement of people’s living standards and the highly progress of urban construction, the management of domestic waste has become increasingly important. To a large extent, the treatment and utilization of domestic waste depends on the physical and chemical composition of the separated waste. However, there is an insufficient research on the characteristics of community waste after mandatory classification. To fulfil the existing research gap, a community that has started with waste separation was chosen for waste generation and separation. Three ways including weighed by community residents, weighed by community cleaners and weighed by automatic electronic scale were conducted in the present study. From households, food waste contained the biggest component, 49%, while the residual waste counted for 32% and the residuals were recyclable waste. When weighed by cleaners, the average amount of separated household food waste was on the range of 0.07-0.23 kg/d/person. In addition, an automatic electronic scale was invented to realize real-time weighing, and the quality waste bin, the peak weight as well as the concentration time for separation were recorded. When compared to the generation of food waste, 6% to 56% of household food waste was separated. In addition, physical and chemical components were conducted for conducting further analysis. The results demonstrate that food waste contains a high purity with a percentage of 98.76%.
Optimization of the aluminum based compound flocculant preparation conditions and fluorine removal performance validation by response surface method
Authors: Zheng Lixiang , Xu Xufeng 
Published: August 2021

Abstract
The aluminum based compound flocculant was prepared with components such as polyaluminum chloride (PAC), calcium oxide (CaO) and polyaluminosilicate ferric oxide (PSAF) by adopting mixed and compound method. On the basis of single factor experiment, the main factors affecting the preparation of aluminum based compound flocculant were selected, and the preparation conditions were optimized through Box-Behnken design experiment and response surface analysis. The results showed that the quadratic polynomial model had significant regression, but the loss of fit term was not noticeable. The determination coefficient R2 is 0.9603, which indicated that the model had good fit. The optimum preparation condition of the aluminum based compound flocculant was as follows: the mass ratio of PAC:CaO:PSAF was 8:4:5. When the influent initial fluorine content was 4.0∼6.0mg/L, the dosage of the flocculant was 0.85mg/L, and the initial pH value was 7.5, the removal rate of fluoride ion (F−) reached 92.95%, the fluoride ion content in the supernatant was less than 1.0mg/L, and the relative error with the predicted value of the model was 2.31%. The response surface curve optimization model was reliable.
Development direction and focus of new energy industry in Jilin Province
Authors: Qu Chunyan , Guan Jie , Wang Tao 
Published: August 2021

Abstract
The choice of new energy industry is the key content of the development decision-making of urban new energy industry. Currently, the important problem to be solved in the field of industrial development in China is to adopt scientific methods to select new energy industry conforming to the national industrial adjustment and the characteristics of new energy industry, based on the the analysis of the current situation of new energy development in Jilin Province with a reference to the development rule and trend of new energy industry in developed areas in China and abroad. With the basic principle and method of group decision and fuzzy preference relationship, this paper introduces the consistency into the new energy industry selection, constructs the model of new energy industry selection, and proposes the new method of new energy industry selection. With the above methods, evaluation indexes including the industrial scale economy effect and the resources concentration degree, ability to absorb scientific and technological achievements and technological innovation, the industrial correlation effect, the social benefit, the sustainability were adopted, and the emphases and directions of new energy industry development in Jilin Province were selected.
Reservoir forming conditions and risk exploration techniques of bedrock in the central paleouplift of the northern Songliao Basin
Authors: Bai Xuefeng 
Published: August 2021

Abstract
Bedrock in the central paleouplift of the northern Songliao Basin presents favorable conditions for forming natural gas reservoirs, high-yield industrial gas was produced from the weathered crust of bedrock by risk exploration well Lp1, which means a great breakthrough in the exploration of bedrock gas reservoirs. In order to evaluate the exploration potential of bedrock gas reservoirs in the northern Songliao Basin, this paper systematically summarizes the exploration history, accumulation conditions and main controlling factors of bedrock gas reservoirs, and a set of technical methods for bedrock gas risk exploration has been established. Research results show that the major exploration breakthrough of the bedrock weathering crust proves that the bedrock in the basin has great potential for oil and gas exploration, and has strengthened the determination and confidence in the transformation of exploration ideas and the expansion of new exploration fields.