Influence Of Secondary Factors Research Articles

Prevalence and patterns of multimorbidity in chronic diseases in Guangzhou, China: a data mining study in the residents’ health records system among 31 708 community-dwelling elderly people

ObjectivesExamination of the prevalence, influence factors and patterns of multimorbidity among the elderly people in Guangzhou, China.DesignCross-sectional study.Participants31 708 community-dwelling elderly people aged 65 and over.Primary and secondary outcome measuresPrevalence,...

Application of the MaxEnt model in improving the accuracy of ecological red line identification: A case study of Zhanjiang, China

China's Ecological protection Red Lines (ERLs) policy has proven effective in protecting ecological resources, restoring ecosystems and promoting regional ecological civilization. However, the existing methods for identifying high-value ecological conservation land are insufficiently less precise and quantitative, which affects the implementation of the ERL policy. In this study, the Maximum Entropy (MaxEnt) model was introduced into the identification work of ERLs. This paper began with an assessment of the ecological status of Zhanjiang based on the methodology for assessing Ecosystem Services (ESs) function in the “Guidelines for the Delineation of Ecological Protection Red Lines”. On this basis, the MaxEnt model was used to predict the extent of potential high-value ecological protection land through sample training and quantify the contribution of impact factors common to ecological planning work. The following conclusions were obtained: The regional ecosystem of Zhanjiang had a good function of soil and water conservation services and a poor function of windbreak and sand-fixation services. The importance of ESs was strongest in western Leizhou and the southeast coastal region of Xuwen and weakest in Wuchuan and central Xuwen. Among the contributions of influencing factors to identify high-value ecological land, natural factors were the dominant influencing factors, and anthropogenic factors were the secondary influencing factors. Meteorological factors represented by dryness made the greatest information contribution to identifying high-value ecological protection land at 42.0%, followed by surface vegetation biomass (represented by NPP) at 37.1%. The remaining impact factors contributed less than 10.0%, and the distance from the road factor contributed 0 in this prediction. The MaxEnt model, when applied to the delineation of ERLs, has been proven to be effective in improving the accuracy of identifying high-value ecological land and discovering areas with conservation value that traditional assessment methods have overlooked. It will help to provide a reasonable basis for the identification of ERLs and promote the implementation of ERL policy.

Aerosol optical characteristics in the urban area of Rome, Italy, and their impact on the UV index

Abstract. The impact of the aerosol optical properties on the ultraviolet index (UVI) in the urban area of Rome is investigated in this study. In particular, the influence of aerosol optical depth (AOD) and single scattering albedo (SSA), estimated at the wavelength of 340 nm, and of the Ångström exponent, calculated in the range 340–500 nm, over a period of 11 years (2010–2020) in the months from March to September are analyzed. The UVI is monitored by a Brewer spectrophotometer, whereas measurements of the direct Sun and diffuse sky irradiances are performed by a co-located PREDE-POM sun–sky radiometer of the ESR/SKYNET network; the aerosol optical properties are obtained by the Skyrad MRIv2 retrieval. A novel method, based on physical principles and easily adaptable to other contexts, is developed to extrapolate the aerosol properties to the UV range during periods when only visible to near-infrared measurements are available. The retrievals from the sun–sky radiometer are consistent with the chemical characterization of urban PM10 (particulate matter 10 mm or less in diameter) samples collected during an intensive field campaign held in summer 2011 at the same site (URBan Sustainability Related to Observed and Monitored Aerosol – URBS ROMA). The PM macro components identified during the campaign are grouped in order to evaluate the contribution of the main macro sources (soil, sea, secondary inorganic, organics, and traffic) whose relative role is indeed expected to strongly affect the aerosol absorption capability. The surface forcing efficiency, calculated as the change in the UV index for a unit AOD variation, shows that AOD is the primary parameter affecting the surface irradiance under clear-sky conditions in Rome. SSA and the Ångström exponent are also identified as secondary influencing factors, i.e., the surface forcing efficiency is found to be greater for smaller zenith angles and for larger and more absorbent particles in the UV range (such as, e.g., mineral dust).

Sintering and Smelting Property Investigations of Ludwigite

In this paper, orthogonal experiments are designed to study the sintering and smelting characteristics of the ludwigite ore. The predominant influencing factors of the optimal ratio, basicity and carbon content on different single sintering indexes, including the vertical sintering speed, yield rate, drum strength and low-temperature reduction pulverization index, are firstly explored by the range analysis method, and the main influencing factors on comprehensive indexes are obtained by a weighted scoring method based on different single index investigation. Considering the sintering characteristics, the primary and secondary influencing factors are: ordinary ore ratio, carbon content and basicity, and the optimal ore blending scheme is: basicity 1.7, ordinary ore blending ratio 60% and carbon content 5%. In terms of the smelting characteristics, the research obtains the order of the influencing factors on the softening start temperature, softening end temperature, softening zone, smelting start temperature, dripping temperature, smelting-dripping zone, maximum pressure difference and gas permeability index of the ludwigite sinters by simply considering various single smelting indexes. On this basis, considering the comprehensive softening-melting-dripping characteristics, the primary and secondary influencing factors are: carbon content, ordinary ore ratio and basicity, and the optimal ore blending scheme is: basicity 1.9, ordinary ore blending ratio 60% and a carbon content of 5.5%. Comprehensively, considering the sintering and smelting property of the ludwigite ore, the primary and secondary influencing factors are: carbon content, ordinary ore ratio and basicity, and the optimal ore blending scheme is: basicity 1.9, ordinary ore blending ratio 60% and a carbon content of 5.5%.

A Carbon Price Prediction Model Based on the Secondary Decomposition Algorithm and Influencing Factors

Carbon emission reduction is now a global issue, and the prediction of carbon trading market prices is an important means of reducing emissions. This paper innovatively proposes a second decomposition carbon price prediction model based on the nuclear extreme learning machine optimized by the Sparrow search algorithm and considers the structural and nonstructural influencing factors in the model. Firstly, empirical mode decomposition (EMD) is used to decompose the carbon price data and variational mode decomposition (VMD) is used to decompose Intrinsic Mode Function 1 (IMF1), and the decomposition of carbon prices is used as part of the input of the prediction model. Then, a maximum correlation minimum redundancy algorithm (mRMR) is used to preprocess the structural and nonstructural factors as another part of the input of the prediction model. After the Sparrow search algorithm (SSA) optimizes the relevant parameters of Extreme Learning Machine with Kernel (KELM), the model is used for prediction. Finally, in the empirical study, this paper selects two typical carbon trading markets in China for analysis. In the Guangdong and Hubei markets, the EMD-VMD-SSA-KELM model is superior to other models. It shows that this model has good robustness and validity.

Determining factors of cities’ centrality in the interregional innovation networks of China’s biomedical industry

This study analyzed the determinants of regions’ degree centrality as well as their variation over time in interregional innovation networks and compared the differences in factors between developed and less developed regions(core and periphery). Focusing on China’s biomedical industry, we used the prefecture-level invention co-patents data (2012–2017) to construct intercity networks and related cities’ centrality to sector-region-specific factors. We found: (1) A “convergence” process of regional embeddedness exists in innovation networks among cities. (2) The volume of national public funding for fundamental researches in the biomedical industry plays the most important role in cities’ centrality, regardless of developed or undeveloped cities. (3) For the developed cities’ centrality position, the intensity of intraregional collaboration in the biomedical industry is the secondary influencing factor, besides, other positive factors involve innovation performance, industrial market application, and cluster competitiveness, but it does not affect peripheral cities. (4) The second most influential factor in peripheral cities’ centrality is the number of biomedical firms. We concluded that despite the influence of path dependence, in the field of the analytical industry, China’s public funding for basic research has narrowed the gap in networking capability between the developed and backward cities.

Enlightenment of China’s University Teachers’ Entrepreneurial Awareness for Entrepreneurship Education

This study uses a combination of qualitative and quantitative methods to study the understanding of China’s university teachers (hereinafter referred to as teachers) on the preparation period of entrepreneurship. Through questionnaire survey, factor analysis and fuzzy evaluation, we get the classification of the factors of entrepreneurship by teachers, including education factors, social factors, and policy factors.Teachers believe that the most important primary influencing factors of entrepreneurship formation is founders’ fundamentals, the most important secondary influencing factors is social factors. In addition, the main impact of teacher entrepreneurship awareness on entrepreneurship education is as follows: in the competition and practice of entrepreneurial projects, on-campus entrepreneurial teachers mainly participate as assistants and they are quite passive. It may be because that their participation motivation is departed from the purpose of entrepreneurship. Off-campus entrepreneurship tutors focus more on the ability of the social entrepreneurial team to marketize the products or services.

Optimization Design and Internal Flow Field Study of Open‐Design Vortex Pump

To determine the influences of the main structural parameters on open‐design vortex pump performance, optimize the vortex pump performance, and reduce the running vibration and improve stability, orthogonal testing method was introduced in this paper. The selected main factors included impeller outer diameter (D2), impeller outlet width (b2), outlet setting angle of impeller (β2), and inlet setting angle of impeller (β1), and the nine types of impellers were coded according to orthogonal table. After obtaining the preliminarily optimum value range for each factor through range analysis, comprehensive analysis was employed based on the orthogonal test to investigate the main factors and identify the primary and secondary influencing factors affecting the performance of the vortex pump. An optimization scheme was obtained for further design. The results show that the numerical calculation results of the optimization scheme pump are in good agreement with the test results, and it shows the feasibility of the numerical calculation method. The testing results showed that efficiency and head of the optimal model were 4.2% and 9 m higher than those of the prototype model, respectively. Improved efficiency and head met the design requirements. The orthogonal testing method proved the feasibility of performance optimization of the vortex pump. The backflow occurs at the pump entrance and rotates in the same direction with impeller. It moves along the pipe wall from the lateral cavity to the inlet and encourters with the approaching flow.

Effect of process parameters and materials on the dimensional accuracy of FDM parts

The application of FDM technique for prototyping purposes in the industries such as aerospace and medicine has brought to attention the importance of dimensional accuracy of the manufactured models. The dimensional accuracy of FDM printed parts depends on various process parameters including layer thickness, raster width, infill pattern, etc. that influence the overall part accuracy. The purpose of this study is to make a comprehensive review of publications that investigated the effect of process parameters on the dimensional accuracy of FDM printed parts in order to understand the individual effect of each process parameter as well as to find out the optimal levels of each parameter according to the types of material. Overall 31 articles that investigated the influence of three process parameters, namely layer thickness, extrusion temperature, and part orientation were reviewed and summarized in terms of the material types that were used such as ABS, PLA, and other resins. The main findings indicating the optimal level of process parameters and the methodology of each article was summarized in the tables. The current results of the research found that the layer thickness values between 0.1 mm and 0.2 mm are preferable for ABS and PLA parts, whereas ASA and Nylon parts tend to be accurate with higher layer thickness values. Low values of extrusion temperature are found to be preferable, this parameter is also less dependent on material type. In terms of part orientation, 0° and 90° are found to be optimal levels for ABS and PLA printed parts, respectively. In addition, the optimal level of each process parameter is likely to vary with secondary factors such as the geometry of the part, resin type, and the different dimensions of the part. Therefore, it was concluded that in understanding the effect of each process parameter on the dimensional accuracy of FDM printed parts, the influence of secondary factors should also be considered and investigated.

An Evaluation System for Sustainable Urban Space Development Based in Green Urbanism Principles—A Case Study Based on the Qin-Ba Mountain Area in China

Since the 20th century, the deterioration of the ecological environment around the world has challenged urban space construction. With the development of urbanization, the consumption of resources and energy has increased, the level of biodiversity has decreased, environmental pollution is approaching the critical level, and the contradiction between human habitat activity and ecological environment has become increasingly prominent. The sustainable development of urban space along with its economic and social benefits, taking into account the quality of life and ecological environment, has become a new and important subject that needs to be explored. In this study, the indices of the evaluation system for sustainable urban spatial development in regions with underdeveloped economies but rich in ecological resources are arranged in sequence through the systematic coupling analysis of collaborative evaluation information and a quantitative analysis. The influences of urban space elements on sustainable urban development are disclosed. On the basis of the generated data, an evaluation system for sustainable urban spatial development with a complete set of information is proposed. The proposed system is applicable to urban spatial development evaluation in regions in China with underdeveloped economies but rich in ecological capital. First, the basic concept of system coupling is introduced, and a coupling relationship between urban sustainable development and urban space is proposed. Second, the elements of urban space and the sustainable development in the Qin-Ba mountain area are extracted, and the precedence diagram method is used to construct a sustainable evaluation system for urban space development in the Qin-Ba mountain area. Third, the sustainable evaluation process of urban spatial development is proposed. Finally, the sustainable evaluation system for urban spatial development in the Qin-Ba mountain area is applied to evaluate the urban spatial development in Shangluo, Qin-Ling Mountains, China. The results show that, among the investigated 14 indicators, the proportion of industrial land use mainly influences sustainable urban spatial development. As for the rest of the index factors, per capita green land area and green coverage ratio of built-up areas, per capita urban construction land area, proportion of forestry area, greening rate of built-up areas, total industrial dust emission density, proportion of cultivated area, and average volume fraction of residential areas are the secondary influencing factors of sustainable urban spatial development. The evaluation system in this research is constructed with the three aspects of “green coordination”, “green development”, and “green sustainability” of sustainable urban spatial development, and it complements the evaluation contents of urban–rural ecological space coordination, land resource protection, and green development community, and so on. The conclusion of this study not only can provide a useful reference for urban spatial development planning for underdeveloped ecological capital areas of China but also can provide a theoretical basis for the management and control policy of sustainable urban spatial development.

Specific Sensing Mechanism Investigation of Surface Acoustic Wave Humidity Sensors Coated With Uniform Graphene Oxide Membrane

Surface acoustic wave (SAW) humidity sensors promise broad prospects for Internet of Things (IoT) applications due to the advantages of low cost, portability, and high sensitivity. However, previous researches mainly focused on developing SAW devices with higher resonant frequencies, or using new sensing materials to improve the performance of SAW humidity sensors. Few researches studied the specific response mechanism of SAW humidity sensors, which restricted further development of the sensors. In this paper, the sensing mechanism of a graphene oxide (GO) film-based SAW humidity sensor is thoroughly studied by investigating the mechanical and electrical parameters of the uniform GO membrane at different relative humidity (from 10% RH to 90% RH). After taking these parameters into consideration for the mechanism analysis, we quantitatively indicate that the mass loading (~800 ppm) and viscoelastic effects (~60 ppm) are the primary and secondary influence factors of the sensor’s humidity response respectively, while the acoustoelectric interaction has little effect on the sensitivity. [2020-0024]

Analysis of the original influencing factors and secondary influencing factors of academic papers

PurposeThe influencing factors of academic papers have always been the focus of attention in the field of Scientometrics. Exploring the influencing factors of altmetrics indicators and traditional literature indicators on academic papers is beneficial to better explore the potential significance and value of academic papers in the evaluation of scientific research. The paper aims to discuss these issues.Design/methodology/approachBased on the latest JCR citation report, this paper selects 22 academic journals in the JIF Quartile Q1 journal of Information Science and Library Science, and then obtains the evaluation data of these journal papers from WOS database and Altmetric.com. This paper uses literature measurement, correlation analysis and regression analysis to explore the influencing factors of the paper.FindingsThe results show that the original influencing factors of academic papers have a significant impact on secondary influencing factors. What is more obvious is that the number of references (nr) presents a significant positive correlation with the total number of times (Z9), the number of uses (U1) and (U2).Originality/valueThis paper combines traditional literature indicators with Altmetrics indicators to study the influencing factors through primary influencing factors and secondary influencing factors. Through research, it denies the phenomenon that academic circles have published academic papers in the world in recent years to overemphasize certain factors to improve the influence of the paper.

Analysis of Geographically Anomalous 2019 Novel Coronavirus Transmission in China

Approximately in the late-December of 2019, the coronavirus disease outbreak took place in China. COVID-19 (Coronavirus Disease 2019) is contagious and detrimental to the human body, which can even lead to death. As a result, the understanding of COVID-19 has become especially important. This paper studies four cases of anomalous disease-spreading in China (Guangdong Province, Heilongjiang province, Tianjin municipality, and Guizhou province) and analyzes four influencing factors of the transmission (temperature, transportation and passenger traffic volume, household size and distribution, and awareness). Major conclusions in this paper are as follows. Transportation and passenger traffic volume and the number of larger households are positively related to the extent of disease-spreading; the degree of awareness is negatively associated with the extent of disease-spreading. Provinces, municipalities, and autonomous regions with a more urbanized distribution of households are prone to experience a greater extent of disease transmission. Although the novel coronavirus prefers colder environment, temperature appears to be a secondary influencing factor, as regions with negative temperatures have fewer diagnoses. Disease transmission in Guangdong province is caused by a high volume of passenger traffic, large and urbanized households, and low awareness. Heilongjiang province is mainly a result of high passenger traffic volume, long travelling trips, and low public awareness. Guizhou province is benefited from high awareness, limited passenger volume, and scattered households. Tianjin municipality is protected from the severe disease-spreading owe to its beneficial temperature, low land transportation volume, and high public and government awareness.

Spatial variability in soil pH and land use as the main influential factor in the red beds of the Nanxiong Basin, China.

Soil pH is the main factor affecting soil nutrient availability and chemical substances in soil. It is of great significance to study the spatial variability of soil pH for the management of soil nutrients and the prediction of soil pollution. In order to explore the causes of spatial variability in soil pH in red-bed areas, the Nanxiong Basin in south China was selected as an example, and soil pH was measured in the topsoil by nested sampling (0–20 cm depth). The spatial variability characteristics of soil pH were analyzed by geostatistics and classical statistical methods, and the main factors influencing spatial variability in soil pH are discussed. The coefficient of variation in the red-bed areas of Nanxiong Basin was 17.18%, indicating moderate variability. Geostatistical analysis showed that the spherical model is the optimal theoretical model for explaining variability in soil pH, which is influenced by both structural and random factors. Analysis of the spatial distribution and pattern showed that soil pH is relatively high in the northeast and southwest, and is lower in the northwest. These results indicate that land use patterns and topographic factors are the main and secondary influencing factors, respectively.

Study on the sensitivity of the hydraulic response characteristics of the electronic fuel injector regarding the key structural parameters

The sensitivity of key structural parameters to the hydraulic response characteristics in an electronic fuel injector is investigated. First, the hydraulic response characteristic is defined in detail (the opening/closing delay and the opening/closing time). Second, the key structural parameters influencing the hydraulic response characteristics are derived. Finally, the importance and effects of key structural parameters on hydraulic response characteristics are examined, by using the design of experiments method and the range analysis. Results show that the fuel inlet passage diameter is the primary influencing factor to the opening delay and closing delay, while the control piston diameter has the dominant effect on opening time and closing time. A small opening delay and a small opening time prefer a little fuel inlet passage diameter and control piston diameter; however, they contribute to a large closing time and closing delay. The fuel outlet passage diameter is the secondary influencing factor in opening delay, but the second factor that affects the opening time is the diameter of needle.

永定河流域官厅水库南岸典型林分土壤饱和导水率研究

PDF HTML阅读 XML下载 导出引用 引用提醒 永定河流域官厅水库南岸典型林分土壤饱和导水率研究 DOI: 10.5846/stxb201808281846 作者: 作者单位: 北京林业大学水土保持学院,北京林业大学水土保持学院,北京市园林绿化局,河北省张家口市怀来县林业和草原局,北京林业大学水土保持学院,北京林业大学水土保持学院,北京林业大学水土保持学院 作者简介: 通讯作者: 中图分类号: 基金项目: 北京市园林绿化局委托科技项目（2017HXFWSBXY006） Saturated hydraulic conductivity of soils of typical forests of the south coast of guanting reservoir in Yongding River Watershed Author: Affiliation: College of Soil and Water Conservation,Beijing Forestry University,College of Soil and Water Conservation,Beijing Forestry University,,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为研究永定河流域官厅水库南岸生态水源保护林土壤饱和导水率（Kfs）的特征，科学评价水源保护林功能，选取水源保护林典型林分与当地成林和非林地作对比，采用方差分析、相关分析和因子分析的方法研究土壤理化性质对饱和导水率的影响并根据因子得分排名探究土壤通透性最好的林分。结果表明：（1）土壤饱和导水率随土层深度增加而减小，水源保护林中混交林的饱和导水率大于纯林接近于成林，侧柏×山杏混交林的饱和导水率最高；（2）因子分析结果表明，影响饱和导水率最主要的因素为饱和含水量、容重和有机质含量；次重要因子为土壤砂粒、粉粒和粘粒含量，土壤毛管孔隙度和非毛管孔隙度对本区域饱和导水率影响不大；（3）综合因子得分排名分析，以侧柏×山杏混交林的土壤通透性最好，油松×山杏混交林次之。目前生态水源保护林对土壤通透性的改善优势明显，造林颇具成效。 Abstract:In order to explore the characteristics of saturated hydraulic conductivity (Kfs) of the soils of the south coast of Guanting Reservoir in Yongding River watershed and to assess the function of water resource protection forests scientifically, this study used typical water resource protection forest stands as study objects, which were compared with local mature forests and non-forest land. Variance analysis, correlation analysis, and factor analysis methods were applied to investigate the influence of edaphic physical and chemical properties on saturated hydraulic conductivity, and the forest stands with the best soil permeability were screened according to the score ranking of influencing factors. The results showed that:(1) Saturated hydraulic conductivity decreased as the soil depth increased. The saturated hydraulic conductivity of mixed forests of water resource protection forests was greater than that of pure forests but similar to that of mature forests, among which Platycladus orientalis and Armeniaca sibirica mixed forest had the highest Kfs value; (2) Factor analysis indicated that the primary factors affecting Kfs were saturated moisture, soil bulk density, and soil organic matter content, while the secondary influencing factors were the contents of sand, silt, and clay in soil. Soil capillary porosity and non-capillary porosity had little effects on the Kfs value; (3) According to the score ranking of the comprehensive factors, soil permeability in the P. orientalis and A. sibirica mixed forest was the best, followed by that in the mixed forest of Pinus tabuliformis and A. sibirica. The present study demonstrated that ecological water conservation forests have the superiority in improving soil permeability, and that the afforestation project has shown remarkable achievements. 参考文献 相似文献 引证文献

Orthogonal synthesis of a novel hybrid layered material containing three different zincous components and its photocatalytic property investigation

A novel hybrid layered material–Schiff Base-Zinc Complexes intercalated ZnCr-LDHs-supported ZnO–was synthesized by one-step coprecipitation method and characterized by XRD, UV–vis DRS, SEM, TEM, BET, ICP-AES and XPS analysis. The influences of the three Zn components (intercalated between the layers, supported on the surface, distributed in the host layers of the layered material) on the crystallinity and the photocatalytic activity of ZnO/ZnCr-SalenZn-LDHs for Rhodamine B (RhB) degradation were studied in detail by orthogonal design. The results showed that the percentage of the three components has a great effect on the structure and photocatalytic performance of ZnO/ZnCr-SalenZn-LDHs. The SalenZn intercalated between the layers and the Zn distributed in the layers of the layered material were the main influencing factors, and the ZnO supported on the surface of the layered material was the secondary influencing factor. The optimum initial molar ratios were SalenZn:Cr = 0.5, Zn:Cr = 3, and ZnO:Cr = 0.75, respectively, and the photocatalytic degradation efficiency of RhB reached 96.9%. In addition, a possible mechanism of photocatalysis was discussed from the perspectives of photogenerated reactive species and photoinduced carries transfer. While, the regeneration of the best photocatalytic material was also investigated in detail.

Research on the effect of Fujian free trade zone to Xiamen international shipping center

China free trade zone is an important carrier of the Belt and Road to achieve the internal and external linkage. There are four free trade zones in china. They are in Shanghai, Guangdong, Tianjin and Fujian. Fujian free trade zone supplies greater openness and favorable policies for Xiamen international shipping center, and dispenses with the formalities, reduces shipping costs, and realizes the territory of the commissioner of policies. So it will be in favor of FDI and benefited for employment-generating. It will boost the economy and increase international trade. Firstly this paper found out the influence factors of Fujian free trade zone to Xiamen international shipping center through the investigation. Then index system of these influencing factors was designed. And then the index system was designed into a questionnaire. Relevant experts filled the questionnaire. Then the main influence factors and secondary influence factors were been found. The weights of each index were got by using the method of analytic hierarchy. At last, development strategies of Xiamen international shipping center were been proposed.

Parameterization of oceanic whitecap fraction based on satellite observations

Abstract. In this study, the utility of satellite-based whitecap fraction (W) data for the prediction of sea spray aerosol (SSA) emission rates is explored. More specifically, the study aims at evaluating how an account for natural variability of whitecaps in the W parameterization would affect SSA mass flux predictions when using a sea spray source function (SSSF) based on the discrete whitecap method. The starting point is a data set containing W data for 2006 together with matching wind speed U10 and sea surface temperature (SST) T. Whitecap fraction W was estimated from observations of the ocean surface brightness temperature TB by satellite-borne radiometers at two frequencies (10 and 37 GHz). A global-scale assessment of the data set yielded approximately quadratic correlation between W and U10. A new global W(U10) parameterization was developed and used to evaluate an intrinsic correlation between W and U10 that could have been introduced while estimating W from TB. A regional-scale analysis over different seasons indicated significant differences of the coefficients of regional W(U10) relationships. The effect of SST on W is explicitly accounted for in a new W(U10, T) parameterization. The analysis of W values obtained with the new W(U10) and W(U10, T) parameterizations indicates that the influence of secondary factors on W is for the largest part embedded in the exponent of the wind speed dependence. In addition, the W(U10, T) parameterization is able to partially model the spread (or variability) of the satellite-based W data. The satellite-based parameterization W(U10, T) was applied in an SSSF to estimate the global SSA emission rate. The thus obtained SSA production rate for 2006 of 4.4 × 1012 kg year−1 is within previously reported estimates, however with distinctly different spatial distribution.

Ground settlement during tunneling in groundwater drawdown environment – Influencing factors

In this paper, the results of a parametric study on groundwater drawdown-induced surface settlement during tunneling in water-bearing ground are presented. A calibrated stress–pore pressure coupled finite element model was adopted for the parametric analysis. The results were analyzed to establish the relationships between key design issues, such as the ground surface settlement and groundwater drawdown, and influencing factors. An artificial neural network (ANN)-based sensitivity analysis was performed to obtain insight into the relative importance of the influencing factors. The results indicated that the primary influencing factors on the settlement development are the thickness and stiffness of the soil layer within the drawdown zone and the lining permeability, while the initial void ratio and the permeability of the soil layer were considered secondary influencing factors. Practical implications and findings of the study are discussed.