This study conducted a bibliometric analysis based on the Web of Science publications to provide insights into research activities and tendencies on seawater desalination from 1980 to 2022. A total ...of 7108 publications were retrieved and analyzed using Microsoft Excel, Vosviewer, Biblioshiny, and Biexcel software. The results indicated that the annual outputs of the related scientific articles increased following an exponential pattern with a rate constant of 0.145/year. Desalination, Desalination, and Water Treatment, Journal of Membrane Science and Water Research were the top four journals for publication. Among the countries, China took the leading rank with 1879 publications, followed by the USA, South Korea, and Saudi Arabia with 1014, 527, and 482 publications, respectively. The Chinese Academy of Sciences, Egyptian Knowledge Bank, King Abdullah University of Science Technology were the top three most productive organizations with 199, 194, and 174 publications, respectively. Wang Y from the Dalian University of Technology, China, was the most prolific author with 122 publications. The analysis reveals that China and the USA collaborated the maximum times for seawater desalination research with 122 publications. In keywords, the top three keywords were seawater desalination, desalination, and performance, with occurrences of 2919, 2124, and 1089 times respectively. The highest citations were associated with two articles published in Science and Water Research journals, with citations of 3931 and 2033, respectively. The analysis revealed that most of the research activities were associated with desalination technologies, including membrane desalination and reverse/forward osmosis.
Resource allocation, as an important issue in management science, has drawn a lot of attention from both relative researchers and corporate managers. In recent years, data envelopment analysis (DEA) ...has been popularly applied in this field. In this paper, we propose some new DEA models, which consider both economic and environmental factors in the allocation of a given resource. Three scenarios of the given resource in the next period will be considered: one is larger than that in the present period, another is smaller than that in this period and the third is equal to that in this period. Two objective functions are formulated for the three scenarios, i.e., maximizing the total desirable outputs and minimizing the total undesirable outputs. The approach retains the advantages of traditional DEA, unit-invariant property, objectively-determined weights of inputs and outputs, and perfect dealing with multi-inputs and multi-outputs. An example is also employed to illustrate the approach.
High-power narrow-linewidth continuous fiber lasers have wide applications in the fields of power synthesis, nonlinear frequency conversion, and industrial processing. The output power of kW or even ...MW can be achieved by adopting spectral synthesis. However, in the power amplification process, the nonlinear effect represented by the stimulated Brillouin scattering (SBS) effect limits the further increase of the laser power. And the accompanying self-pulsing effect poses a threat to the safety of the laser system. A high-order phase modulation scheme using a definite time sequence has been proposed to realize the controllable spectral broadening of the seed source, so as to suppress the SBS effect and improve the output power in the amplification stage. In this paper, we demonstrate a real-time definite time sequence generation scheme by using an integrated field-programmable gate array (FPGA) and digital-to-analog converter (DAC). Combined with a single-stage phase modulator, the broadened bandwidth up to 30 GHz and controllable spectral shape can be achieved by adjusting the output waveform of the DAC directly. The generation principles and waveform control methods of real-time sequence are introduced in detail. Proven by a master oscillator power amplifier (MOPA) structure, the laser output power has increased by 30% under the extended bandwidth of 10 GHz compared to the cascaded white noise modulation case. This scheme provides a compact real-time control module for spectral broadening, which lays the foundation for implementing low-cost, compact, and standardized high-power narrow-linewidth fiber lasers.
Cities are primary sites of resource consumption and pollution discharge. As a city with an urbanization rate far higher than the global average, Tianjin is facing severe resource and environmental ...problems caused by its material consumption and emission. In this study, we calculated the material flows between Tianjin and its external environment, as well as among sectors within the city, and constructed an ecological network model of the city to quantify and analyze changes in its flows from 2000 to 2015. We identified the external characteristics of the flows (size and structure of the inputs and outputs) and the internal characteristics (key nodes and ecological relationships), and their changes over time. Tianjin's material inputs and outputs were 750 and 256 Mt, respectively, in 2015 and have increased greatly since 2000. Tianjin's dependence on external inputs of metallic minerals was the city's biggest dependence. The network's key nodes were Internal Environment, Manufacturing, and Recycling, which participated most in the system's key links and must therefore be prioritized to optimize Tianjin's metabolic processes. The most important ecological relationship was exploitation/control (47.9% of all relationships), followed by mutualism (30.9%) and competition (21.2%). These proportions remained stable throughout the study period, but the proportions varied greatly among the nodes. Despite being a key node, the Manufacturing sector only had one mutualism relationship; increasing this sector's mutualism will become the key to making Tianjin's urban metabolism more sustainable. Ecological network analysis' ability to identify key nodes and ecological relationships demonstrates its ability to support efforts to regulate a city's urban material metabolism.
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•We analyzed Tianjin's inputs and outputs of materials from 2000 to 2015.•We identified key sectors based on the size and variation of the integral flows.•We identified the ecological relationships among nodes and analyzed key nodes.
With the increasing application of electrospun PVDF webs in piezoelectric sensors and energy-harvesting devices, it is crucial to understand their responses under complex mechanical excitations. ...However, the dependence of the piezoelectric effect on mechanical excitation properties is not fully comprehended. This study aims to investigate the piezoelectric output of randomly oriented electrospun PVDF nanofiber webs fabricated through different electrospinning processes at various mechanical excitation frequencies. The electrospun PVDF web was sandwiched between two textile electrodes, and its piezoelectric output as a full-textile sensor was measured across a frequency range from 0.1 Hz to 10 Hz. The experimental results revealed that the piezoelectric output of the electrospun PVDF web exhibited a nearly linear increase at excitation frequencies below 1.0 Hz and then reached an almost constant value thereafter up to 10 Hz, which is different from the hybrid PVDF or its copolymer web. Furthermore, the dependency of the piezoelectric output on the excitation frequency was found to be influenced by the specific electrospinning process employed, which determined the crystalline structure of electrospun PVDF nanofibers. These findings suggest that determining an appropriate working frequency for randomly oriented electrospun PVDF nanofiber webs is essential before practical implementation, and the piezoelectric response mode in different mechanical activation frequency ranges can be used to detect different human physiological behaviors.
During the production process of goods and services, sometimes undesirable outputs are difficult to avoid. However, this aspect is often ignored. Hospitals produce patient care, but undesirable ...outputs do arise. The novelty of this paper is to introduce the mortality as an undesirable output into the derivation of the public hospital efficiency measure. Similar to the production of economic goods and pollution where the latter increase along with the former, our description of mortality in hospital is considered as weakly disposable. Based on an extension model of Kuosmanen (2005), we evaluate the public hospital efficiency with and without incorporating mortality under four scenarios. We apply this model to measure public hospital efficiency in Chinese provinces. The results indicate that no matter whether one considers undesirable outputs within the objective functions, it has a significant impact on benchmarking once the mortality is included to define the production technology.
Sustainable development has gained significant attention in the literature due to the increased global awareness of environmental sustainability during the last decade. Sustainable development has ...three aspects, including economic, social, and environmental. The challenge of sustainable development is to establish a balance between these three aspects. Assessing the efficiency of a company contributes comprehensive information to improve its overall performance. Despite numerous studies in this field, the literature lacks studies that simultaneously consider all three aspects of sustainable development, especially the social aspect. The main objective of this paper is to calculate the technical, social, and environmental efficiency scores. We also introduce a new efficiency called sustainable efficiency that merges all three sustainable development aspects in one efficiency score. This study applies two existing data envelopment analysis (DEA) models to evaluate technical, social, environmental, and sustainable efficiencies. These models, namely the three-step method and the modified three-step method, are computationally intensive. Also, this paper introduces two new DEA models, namely the common weight goal programming DEA and the common weight DEA, to assess the efficiencies with much fewer computations. Each model produces results that are different from one another. Therefore, the TOPSIS approach is applied to provide an overall result by integrating the results obtained from the four presented models. For this purpose, the implementation of four TOPSIS models is required. To illustrate the capability and validity of the developed models in efficiency calculation, a case of Iranian airlines is presented. The selected airlines are evaluated in different aspects, and final results are obtained by applying TOPSIS. The findings show that using TOPSIS to combine the results of several DEA models leads to a fully ranking of airlines in four aspects of technical, social, environmental, and sustainable efficiencies. Also, it is recommended to managers to probe pairwise comparison between different efficiencies of airlines in order to find and improve the weak ones.
•Developing a new sensitivity index for models with multivariate outputs.•Measuring the dependence between each input variable and multiple outputs.•The MRGP surrogate model is introduced for ...computing all the sensitivity indices.•Analytical expressions are derived for the covariance decomposition based indices.
The computational models in real-world applications commonly have multivariate dependent outputs of interest, and developing global sensitivity analysis techniques, so as to measure the effect of each input variable on each output as well as their dependence structure, has become a critical task. In this paper, a new moment-independent sensitivity index is firstly developed for quantifying the effect of each input variable on the dependence structure of model outputs. Then, the multiple response Gaussian process (MRGP) surrogate model with separable covariance is introduced for efficiently estimating the existing sensitivity indices for multiple response models and the newly developed one. Some indices are analytically derived based on the hyper-parameters of the MRGP model, while others are numerically estimated. One numerical example and three engineering examples are introduced to compare the newly developed sensitivity index with the classical ones, and to demonstrate the effectiveness of the MRGP-based method in estimating these sensitivity indices.
In this article we analyse the effect of factors external and internal to the firm, on product innovation novelty, and how this effect varies by industry. We estimate three econometric models to ...determine the individual effects of these factors, their joint explanatory power and the effects of interactions among them. The analysis is based on a sample of 6094 manufacturing firms, taken from the Spanish Survey of Technological Innovation 2000. The results indicate that the firm's technological competences, derived from in-house R&D, are the main determinant of product innovation. They also suggest that in the presence of high levels of such competences, the technological opportunities deriving from non-industry agents become less important as determinants of innovation. We show that the determinants of innovation vary depending on the industrial sector and the degree of novelty of the product developed.
The dynamics of retarded shunting inhibitory cellular neural networks (SICNNs) with rectangular input currents is investigated from the asymptotic point of view. It is rigorously proved that such ...networks possess homoclinic and heteroclinic outputs under certain conditions. Illustrative examples that support the theoretical results are provided. Moreover, the extension of the homoclinical structure is numerically demonstrated for unidirectionally coupled retarded SICNNs.
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