Tunghai University

Large-area MoS(2) atomic layers are synthesized on SiO(2) substrates by chemical vapor deposition using MoO(3) and S powders as the reactants. Optical, microscopic and electrical measurements suggest that the synthetic process leads to the growth of MoS(2) monolayer. The TEM images verify that the synthesized MoS(2) sheets are highly crystalline.

The development of biofuels has been considered as an important countermeasure to abate anthropogenic CO2 emissions, suppress deteriorated atmospheric greenhouse effect, and mitigate global warming. To produce biofuels from biomass, thermochemical conversion processes are considered as the most efficient routes wherein torrefaction has the lowest global warming potential. Combustion is the easiest way to consume biomass, which can be burned alone or co-fired with coal to generate heat and power. However, solid biomass fuels are not commonly applied in the industry due to their characteristics of hygroscopic nature and high moisture content, low bulk density and calorific value, poor grindability, low compositional homogeneity, and lower resistance against biological degradation. In recently developing biomass conversion technologies, torrefaction has attracted much attention since it can effectively upgrade solid biomass and produce coal-like fuel. Torrefaction is categorized into dry and wet torrefaction; the former can further be split into non-oxidative and oxidative torrefaction. Despite numerous methods developed, non-oxidative torrefaction, normally termed torrefaction, has a higher potential for practical applications and commercialization when compared to other methods. To provide a comprehensive review of the progress in biomass torrefaction technologies, this study aims to perform an in-depth literature survey of torrefaction principles, processes, systems, and to identify a current trend in practical torrefaction development and environmental performance. Moreover, the encountered challenges and perspectives from torrefaction development are underlined. This state-of-the-art review is conducive to the production and applications of biochar for resource utilization and environmental sustainability. To date, several kinds of reactors have been developed, while there is still no obviously preferred one as they simultaneously have pros and cons. Integrating torrefaction with other processes such as co-firing, gasification, pyrolysis, and ironmaking, etc., makes it more efficient and economically feasible in contrast to using a single process. By virtue of capturing carbon dioxide during the growth stage of biomass, negative carbon emissions can even be achieved from torrefied biomass.

The classical environmental control model assumes that species distribution is determined by the spatial variation of underlying habitat conditions. This niche‐based model has recently been challenged by the neutral theory of biodiversity which assumes that ecological drift is a key process regulating species coexistence. Understanding the mechanisms that maintain biodiversity in communities critically depends on our ability to decompose the variation of diversity into the contributions of different processes affecting it. Here we investigated the effects of pure habitat, pure spatial, and spatially structured habitat processes on the distributions of species richness and species composition in a recently established 24‐ha stem‐mapping plot in the subtropical evergreen broad‐leaved forest of Gutianshan National Nature Reserve in East China. We used the new spatial analysis method of principal coordinates of neighbor matrices (PCNM) to disentangle the contributions of these processes. The results showed that (1) habitat and space jointly explained ∼53% of the variation in richness and ∼65% of the variation in species composition, depending on the scale (sampling unit size); (2) tree diversity (richness and composition) in the Gutianshan forest was dominantly controlled by spatially structured habitat (24%) and habitat‐independent spatial component (29%); the spatially independent habitat contributed a negligible effect (6%); (3) distributions of richness and species composition were strongly affected by altitude and terrain convexity, while the effects of slope and aspect were weak; (4) the spatial distribution of diversity in the forest was dominated by broad‐scaled spatial variation; (5) environmental control on the one hand and unexplained spatial variation on the other (unmeasured environmental variables and neutral processes) corresponded to spatial structures with different scales in the Gutianshan forest plot; and (6) five habitat types were recognized; a few species were statistically significant indicators of three of these habitats, whereas two habitats had no significant indicator species. The results suggest that the diversity of the forest is equally governed by environmental control (30%) and neutral processes (29%). In the fine‐scale analysis (10 × 10 m cells), neutral processes dominated (43%) over environmental control (20%).

Abstract Recently, interest in aluminium ion batteries with aluminium anodes, graphite cathodes and ionic liquid electrolytes has increased; however, much remains to be done to increase the cathode capacity and to understand details of the anion–graphite intercalation mechanism. Here, an aluminium ion battery cell made using pristine natural graphite flakes achieves a specific capacity of ∼110 mAh g −1 with Coulombic efficiency ∼98%, at a current density of 99 mA g −1 (0.9 C) with clear discharge voltage plateaus (2.25–2.0 V and 1.9–1.5 V). The cell has a capacity of 60 mAh g −1 at 6 C, over 6,000 cycles with Coulombic efficiency ∼ 99%. Raman spectroscopy shows two different intercalation processes involving chloroaluminate anions at the two discharging plateaus, while C–Cl bonding on the surface, or edges of natural graphite, is found using X-ray absorption spectroscopy. Finally, theoretical calculations are employed to investigate the intercalation behaviour of choloraluminate anions in the graphite electrode.

Abstract Aim To examine the contribution of large‐diameter trees to biomass, stand structure, and species richness across forest biomes. Location Global. Time period Early 21st century. Major taxa studied Woody plants. Methods We examined the contribution of large trees to forest density, richness and biomass using a global network of 48 large (from 2 to 60 ha) forest plots representing 5,601,473 stems across 9,298 species and 210 plant families. This contribution was assessed using three metrics: the largest 1% of trees ≥ 1 cm diameter at breast height (DBH), all trees ≥ 60 cm DBH, and those rank‐ordered largest trees that cumulatively comprise 50% of forest biomass. Results Averaged across these 48 forest plots, the largest 1% of trees ≥ 1 cm DBH comprised 50% of aboveground live biomass, with hectare‐scale standard deviation of 26%. Trees ≥ 60 cm DBH comprised 41% of aboveground live tree biomass. The size of the largest trees correlated with total forest biomass ( r 2 = .62, p < .001). Large‐diameter trees in high biomass forests represented far fewer species relative to overall forest richness ( r 2 = .45, p < .001). Forests with more diverse large‐diameter tree communities were comprised of smaller trees ( r 2 = .33, p < .001). Lower large‐diameter richness was associated with large‐diameter trees being individuals of more common species ( r 2 = .17, p = .002). The concentration of biomass in the largest 1% of trees declined with increasing absolute latitude ( r 2 = .46, p < .001), as did forest density ( r 2 = .31, p < .001). Forest structural complexity increased with increasing absolute latitude ( r 2 = .26, p < .001). Main conclusions Because large‐diameter trees constitute roughly half of the mature forest biomass worldwide, their dynamics and sensitivities to environmental change represent potentially large controls on global forest carbon cycling. We recommend managing forests for conservation of existing large‐diameter trees or those that can soon reach large diameters as a simple way to conserve and potentially enhance ecosystem services.

The objective of this study was to test Ting-Toomey's (1988a) theory on conflict face-negotiation. More specifically, the study examined the relationship between face maintenance dimensions and conflict styles in Japan, China, South Korea, Taiwan, and the United States. The results were summarized as follows: (1) Cultural variability of individualism-collectivism influences two face maintenance dimensions—self-face concern and other-face concern; (2) Cultural variability influences conflict styles, with U.S. members using a higher degree of dominating conflict style than their Japanese and Korean cohorts, and the Chinese and Taiwanese members using a higher degree of obliging and avoiding conflict management styles than their U.S. counterparts; (3) Overall, face maintenance dimensions served as better predictors to conflict styles rather than conflict styles to face dimensions; (4) Self-face maintenance was associated strongly with dominating conflict style, and other-face maintenance was associated strongly with avoiding, integrating, and compromising styles of conflict management. Directions for future testing of the conflict face-negotiation theory were proffered.

Biofuel has emerged as an alternative source of energy to reduce the emissions of greenhouse gases in the atmosphere and combat global warming. Biofuels are classified into first, second, third and fourth generations. Each of the biofuel generations aims to meet the global energy demand while minimizing environmental impacts. Sustainability is defined as meeting the needs of the current generations without jeopardizing the needs of future generations. The aim of sustainability is to ensure continuous growth of the economy while protecting the environment and societal needs. Thus, this paper aims to evaluate the sustainability of these four generations of biofuels. The objectives are to compare the production of biofuel, the net greenhouse gases emissions, and energy efficiency. This study is important in providing information for the policymakers and researchers in the decision-making for the future development of green energy. Each of the biofuel generations shows different benefits and drawbacks. From this study, we conclude that the first generation biofuel has the highest biofuel production and energy efficiency, but is less effective in meeting the goal of reducing the greenhouse gases emission. The third generation biofuel shows the lowest net greenhouse gases emissions, allowing the reduction of greenhouse gases in the atmosphere. However, the energy required for the processing of the third generation biofuel is higher and, this makes it less environmentally friendly as fossil fuels are used to generate electricity. The third and fourth generation feedstocks are the potential sustainable source for the future production of biofuel. However, more studies need to be done to find an alternative low cost for biofuel production while increasing energy efficiency.

The Ni3S2 nanoparticles with the diameters ranging from 10 to 80 nm are grown on the backbone of conductive multiwalled carbon nanotubes (MWCNTs) using a glucose-assisted hydrothermal method. It is found that the Ni3S2 nanoparticles deposited on MWCNTs disassemble into smaller components after the composite electrode is activated by the consecutive cyclic voltammetry scan in a 2 M KOH solution. Therefore, the active surface area of the Ni3S2 nanoparticles is increased, which further enhances the capacitive performance of the composite electrode. Because the synergistic effect of the Ni3S2 nanoparticles and MWCNTs on the capacitive performance of the composite electrode is pronounced, the composite electrode shows a high specific capacitance of 800 F/g and great cycling stability at a current density of 3.2 A/g. To examine the capacitive performance of the composite electrode in a full-cell configuration, an asymmetric supercapacitor device was fabricated by using the composite of Ni3S2 and MWCNTs as the cathode and activated carbon as the anode. The fabricated device can be operated reversibly between 0 and 1.6 V, and obtain a high specific capacitance of 55.8 F/g at 1 A/g, which delivers a maximum energy density of 19.8 Wh/kg at a power density of 798 W/kg. Furthermore, the asymmetric supercapacitor shows great stability based on the fact that the device retains 90% of its initial capacitance after a consecutive 5000 cycles of galvanostatic charge-discharge performed at a current density of 4 A/g.

Global issues such as environmental problems and food security are currently of concern to all of us. Circular bioeconomy is a promising approach towards resolving these global issues. The production of bioenergy and biomaterials can sustain the energy-environment nexus as well as substitute the devoid of petroleum as the production feedstock, thereby contributing to a cleaner and low carbon environment. In addition, assimilation of waste into bioprocesses for the production of useful products and metabolites lead towards a sustainable circular bioeconomy. This review aims to highlight the waste biorefinery as a sustainable bio-based circular economy, and, therefore, promoting a greener environment. Several case studies on the bioprocesses utilising waste for biopolymers and bio-lipids production as well as bioprocesses incorporated with wastewater treatment are well discussed. The strategy of waste biorefinery integrated with circular bioeconomy in the perspectives of unravelling the global issues can help to tackle carbon management and greenhouse gas emissions. A waste biorefinery-circular bioeconomy strategy represents a low carbon economy by reducing greenhouse gases footprint, and holds great prospects for a sustainable and greener world.

On 1 March 2019, the United Nations (UN) General Assembly (New York) declared 2021–2030 the “UN Decade on Ecosystem Restoration.” This call to action has the purpose of recognizing the need to massively accelerate global restoration of degraded ecosystems, to fight the climate heating crisis, enhance food security, provide clean water and protect biodiversity on the planet. The scale of restoration will be key; for example, the Bonn Challenge has the goal to restore 350 million km2 (almost the size of India) of degraded terrestrial ecosystems by 2030. However, international support for restoration of “blue” coastal ecosystems, which provide an impressive array of benefits to people, has lagged. Only the Global Mangrove Alliance (https://mangrovealliance.org/) comes close to the Bonn Challenge, with the aim of increasing the global area of mangroves by 20% by 2030. However, mangrove scientists have reservations about this target, voicing concerns that it is unrealistic and may prompt inappropriate practices in attempting to reach this target (Lee et al., 2019). The decade of ecosystem restoration declaration also coincides with the UN Decade of Ocean Science for Sustainable Development, which aims to reverse deterioration in ocean health. If executed in a holistic and coordinated manner, signatory nations could stand to deliver on both these UN calls to action.

Summary The relationship between species richness and ecosystem function, as measured by productivity or biomass, is of long‐standing theoretical and practical interest in ecology. This is especially true for forests, which represent a majority of global biomass, productivity and biodiversity. Here, we conduct an analysis of relationships between tree species richness, biomass and productivity in 25 forest plots of area 8–50 ha from across the world. The data were collected using standardized protocols, obviating the need to correct for methodological differences that plague many studies on this topic. We found that at very small spatial grains (0.04 ha) species richness was generally positively related to productivity and biomass within plots, with a doubling of species richness corresponding to an average 48% increase in productivity and 53% increase in biomass. At larger spatial grains (0.25 ha, 1 ha), results were mixed, with negative relationships becoming more common. The results were qualitatively similar but much weaker when we controlled for stem density: at the 0.04 ha spatial grain, a doubling of species richness corresponded to a 5% increase in productivity and 7% increase in biomass. Productivity and biomass were themselves almost always positively related at all spatial grains. Synthesis . This is the first cross‐site study of the effect of tree species richness on forest biomass and productivity that systematically varies spatial grain within a controlled methodology. The scale‐dependent results are consistent with theoretical models in which sampling effects and niche complementarity dominate at small scales, while environmental gradients drive patterns at large scales. Our study shows that the relationship of tree species richness with biomass and productivity changes qualitatively when moving from scales typical of forest surveys (0.04 ha) to slightly larger scales (0.25 and 1 ha). This needs to be recognized in forest conservation policy and management.

The theory of metabolic ecology predicts specific relationships among tree stem diameter, biomass, height, growth and mortality. As demographic rates are important to estimates of carbon fluxes in forests, this theory might offer important insights into the global carbon budget, and deserves careful assessment. We assembled data from 10 old-growth tropical forests encompassing censuses of 367 ha and > 1.7 million trees to test the theory's predictions. We also developed a set of alternative predictions that retained some assumptions of metabolic ecology while also considering how availability of a key limiting resource, light, changes with tree size. Our results show that there are no universal scaling relationships of growth or mortality with size among trees in tropical forests. Observed patterns were consistent with our alternative model in the one site where we had the data necessary to evaluate it, and were inconsistent with the predictions of metabolic ecology in all forests.

A 3D graphitic foam vertically aligned graphitic structure and a low density of defects is derived through chloroaluminate anion intercalation of graphite followed by thermal expansion and electrochemical hydrogen evolution. Such aligned graphitic structure affords excellent Al-ion battery characteristics with a discharge capacity of ≈60 mA h g−1 under a high charge and discharge current density of 12 000 mA g−1 over ≈4000 cycles. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Purpose The relationship between online reviews and purchase intention has been studied in previous research. However, there was little knowledge about the effect of information quality and the social presence of online reviews on purchase intention based on the stimulus-organism-response ( S - O - R ) framework. The purpose of this study is to explore the intrinsic relationship between the stimulus (perceived information quality and social presence) generated from online reviews and the response (purchase intention). Design/methodology/approach This study developed a research model by applying the S - O - R framework to test the proposed hypotheses. A combination of a web-based experiment and an online survey was employed to collect data. Hypotheses were empirically tested using Smart PLS. Findings The PLS analysis shows that both perceived information quality and the social presence of online reviews positively affect trust. Moreover, satisfaction with online reviews affects purchase intention, whereas trust has a positive impact on satisfaction, playing a mediating role between two stimuli and satisfaction. Besides, perceived information quality of positive online reviews is found to have a more significant impact on trust, satisfaction and purchase intention. Originality/value The results of this study are of great value for expanding both theoretical research and practical applications of online reviews in relation to purchase intention. This study with a new research model reveals the understanding of how the purchase intention will be motivated by online reviews. Meanwhile, the moderating effects and the mediating effects are also discussed.

Theory predicts that higher biodiversity in the tropics is maintained by specialized interactions among plants and their natural enemies that result in conspecific negative density dependence (CNDD). By using more than 3000 species and nearly 2.4 million trees across 24 forest plots worldwide, we show that global patterns in tree species diversity reflect not only stronger CNDD at tropical versus temperate latitudes but also a latitudinal shift in the relationship between CNDD and species abundance. CNDD was stronger for rare species at tropical versus temperate latitudes, potentially causing the persistence of greater numbers of rare species in the tropics. Our study reveals fundamental differences in the nature of local-scale biotic interactions that contribute to the maintenance of species diversity across temperate and tropical communities.

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper proposes a reconfiguration methodology based on an Ant Colony Algorithm (ACA) that aims at achieving the minimum power loss and increment load balance factor of radial distribution networks with distributed generators. A 33-bus distribution system and a Tai-Power 11.4-kV distribution system were selected for optimizing the configuration and to demonstrate the effectiveness of the proposed methodology for solving the optimal switching operation of distribution systems. The simulation results have shown that lower system loss and better load balancing will be attained at a distribution system with distributed generation (DG) compared to a system without DG. Furthermore, the simulation results also satisfy and suitability reference merits of the proposal method. </para>

Anthropogenic climate change, principally induced by the large volume of carbon dioxide emission from the global economy driven by fossil fuels, has been observed and scientifically proven as a major threat to civilization. Meanwhile, fossil fuel depletion has been identified as a future challenge. Lignocellulosic biomass in the form of organic residues appears to be the most promising option as renewable feedstock for the generation of energy and platform chemicals. As of today, relatively little bioenergy comes from lignocellulosic biomass as compared to feedstock such as starch and sugarcane, primarily due to high cost of production involving pretreatment steps required to fragment biomass components via disruption of the natural recalcitrant structure of these rigid polymers; low efficiency of enzymatic hydrolysis of refractory feedstock presents a major challenge. The valorization of lignin and cellulose into energy products or chemical products is contingent on the effectiveness of selective depolymerization of the pretreatment regime which typically involve harsh pyrolytic and solvothermal processes assisted by corrosive acids or alkaline reagents. These unselective methods decompose lignin into many products that may not be energetically or chemically valuable, or even biologically inhibitory. Exploring milder, selective and greener processes, therefore, has become a critical subject of study for the valorization of these materials in the last decade. Efficient alternative activation processes such as microwave- and ultrasound irradiation are being explored as replacements for pyrolysis and hydrothermolysis, while milder options such as advanced oxidative and catalytic processes should be considered as choices to harsher acid and alkaline processes. Herein, we critically abridge the research on chemical oxidative techniques for the pretreatment of lignocellulosics with the explicit aim to rationalize the objectives of the biomass pretreatment step and the problems associated with the conventional processes. The mechanisms of reaction pathways, selectivity and efficiency of end-products obtained using greener processes such as ozonolysis, photocatalysis, oxidative catalysis, electrochemical oxidation, and Fenton or Fenton-like reactions, as applied to depolymerization of lignocellulosic biomass are summarized with deliberation on future prospects of biorefineries with greener pretreatment processes in the context of the life cycle assessment.

Cycle-life of the particulate electrode of Si, either with or without carbon coating, for Li-ion battery has significantly been improved by using a modified elastomeric binder containing styrene-butadiene-rubber (SBR) and sodium-carboxyl-methyl-cellulose (SCMC). Compared with poly-vinylidene-fluoride (PVdF), the mixture binder shows smaller moduli, a larger maximum elongation, a stronger adhesion strength on Cu current collector, and much smaller solvent-absorption in organic carbonate. There were demonstrated cycle lives of for bare Si at 600 mAh/g or carbon-coated Si at 1000 mAh/g, as contrast to for PVdF-bound electrode in all cases. © 2004 The Electrochemical Society. All rights reserved.

During the past few years, severe air-pollution problem has garnered worldwide attention due to its effect on health and wellbeing of individuals. As a result, the analysis and prediction of air pollution has attracted a good deal of interest among researchers. The research areas include traditional machine learning, neural networks and deep learning. How to effectively and accurately predict air pollution becomes an important issue. In this paper, we propose an Aggregated LSTM (Long Short-Term Memory) model (ALSTM) based on the LSTM deep learning method. In this new model, we combine local air quality monitoring station, the station in nearby industrial areas, and the stations for external pollution sources. To improve prediction accuracy, we aggregate three LSTM models into a predictive model for early predictions based on external sources of pollution and information from nearby industrial air quality stations. We exploited the data with 17 attributes collected by Taiwan Environmental Protection Agency from 2012 to 2017 as the training data to build the ALSTM forecasting model, and we tested the model using the data collected in 2018. We conducted some experiments to compare our new ALSTM model with SVR (Support Vector Machine based Regression), GBTR (Gradient Boosted Tree Regression), LSTM, etc., in the prediction of PM2.5 for 1–8 h, and evaluated them using various assessment techniques, such as MAE, RMSE, and MAPE. The results reveal that the proposed aggregated model can effectively improve the accuracy of prediction.

Lignocellulosic biomass has been recognized as promising feedstock for biofuels production. However, the high cost of pretreatment is one of the major challenges hindering large-scale production of biofuels from these abundant, indigenously-available, and economic feedstock. In addition to high capital and operation cost, high water consumption is also regarded as a challenge unfavorably affecting the pretreatment performance. In the present review, advances in lignocellulose pretreatment technologies for biofuels production are reviewed and critically discussed. Moreover, the challenges faced and future research needs are addressed especially in optimization of operating parameters and assessment of total cost of biofuel production from lignocellulose biomass at large scale by using different pretreatment methods. Such information would pave the way for industrial-scale lignocellulosic biofuels production. Overall, it is important to ensure that throughout lignocellulosic bioethanol production processes, favorable features such as maximal energy saving, waste recycling, wastewater recycling, recovery of materials, and biorefinery approach are considered.