of the 2D structures has approached its limit (< 90%) due to which the energy loss via reflection (2-5%) and thermal radiation heat loss (8-12%) occurs in all the 2D structures.One of the effective strategies for further improving the vapor-generation efficiency is to decrease the surface temperature of the absorber by increasing the surface area within a given projection area. [22] Some unprecedented vapor-generation rates have been reported in various 3D generators, which are all beyond the input solar energy limit. [23][24][25] Here, we have found that bamboos, as a natural hierarchical cellular material, can be excellent 3D solar vapor-generation devices due to their unique structural features. By a simple carbonization progress, the bamboos maintain remarkable mechanical property. Meanwhile, the carbonized bamboo-based evaporator possesses the following advantages: 1) natural hydrophilicity; 2) numerous aligned microchannels acting as highways for rapid water transport; 3) high light absorptance in a broad spectral range; 4) reduced thermal radiation heat loss; 5) lower average temperature than environment; 6) reduced vaporization enthalpy of water confined in the bamboo mesh; 7) remarkable mechanical properties; 8) ability of salt self-cleaning; 9) good scalability and low cost. As a result, a floating carbonized bamboo sample can evaporate water with an extremely high vapor-generation rate of 3.13 kg m −2 h −1 under 1 sun illumination. It also shows superior reusability and stability for solar vapor generation, without any performance degradation after cycling 360 h. The carbonized bamboo shows favorable overall performance compared with other reported solar vapor generators and has attractive applications in desalination as well asindustrial and domestic wastewater abatement. All of these features are elucidated below in detail.Bamboo is the fastest-growing and highest-yielding hierarchical cellular material on the Earth. A typical bamboo reaches maturity within months and ultimate mechanical properties within few years, making it one of the most renewable resources. [26] Figure 1a-c shows the illustration of the design concept for a bamboo-based solar vapor-generation device. Bamboo tubes with desired height were cut from the natural bamboo and were carbonized to make it dark. The carbonized Given the global challenges of water scarcity, solar-driven vapor generation has become a renewed topic as an energy-efficient way for clean water production. Here, it is revealed that bamboo, as a natural hierarchical cellular material, can be an excellent 3D solar vapor-generation device by a simple carbonization progress. A floating carbonized bamboo sample evaporates water with an extremely high vapor-generation rate of 3.13 kg m −2 h −1 under 1 sun illumination. The high evaporation rate is achieved by the unique natural structure of bamboos. The inner wall of bamboo recovers the diffuse light energy and the thermal radiation heat loss from the 3D bamboo bottom, and the outer wall captures energy from the warmer...

Smart contract security is an emerging research area that deals with security issues arising from the execution of smart contracts in a blockchain system. Generally, a smart contract is a piece of executable code that automatically runs on the blockchain to enforce an agreement preset between parties involved in the transaction. As an innovative technology, smart contracts have been applied in various business areas, such as digital asset exchange, supply chains, crowdfunding, and intellectual property. Unfortunately, many security issues in smart contracts have been reported in the media, often leading to substantial financial losses. These security issues pose new challenges to security research because the execution environment of smart contracts is based on blockchain computing and its decentralized nature of execution. Thus far, many partial solutions have been proposed to address specific aspects of these security issues, and the trend is to develop new methods and tools to automatically detect common security vulnerabilities. However, smart contract security is systematic engineering that should be explored from a global perspective, and a comprehensive study of issues in smart contract security is urgently needed. To this end, we conduct a literature review of smart contract security from a software lifecycle perspective. We first analyze the key features of blockchain that can cause security issues in smart contracts and then summarize the common security vulnerabilities of smart contracts. To address these vulnerabilities, we examine recent advances in smart contract security spanning four development phases: 1) security design; 2) security implementation; 3) testing before deployment; and 4) monitoring and analysis. Finally, we outline emerging challenges and opportunities in smart contract security for blockchain engineers and researchers.

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Purpose The purpose of this paper is to explore how linguistic style and message substance influence persuasion in civic crowdfunding marketplaces in which written narrative pitch become a vital communication to attract private contributions to public goods and services. Drawing on the elaboration likelihood model (ELM), the authors operationalize the linguistic style of the narrative pitch as language power and message substance as issue-relevant argument quality. In this paper, the authors examine how characteristics of both style and message are related to the outcome of civic crowdfunded projects. Design/methodology/approach The data on civic crowdfunding projects were retrieved from Spacehive, the platform that dedicated mainly to civic projects ranging from community programs, social-oriented enterprises, to infrastructure or facility development. Each of the narrative samples is analyzed using a computerized text analysis package called the Linguistic Inquiry and Word Count to extract the features of the linguistic style and message substance in the narratives. The logistic regression models are estimated to assess the impact of both linguistic style and message substance on crowdfunding decisions. Findings The results show that funding outcomes can be improved with psychological language dimensions (i.e. positive affective and perceptual language). However, extensive use of social language does not help project creators to increase their chance of funding performance; but instead, such language reduces the likelihood of project success. Additionally, message substance or issue-relevant information such as money and risk language influences funding outcome. Originality/value Very few empirical studies investigated the differential effects of language style and message substance on funding performance of crowdfunding campaigns. The authors draw upon the dual process of persuasion as a theoretical base to identify a comprehensive set of linguistic style and message substance and to examine the role of such features in an emerging civic crowdfunding market. This study advances the application of the dual process in ELM by identifying and examining distinct persuasive cues originating from linguistics styles and message contents.

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