Economic potential of bioremediation using immobilized microalgae-based microbial fuel cells

Clean Technologies and Environmental Policy - The cathodic microalgae-based MFC converts the nutrients within wastewater and produces oxygen as oxygen supply for cathodic reactions, leading to the...     

Intensifying Heat Using MOF-Isolated Graphene for Solar-Driven Seawater Desalination at 98% Solar-to-Thermal Efficiency

Photothermal materials are crucial for diverse heating applications, but it remains challenging to achieve high energy conversion efficiency due to the difficulty to concurrently improve light absorbance and suppress heat loss. Herein, a zeolitic imidazolate framework-isolated graphene (G@ZIF) nanohybrid is demonstrated that utilizes ultrathin, heat-insulating ZIF layers, and G@ZIF interfacial nanocavity to synergistically intensify light absorbance and heat localization. Under artificial sunlight illumination (≈1 kW m⁻²), the G@ZIF film attains a maximum temperature of 120 °C in an open environment with a 98% solar-to-thermal conversion efficiency. Importantly, the porous ZIF layer allows small molecules/media to enter and access the embedded hot graphene surface for targeted heat transfer in practical applications. As a proof-of-concept, the G@ZIF-based steam generator realizes 96% energy conversion from light to vapor with near-perfect desalination and water purification efficiencies (>99.9%). This design is generic and can be extended to other photothermal systems for advanced solar-thermal applications, including catalysis, water treatments, sterilization, and mechanical actuation.     

Neural network cost estimates for heart bypass surgery

This paper reports on the results of using artificial neural network (ANN) technology to estimate treatment costs of heart bypass patients based on their diagnostic condition and clinical criteria. Our applications include: (1) predicting total episode cost using clinical data; (2) a method for providing rapid feedback to assess change in total costs within a turbulent environment; and (3) a procedure for identifying activity-based cost driver candidates that would normally not surface from an analysis of accounting data. Clinical data were collected on 250 heart bypass patients at the University of Ottawa Heart Institute. The data analysed support the following conclusions: (1) clinical and diagnostic indicators obtained before surgery for individual patients can be used to estimate the total cost of their heart bypass surgery; (2) the average cost estimate error decreases as we add clinical information available during and after the surgical event; (3) the procedure used to estimate individual patient cost does not require access to accounting records; (4) the forecasting system we describe may improve exception reporting for individual patients by tracking costs and clinical criteria on a real-time basis throughout the treatment episode.     

Semantic retrieval of multimedia by concept languages: treating semantic concepts like words

This paper presents a retrieval approach that uses concept languages to deal with nonverbally expressed information in multimedia. In operation, a finite number of elecepts of a concept language are identified and used to index multimedia documents. The elecepts then allow a large number of compound semantic queries to be expressed and operated as sentences of elecepts. We believe that managing semantics by concept languages is a prudent proposition. Not only does it extend an intuitive query regime where semantic queries can be specified more expressively and extensively, the approach also allows concept detection to be restricted to a more manageable sum of semantic classes. Two example applications are discussed in the paper. One uses a color artistry language to retrieve art images and the other utilizes a tennis concept language to retrieve tennis videos     

Mobile Technology in the Classroom: What Drives Student-Lecturer Interactions?

Online learning when combined with mobile technology transforms the traditional classrooms from teacher-centered to student-centered classrooms. Despite the widespread use of mobile technology among students and educators today, limited researches have been conducted to study the effects of using mobile technology to enhance student–lecturer interactions. In addition, existing theories of technology acceptances, chiefly Information System Success Model (ISSM), Motivational Model (MM), Social Cognitive Theory (SCT), Technology Acceptance Model (TAM), and Cultural Dimension Theory (CDT) are widely recognized for their predictive power in determining adoption intentions. In this study, determinants from all five theories were unified and examined, namely system quality and information quality from ISSM, enjoyment from MM, perceived usefulness and perceived ease of use from TAM, self-efficacy from SCT, and uncertainty avoidance from CDT as predictors of adoption intention in the context of predicting student–lecturer interactions. This empirical study was conducted using an online survey. Data collected from the samples (n = 328) were analyzed using PLS-SEM. Results obtained exhibited adequate explanatory power, where information quality, system quality, enjoyment, and uncertainty avoidance significantly predict adoption intention, while perceived usefulness, perceived ease of use, and self-efficacy were insignificant. Secondly, each theory was independently analyzed, and the predictive power and relevance of ISSM, MM, TAM, and UDT confirmed the importance and relevance of these theories. Results obtained provided a comprehensive understanding of the factors that significantly affect students’ intentions to use mobile technology to interact with their lecturers on academic matters. The discussions and implications of this study are crucial for researchers and practitioners of educational technologies in higher education.     

Concurrent Synthesis of High‐Performance Monolayer Transition Metal Disulfides

To date, the chemical vapor deposition (CVD) approach has been widely used for the growth of transition metal dichalcogenides (TMDs). However, the reported CVD methods to synthesize TMDs cannot be used to grow more than one type of TMDs. This work reports a promising CVD technique to concurrently synthesize multiple monolayer transition metal disulfides once. The optoelectrical characterization and high‐resolution transmission electron microscopy show the high quality of monolayer crystals, and, more importantly, there is no mixing between different precursors during the growth process, which has been investigated by considering the gas flow dynamics and concentration distribution of precursors in our setup. This strategy indicates the promising future for the batch production of 2D materials and the concurrent synthesis techniques in standard state‐of‐the‐art complementary metal‐oxide‐semiconductor (CMOS) fabrication technology.     

Observer‐based H ∞ control on nonhomogeneous Markov jump systems with nonlinear input

This paper considers the problem of observer‐based H _∞ controller design for a class of discrete‐time nonhomogeneous Markov jump systems with nonlinear input. Actuator saturation is considered to be a nonlinear input of such system and the time‐varying transition probability matrix in the system is described as a polytope set. Furthermore, a mode‐dependent and parameter‐dependent Lyapunov function is investigated, and a sufficient condition is derived to design observer‐based controllers such that the resulting error dynamical system is stochastically stable and a prescribed H _∞ performance is achieved. Finally, estimation of attraction domain of such nonhomogeneous Markov jump systems is also made. A simulation example shows the effectiveness of developed techniques. Copyright © 2013 John Wiley & Sons, Ltd.