No abstract

No abstract

Silicon carbide (SiC) ceramic and related materials are widely used in various military and engineering fields. The emergence of additive manufacturing (AM) technologies provides a new approach for the fabrication of SiC ceramic products. This article systematically reviews the additive manufacturing technologies of SiC ceramic developed in recent years, including Indirect Additive Manufacturing (Indirect AM) and Direct Additive Manufacturing (Direct AM) technologies. This review also summarizes the key scientific and technological challenges for the additive manufacturing of SiC ceramic, and also forecasts its possible future opportunities. This paper aims to provide a helpful guidance for the additive manufacturing of SiC ceramic and other structural ceramics.

No abstract

With widely deployed WiFi network and the uniqueness feature (fingerprint) of wireless channel information, fingerprinting based WiFi positioning is currently the mainstream indoor positioning method, in which fingerprint database construction is crucial. However, for accuracy, this approach requires enough data to be sampled at many reference points, which consumes excessive efforts and time. In this paper, we collect Channel State Information (CSI) data at reference points by the method of device-free localization, then we convert collected CSI data into amplitude feature maps and extend the fingerprint database using the proposed Amplitude-Feature Deep Convolutional Generative Adversarial Network (AF-DCGAN) model. The use of AF-DCGAN accelerates convergence during the training phase, and substantially increases the diversity of the CSI amplitude feature map. The extended fingerprint database both reduces the human effort involved in fingerprint database construction and the accuracy of an indoor localization system, as demonstrated in the experiments.

No abstract

No abstract

Hardware-in-the-loop simulation Transients Transfer function a b s t r a c t Direct-fired fuel cell gas turbine hybrid power system responses to open-loop transients were evaluated using a hardware-based simulation of an integrated solid oxide fuel cell gas turbine (SOFC/GT) hybrid system, implemented through the Hybrid Performance (Hyper) facility at the U.S. Department of Energy, National Energy Technology Laboratory (NETL). A disturbance in the cathode inlet air mass flow was performed by manipulating a hot-air bypass valve implemented in the hardware component. Two tests were performed; the fuel cell stack subsystem numerical simulation model was both decoupled and fully coupled with the gas turbine hardware component. The dynamic responses of the entire SOFC/GT hybrid system were studied in this paper. The reduction of cathode airflow resulted in a sharp decrease and partial recovery of the fuel cell thermal effluent in 10 s. In contrast, the turbine rotational speed did not exhibit a similar trend. The transfer functions of several important variables in the fuel cell stack subsystem and gas turbine subsystem were developed to be used in the future control method development. The importance of the cathode airflow regulation was quantified through transfer functions. The management of cathode airflow was also suggested to be a potential strategy to increase the life of fuel cells by reducing the thermal impact of operational transients on the fuel cell subsystem.ScienceDirect j o urn al h om epa ge: www.elsev ier.com/locate/he i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 4 0 ( 2 0 1 5 ) 1 9 6 7 e1 9 7 9 http://dx.