Abstract: In the present study, results from three different CO2 capture experimental scales (laboratory, pilot unit, and a larger pilot unit), using aqueous amine solutions of methyldiethanolamine (MDEA) 20 wt %, are compared in terms of loading capacity. All three tested scales produced results regarding CO2 absorption using MDEA aqueous solutions, which were largely in accordance with the theoretical loading capacity of the used amine. Nevertheless, the observed differences between the theoretical and actual absorption behaviors of MDEA solutions for the different scales can be justified with the relative weight that process variables exhibit when the process is scaled up. Therefore, in order to achieve a correct scale-up of the process, simulations should be performed in order to define the best set of operational parameters in order to achieve high production yields and therefore more process profitability.
Abstract: Brain-machine interfaces (BMIs) are broadly defined as systems that establish direct communications between living brain tissue and external devices, such as artificial arms. By sensing and interpreting neuronal activities to actuate an external device, BMI-based neuroprostheses hold great promise in rehabilitating motor disabled subjects, such as amputees. In this paper, we develop a control-theoretic analysis of a BMI-based neuroprosthetic system for voluntary single joint reaching task in the absence of visual feedback. Using synthetic data obtained through the simulation of an experimentally validated psycho-physiological cortical circuit model, both the Wiener filter and the Kalman filter based linear decoders are developed. We analyze the performance of both decoders in the presence and in the absence of natural proprioceptive feedback information. By performing simulations, we show that the performance of both decoders degrades significantly in the absence of the natural proprioception. To recover the performance of these decoders, we propose two problems, namely tracking the desired position trajectory and tracking the firing rate trajectory of neurons which encode the proprioception, in the model predictive control framework to design optimal artificial sensory feedback. Our results indicate that while the position trajectory based design can only recover the position and velocity trajectories, the firing rate trajectory based design can recover the performance of the motor task along with the recovery of firing rates in other cortical regions. Finally, we extend our design by incorporating a network of spiking neurons and designing artificial sensory feedback in the form of a charged balanced biphasic stimulating current.
Abstract: Plenoptic imaging is a novel optical technique for three-dimensional imaging in a single shot. It is enabled by the simultaneous measurement of both the location and the propagation direction of light in a given scene. In the standard approach, the maximum spatial and angular resolutions are inversely proportional, and so are the resolution and the maximum achievable depth of focus of the 3D image. We have recently proposed a method to overcome such fundamental limits by combining plenoptic imaging with an intriguing correlation remote-imaging technique: ghost imaging. Here, we theoretically demonstrate that correlation plenoptic imaging can be effectively achieved by exploiting the position-momentum entanglement characterizing spontaneous parametric down-conversion (SPDC) photon pairs. As a proof-of-principle demonstration, we shall show that correlation plenoptic imaging with entangled photons may enable the refocusing of an out-of-focus image at the same depth of focus of a standard plenoptic device, but without sacrificing diffraction-limited image resolution.
Abstract: The major barrier for optical quantum information technologies is the absence of reliable single photons sources providing non-classical light states on demand which can be easily and reliably integrated with standard processing protocols for quantum device fabrication. New methods of generation at room temperature of single photons are therefore needed. Heralded single photon sources are presently being sought based on different methods built on different materials. Silicon Carbide (SiC) has the potentials to serve as the preferred material for quantum applications. Here, we review the latest advances in single photon generation at room temperatures based on SiC.
Abstract: CO2 captured from fossil-fueled power generation plants is said to be economically transported via pipelines over long distances. The CO2 must be compressed to pipeline specifications using compressors and pumps that are driven by gas turbine (GT) or other prime movers. This paper presents the evaluation of actual work transfer or required prime power by modeling the governing equations of compression using the Peng–Robinson equation of state (PR-EOS). A computer code was developed to carry out the modeling and subsequent simulation of the compression power requirement. The simulation of prime mover power was carried out for different technology (head per stage) of the compressor ranging from 10-staged compression to double stage compression. The results show that the current technology of the centrifugal compressor could require as much as 23MW of prime mover power to compress 1.5 million tonnes per year of CO2—a projected equivalent CO2 released from a 530MW combined cycle gas turbine (CCGT) power generation plant.
Abstract: Membrane gas separation for carbon capture has traditionally been focused on high pressure applications, such as pre-combustion capture and natural gas sweetening. Recently a membrane-cryogenic combined process has been shown to be cost competitive for post-combustion capture from coal fired power stations. Here, the membrane-cryogenic combined process is investigated for application to post-combustion carbon capture from the flue gas of a Natural Gas Combined Cycle (NGCC) process. This process involves a three-membrane process, where the combustion air is used as the sweep gas on the second membrane stage to recycle CO2 through the turbine. This ensures high CO2 recovery and also increases the CO2 partial pressure in the flue gas. The three-CO2-selective membrane process with liquefaction and O2-enrichment was found to have a cost of capture higher than the corresponding process for coal post-combustion capture. This was attributed to the large size and energy duty of the gas handling equipment, especially the feed blower, because of the high gas throughput in the system caused by significant CO2 recycling. In addition, the economics were uncompetitive compared to a modelled solvent absorption processes for NGCC.