An aircraft Earth station for general aviation

While the focus has been international commercial air traffic, an opportunity exists to provide satellite communications to smaller aircraft. For these users equipment cost and weight critically impact the decision to install satellite communications equipment. Less apparent to the operator is the need for a system infrastructure that will be supported both regionally and internationally and that is compatible with the ground segment being installed for commercial aeronautical satellite communications. A system concept is described as well as a low cost terminal that are intended to satisfy the small aircraft market

Proceedings of the Fifth International Mobile Satellite Conference 1997

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments

Multiple target data-driven models to enable sustainable process manufacturing: An industrial bioprocess case study

Process manufacturing industries constantly strive to make their processes increasingly sustainable from an environmental and economic perspective. A manufacturing system model is a powerful tool to holistically evaluate various manufacturing configurations to determine the most sustainable one. Previously models of process manufacturing systems are typically single target models, trained to fit and/or predict data for a single output variable. However, process manufacturing systems produce a variety of outputs with multiple, sometimes contradictory, sustainability implications. These systems require multiple target models to find the most sustainable manufacturing configuration which considers all outputs. A novel bioprocess that treats process wastewaters to reduce pollutant load for reuse, while simultaneously generating energy in the form of biogas was studied. Multiple target models were developed to predict the percentage removal of chemical oxygen demand and total suspended solids, in addition to the biogas (as volume of methane) produced. Predictions from the models were able to reduce wastewater treatment costs by 17.0%. Eight models were developed and statistically evaluated by the coefficient of determination (R2), normalised root mean square error (nRMSE) and mean absolute percentage error (MAPE). An artificial neural network model built following the ensemble of regressor chains demonstrated the best multi target model performance, averaged across all the bioprocess’s outputs (R2 of 0.99, nRMSE of 0.02, MAPE of 1.74). The model is able to react to new regulations and legislation and/or variations in company, sector, world circumstances to provide the most up to date sustainable manufacturing configuration

Data-driven modelling for resource recovery: Data volume, variability, and visualisation for an industrial bioprocess

Advances in industrial digital technologies have led to an increasing volume of data generated from industrial bioprocesses, which can be utilised within data-driven models (DDM). However, data volume and variability complications make developing models that captures the underlying biological nature of the bioprocesses challenging. In this study, a framework for developing data-driven models of bioprocesses is proposed and evaluated by modelling an industrial bioprocess, which treats industrial or agrifood wastewaters whilst simultaneously generating bioenergy. Six models were developed to predict the reduction in chemical oxygen demand from the wastewater by the bioprocess and statistically evaluated using both testing data (randomly partitioned data from the model development) and unseen data (new data not used during the model development). The statistical error metrics employed were the coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE) and mean absolute percentage error (MAPE). The stacked neural network model was best able to model the bioprocess, having the highest accuracy on the testing data (R2: 0.98; RMSE: 1.29; MAE: 2.27; MAPE: 4.08) and the unseen data (R2: 0.82; RMSE: 2.57; MAE: 1.75; MAPE: 3.68). Data visualisation is used to observe (or confirm) whether new data points are within the model boundaries, helping to increase confidence in the model’s predictions on future data

The HOSTS survey: evidence for an extended dust disk and constraints on the presence of giant planets in the Habitable Zone of β\beta Leo

The young (50-400 Myr) A3V star $\beta$ Leo is a primary target to study the formation history and evolution of extrasolar planetary systems as one of the few stars with known hot ($\sim$1600$^\circ$K), warm ($\sim$600$^\circ$K), and cold ($\sim$120$^\circ$K) dust belt components. In this paper, we present deep mid-infrared measurements of the warm dust brightness obtained with the Large Binocular Telescope Interferometer (LBTI) as part of its exozodiacal dust survey (HOSTS). The measured excess is 0.47\%$\pm$0.050\% within the central 1.5 au, rising to 0.81\%$\pm$0.026\% within 4.5 au, outside the habitable zone of $\beta$~Leo. This dust level is 50 $\pm$ 10 times greater than in the solar system's zodiacal cloud. Poynting-Robertson drag on the cold dust detected by Spitzer and Herschel under-predicts the dust present in the habitable zone of $\beta$~Leo, suggesting an additional delivery mechanism (e.g.,~comets) or an additional belt at $\sim$5.5 au. A model of these dust components is provided which implies the absence of planets more than a few Saturn masses between $\sim$5 au and the outer belt at $\sim$40 au. We also observationally constrain giant planets with the LBTI imaging channel at 3.8~$\mu$m wavelength. Assuming an age of 50 Myr, any planet in the system between approximately 5 au to 50 au must be less than a few Jupiter masses, consistent with our dust model. Taken together, these observations showcase the deep contrasts and detection capabilities attainable by the LBTI for both warm exozodiacal dust and giant exoplanets in or near the habitable zone of nearby stars.Comment: 11 pages, 9 figures, accepted for publication in Astronomical Journa

Efficacy of the Oxygen-Charged Static Two-Layer Method for Short-Term Pancreas Preservation and Islet Isolation From Nonhuman Primate and Human Pancreata

Previous reports indicate that the two-layer method (TLM) of human pancreas preservation is superior to University of Wisconsin solution (UW) when pancreata are preserved for extended periods (i.e., \u3e24 h) prior to islet isolation. In this study, the efficacy of using the TLM for preserving pancreata for short periods (i.e., \u3c13 h) was evaluated using both nonhuman primate and human pancreata preserved with a TLM kit precharged with oxygen. An oxygen precharged TLM (static TLM) was established and compared with the original TLM with continuous oxygen supply. For the static TLM, the perfluorochemical was fully oxygenated and the oxygen supply removed prior to pancreas preservation. In the primate model, pancreata were preserved by the static TLM, the original TLM, and UW for 5 h prior to islet isolation. In the human model, pancreata were preserved with the static TLM or the original TLM or UW for 4–13 h. Both primate and human pancreata were processed by intraductal collagenase injection and digestion followed by continuous density gradient purification to isolate islets. Islets were assessed for islet yield, purity, viability, and in vitro functionality. In the primate model, islet yield, viability, and in vitro functionality were significantly improved by both the static TLM and the original TLM with similar results. Postculture islet yields were 23,877 ± 3619 IE/g in the static TLM, 21,895 ± 3742 IE/g in the original TLM, and 6773 ± 735 IE/g in UW. In the human model, both the static TLM and the original TLM significantly increased islet yield compared with UW with postculture islet yields of 2659 ± 549 IE/g in the static TLM, 2244 ± 557 IE/g in the original TLM, and 1293 ± 451 IE/g in UW. Nonhuman primate and human pancreata stored in the static TLM, immediately upon procurement, yield isolated islets of a substantially higher quantity than when pancreata are stored in UW. Thus, the use of the static TLM should replace the use of UW for storage of pancreata during transport prior to islet isolation