We evaluated the performance of trimethylamine−carbon dioxide (TMA−CO 2 ) as a potential thermolytic draw solution for engineered osmosis. Water flux and reverse solute flux with TMA−CO 2 draw solution were measured in forward osmosis (FO) and pressure retarded osmosis (PRO) modes using thin-film composite (TFC) and cellulose triacetate (CTA) FO membranes.Water flux with the TMA−CO 2 draw solution was comparable to that obtained with the more common ammonia−carbon dioxide (NH 3 −CO 2 ) thermolytic draw solution at similar (1 M) concentration. Using a TFC-FO membrane, the water fluxes produced by 1 M TMA−CO 2 and NH 3 −CO 2 draw solutions with a DI water feed were, respectively, 33.4 and 35.6 L m -2 h -1 in PRO mode and 14.5 and 15.2 L m -2 h -1 in FO mode. Reverse draw permeation of TMA−CO 2 was relatively low compared to NH 3 −CO 2 , ranging from 0.1 to 0.2 mol m -2 h -1 in all experiments, due to the larger molecular size of TMA. Thermal separation and recovery efficiency for TMA−CO 2 was compared to NH 3 −CO 2 by modeling low-temperature vacuum distillation utilizing low-grade heat sources. We also discuss possible challenges in the use TMA−CO 2 , including potential adverse impact on human health and environments. Osmosis  − = D S J k J J B k J D S J A J FO w

This quantitative research aims to compare environmental and human health impacts associated with two recycling technologies of CFRP waste. The 'baseline' recycling technology is the conventional thermolysis process via pyrolysis and the 'alternative' recycling technology is an emerging chemical treatment via solvolysis using supercritical water (SCW) to digest the thermoset matrix. Two Gate-to-Gate recycling models are developed using GaBi LCA platform. The selected functional unit (FU) is 1 kg CFRP waste and the geographical boundary of this comparative LCIA is defined to be within the U.S. The results of this comparative assessment brought to light new insights about the environmental and human health impacts of CFRP waste recycling via solvolysis using SCW and, therefore, helped close a gap in the current state of knowledge about sustainability of SCW-based solvolysis as compared to pyrolysis. Two research questions are posed to identify whether solvolysis recycling offers more environmental and human health gains relative to the conventional pyrolysis recycling. These research questions lay the basis for formulating two null hypotheses (H and H) and their associated research hypotheses (H and H). LCIA results interpretation included 'base case' scenarios, 'sensitivity studies,' and 'scenarios analysis.' The results revealed that: (a) recycling via solvolysis using SCW exhibits no gains in environmental and human health impacts relative to those impacts associated with recycling via pyrolysis and (b) use of natural gas in lieu of electricity for pyrolyzer's heating reduces the environmental and human health impacts by 37% (lowest) and up to 95.7% (highest). It is recommended that on-going experimental efforts that focus only on identifying the best solvent for solvolysis-based recycling should also consider quantification of the energy intensity as well as environmental and human health impacts of the proposed solvents.

No abstract

This research aims to perform comparative impact assessment for production of conventional aluminum alloy (AlMg3) used in aircraft fuselage and lighter weight carbon-fiber reinforced polymer (CFRP). The assessment framework is demonstrated by postulating an alternative scenario where AlMg3 in Boeing B737-800 fuselage is substituted with CFRP to reduce the fuselage weight by about 4.3 tons. OpenLCA 1.4.2 platform, including Ecoinvent v2.2 database and TRACE 2.1 for impact assessment, is used to quantify and compare impact categories of the base case (using AlMg3) and alternative scenarios. The mass ratio of carbon fiber (CF) to polypropylene (PP) matrix in CFRP is used as a sensitivity parameter and Monte Carlo sampling technique is employed to quantify assessment's uncertainties. The results identify environmental hot spots in CF production process and show that AlMg3 production has the largest global warming footprint followed by CFRP (containing 53.8 wt.% CF), then CFRP Highlights  Quantified potential benefits of replacing AlMg3 with CFRP in aircraft fuselage.  Compared impact categories for production of AlMg3 and CFRP of different CF content.  Conducted uncertainty analysis of impact categories using Monte Carlo technique.  Identified environmental hot-spot steps in PAN-based CF production process.  Proposed approaches for commercial aviation to cultivate a net positive environment.

This paper presents and in-depth analysis of All-Electric-Aircraft (AEA) architectures. The aim of this work is to provide a global vision of the current AEA state of art, to estimate main technological gaps and drivers and to identify the most promising architecture configuration for future electrical aircraft in the context of a twin propeller 20 MW aircraft. The comparison between architectures is done based on three different figures of merit: reliability, efficiency and specific power density. The methodology presented and the trade studies are applied to a narrowbody aircraft of 20 MW, equivalent to an Airbus A320, and following current efforts of government agencies to achieve cleaner air mobility within the next two decades.