Abbas S. Milani’s research while affiliated with University of British Columbia and other places

Advanced treatment options of cerebral aneurysms (CAs), in particular percutaneous treatment, are gaining fast attention by researchers and practitioners. The eCLIPs implant (product of Evasc Neurovascular Enterprises, Vancouver, Canada) has recently revolutionized the percutaneous treatment of CAs by offering innovative solutions to the challenges pertinent to other neurovascular devices, i.e. excessive vessel injury caused by device and artery interaction and blocking the daughter vessels in bifurcation cases. However, in a subset of CAs at the bifurcation location with fusiform pathology, eCLIPs fails to provide sufficient neck bridging, where a gap exists between the device structure and the aneurysm/artery wall upon device deployment. We have proposed an innovative solution for this problem by developing a new design for the eCLIPs (VR-e) by making the length of device ribs variable to cover such an inflow gap. We have developed a new computational framework to optimize the new product development process and evaluate the device behavior during crimping into a catheter and expansion at the aneurysm neck, which is not possible by testing a new device for the endovascular application experimentally. In spite of the longer rib span in the VR-e over eCLIPs, the device structure has not experienced plastic deformation during the crimping process. The VR-e device fully expanded and covered the inflow gap when deployed at the neck.

Among different types of Fiber Reinforced Polymer (FRP) composites, the conventional Glass Fiber Reinforced Polymers (GFRPs), along with the emerging natural fiber replacement options, have attracted widespread attention in different manufacturing sectors. Despite their light weight and high specific strength and stiffness, the long-term durability of these composites remains a gray area, often forcing designers to incorporate large safety factors to account for uncertainties in estimating aging limits. This manuscript aims to provide a review of the fundamentals and case studies on natural and accelerated weathering degradation processes of GFRPs and select Natural Fiber Reinforced Polymers (NFRPs) that involve climatic exposure. Main degradation agents considered range from tap water, moisture, UV, sea water and corrosion. Emphasis is made to differentiate between reported weathering effects on GFRPs and NFRPs, primarily owing to the hydrophilic nature of natural fibers.

High‐performance wearable textiles made from poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) hold great promise for electromagnetic interference (EMI) shielding in military and healthcare systems. However, achieving an optimal balance of resilience, flexibility, and electrical properties is challenging due to weak interfacial interactions between PEDOT:PSS and the host substrates. In this study, a robust and stretchable wearable textile fabricated via vacuum‐assisted impregnation of PEDOT:PSS is presented onto an electrospun polyurethane (PU) nanofiber mat. The process creates a convoluted interlock network at the interface layer between PEDOT:PSS and PU nanofiber mat, enhanced by the large contact area, effective chemical interactions, and vacuum‐induced pressure. This results in exceptional tensile strength of 51.2 MPa, 207% elongation, and 86% elastic recovery, surpassing the practical requirement threshold of wearable textiles and fibers. The robust PU‐PEDOT:PSS nanofiber mat shows a normalized EMI shielding effectiveness value of 365.2 dB mm⁻¹ at an ultrathin thickness of 100 µm. This textile is capable of maintaining its shielding performance after continuous loading and unloading cyclic tests up to 100% strain. Additionally, a one‐step, durable, fluorine‐free spray coating is introduced to protect the textile from moisture and dust, thereby extending its service life for practical outdoor applications.

In recent years, bio-based materials have attracted sizable attention as a compelling choice for the development of environmentally friendly engineering products. Using natural fibres, as one of the prominent examples of bio-material sources, requires pre-processing decisions on biomass collection and size reduction. Such decisions play a critical role in the viability and profitability of underlying Supply Chain (SC), namely for the fibers conversion into a value-added product. Moreover, a holistic decision process should include economic as well as environmental, social, and technical impacts of the SC. In this paper, a multi-criteria decision-making model, based on the Analytic Network Process (ANP), is developed to support the sustainable development of a hemp-based biocomposite SC by integrating economic, environmental, social, and technical parameters. For economic and environmental impacts, outputs of the techno-economic and life cycle assessment models are used to quantify the required decision factors. For the social dimension, the number of potential job opportunities is included. Expert’s opinion on expected product quality (technical factor) for each alternative is also considered using qualitative/fuzzy data collection. The results identified the most appropriate biomass pre-processing equipment set, which would assist the SC managers in utilizing the available natural resources in a holistically sustainable manner. Moreover, to investigate the robustness of the model, a sensitivity analysis of the decision-makers preferences over decision indicators is conducted.

Bioproducts deriving from biomass are regarded as potential substitutes for products made from fossil fuels to mitigate global warming, climate change, and fossil fuel depletion. However, the environmental benefits of bioproducts for both humans and ecosystems, resulted mainly from agricultural practices, are in question. This study provides an environmental cradle-to-gate life cycle analysis (LCA) for a case study of a hemp-based biocomposite supply chain, involving agricultural activities, preprocessing, transportation, and bioconversion processes. Furthermore, the LCA comparison with petroleum-based composites is carried out using SimaPro software. The results show that the emission profile associated with the production of biocomposites is closely tied to the agricultural sector. This is primarily due to factors such as the consumption of diesel in agricultural machinery and nutrient runoff into water bodies resulting from nitrogen fertilizer use. In this regard, this study examines eight cases of agricultural practices, focusing on incorporating organic fertilizer and natural gas fuel sources in agricultural machinery. Implementing these approaches results in an 80%, 70%, 60%, and 50% reduction in non-carcinogenic, carcinogenic, ecotoxicity, and eutrophication impact categories, respectively. Using an analysis of variance (ANOVA), it is revealed that the selection of energy sources for agricultural machinery and the type of fertilizer used in hemp cultivation significantly influence most environmental impact categories, except for carcinogenic impacts, which remain unaffected by fertilizer type. Ultimately, the management strategy involves replacing 100% of nitrogen fertilizer with compost and substituting diesel fuel with natural gas in agricultural machinery. This approach results in the most substantial improvement in the overall environmental profile.

Plant-based fiber-reinforced composites are developed by researchers to reduce the use of fossil-based products and alleviate global warming. While significant research efforts have been devoted to examine the economic assessment of different processes/technologies in biomass supply chain (SC) for producing biomaterials, no earlier study, to the best of our knowledge, assessed biomass pre-processing equipment options considering uncertainty in economic performance. In this regard, this chapter employs multicriteria decision making (MCDM) to assess a combination of full-screen/half-screen hammer mill and square/round baler in a hemp-based biocomposites production case study. To do so, the techno-economic analysis is used to quantify various economic criteria including net present value (NPV) at conditional value at risk, Mean NPV derived from Monte-Carlo Simulation, and selling price (SP) variations. The results indicate that a 15% annual cost savings can be achieved by selecting equipment with higher capacity and efficiency, which in this case is a full-screen hammer mill and square baler equipment option. This configuration results in a higher NPV under risk along with a lower SP fluctuation given market uncertainties. On the other hand, the MCDM results show that the alternative with the highest NPV without risk does not necessarily obtain the highest rank, which suggests the importance of considering both deterministic and stochastic criteria in the analysis. Through this model, the biocomposite product SP is estimated at $2,226/ton, which is comparable with its substitute product price in the market. In addition, it is revealed that a 20% fluctuation in the SP, which is the most influential factor, results in a 72% change in NPV.