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On a novel co-rotating synchronous turbine mode operation in a centrifugal compressor
No full textA novel co-rotating, synchronous, reverse flow turbine mode operation in a Centrifugal Compressor (CC) is investigated, and methods to enable this mode, its working principles, flow field features and key performance characteristics are described. This is done by using 3D RANS flow field simulations on a simplified variant of the NASA High Efficiency Centrifugal Compressor (HECC) geometry, which represents a typical state-of-the-art in design practice. The novel co-rotating turbine mode is elucidated by first considering the baseline contra-rotating, reverse flow turbine mode as would be expected from the conventional four quadrant CC operation map. This baseline contra-rotating turbine mode is also hitherto undescribed in the literature for CC. Therefore, the flow field and performance metrics in the baseline contra-rotating mode is utilized to provide insights into the possibility of engineering design elements that can enable the novel co-rotating turbine mode.
The novel co-rotating, turbine mode is found to be enabled by the introduction of a suitable swirl generation mechanism that will direct the flow on to the impeller wheel suction side to give it a rotational impulse to spin from the suction to the pressure side as in nominal operation. The flow expansion through the reversed impeller wheel flow path with radius reduction enables power production. In the novel co-rotating, turbine mode, the flow leaves the impeller wheel in the same direction as it enters because of the direction of rotation and impeller inlet flow angle. However, this does not significantly impact power production because of the reduced radius weighting of the absolute swirl at the impeller inlet. An exemplary co-rotating turbine mode enabling configuration with 45° rotated diffuser vanes is found to handle up to 46% higher reverse flow and yield 6.25% higher peak power output even with a 16% lower absolute swirl velocity change as compared to the baseline contra-rotating mode. Additionally, the novel mode indicates better low speed power profile and wheel terminal speed as well. Alternative embodiments to enable the co-rotating mode like drilled feed ports and guide vane arrangements are discussed in the work. The hitherto undescribed co-rotating turbine mode operation is unique in the ability to produce and absorb power in the same shaft for bladed turbomachinery. Therefore, purposeful utilization of this mode could enable the design of better, robust, optimized systems for aerospace and energy applications.The authors would like to express their gratitude to Rolls-Royce plc. for supporting this research and for permission to publish the paper. The work was carried out under InnovateUK – Aerospace Technology Institute (ATI) Project PINES.ASME Turbo Expo 2025: Turbomachinery Technical Conference and Expositio
What drives passengers towards sustainable aviation? A segmentation study of travel behaviour and environmental concern in Spain
Get PDFAir travel significantly contributes to greenhouse gas emissions, posing challenges for climate action. This study examines the attitudes and behaviours of Spanish air passengers, focusing on the relationship between environmental concerns and travel choices. Based on a survey of 1,206 participants, we employed exploratory factor analysis to identify three attitudinal clusters: “Status quo flyers,” “Environmentally conscious low-flyers,” and “Pragmatic moderates”. These segments display significant differences in travel frequency, environmental concern, perception of aviation’s impact, and willingness to adopt sustainable alternatives. While environmentally conscious travellers express willingness to reduce air travel, frequent flyers often resist behavioural changes, highlighting a persistent attitude-behaviour gap. The results emphasise the importance of targeted strategies to address the attitude-behaviour gap and promote sustainability in aviation. This research provides actionable insights for policymakers and industry stakeholders to foster sustainable travel behaviours in one of Europe’s largest aviation markets.Ministry of Economy, Industry and CompetitivenessThis research received internal funding from the “Accelerator Scheme” of Universitat Oberta de Catalunya to cover part of the survey costs.This research is also part of the INVESTIGO Programme of the Spanish Government and the NextGenerationEU.Case Studies on Transport Polic
Advances in gecko-inspired climbing robots: from biology to robotics—a review
No full textWall-climbing robots have garnered significant attention for their ability to operate in hazardous environments. Among these, bioinspired gecko robots exhibit exceptional adaptability and climbing performance due to their flexible morphology and intelligent motion strategies. This review systematically analyzes studies published between 2000–2025, sourced from IEEE Xplore, Web of Science, and Scopus databases, to explore the biological principles of gecko adhesion and locomotion. A structured literature review methodology is employed, through which representative climbing robots are systematically categorized based on spine flexibility (rigid vs. flexible) and attachment mechanisms (adhesive, suction, claw-based). We analyze various motion control strategies, from hierarchical architectures to advanced neural algorithms, with a focus on central pattern generator (CPG)-based systems. By synthesizing current research and technological advancements, this paper provides a roadmap for developing more efficient, adaptive, and intelligent wall-climbing robots, addressing key challenges and future directions in the field.Electronic
An investigation into the preparation and characteristics of carbonized rice straw for black food dye
Get PDFTraditional natural dye sources have limitations in terms of variability and availability. This study investigate explored rice straw as a sustainable food dyes, focusing on carbonised rice straw (CRS). The aim was to reduce the CRS silica content to meet the regulatory standards without compromising the dye quality. Various treatments with Sonication, HCl, NaOH, and pressurised NaOH effectively reduced silica to 0.96%, accompanied by increased sodium content. Optimisation of the NaOH concentration seeks to balance the silica reduction and sodium levels. Additionally, the impact of sonication on CRS particle size was assessed to enhance dye stability. The results showed that sonication effectively reduced CRS particle size, with longer durations and higher amplitudes leading to smaller particles and decreased sedimentation rates, indicating enhanced suspension stability. Optimised sonication conditions produced a liquid dye with desirable traits, including uniform particle distribution and minimal sedimentation at 9.0%. This study highlights the potential of rice straw as a sustainable and cost-effective alternative for black food dye production. By refining silica reduction and sonication processing techniques, CRS-derived black food dyes can meet quality standards, reduce agricultural waste, and support sustainable food production.This research was funded by Universitas Brawijaya in the Assistant Professor Research Program 2020, grant number 1503/UN10.F10/PN/2020.Cogent Food & Agricultur
An overview of essential methods for preservation of sweet potato roots: a mini-review
Get PDFSweet potato is an essential and nutritious staple root crop in many parts of the world. This crop is multipurpose, humans consume the storage roots, while above-ground biomass is used for livestock feed. However, the roots are susceptible to sprouting during postharvest storage. Additionally, sweet potatoes are prone to postharvest diseases such as root rot, black rot, and soft rot. Various technologies have been used to preserve the quality of sweet potatoes. Studies have shown that techniques such as hot water, essential oils, and edible coatings effectively control postharvest disorders and diseases. Furthermore, treatments such as ethylene have been used to preserve sweet potato quality. However, negative outcomes such as root decay have been reported. As a result, the combination of 1-methylcyclopropene (1-MCP) and ethylene has been evaluated as a potential strategy for maintaining the quality of sweet potatoes. This mini-review examines the key postharvest techniques used for sweet potatoes. Also, the challenges of ethylene, 1-MCP, and hot water treatment are critically discussed.This research was funded by the National Research Foundation’s Postdoctoral Grant [PSTD2204193764-PR-2023]The Journal of Horticultural Science and Biotechnolog
Integrating circular economy practices into renewable energy in the manufacturing sector: a systematic review of the literature
Get PDFThis article belongs to the Special Issue Circular Economy, Energy Systems, New Trends and Innovations in Renewable Energy TechnologiesThe primary aim of this paper is to survey the literature’s coverage of integrating circular economy practices with renewable energy sources in the manufacturing sector. A systematic review of 107 peer-reviewed articles published between 2018 and 2023 in journals within the Web of Science and Scopus databases was conducted. The review documented CE and RE applications in emerging economies across Africa, Asia, and South America, assessing the overall characteristics of the research, its methodological rigour, and the barriers to or facilitators of CE and RE integration. Integration refers to the implementation of at least one CE practice, as well as one or more RE sources, in a single context, like manufacturing. A total of 14 practices were included in this analysis because they were mentioned at least 10 times by varying authors. The practice list includes recycling (mentioned in 74 articles), reducing materials (57), remanufacturing (53), the reuse of materials (51), waste minimisation (48), renewable energy use (43), consumer awareness (38), repurposing (35), refuse (33), education and training (28), environmentally friendly design (22), environmental criteria for supplier selection (17), reverse logistics (16), and stakeholder collaboration (14). Recycling, life cycle assessment, and end-of-life management were the most common CE practices in the literature. Additionally, solar power and bioenergy emerged as the most frequently recurring areas of integration for CE practices within the RE realms. Governmental support, incentives, research and development, and strong environmental legislation were found to be the most frequently recurring facilitators of effective CE and RE integration. Organisational resistance, bureaucratic red tape, lack of human capital, limited stakeholder involvement, and insufficient collaboration were found to be important barriers to effective integration between CE and RE.Sustainabilit
Transformation of solid and liquid wastes into fertiliser to minimize urban catchment pollution
No full textDecentralised treatment systems play a critical role in managing faecal sludge (FS) in sub-Saharan
Africa (SSA) where safely managed sanitation is lagging with 79% of the population without it. The
systems that treat FS and food waste (FW) into faecal derived fertilisers (FDFs) play a more critical role
in linking safely managed sanitation to improved food security. To recover nutrients and organic
matter to their fullest potential is urgent in the context of SSA. The International Water Management
Institute (IWMI) and partners have led research to convert urban FS and FW through co-composting
into various FDF for use in agriculture. Though some strides have been made in developing and
commercialising FDF, there are still some research and knowledge gaps including limited information
on nutrient and pathogen flow in the decentralised FS and FW treatment system; limited information
on the shelf life of stored FDF and on residual effect of FDF application on crops and soil. Hence, this
study aimed to generate new knowledge and understanding on the recovery of nutrients and E. coli
inactivation during treatment and use of fertiliser produced from FS and solid waste. The methodology
involved different experimental set-ups to collect primary data. This followed an end-to-end
monitoring of FS and FW treatment to produce FDF, storage of FDF and the use of the FDF in successive
lettuce cultivation. Findings from this study, show that between 50-70% of total N from FS is lost at
the dewatering stage of treatment. More than 50% of total N is lost during co-composting. While E.
coli inactivation efficiency of the dewatering process is minimal (0-14%) in the percolate, dewatered
FS on the other hand observed higher E. coli inactivation efficiency of 88-98% (1-2 log reductions).
Inactivation efficiency of co-composting stage for E. coli was 100%. No detectable presence of
indigenous E. coli was observed in FDF at the end of storage. Storage temperature and duration did
not affect re-growth of indigenous E. coli in co-composted FDF. Longer storage of enriched FDF co-
compost (NECo) under lower temperatures resulted in decreasing NH4-N concentrations. The field
experiment show, residual effect of FDF co-compost (Co) gave lettuce yield of 344% more compared
to the control by the second cycle. E. coli was absent on lettuce after successive cultivations. Co plots
had higher gross margins/profit per cycle of cultivation. The ROI for Co was 385.7 for first cycle and
309.2 for second cycle.PhD in Environment and Agrifoo
An experimental investigation into fracture resistance of carbon fibre sheet moulding compound
Get PDFCarbon Fibre Sheet Moulding Compound (CF-SMC) is an attractive material due to its good formability and green credentials. However, there is a lack of reliable fracture data, posing challenges when analysing CF-SMC materials which already have built-in randomness. Fracture Resistance curves (R-curves) and their variability have not been reported before for CF-SMC materials. This knowledge gap in the literature is addressed through Double Cantilever Beam (DCB) and first End Loaded Split (ELS) tests on CF-SMC. This work also explains the toughening mechanisms in CF-SMC materials during interlaminar fracture. Under Mode I, the toughening mechanism is fibre bridging while it is crack migration for Mode II. The new R-curve data provides new insights into the interlaminar fracture behaviour of CF-SMC materials and can be used as invaluable inputs for their failure analyses.Engineering Fracture Mechanic
The influence of microscopic features on the self-cleaning ability of 3D printed fabric-like structures
No full textSelf-cleaning surfaces are getting significant attention within multiple scientific
and industrial fields. Especially for textile fabrics, it is observed that self-cleaning
textile fabric surfaces are created by manipulating the surface features with the
help of coatings and nanoparticles, which are considered costly and far more
complicated. However, the exploration of the potential for self-cleaning by
controlling the fabrication parameters of textile fabrics at the microscopic level
has not been addressed. The purpose of this study was to establish the context
of self-cleaning textile fabrics by controlling the fabrication parameters of the
fabric at the microscopic level. The control of the fabrication parameters is not
easy in conventional fabric manufacturing techniques. Due to this reason, most
textile fabrics use surface coating methods for self-cleaning features.
The current evolution in 3D printed technology provides an opportunity to control
the fabrication parameters during fabric manufacturing and generate self-
cleaning features at the woven structural level. This study focuses on the
possibility of developing a 3D-printed self-cleaning textile fabric using different
printing parameters. It also identifies the significance of the fabric’s microscopic
features, such as porosity, surface roughness, and wettability, along with the
aesthetic look after optimizing these features. Further, the influence of these
features on mechanical strength at the fabric woven structure level was tested.
The optimization of printing parameters was modelled to identify the optimum
self-cleaning properties for the 3D-printed specimens and the validation model
was accomplished under a set of experimental methods.
The study includes the combination of three printing parameters: layer height (LH)
(0.15, 0.13, 0.10 ) and extruder width (EW) (0.5, 0.4, 0.3 ), along with two
different angular printing orientations (O) (45 ° and 90 °). The other parameters,
such as nozzle temperature (℃), print speed (/), and infill density (%),
remained constant for all the samples. Three different thermoplastic flexible
filaments printing materials are used: thermoplastic polyurethane (TPU 98A),
thermoplastic elastomers (TPE felaflex), and thermoplastic co-polyester (TPC
flex45). The 162 prepared samples are tested based on an experimental scheme
to evaluate the self-cleaning ability. The microscopic features (porosity,
roughness, and wettability) which are mainly responsible for this ability, are
measured and recorded to evaluate and compare the best values for self-
cleaning between the three chosen materials. The data are analysed to define
the optimal self-cleaning number. Lastly, the experimental outputs are used in
analytical calculations to find the relationship between changes in printing
parameters and microscopic features.
The study revealed that the printing parameters significantly affect the self-
cleaning properties when optimizing the selection of the process parameter
combination of layer height, extruder width, and printing orientation. The study
successfully created a linear regression model to demonstrate the relationship
between 3D printing parameters (layer height, extruder width, and orientation)
and the self-cleaning microscopic features of the 3D-printed polymeric textile
fabrics. It also identified that the (TPE) has a better self-cleaning ability than the
other two materials.PhD in Manufacturin
Sanitation infrastructure and faecal flow – SanIFFlow: a spatial mapping tool for integrated planning and management of sanitation in unsewered urban areas
Get PDFProper sanitation is vital for public health, particularly in urban areas. However, planning and managing sanitation systems in secondary cities within economically developing countries presents persistent challenges, largely due to a lack of spatial understanding and representation. To address these challenges, this study introduces SanIFFlow (Sanitation Infrastructure and Faecal Flow), a spatial analytical approach focused on a city-scale, ward-level model. SanIFFlow provides an actionable insights into infrastructural attributes and faecal flow dynamics, tailored to the practical governance capacities of the city's existing management framework. By leveraging open-source data on buildings, population, and drainage network, the method offers a detailed spatial representation of faecal matter sources and movement pathways within urban catchments. This approach enables strategic sanitation planning and proactive management, identifying high-risk areas and supporting targeted interventions, such as ward-level infrastructure upgrades. SanIFFlow represents a scalable, data-driven tool designed to enhance urban sanitation management in resource-constrained settings.Engineering and Physical Sciences Research Council (EPSRC)This work was supported by the UKRI Engineering and Physical Science Research Council (EPSRC) through a Ph.D. studentship received by the first author (M.S. S.) as part of the EPSRC Centre for Doctoral Training in Water and Waste Infrastructure and Services Engineered for Resilience (Water-WISER). EPSRC Grant No.: EP/S022066/1.Geomatic