Engineering: Journal Articles
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Item Open Access 3D Robotic Control of Optical Swarms at Micro-Scale(Institute of Electrical and Electronics Engineers (IEEE), 2025) Carlisle N; Nock, Volker; Williams MAK; Whitby CP; Chen JLY; Avci EOptical force-induced assembly is a promising yet scarcely explored approach for developing functional tools and objects at the microscale, with a wide range of potential applications. Our previous work was the first to investigate the manipulation of these assemblies in the XY plane. Here, we expand on these techniques by systematically exploring optical trap manipulation with the addition of Z-axis control. Manipulation of the Z-axis is referred to as axial displacement and is a viable approach for actively manipulating the assembly morphology. Experiments are conducted for the first time to explore and detail the response of the assembly during active 3D trap manipulation, informing the development of an autonomous control algorithm over the 2D area of the assembly during motion. This control presents techniques to increase assembly stability or alter the area of the assembly for tasks such as passing through constrictions. This work aims to develop the control techniques required to create a unique micromanufacturing approach inspired by the Kilobot thousand-robot swarm.Item Open Access Estimating individual tree DBH and biomass of durable Eucalyptus using UAV LiDAR(Elsevier BV, 2025) Ye, Ning; Mason , Euan; Xu , Cong; morgenroth, justinFast-growing eucalyptus species, used as vineyard posts in New Zealand’s Marlborough region, offer both durability and potential carbon sequestration benefits. However, the scale of carbon sequestration by these species remains unexplored. This study aimed to estimate individual tree dimensions (diameter at breast height, DBH) and above-ground biomass (AGB) for Eucalyptus globoidea and E. bosistoana using light detection and ranging (LiDAR) data acquired by an unpiloted aerial vehicle (UAV). LiDAR data were captured before destructive sampling, and 96 individual tree LiDAR metrics were extracted. Three machine learning (ML) models, including Partial Least Squares Regression (PLSR), Random Forest, and Extreme Gradient Boosting (XGBoost), were trained. Model performance was evaluated using the root mean square error and coefficient of determination (R2 ). SHapley Additive exPlanations (SHAP) analysis was employed to explain model predictions and evaluate input variables. Results showed that among the ML models, XGBoost and PLSR demonstrated superior performance, with the former yielding the highest R2 values for AGB (0.903) and the latter getting the highest R2 values for DBH (0.829). SHAP analysis highlighted that LiDAR height and voxel metrics were the most important factors influencing AGB and DBH predictions. These findings demonstrate that UAV LiDAR can provide efficient and accurate AGB estimates in eucalyptus plantations, supporting the wine industry’s carbon neutrality efforts.Item Open Access On-chip non-contact mechanical cell stimulation - quantification of SKOV-3 alignment to suspended microstructures(Elsevier BV, 2025) Onal S; Alkaisi, Maan; Nock, VolkerAlthough the accumulation of random genetic mutations has been traditionally viewed as the main cause of cancer progression, altered mechanobiological profiles of the cells and microenvironment also play a major role as a mutation-independent element. To probe the latter, we have previously reported a microfluidic cell-culture platform with an integrated flexible actuator and its application for sequential cyclic compression of cancer cells. The platform is composed of a control microchannel in a top layer for introducing external pressure, and a polydimethylsiloxane (PDMS) membrane from which a monolithically-integrated actuator protrudes downwards into a cell-culture microchannel. When actuated, the integrated actuator, referred to as micro-piston, transfers the pressure from the control channel as a mechanical force to the cells underneath. When not actuated, the micro-piston remains suspended above cells, separated from the latter via a liquid-filled gap of ∼108 μm. Despite the lack of direct physical contact between the micro-piston and cells in the latter arrangement, we observed distinct alignment of SKOV-3 ovarian cancer cells to the piston shape. To characterize this observation, micro-piston localization, shape, and size were adjusted and the directionality of a mono-layer of SKOV-3 cells relative to the suspended structure was probed. Cell alignment analysis was performed in a novel, label-free approach by measuring elongation angles of whole cell bodies with respect to micro-piston peripheries. Alignment of SKOV-3 cells to the structure outline was significant for circular, triangular and square micro-piston when compared to control areas without micro-piston on the same chip. The effect was present irrespective of whether cells were loaded with micro-pistons in static position (∼108 μm gap) or actively retracted using vacuum (>108 μm gap). Similar alignment was not observed for MCF7 cancer cells and MCF10A non-cancerous epithelial cells. The reported observation of directional movement and growth of SKOV-3 cells towards the region under micro pistons point towards a to-date unexplored mechanotactic behavior of these cells, warranting future investigations regarding the mechanisms involved and the role these may play in cancerItem Open Access Observations of Ruapehu Crater Lake (Te Wai ā-moe) and implications for lake dynamics and volcano monitoring(Springer Science and Business Media LLC, 2024) Ching C; Kennedy , Ben; Watson, Leighton; Cole, Jim; Nichols, Alexander; Christenson B; Keys HJR; Gabrielsen H; Procter J; Asher C; Britten KAll historical eruptions at Ruapehu have occurred from its Crater Lake, Te Wai ā-moe. This study aims to better understand Crater Lake dynamics by using visible light and long wavelength infrared images of the lake. Over 10,000 images from 1902 – 2021 were analysed to produce a time-series of lake observations. Our results show that visible light observations reveal colour changes on the entire Crater Lake surface from blue to grey, and localised grey, yellow, and black discolourations. Grey discolourations are interpreted as localised upwellings of lake-floor sediment, and yellow and black material to comprise vent-hosted sulphur/sulphides, both transported by volcanic fluids from subaqueous vents to the surface. The locations of upwellings were used to identify five vent locations beneath Crater Lake, three more vents than were previously recognised. Upwellings appeared and disappeared in 10 min. Steam above the lake surface was controlled by both lake temperature and cloud conditions. Blue lakes were most common in summer and autumn, implying a relationship with ice or snow melt entering the lake. Grey lakes were observed in the month before 97% of eruptions, suggesting a correlation between a grey lake and eruption precursors. Crater Lake processes are illustrated by three regimes. Regime 1, a vigorously convecting grey lake associated with steam, eruptions, and more frequently the high end of recorded lake temperatures (within the range of 7 – 69 °C). Regime 2, a blue lake to occasionally green that typically occurs in summer and autumn when ice or snow melt is significant and is associated with generally the low end of lake temperatures and reduced volcanic fluid input. Regime 3, a blue-grey lake, the most observed lake colour in this study and effectively a balance between volcanic and seasonal processes. We suggest that an array of cameras would be useful additions to the current volcano monitoring network at Ruapehu.Item Open Access State-of-the-Art Review: Electronic Warfare against Radar Systems(Institute of Electrical and Electronics Engineers (IEEE), 2025) Reddy R; Sinha, SaurabhThe electromagnetic spectrum (EMS) is emerging as a sixth battlespace domain in military applications and is essential for wireless communications and remote sensing. Due to the demand for EMS, it is increasingly contested, congested, constrained, and shared. Evolving threats, doctrine, and tactics drive significant advancements in the battlespace. Electronic Warfare (EW) or Electromagnetic Warfare products need to keep pace by leveraging advances in technology driven by Industry 4.0, artificial intelligence (AI), direct radio frequency (RF) sampling, RF System on Chip (RFSoC), and ultrawideband antenna arrays. These trends drive a need for technology-intensive innovation in EW products underpinned by a coherent business product-technology strategy. This article reviews advancements in Electronic Warfare against radar systems using a novel approach that integrates quantitative bibliometric and patentometric analyses with a qualitative assessment of EW architectures, Electronic Attack (EA) algorithms, and Electronic Support (ES) algorithms. This article marks the first instance of such a methodology being applied to systematically assess the landscape of research publications and technological innovations in the field of EW against radar systems. A taxonomy of EW System Types by military domain against radar and their role in the modern battlefield is presented together with their typical role and real-world examples. The quantitative and qualitative insights are synthesized to outline a notional next-generation EW architecture and a technology roadmap for its realization that researchers can use to guide the development of innovative EW technologies and methodologies and by EW practitioners to inform system design, operational deployment, and capability enhancements.Item Open Access Advancing urban forest and ecosystem service assessment through the integration of remote sensing and i-Tree Eco: A systematic review(Elsevier BV, 2025) Sharma , Gunjan; morgenroth, justin; Richards , Daniel R.; Ye, NingUrban forests support the health and well-being of billions of people living in cities globally. To better manage urban forests, it is crucial to assess their ecosystem services. This systematic review analyzes two established urban forest assessment approaches—i-Tree Eco and remote sensing—which have developed independently but hold significant potential for integration. The review, comprising the years 2008 to 2022, evaluates the current status of both methods in assessing urban forest structure and ecosystem services, highlighting opportunities for synergy. The literature shows that while both approaches primarily focus on regulatory services, remote sensing offers more versatile tools for assessing a broader range of ecosystem services beyond i-Tree's standardized scope. Remote sensing holds potential to enhance i-Tree Eco by providing structural and location-specific data at scale, albeit with varying accuracies. Studies have shown that LiDAR data reliably derives tree height and crown width, and that, in combination with multispectral and hyperspectral imagery, it enhances species identification. Additionally, mobile, and terrestrial laser scanners accurately estimate diameter at breast height. However, gaps remain in using remote sensing to assess crown characteristics like crown missing and dieback, which, though not critical, are useful for enhancing ecosystem service estimates in i-Tree Eco. Despite the potential of remote sensing to automate urban tree inventories, limited research has shown its successful integration with i-Tree Eco. Future research should standardize remote sensing techniques for assessing tree crown health. Additionally, further work is needed on quantifying differences between remote sensing and groundbased measurements, with the aim of evaluating uncertainty levels and understanding how these uncertainties impact the reliability and usefulness of data for policymaking and planning.Item Open Access Research priorities of endometriosis patients and supporters in Aotearoa New Zealand(Wiley, 2024) Ellis , Katherine; Wood , RachaelBackground: In New Zealand, an estimated 10% of women and people presumed female at birth have endometriosis, a disease characterised by the presence of tissue similar to the lining of the uterus, outside of the uterus. Aims: The purpose of this study was to characterise the research priorities of New Zealand endometriosis patients and their support networks in alignment with an Australian study. This will allow researchers to be able to ensure their research aligns with closing research gaps prioritised by those who directly experience the impacts of the disease. Methods and Materials: There were 1262 responses to an online Qualtrics survey advertised through Endometriosis New Zealand's social media accounts and mailing list to reach endometriosis patients and their support networks. Results: Overall, the highest research priorities for surgically or radiologically confirmed endometriosis patients, clinically suspected endometriosis patients, chronic pelvic pain patients, and their parents, partners, family members and friends were the management and treatment of endometriosis, followed by understanding endometriosis' cause, and improved capacity to diagnose endometriosis earlier. The key differences between the priorities of symptomatic participants and supporters were that symptomatic participants placed a significantly higher priority on understanding the cause of endometriosis, and supporters placed a significantly higher priority on improving the diagnosis of endometriosis. Conclusions: There is alignment between the ranking of general research priority areas for endometriosis in Australasia, allowing for clear priorities for future research teams to structure their work around patient-centredness.Item Open Access Generalised random tessellation stratified sampling over auxiliary spaces(2025) Robertson, Blair; Price , C. J.; Reale , M.; Brown , J. A.Generalised Random Tessellation Stratified (GRTS) is a popular spatially balanced sampling design. GRTS can draw spatially balanced probability samples in two dimensions but has not been used to sample higher-dimensional auxiliary spaces. This article considers applying dimensionality reduction techniques to multidimensional auxiliary spaces to allow GRTS to be used to sample them. The aim is to improve the precision of GRTS-based estimators of population characteristics by incorporating auxiliary information into the GRTS sample. We numerically evaluate two dimensionality reduction techniques for equal and unequal probability samples on two spatial populations. Multipurpose surveys are also considered. Results show that GRTS samples from these two-dimensional spaces can improve the precision of GRTS over spatial coordinates.Item Open Access Exploring the Pedagogical Implications of Virtual Labs: A Case Study of the Ward Design Project(2025) Sharifkhani, Maryam; Davidson , Jonathan; Walsh , Christian; Evans-Freeman , Jan; Brown , Cheryl; MacCallum , KathrynVirtual labs (VLs) are increasingly transforming education, replacing or supplementing traditional labs in response to technological advances and remote learning demands. This study explores how adopting 3D VLs, Ward Design in our case, affects lecturers' teaching and students' learning experiences, focusing on areas like engagement, contextual learning, and collaborative learning. In this study, we draw on Dalgarno and Lee's model for virtual learning environments (VLEs) as the framework for our analysis. Qualitative research methods informed our exploration. Findings reveal VLs' positive impact on diverse 'Learning Benefits'. VLs can significantly enhance student engagement by offering an interactive and self‐paced learning experience. Additionally, VLs provided opportunities for contextual learning, enabling students to apply skills in realistic, virtual settings. However, limitations in replicating collaborative learning and organic, real‐world exploration within virtual environments were noted. The study also highlighted various challenges associated with cognitive load, such as the unfamiliarity of the technology, technical difficulties, and discomfort with VR tools, all of which at times hindered the learning experience. Our findings suggest that combining VLs with physical field trips could optimise the learning experience, addressing these limitations. This study contributes to the understanding of VLs' potential and challenges in education, informing their effective implementation to enhance teaching and learning.Item Unknown A decade to wait: Update on the average delay to diagnosis for endometriosis in Aotearoa New Zealand(Wiley, 2024) Ellis , Katherine; Wood , RachaelEndometriosis is a common condition with varying delays from symptom onset to diagnosis reported internationally. In New Zealand, the previously accepted average delay to diagnosis was 8.6–8.7 years. An online survey completed by the largest cohort of self-reported New Zealand-confirmed endometriosis patients (n = 1024) for the collection of delay to diagnosis was conducted in September and October of 2023. The results revealed an average delay of 9.7 ± 7.1 years overall, with a significantly longer delay in the North Island than in the South. This study identifies potential factors for future research that may influence diagnostic delays in New Zealand.Item Unknown Experimental collisions of varying roughness wetted particles in the pendular regime compared to numerical simulations(American Physical Society (APS), 2024) Punch , Oscar J.; Holland, Daniel; Baumann , Andreas; Eberhard , PeterIn this work rectilinear collisions of spheres coated in a thin viscous liquid film are considered, where the surface roughness of the spheres was varied. Experiments were performed using a Newton's cradle apparatus and the collision dynamics was measured using particle tracking velocimetry. The experiments showed that the dry and wet coefficient of restitution decreases as the roughness increases. Experimental collisions are compared with numerical simulations to examine criteria that limit the viscous force. We show that a model in which the liquid undergoes a glass transition is in excellent agreement with experimental measurements for smooth spheres, i.e., when the roughness of the spheres is less than the glass transition length. For rough particles, a constant minimum separation distance is more accurate than the glass transition model, which is consistent with the idea that contact occurs on the roughness elements. Furthermore, smoothed particle hydrodynamics (SPH) simulations were used to examine the viscous flow in detail. The SPH simulations accurately predicted the collision outcome for smooth spheres and showed that the maximum pressure was greater than the glass transition pressure used for the discrete element method simulations, supporting the feasibility of the glass transition model. The SPH simulations of rough particles indicate that during a collision the interstitial liquid flows through microchannels between roughness elements as a mechanism to alleviate pressure buildup, and reduce the viscous force consistent with the experimental observations.Item Unknown Enhanced redox performance of cement-modified Fe-based oxygen carrier during biomass chemical looping gasification(2025) Zhang , Xueqi; Yip, Alex; Rosas , Santiago; Nusheh , Mohammad; Pang , ShushengIn this study, a novel Fe-based OC was synthesized based on cement chemically bonded hematite, containing multiple-component calcium ferrites. Its cyclic performance was evaluated over 10 cycles of BCLG at 850, 900 and 950 C, respectively, in a batch fluidized-bed reactor. Fresh and used OCs were characterized using TGA, XPS, XRD and SEM/EDS techniques. The best cyclic reactivity was achieved at 950 ◦ gasification efficiency of 91.3 % and H 2 C, resulting in an average ◦ /CO ratio of 2.4 due to superior oxygen diffusivity. At 850 C, the OC underwent elemental reorganization under repeated limited reduction and complete reoxidation. This structure evolution significantly improved the high-temperature redox reactivity of the used OC (OC850-M10) with the maximum mass loss rate of 4%/min during the TGA tests, compared to 2.6 %/min for fresh OC. For used OCs after 10 cycles at 900 ◦ ◦ C (OC900-M10) and 950 ◦ C (OC950-M10), increased oxygen vacancies in OC900-M10 compensated for reactivity loss caused by Fe enrichment, while reactive oxygen accessibility in OC950-M10 was moderately constrained by Fe segregation beyond a critical threshold. Despite the agglomeration after 20 cycles at 950 C, enhanced overlaying of Fe and inert species further homogenized Fe phases, allowing for the restoration of 98 % of active oxygen after gentle crushing. Moreover, the addition of cement also improved crushing strength (>3 N) over cycling, partially due to the growth of Al 2 O f lower-shaped phases in internal voids. These findings suggest that chemical incorporation of cement with hematite prolonged OC longevity.Item Unknown Waste-derived CaO from green mussel shells as a highly stabilized and superior sorbent for cyclic CO2 capture(2025) Isnaini , Muhammad Dody; Jongsomjit , Bunjerd; Yip, Alex; Phisalaphong , MuenduenThis study aims to mitigate CO2 emissions by utilizing and developing diverse waste natural resources as calcium oxide precursors, prepared through the citric acid-assisted sol-gel method, to improve capturing capacity in cyclic carbonation/calcination reactions. The study evaluates the influence of carbonation temperature ranging from 550-750 °C, and CO2 flow rates (comprising 15 vol% of CO2 gas feed) ranging from 9-15 mL/min and assesses the stability of CaO derived from waste natural resources concerning cyclic CO2 capture performance. Furthermore, characterization of CaO derived from waste natural resources and the spent sorbent was conducted using nitrogen adsorption-desorption analysis, X-ray diffraction (XRD), X-ray fluorescence (XRF), carbon dioxide temperature-programmed desorption (CO2-TPD), thermogravimetric analysis (TG/DTG), and field-emission scanning electron microscopy (FE-87 SEM).Item Unknown Survey of General Practitioner Perspectives on Endometriosis Diagnosis, Referrals, Management and Guidelines in New Zealand(Wiley, 2024) Ellis , Katherine; Meador , Alina; Ponnampalam , Anna; Wood, RachaelIntroduction: There is a growing body of literature concerning endometriosis patients' perspectives on the healthcare system and endometriosis care in New Zealand. However, there is little research available on the perspectives of general practitioners (GPs) internationally, and none currently in New Zealand. The purpose of this study is to address New Zealand GPs' understanding of and approach to endometriosis diagnosis, referrals, management and guidelines. Methods and Materials: An online, anonymous survey was shared with 869 GP clinics and completed by 185 New Zealand-based GPs regarding their awareness and application of the inaugural 2020 ‘Diagnosis and Management of Endometriosis in New Zealand’ guidelines, their perception of their endometriosis knowledge, the diagnostic value they assign to symptoms, the treatments they recommend and the reasons they refer patients to specialist gynaecologists. Differences between groups were conducted using Chi-squared tests, and text answers were assessed thematically using inductive, semantic coding. Results: All 185 GPs had gynaecology consults, and 73% had gynaecology consults every week. Despite 65% being aware of the 2020 guidelines, only 35% overall had read them. Only 52% of GPs considered themselves to know enough about endometriosis for their routine practice. The most common treatment to be considered first line was intrauterine contraceptive devices (IUDs; 96%), whereas the most common alternative treatment recommended was exercise (69%). The most common reason for referral to specialist care was the failure of all attempted treatments (84%). Conclusions: Many of the study's results align with current New Zealand and international endometriosis guidelines, particularly the prioritisation of progestin-only therapies, the reduced emphasis on surgical treatment as the first line and the low rates of alternative treatment recommendations. This study also highlights the need to improve awareness of inappropriate GP recommendations, including long-term treatment with prescription-only pain relief such as codeine and pregnancy for symptomatic relief. Patient or Public Contribution: Two of the authors involved in the design and conduct of the study, data interpretation and manuscript preparation have sought care for endometriosis. Trial Registration: NA.Item Unknown A framework for evolving assumptions in risk analysis(Wiley, online-publication-date) Hardaway, Kendrick; Flage , RogerAbstractRisk assessment can be used to evaluate the risks of complex systems and emerging technologies, such as the human–climate nexus and automation technologies, and to inform pathways and policies. Due to the interconnected and evolutionary features of such topics, risk analysts must navigate the dynamics of changing assumptions and probabilities in the risk assessment. However, the current risk analysis approach neglects to a large extent an explicit consideration of these dynamics, either oversimplifying complex systems or neglecting the likely human response to emerging technologies. In this article, we outline why the evolutionary dynamics of assumptions and probabilities in a risk assessment must receive close attention, and then we provide a possible framework through which to consider the dynamics. Ultimately, we propose a formal approach to conceptualizing and implementing the risk description with respect to feedback loops and complex adaptive systems.Item Unknown Improving Passive Discovery for IEEE 802.15.4-based Mobile Body Sensor Networks(Informa UK Limited, 2016) Ali , A; Willig, AndreasWe investigate passive discovery of IEEE 802.15.4-based body sensor networks (BSNs). BSNs are wearable networks that monitor the vital functions of the body while the person can roam around freely. One challenging task that BSNs have to perform is the discovery of certain coordinator nodes, for example, gateways towards data processing and storage services. We are presenting a cooperative passive discovery scheme (the rumour-based scheme) for the beacon-enabled mode. We consider a simple scenario where a specific mobile BSN is searching for a specific destination network. We evaluate the performance of our scheme in terms of the average discovery time and the discovery probability using simulations. We also assess the influence of some important system parameters, e.g. the speed of mobile BSNs, the beacon order, the mobility model or the number of nodes used for discovery. The results show that our strategy can significantly reduce the time required to discover the target network.Item Unknown Detecting and measuring fine-scale urban tree canopy loss with deep learning and remote sensing(2025) Pedley D; morgenroth, justinUrban trees provide a multitude of environmental and amenity benefits for city occupants yet face ongoing risk of removal due to urban pressures and the preferences of landowners. Understanding the extent and location of canopy loss is critical for the effective management of urban forests. Although city-scale assessments of urban forest canopy cover are common, the accurate identification of fine-scale canopy loss remains challenging. Evaluating change at the property scale is of particular importance given the localised benefits of urban trees and the scale at which tree removal decisions are made. The objective of this study was to develop a method to accurately detect and quantify the city-wide loss of urban tree canopy (UTC) at the scale of individual properties using publicly available remote sensing data. The study area was the city of Christchurch, New Zealand, with the study focussed on UTC loss that occurred between 2016 and 2021. To accurately delineate the 2016 UTC, a semantic segmentation deep learning model (Deep-Labv3+) was pretrained using existing UTC data and fine-tuned using high resolution aerial imagery. The output of this model was then segmented into polygons representing individual trees using the Segment Anything Model. To overcome poor alignment of aerial imagery, LiDAR point cloud data was utilised to identify changes in height between 2016 and 2021, which was overlaid across the 2016 UTC to map areas of UTC loss. The accuracy of UTC loss predictions was validated using a visual comparison of aerial imagery and LiDAR data, with UTC loss quantified for each property within the study area. The loss detection method achieved accurate results for the property-scale identification of UTC loss, including a mean F1 score of 0.934 and a mean IOU of 0.883. Precision values were higher than recall values (0.941 compared to 0.811), which reflected a deliberately conservative approach to avoid false positive detections. Approximately 14.5% of 2016 UTC was lost by 2021, with 74.9% of the UTC loss occurring on residential land. This research provides a novel geospatial method for evaluating fine-scale city-wide tree dynamics using remote sensing data of varying type and quality with imperfect alignment. This creates the opportunity for detailed evaluation of the drivers of UTC loss on individual properties to enable better management of existing urban forests.Item Unknown Copper-based electrocatalyst for hydrogen evolution in water(Royal Society of Chemistry (RSC), 2024) Abudayyeh AM; Bennington MS; Hamonnet J; Marshall, Aaron; Brooker SIn aqueous pH 7 phosphate buffer, during controlled potential electrolysis (CPE) at −1.10 V vs. Ag|AgCl the literature square planar copper complex, [CuIILEt]BF4 (1), forms a heterogeneous deposit on the glassy carbon working electrode (GCWE) that is a stable and effective hydrogen evolution reaction (HER) electrocatalyst. Specifically, CPE for 20 hours using a small GCWE (A = 0.071 cm2) gave a turnover number (TON) of 364, with ongoing activity. During CPE the brownish-yellow colour of the working solution fades, and a deposit is observed on the small GCWE. Repeating this CPE experiment in a larger cell with a larger GCWE (A = 2.7 cm2), connected to a gas chromatograph, resulted in a TON of 2628 after 2.6 days, with FE = 93%, and with activity ongoing. After this CPE, the working solution had faded to nearly colourless, and visual inspection of the large GCWE showed a material had deposited on the surface. In a ‘rinse and repeat test’, this heterogeneous deposit was used for further CPE, in a freshly prepared working solution minus fresh catalyst, which resulted in similar ongoing HER activity to before, consistent with the surface deposited material being the active HER catalyst. EDS, PXRD and SEM analysis of this deposit shows that copper and oxygen are the main components present, most likely comprising copper and copper(i) oxide ((Cu2O)n) formed from 1. The use of 1 leads to a deposit that is more catalytically active than that formed when starting with a simple copper salt (control), likely due to it forming a more robustly attached deposit, which also enables the observed long-lived catalytic activity.Item Unknown Laboratory demonstration of atmospheric tomography using the geometric wavefront sensor(SPIE-Intl Soc Optical Eng, 2025) Hickman S; Weddell S; Clare, RichardThis paper studies the geometric wavefront sensor (WFS) as part of the develop ment of an astronomical imaging instrument for the University of Canterbury Mount John Observatory, which combines adaptive optics and computer post-processing techniques for astronomical observations over a wide field of view by utilizing the geometric WFS and atmospheric tomography. Specifically, this paper investigate the geometric WFS’s capability to estimate wavefronts of multiple artificial guide stars, as well as to demonstrate atmospheric tomography, on a modified optical test bench in an open loop. A technique to simulate atmospheric turbulence in the laboratory is explored and is found to suitably create multiple atmospheric layers artificially; this technique permits wavefront phase aberrations of multiple artificial guide stars to be simulated simultaneously with varying degrees of overlap (i.e., changing the altitude of the atmospheric turbulence layer, or atmospheric tomography meta-pupil) without altering the physical optical path. Atmospheric tomography is then physically demonstrated on the modified optical test bench using the technique and calibrated geometric WFS.Item Open Access Development of Extrudable Hydrogels Based on Carboxymethyl Cellulose–Gelatin Complex Coacervates(MDPI AG, 2025) Gharanjig , Hamid; Najaf Zadeh, Hossein; Stevens , Campbell; Abhayawardhana , Pram; Huber, Tim; Nazmi, Ali RezaThis study investigates the 3D extrusion printing of a carboxymethyl cellulose (CMC)–gelatin complex coacervate system. Various CMC–gelatin coacervate hydrogels were prepared and analyzed to achieve this goal. The impact of the CMC–gelatin ratio, pH, and total biopolymer concentration on coacervation formation and rheological properties was evaluated to characterize the printability of the samples. Turbidity results indicated that the molecular interactions between gelatin and CMC biopolymers are significantly pH-dependent, occurring within the range of pH 3.7 to pH 5.6 for the tested compositions. Confocal Laser Scanning Microscopy (CLSM) confirmed the presence of coacervates as spherical particles within the optimal coacervation range. Scanning electron microscopy micrographs supported the CLSM findings, revealing greater porosity within this optimal pH range. Rheological characterization demonstrated that all CMC–gelatin hydrogels exhibited pseudoplastic behavior, with an inverse correlation between increased coacervation and decreased shear viscosity. Additionally, the coacervates displayed lower tackiness compared to gelatin hydrogels, with the maximum tackiness normal force for various CMC–gelatin ratios ranging from 1 to 15 N, notably lower than the 29 N observed for gelatin hydrogels. Mixtures with CMC–gelatin ratios of 1:15 and 1:20 exhibited the best shear recovery behavior, maintaining higher strength after shear load. The maximum strength of the CMC–gelatin coacervate system was found at a biopolymer concentration of 6%. However, lower biopolymer content allowed for consistent extrusion. Importantly, all tested samples were successfully extruded at 22 ± 2 °C, with the 1:15 biopolymer ratio yielding the most consistent printed quality. Our research highlights the promise of the CMC–gelatin coacervate system for 3D printing applications, particularly in areas that demand precise material deposition and adjustable properties.