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Molecularly imprinted polymers electrochemical sensing: the effect of inhomogeneous binding sites on the measurements. a comparison between imprinted polyaniline versus nanoMIP-Doped polyaniline electrodes for the EIS detection of 17β-Estradiol
Get PDFMolecularly imprinted polymers (MIPs) are synthetic receptors made by template-assisted synthesis. MIPs might be ideal receptors for sensing devices, given the possibility to custom-design selectivity and affinity toward a targeted analyte and their robustness and ability to withstand harsh conditions. However, the synthesis of MIP is an inherently random process that produces a statistical distribution of binding sites, characterized by a variety of affinities. This is verified both for bulk MIP materials and for MIP's thin layers. In the present work, we aimed at assessing the effects of inhomogeneous versus homogeneous imprinted binding sites on electrochemical sensing measurements, and the possible implications on the sensor's performance. In the example of an Electrochemical Impedance Spectroscopy (EIS) sensor for the 17β-estradiol (E2) hormone, the scenario of inhomogeneous binding sites was studied by modifying electrodes with an E2-MIP polyaniline (PANI) thin layer, called the "Imprinted PANI layer". In contrast, the condition of discrete and uniform binding sites was epitomized by electrodes modified with a thin PANI layer purposedly doped with E2-MIP nanoparticles (nanoMIPs), which were referred to as "nanoMIP-doped PANI". The behaviors of the two EIS sensors were compared. Interestingly, the sensitivity of the nanoMIP-doped PANI was almost twice with respect to that of the imprinted PANI layer, strongly suggesting that the homogeneity of the binding sites has a fundamental role in the sensor's development. The nanoMIP-doped PANI sensor, which showed a response for E2 in the range 36.7 pM-36.7 nM and had a limit of detection of 2.86 pg/mL, was used to determine E2 in wastewater.Italian Ministry of Research and University doctoral program PON PNRR D.M.351ACS Sensor
Genetic dissection of minerals and phytate content in pearl millet germplasm panel using genome‐wide association study
Get PDFBillions of people around the world suffer from malnutrition, leading to severe adverse health effects. Pearl millet (Pennisetum glaucum) is a multifaceted versatile crop with excellent nutritional profile which can help to combat nutritional disorders and climate change. In this study, we evaluated the global pearl millet germplasm panel known as PMiGAP for natural variation and genetic maker trait associations for important minerals, that is, iron, zinc, calcium, magnesium, potassium and sodium along with phytate. The genotypes IP‐15947, IP‐5121, IP‐4020, IP‐12768, IP‐5695, IP‐8786 and IP‐11310 were found to be superior for majority of minerals examined but had lower phytate‐to‐zinc ratio. Phytate/mineral molar ratios are typically used to predict the bioavailability of iron and calcium contents in grains, and surprisingly none of the PMiGAP genotypes showed such ratios below threshold indicating PMiGAP entries studied in this study seriously suffer from bioavailability issues of these minerals. On the other hand, 73 genotypes had lower zinc/phytate ratio than the threshold in the germplasm panel. Iron and zinc content had significant positive association among them but phytate content in general was not significantly correlated with minerals except for magnesium and potassium. A genome‐wide association study using 456 K SNPs identified 74 significant marker–trait associations and 59 candidate genes around 50 Kb distance near the significant SNPs. Ten significant SNPs were found within the candidate genes. The associated markers and the candidate genes provide new insights into the genetic architecture of the mineral traits studied and will facilitate marker‐assisted selection to accelerate breeding of such minerals in future varieties to combat rising malnutrition problem via diet.Biotechnology and Biological Sciences Research Council, Grant/Award Number: BB/F004133/1 and BB/ M502728/1; Science and Engineering Research Board (SERB), Government of India, Grant/Award Number: SIR/2022/001225Food and Energy Securit
Installed nacelle aerodynamics at cruise and windmilling conditions
Get PDFPurpose
The decrease in specific thrust achieved by Ultra-High Bypass Ratio (UHBPR) aero-engines allows for a reduction in specific fuel consumption. However, the typical associated larger fan size might increase the nacelle drag, weight and the detrimental interference effects with the airframe. Consequently, the benefits from the new UHBPR aero-engine cycle may be eroded. This paper aims to evaluate the potential improvement in the aerodynamic performance of compact nacelles for installed aero-engine configuration.
Design/methodology/approach
Drooped and scarfed non-axisymmetric compact and conventional nacelle designs were down selected from a multi-point CFD-based optimisation. These were computationally assessed at a set of installation positions on a contemporary wide-body, twin-engine transonic aircraft. Both cruise and off-design conditions were evaluated. A thrust and drag accounting method was applied to evaluate different aircraft, powerplant and nacelle performance metrics.
Findings
The aircraft with the compact nacelle configuration installed at a typical installation position provided a reduction in aircraft cruise fuel consumption of 0.44% relative to the conventional architecture. However, at the same installation position, the compact design exhibits a large flow separation at windmilling conditions that is translated into an overall aircraft drag penalty of approximately 5.6% of the standard cruise net thrust. Additionally, the interference effects of a compact nacelle are more sensitive to deviations in mass flow capture ratio (MFCR) from the nominal windmilling diversion condition.
Originality/value
This work provides a comprehensive analysis of not only the performance but also the aerodynamics at an aircraft level of compact nacelles compared to conventional configurations for a range of installations positions at cruise. Additionally, the engine-airframe integration aerodynamics is assessed at an off-design windmilling condition which constitutes a key novelty of this paper.Aircraft Engineering and Aerospace Technolog
Selection and aggregation of low-cost particle sensors for outdoor particulate matter measurement
Get PDFA growing number of low-cost sensors (LCS) have been used to monitor air pollution in outdoor air. The benefit of utilizing LCS lies in its ability to offer increased spatial coverage, which provides real-time measurements at a reduced cost. The selection and combination of low-cost sensors represent the primary challenge in conducting observations using such sensors. This paper employs a sensor quality ranking strategy, utilizing random forest (RF) for aggregating the selected LCS combination, followed by evaluating the correction results using various model evaluation metrics. The LCS used in this study, regardless of their quality grades, achieves a coefficient of determination of 0.93 or higher after model calibration, indicating the effectiveness of employing RF for aggregation. It is found that using a pair of top and averaged LCS can significantly enhance the measurement quality by 25% in RMSE. Using RF to calibrate a single LCS increases the measurement performance at least two times in terms of MSE, RMSE, and MAE. Using paired LCS with RF aggregation for measuring PM2.5, the aggregated observation significantly approximates the reference measurement with R2=0.986
Managing disruptions in complex projects: the antifragility hierarchy
Get PDFProjects are prone to a variety of disruptions across their development cycle, requiring
that effective organizations develop strategies for proactively recognizing disruption
likelihood and swiftly responding to these events. This paper explores a hierarchy of
responses to disruption, based on Taleb’s (2012) theory of antifragile system behavior.
Following this reasoning, we suggest that when faced with project disruptions,
organizations need to investigate the means to trigger a “convex” response that
increases value through antifragile thinking. We propose an “antifragile hierarchy” in
which four key responses to project disruption are demonstrated, with a range of
strategies available for addressing these disruptions. This hierarchy offers a novel
conceptualization of responses to project disruption events, suggesting that the options
available to organizations facing disruptions range from fragile (the least effective) to
antifragile (the most constructive). Finally, we offer a set of strategies for effectively
responding to disruptions to promote antifragility in projects
Influence of monomer structure and catalyst concentration on topological transition and dynamic properties of dicarboxylic acid‐epoxy vitrimers
Get PDFThis study delineates the dependence of thermophysical behavior of acid‐epoxy vitrimers on their formulation. The stress relaxation due to the bond exchange reaction and the glass transition temperature of acid epoxy vitrimers are investigated, with respect to the influence of catalyst content and acid chain length. This is carried out for a range of dicarboxylic acids and catalyst concentrations formulated and characterized using calorimetry and dynamic mechanical analysis. The influence of acid chain length on the bond exchange rate, topological transition, and glass transition temperatures of the vitrimers is found to be significant. The activation energy of the exchange reaction varies over a wide range from 73 to 104 kJ/mol and the topology freezing temperature from 66 to 136°C with the behavior governed by the interplay between crosslinking density, network flexibility and density and distance of functional groups, with an increase of catalyst concentration leading to lower topological transition temperature and the dependence on chain length showing non‐monotonic behavior. The glass transition decreases by about 30°C as the carbon chain length increases from 6 to 14 carbons due to enhanced monomer flexibility and is not affected by the concentration of catalyst.Journal of Applied Polymer Scienc
Neutron tomography reveals extensive modern modification in Iron Age Iranian swords
Get PDFEarly Iron Age Iranian bladed weaponry plays a significant role in discussions of metallurgical development in the ancient Near East. Due to its ubiquity in museum collections, as well as co-occurrence of bronze, iron, and bimetallic forms, it figures prominently in debates about the early ironworking techniques in the late 2nd and early 1st millennia BCE. However, dispersed collections, often lacking secure archaeological context, have made comprehensive assessment difficult. One major type of bladed weaponry, the so-called split-ear pommel swords have been the subject of much discussion, particularly around the presence of an iron core identified in many examples. Neutron tomography was applied to eight swords of this type to image their inner structure, assess the manufacturing process and determine possible recent modifications—the first time this technique has been applied to bronze Iranian weaponry of any period. The objects were recovered by the Border Force after being seized on entry to the UK and will be repatriated to Iran, providing an opportunity to investigate both ancient manufacture and modern (illicit) modifications. The results reveal extensive modern modification, namely the replacement of original blades—often made of iron—with different (but probably also ancient) bronze blades, conclusively showing that “iron cores” were not a technological feature in these bronze swords, but a result of modern tampering. Widespread iron blade replacement has masked the true extent of the production of bimetallic weapons and obscured the technological choices of early ironworkers. Given the centrality of unprovenanced objects in discussions of Iranian Iron Age metallurgy, these modifications have negative consequences for efforts to map the process of iron innovation.This work was supported by an ISIS Facility Development Studentship from the Science and Technology Facilities Council and Cranfield University. Experiments at the ISIS Neutron and Muon Source were supported by a beamtime allocation RB2220602 and RB2310309 from the Science and Technology Facilities Council.Journal of Archaeological Scienc
Measurements and analysis of the radar cross section of chaff dipoles
Get PDFA free space test method to measure the Radar Cross Section (RCS) of single dipole elements is presented. The method is such that dipoles can be measured over a large range of frequencies, in free space and without the need of an anechoic chamber. The setup employs with a Vector Network Analyser (VNA) synchronised to a rotating turntable that controls the position of the transmitting and receiving antennas and the polarisation of the irradiated electric field. Measurements are collected for chaff dipoles made of copper wire, microwire and aluminised glass, from 5 to 11 GHz, to allow a comparison of chaff RCS properties with respect to chaff material and method of fabrication. Measurements of the copper wire chaff also allowed a comparison with existing theoretical predictions of chaff reflectivity. An analysis and a comparison of the results is presented. Results show that the experimental trends of the chaff RCS curves agree with the theoretical RCS curves for perfectly conducting wires. They also show that copper wire provides the strongest reflective chaff followed by the aluminised glass and the microwire.This work has been supported by the UK MOD Centre for Defence and Enterprise (CDE 33811 Phase 2 –Research and Development into Chaff Improvement Programme Phase 2). Dstl Contract No. DSTL/AGR/00623/01.IET Radar, Sonar & Navigatio
Editorial: FEAST of biosensors: food, environmental, and agricultural sensing techniques
Get PDFBiosensors are analytical devices that involve biological elements, such as nucleic acids, antibodies, enzymes, cells and microorganisms with a physicochemical (such as optical, electrical and mechanical) detectors. In the last 5 years the number of publications with the keyword “biosensor” is over 5,000 per year from the Web of Science and various biosensors are being designed and fabricated for high-efficiency, multiplex-functionality and high-flexibility sensing applications in the field of food, environment and agriculture. Many existing biosensors have the inherent capacity to achieve such goals; however, they require further development into and make it more easy-to-use and reduce cost without compromising the analytical performance such as sensitivity and specificity, as well as at a greater scale than heretofore possible.Frontiers in Bioengineering and Biotechnolog
Aircraft skin machine learning-based defect detection and size estimation in visual inspections
Get PDFAircraft maintenance is a complex process that requires a highly trained, qualified, and experienced team. The most frequent task in this process is the visual inspection of the airframe structure and engine for surface and sub-surface cracks, impact damage, corrosion, and other irregularities. Automated defect detection is a valuable tool for maintenance engineers to ensure safety and condition monitoring. The proposed approach is to process the captured feedback using various deep learning architectures to achieve the highest performance defect detections. Additionally, an algorithm is proposed to estimate the size of the detected defect. The team collaborated with TUI’s Airline Maintenance Team at Luton Airport, allowing us to fly a drone inside the hangar and use handheld cameras to collect representative data from their aircraft fleet. After a comprehensive dataset was constructed, multiple deep-learning architectures were developed and evaluated. The models were optimized for detecting various aircraft skin defects, with a focus on the challenging task of dent detection. The size estimation approach was evaluated in both controlled laboratory conditions and real-world hangar environments, providing insights into practical implementation challenges.Engineering and Physical Sciences Research Council, Research England, Boeing (United States)This research was supported and funded by the British Engineering and Physics Sciences Research Council (EPSRC IAA project) and Boeing Company.Technologie