Broadband Fourier transform spectroscopy of quantum emitters photoluminescence with sub-nanosecond temporal resolution

The spectral characterization of quantum emitter luminescence over broad wavelength ranges and fast timescales is important for applications ranging from biophysics to quantum technologies. Here we present the application of time-domain Fourier transform spectroscopy, based on a compact and stable birefringent interferometer coupled to low-dark-count superconducting single-photon detectors, to the study of quantum emitters. We experimentally demonstrate that the system enables spectroscopy of quantum emitters over a broad wavelength interval from the near-infrared to the telecom range, where grating-based spectrometers coupled to InGaAs cameras are typically noisy and inefficient. We further show that the high temporal resolution of single-photon detectors, which can be on the order of tens of picoseconds, enables the monitoring of spin-dependent spectral changes on sub-nanosecond timescales

Pathogenic Acanthamoeba Griffini Genotype T3 Isolated From a Geothermal Water Park, Malaysia

Free-living amoebae of the genus Acanthamoeba can cause amoebic encephalitis and keratitis infections. Investigations have been conducted to identify the direct and indirect virulence parameters to establish the pathogenic potential of this amphizoic amoeba due to its widespread distribution. The current study sampled ten sites along a stream in Sungai Klah Geothermal Park, Perak, Malaysia, and seven sites showed the presence of Acanthamoeba. Using a combination of morphology examination and molecular analysis, the samples were identified as A. castellanii, A. griffini, A. lenticulate (putative), and A. polyphaga, belonging to genotypes T3 (n = 2), T4 (n = 4) and T5 (n = 1). An isolate SKGP-5, A. griffini genotype T3 exhibited the highest level of cytotoxicity (based on a HeLa cell monolayer assay and detection of secreted serine proteases) and potential pathogenicity as evidenced by tolerance to the temperature of 42°C and 1M mannitol (hyperosmotic solution). This is the first discovery of a pathogenic A. griffini genotype T3 isolate at a public recreational hot spring in Malaysia, indicating the need for regular monitoring of microorganisms that pose a threat to public health in such settings.</p

Enhanced Permeability Estimation in Microporous Rocks Using a Hybrid Macropore-Darcy Approach

This study presents a novel workflow for constructing hybrid macropore-Darcy models from micro-CT images of microporous rocks. In our approach, macropore networks are extracted using established methods, while the microporosity is characterised through segmented phase classification and incorporated into the model as Darcy cells. Effectively, Darcy cells capture the micro scale connectivity variations that are missing in the macroscopic networks. This dual entity model thus incorporates both the conventional macroscopic pore structure and the critical flow pathways present in the under-resolved microporous regions. The proposed workflow is rigorously validated by comparing the permeability estimates with direct numerical simulation (DNS) results and experimental measurements. Our findings demonstrate that this hybrid approach reliably reproduces fluid flow behaviour in complex porous media while significantly reducing computational demands, offering a promising tool for advanced groundwater modelling and water resource management

The effect of run duration, gait variable and Lyapunov exponent algorithm on the inter-session reliability of local dynamic stability in healthy young people

Local dynamic stability (LDS) of gait has been used to differentiate between healthy and injured populations, establishing its potential as an indicator of healthy gait and a new objective measure to assess gait function following injury. For LDS to be a reliable assessment tool of healthy gait progression during rehabilitation, it must provide consistent and sensitive inter-session measures. Methodological factors such as trial duration, gait variable, and Lyapunov Exponent (LyE) algorithm can influence LDS estimation and its reliability. Young people are a high-risk population for sport-related injuries, and running is a key activity during rehabilitation and is regularly assessed. Therefore, the effects of run duration, gait variable, and LyE algorithm choice on the reliability and sensitivity of inter-session LDS measures in young people were investigated. Sixteen healthy participants ran on a treadmill on two separate sessions (difference of 7 ± 5 days). LDS was calculated using both the Rosenstein and Wolf algorithm for durations of 1-, 2-, 3-, 4- and 5-min of knee flexion angle and medio-lateral acceleration of the pelvis and thorax from each session. The relative and absolute reliability between sessions was calculated using the intraclass correlation coefficient and standard error of measurement. The sensitivity of inter-session LDS change was quantified by the minimal detectable change. Results showed that longer run durations produced higher relative reliability and a minimum run duration of 4 min is recommended to achieve moderate-to-good inter-session reliability across all gait variables and LyE algorithms. However, shorter durations of 2–3 min may still be sufficient when using medio-lateral pelvis acceleration or knee flexion angle, particularly with the Rosenstein algorithm, which also improves sensitivity to change. These findings provide practical guidance for methodological choices when calculating LDS in young people during running and support their potential use as reliable tools for monitoring gait function and tracking rehabilitation progress in young people following injury

Design of 3-D Printed Coaxial Filter Based on Modified Two-Section Stepped Impedance Resonator

This letter proposed a kind of modified two-section coaxial stepped impedance resonator. The analysis expression was given for the first time to obtain the fundamental resonant frequency ( f0 ). In addition, the simulated results showed that the modified resonator can achieve more compact volumes, wider spurious stopband, and higher unloaded quality ( Qu ) factors compared to the published works. A four-pole bandpass filter was designed for validation, which presents the 2216 Qu , 8.4 f0 stopband range with an electrical length (EL) of ~1/15 wavelength. Direct 3-D metal printing technique was adopted to manufacture the filter for a rapid experimental demonstration. As a result, the measured results agreed well with the simulated ones

Silicate Scale Prevention During Low Temperature Geothermal Brine Production Using a Polymer-Based Scale Inhibitor/Dispersant

Silicate scaling is recognized as a potential operational problem for geothermal power plants. In this work, a static bottle test methodology was developed to assist in identifying efficient silicate inhibitors/dispersants with 80-90% performance, applicable for low enthalpy geothermal heat recovery systems. To investigate products to control amorphous silicate and magnesium silicate scale, the inhibition efficiency (IE) and potential mechanism of a sulphonated polymer-based scale inhibitor/dispersant, denoted A5, were studied. The most common metal ion to combine with silicate in power plants is magnesium. In this work, magnesium at an initial concentration of 120ppm, was allowed to react with silicate ions (1880ppm) for 3 days, during silicate scaling static bottle tests (at 60ºC and 95ºC; pH 8.5). The scale inhibitor A5 IE performance was evaluated over a concentration range of 20-500ppm. To investigate the inhibition mechanism of A5, the concentration of sulphur, contained within its structure, was monitored alongside the scaling ion consumption of magnesium and silicate by Inductively Coupled Plasma – Optical Emissions Spectrometer (ICP-OES) throughout the test duration. The 60ºC results are similar whether the scale inhibitor A5 is deployed in magnesium brine or silicate brine. For 20ppm A5, there is less than 60% silicate and magnesium IE at 2hrs and no performance after 22hrs and 3 days. A5 shows 60-85% silicate and magnesium IE performance at 50ppm and above. The most consistent results are measured for A5 in magnesium brine before brine mixing and hence this method is used for subsequent testing. Due to low A5 consumption (&amp;lt; 20%) at 50-500ppm, despite displaying a moderate 60-85% IE performance, it is believed A5 is performing as a dispersant rather than a scale inhibitor. At higher temperature, 95°C, ≥100ppm A5 is required to control silicate scale effectively (cf. 50ppm A5 at 60oC). It appears A5 is less effective at preventing magnesium silicate scale (60-70% IE) as opposed to amorphous silicate scale (80-90% IE). The highest A5 consumption is found at 50-60% for 20ppm and 50ppm, whilst at 100ppm and 200ppm, less than 10% is consumed. These 95ºC results also confirm that A5 is acting as a dispersant, since it is not being consumed during its effective IE performance. A successful investigation of the initial formulation of scale inhibitor in magnesium brine prior to mixing was performed for the first time, due to observed inconsistencies during SI/silicate brine test regimes. This has provided greater confidence in the A5 inhibition performance results. The novel approach of monitoring the scale inhibitor, based on its sulphur content, by ICP-OES, means further insights relating to the inhibition mechanisms can be determined, thus advancing our knowledge of the mechanism of how silicate inhibitors/dispersants work

Enhancing Thermal Management in Protective Textiles Using Hydrated Salt as Phase Change Materials

The thermal properties of textiles are essential for ensuring the comfort of both fabric and clothing systems. Phase change materials (PCMs), which contain latent heat, play a significant role in this area. As ambient temperature fluctuates, PCMs absorb heat, melt or release heat, and solidify. Throughout these melting and crystallizing processes, the temperature of the PCM remains constant. Integrating suitable PCMs into garments helps maintain a stable temperature within the micro-environment between the garment and the wearer. The effectiveness depends on the quantity of PCMs used. This study synthesised and evaluated a novel type of nano-capsule containing PCM Glauber’s salt. Advanced techniques such as Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), and Fourier-Transform Infrared Spectroscopy (FTIR) were employed to analyze the developed nano-capsules. Additionally, a finite element model was created to enhance the understanding of the thermal mechanisms in textiles incorporating PCMs. This comprehensive analysis aims to promote the application of PCMs in protective textiles, contributing to developing next-generation materials that provide thermal regulation and protection for the wearer

On the accuracy of Eulerian-Lagrangian CFD simulations for spray evaporation in turbulent flow

CFD simulation of droplet evaporation in turbulent flows is challenging as the accuracy and reliability of the results strongly depend on the available sub-models and their modeling parameters. This study presents a systematic sensitivity analysis focused on the impact of the most widely used discrete random walk (DRW) model, the constant time scale coefficient (CL), the turbulence model, and the drag coefficient model. CFD simulations with the Eulerian-Lagrangian approach are employed. The analysis is based on grid-sensitivity analysis and validation with measurements of spray evaporation in a heated turbulent airflow. The results show that using the DRW model leads to a good agreement between the CFD results and the experimental data of droplet size and droplet mean velocity, attributed to the turbulent fluctuations inducing droplet dispersion. The best performance is observed for the standard k-ε turbulence model with CL = 0.30 and 0.45. This is mainly attributed to the reasonable interaction time between droplets and turbulent eddies at these CL values. The three drag coefficient models (i.e., Spherical, Ischii-Zuber, and Grace) lead to similar results due to the low droplet Reynolds number