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Bismuth-Assisted Synthesis of Low-Dimensional Copper Halide for X-ray Imaging Scintillators
No full textLead-free perovskite-related materials are gaining significant attention as X-ray scintillators due to their low toxicity and high X-ray absorption cross section, which leads to a high light yield. The zero-dimensional copper halide Cs3Cu2I5 (CCI) exhibits a very high photoluminescence quantum yield and blue emission, making it compatible with photomultipliers with a higher photon detection efficiency in this wavelength range. However, the oxidation of copper, along with the phase transition to a less emissive one-dimensional copper halide, presents significant stability challenges for these powerful scintillation materials, ultimately limiting their potential for future commercialization. In this work, we propose heavy atom doping with bismuth, which not only enhances the oxidation resistance of copper but also inhibits the phase transformation. By addition of trivalent bismuth during the antisolvent synthesis, we achieved nearly 60% increase in radioluminescence and a spatial resolution of 19 lp/mm while maintaining the original blue emission. We also compared the scintillation properties of our CCI:Bi with those of commercial LYSO:Ce, both of which emit at a peak wavelength of 450 nm. By irradiating the materials at varying dose rates, we evaluated their sensitivity to changes in irradiation. LYSO:Ce generates 33,000 photons/MeV, while our CCI:Bi produces over 66,000 photons/MeV, based on radioluminescence area comparisons. Furthermore, the calculated detection limits are 46 nGy/s for CCI:Bi─over 100 times lower than the standard dose for medical examinations─and 95 nGy/s for LYSO:Ce. These findings underscore the significant potential of CCI:Bi as a highly sensitive and stable X-ray scintillator.This work was supported by the King Abdullah University of Science and Technology (KAUST)
Q-POP-IMT: An open-source phase-field software for simulating insulator-metal transition processes in quantum materials
No full textInsulator-metal transitions in quantum materials have important potential applications in areas such as field-effect transistors and neuromorphic computing. Here we present an initial release of the Q-POP-IMT module, an open-source phase-field software for simulating mesoscopic, nonequilibrium processes of insulator-metal transitions in quantum materials. Q-POP-IMT solves the phase-field equations of evolution that describe insulator-metal transitions at the mesoscale using the finite element method. It currently utilizes the powerful FEniCS library to define and solve finite element problems. Thanks to the finite element method, the code can address general boundary conditions such as a complex integral boundary condition corresponding to one of the most common setups in experiments and applications. We demonstrate the usage of the code through simulating the neuron-like voltage self-oscillation phenomenon in a prototypical correlated material, vanadium dioxide
Turbulence-chemistry interactions in piloted partially premixed cracked ammonia-air flames with high Reynolds numbers
No full textThis study investigates turbulence-chemistry interactions in piloted NH₃/H₂/N₂-air flames at Reynolds numbers of 24,000, 32,000, and 36,000, referred to as Flames D, E, and F, respectively. Raman/Rayleigh scattering and NH₂/OH-LIF measurements are used to analyze flame structure in mixture fraction and temperature space as well as physical space. Probability density functions (PDFs) provide insights on local extinction behavior, while conditional means of the NH3/H2 ratio yield insights on differential diffusion. With increasing Re, the flames exhibit stronger entrainment, leading to higher fluctuations in the outer shear layers between the piloted products and coflow air in the near-field (Z/D = 1-2). At Z/D > 15, enhanced turbulent mixing at higher Re results in lower NH₃, H₂, mixture fraction, OH, and NH₂ downstream. The local extinction probability increases with Re, with significant extinction observed in Flames E and F. Three distinct reaction zones are identified, corresponding to peak OH, peak temperature, and peak NH₂. Extinction initially occurs in the fuel-lean side, followed by the fuel-rich side. Reignition occurs earlier in Flame E (by Z/D = 10), whereas in Flame F, it is delayed until Z/D = 20. The flame structure reveals a balance between differential diffusion effects and turbulent mixing in the fuel-rich regions for all three flames. Further downstream, differential diffusion effects are more pronounced in Flame D, resulting in a higher NH₃/H₂ ratio, while in Flames E and F, the influence of differential diffusion diminishes due to the higher Re. This series of flames (D, E, and F) provides a valuable dataset for validating ammonia combustion models, particularly in the context of differential diffusion, local extinction, and turbulence-chemistry interactions in high-Reynolds-number flows.The experiments in this publication were performed at King Abdullah University of Science and Technology under CRG10 grant # URF/1/4683-01-01
Biologically Driven Coral Growth Reconstruction
No full textWe present a simulation-driven framework for reconstructing branching coral colonies from compressed skeletal representations. Our method extracts a compact graph-based skeleton tailored to coral morphology, reducing memory requirements by up to three orders of magnitude compared to mesh-based representations. Guided by this skeleton, we simulate polyp-level growth using biologically inspired rules, producing temporally coherent reconstructions. This approach enables biologically plausible reconstruction, visualization, and large-scale analysis of coral colonies without reliance on storage-intensive mesh data, and paves the way for further computational coral simulation
Design and Optimization of Two-Stage Bias Control for DD-MZM-Based Coherent Optical Modulation
No full textThis paper presents an optimized control framework for generating quadrature phase-shift keying (QPSK) optical signals using dual-drive Mach-Zehnder modulators (DD-MZMs). QPSK modulation in high-speed optical systems demands precise control of parameters like bias and peak-to-peak (P2P) voltages to ensure stable signal output and low bit error rates (BER). To address this, we introduce a two-stage automatic voltage control (TAVC) algorithm designed to track and optimize MZM and MZI bias voltages in real-time, even under environmental disturbances such as temperature fluctuations and device aging. Theoretical models are developed to quantify phase bias voltage jitter effects on BER, providing insights into selecting optimal P2P voltage offset values based on photodetector (PD) noise levels. Simulation results validate the proposed framework's effectiveness in achieving minimal BER and robust signal stability. This work contributes to advancing control methodologies for high-speed optical communications, paving the way for reliable QPSK signal generation in noise-prone environments
Transient Fluted Films behind Falling Water Columns
No full textWhen a column of water drains from a vertical tube, it often leaves behind a trailing film that forms intricate, axisymmetric liquid structures. Using high-speed imaging and first-principles modeling, we investigate the formation and breakup of these fluted films and demonstrate that their diverse morphologies arise from the evolving balance of inertia, surface tension, gravity, and viscous forces. By analyzing the characteristic timescales for film emergence, retraction, and rupture, we classify the observed behaviors into distinct regimes and predict the transitions between them. Our theoretical framework captures the transient velocity and thickness of the film at the tube exit and yields regime boundaries that closely match experimental observations. These results not only explain a deceptively simple fluid dynamic system but also provide insight into film stability, merging, and rupture processes relevant to falling film evaporators, coating flows, and capillary-inertial instabilities across soft matter and multiphase systems.M.\u2009B.\u2009J., T.\u2009T.\u2009T., and J.\u2009B. acknowledge funding from the Office of Naval Research, Navy Undersea Research Program (Grant No. N000141812334), monitored by Ms. Maria Medeiros. J.\u2009B. acknowledges funding from the Naval Undersea Warfare Center In-House Laboratory Independent Research program, monitored by Dr. Elizabeth Magliula. N.\u2009B.\u2009S. and T.\u2009T.\u2009T. acknowledge funding from the Utah State University Research and Graduate Studies Development Grant Program
CCDC 2389635: Experimental Crystal Structure Determination : catena-[(mu-iodo)-(pyridine)-copper(i)]
No full textAn entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures
Probiotics prevent mortality of thermal-sensitive corals exposed to short-term heat stress.
No full textThe use of coral probiotics, i.e. beneficial microorganisms for corals (BMCs), is a novel approach to enhancing coral health under heat stress conditions. While BMCs mitigate coral bleaching and mortality during prolonged heat stress conditions, their effectiveness in mitigating short-term acute heat stress remains understudied. This study investigates BMCs effects on two Red Sea hard coral species, Acropora cf. hemprichii and Pocillopora verrucosa, during short-term heat stress. Twelve coral fragments per species were allocated to each treatment across two temperature regimes (26°C and 32°C) for 48 hours, with half receiving BMC inoculation and half serving as controls. Results show BMC supplementation significantly prevented mortality in Acropora cf. hemprichii at 32°C, contrasting with a 100% mortality observed in the control group. Specifically, probiotic-inoculated Acropora cf. hemprichii at 32°C exhibited preserved primary production, a 12–13 fold increase in algal cell densities, 4–5 times higher FV/Fm ratios, and 4–5 and 2–3 times higher chlorophyll a and c2 concentrations, respectively, compared to their untreated conspecifics. All P. verrucosa colonies survived the 32°C exposure without tissue loss or reduced holobiont function in both control and BMC treatments. These findings underscore the rapid effects of BMC inoculation, initiated just two hours prior to acute heat stress, in protecting heat-sensitive Acropora cf. hemprichii against mortality and adverse photo-physiological changes, with beneficial effects visible within two days. Recognizing the critical timeframe for beneficial effects is paramount for management strategies to address heat-sensitive corals on natural reefs, such as implementing probiotic interventions before anticipated marine heatwaves.We would like to thank the team at the Microbiomes lab and KAUST Core Labs and CMOR staff for their technical and logistics support for laboratory processing and diving operations with a special thanks to Miguel Viegas. R.S.P acknowledges KAUST funding BAS/1/1095-01-01
A Reconfigurable Mem-Element Using CMOS Current Amplifiers
No full textThere is a plethora of mem-element emulators using different active devices, current amplifier (CA) based memristor, memcapacitors, and meminductor have not been reported in the literature. Although the CA is one of the four fundamental amplifier types, its applications has been limited because synthesis of CA based circuits is challenging. The main contributions of this paper are presenting these missing emulator circuits and demonstrating the realization of a novel universal reconfigurable mem-element using CAs realized in CMOS technology. Since CAs have the potential advantage of offering wide bandwidth compared to its voltage-mode counterparts, these new circuits inherently would exhibit improved frequency response. Various types of mem-elements using only CAs and a multiplier are developed in this work. Starting from the mathematical foundation of the linear model of a mem-element, this work provides a systematic approach leading to the design of a novel reconfigurable mem-element based on CAs. The proposed mem-elements are designed in 180 nm TSMC CMOS process. Cadence simulations show an operating frequency up to 1 MHz while consuming less than 3 mW. Also, experimental results using a prototype implemented using commercially available ICs show the validity of the proposed designs.No funding was received to assist with the preparation of this manuscript
Interfacial Chemistry of Plasticizer to Invoke High-Performance Silicon Anodes for Quasi-Solid Lithium-Ion Batteries
No full textQuasi-esolid lithium-ion batteries, integrating quasi-solid polymer electrolytes (QSPEs) and high-capacity silicon (Si) anodes, exhibit great promise for next-generation energy storage due to their high energy density and improved safety. However, their practical application is significantly hindered by poor electrolyte-electrode interface compatibility associated with plasticizers in QSPEs. Herein, a novel QSPE based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) is developed by introducing diethylene glycol dimethyl ether (DEGDME) and fluoroethylene carbonate (FEC) as plasticizers. These plasticizers synergistically promote the formation of favorable interfacial clusters on the Si anode, enabling rapid de-solvation and high reduction stability, which effectively mitigates electrolyte decomposition and enhances the stability of the electrolyte–electrode interface. Consequently, the designed QSPE delivers excellent ionic conductivity of 2.14 mS cm−1 and enables the Si anode to maintain a specific capacity of 1843.6 mAh g−1 after 200 cycles at 2 A g−1 and demonstrates excellent rate performance over 10 A g−1. Moreover, this work sheds new light on the molecular-level evolution of plasticizers at the solid-state electrolyte–electrode interface and elucidates their significant synergistic effect on electrode performance, providing a guideline for designing QSPEs that stabilize Si anodes by prioritizing interfacial compatibility alongside ionic conductivity.<br