Fast Transition Research Articles

Practical tips for a fast and successful transition to an online curriculum.

The COVID-19 pandemic and the following lockdown forced educational institutions to transform their face-to-face curriculum into an online programme in a matter of weeks. In this article, we present 12 tips for a successful transition based on the challenges that we faced in the Bachelor of Medicine at Amsterdam Medical Centre. These tips are divided in four main themes: infrastructure, faculty development, student engagement, and teaching activities. The Community of Inquiry model is used as backbone in all tips, since the three elements, teaching presence, social presence, and cognitive presence are essential factors in effective online education. These tips can be useful for everyone who wants to implement online education in their curriculum, whether borne out of necessity or by design.

Effect of installing branch-shaped fin on cold energy saving during freezing considering nanomaterial

This research examines the solidification through a finned tank containing alumina nano-powders and water as PCM (phase change material). Mathematical models were developed, assuming a uniform concentration of nano-powders and neglecting convective term effects. The model includes three time-dependent terms, discretized using an implicit approach, with solutions obtained via the Galerkin method and convergence achieved using an adaptive mesh. The thermal conductivity of NEPCM improves with increased concentration (ϕ), resulting in a faster transition from liquid NEPCM to ice. For pure water, the complete freezing time is 6795.38 s; however, with additives, this time is reduced by 26.78 %. Additionally, using powders with a higher "m" value further accelerates the freezing process, decreasing the completion time by about 6.98 %. The effect of powder configuration becomes more pronounced with increasing concentration. These findings are crucial for enhancing the sustainability of natural resources by improving cold storage and solidification processes.

Optical pulse-induced ultrafast antiferrodistortive transition in SrTiO3

The ultrafast dynamics of the antiferrodistortive phase transition in perovskite SrTiO3 is monitored via time-domain Brillouin scattering. Using femtosecond optical pulses, we initiate a thermally driven tetragonal-to-cubic structural transformation and detect the crystal phase through changes in the frequency of Brillouin oscillations (BO) induced by propagating acoustic phonons. Coupling the measured BO frequency with a spatiotemporal heat diffusion model, we demonstrate that, for a sample kept in the tetragonal phase, deposition of sufficient thermal energy induces a rapid transformation of the heat-affected region to the cubic phase. The initial phase change is followed by a slower reverse cubic-to-tetragonal phase transformation occurring on a timescale of hundreds of picoseconds. We attribute this ultrafast phase transformation in the perovskite to a structural resemblance between atomic displacements of the R-point soft optic mode of the cubic phase and the tetragonal phase, both characterized by anti-phase rotation of oxygen octahedra. The structural relaxation time exhibits a strong temperature dependence consistent with the prediction of the equation of motion describing collective oxygen octahedra rotation based on the energy landscape of the phenomenological Landau theory of phase transitions. Evidence of such a fast structural transition in perovskites can open up new avenues in information processing and energy storage sectors.

Effects of mass and damping ratios on the flow-induced vibration of two staggered circular cylinders

The mass ratio between structure and fluid and the structural damping ratio have been shown to significantly affect the flow-induced vibration (FIV) of an isolated circular cylinder. Their influences on multiple staggered circular cylinders commonly found in offshore structures have, however, not been clearly understood. This study numerically investigates the vibration responses and flow field of two staggered circular cylinders with the shear stress transfer k–ω turbulence model and the overset mesh method. The accuracy of the numerical method adopted is validated against published experimental results, and the effects of the mass ratio and damping ratio on FIV are systematically investigated. The structural responses of the two cylinders are found more sensitive to the mass ratio than the damping ratio. The amplitude of vibration increases, in general, with a reduction in the mass ratio or damping ratio, and the vibration is much more significant when the mass ratio is less or equal to unity as compared to those from other mass ratio values. A reduction in the mass ratio is found leading to more diverse vortex shedding modes with fast transition from one into another. The self-excited dynamic forces represented by the added mass ratio ma* and added damping ratio ζa are further analyzed. It is found that the added mass ratio is positive under low inflow velocity, and it gradually becomes negative with higher inflow velocity. The added damping ratio is generally negative under low inflow velocity and it increases with the inflow velocity. Furthermore, the added damping ratio decreases with the inflow velocity only when the mass ratio is smaller than unity.

The Impact of Surface Structure Changes on the Aerodynamic Characteristics of Modern Soccer Balls

PURPOSE This study comprehensively examined the aerodynamic and flight characteristics of modern soccer balls, focusing on their design evolution and performance attributes. METHODS The aerodynamic characteristics of five types of World Cup balls (2006 Germany World Cup, 2010 South Africa World Cup, 2014 Brazil World Cup, 2018 Russia World Cup, 2022 Qatar World Cup) and five types of Euro tournament balls (EURO2008, EURO2012, EURO2016, EURO2020, EURO2024) were examined, along with their respective design changes. RESULTS Through detailed analysis, significant variations in aerodynamic properties among soccer balls used in various tournaments were identified. Recent advancements have resulted in faster transitions towards critical Reynolds numbers, indicating improved stability in flight trajectories. This enhancement was attributed to the augmentation of surface roughness, which plays a crucial role in enhancing aerodynamic stability and overall performance. 2D simulations simulating powerful goalkeeper kicks revealed distinct differences in flight distances among different soccer balls; the Jabulani ball used in the 2010 World Cup exhibited the longest flight distance, while that of the 2024 Euro ball was the shortest. CONCLUSIONS Variations in surface texture significantly impact aerodynamic properties, affecting flight distance, arrival time, and height. This study underscores the significant design enhancements in modern soccer balls that optimize aerodynamic stability and performance, with modifications aimed at improving flight characteristics and enriching player experience.

Bidirectional Voltage Regulation for Integrated Photovoltachromic Device Based on P3HT-Electrochromic Unit and Perovskite/Organic Tandem Solar Cells.

Integrated electrochromic devices powered by photovoltaic cells have evoked a lot of interest due to their promising commercial prospects. However, their application has been restricted by the voltage adaption between the self-powered voltage and the color-changing threshold voltage (Vt). Herein, a strategy of bidirectional voltage regulating is proposed to develop a novel stand-alone integrated photovoltachromic device (I-PVCD), which integrates perovskite/organic tandem solar cells (P/O-TSCs) to drive color-changing process of conjugated poly(3-hexylthiophene) (P3HT) films. To lower the driving-voltage of electrochromic layer, C60 is introduced to decrease the onset oxidation potential of P3HT film, and thus leading to a reduced Vt of 0.70V benefiting from the enhanced highest occupied molecular orbital level and decreased charge transfer resistance from 67.46 to 49.89 Ω. Simultaneously, PBDB-T is utilized as the hole transport layer in the interconnecting layer of CsPbI2Br/PTB7-Th:IEICO-4F P/O-TSC to improve its open-circuit voltage (Voc) to 1.85V. Under their synergetic merits, a I-PVCD with a wider self-adaptive voltage range is achieved. This device can undergo fast and reversible chromic transition from beautiful magenta to transparent only under the solar radiation, and demonstrates a coloration efficiency of 351.90 cm2 C-1 and a switching time of 2 s besides its excellent operating reliability.

Origin for the fast II-I phase transition of vacuum carbon-coated isotactic poly(1-butene) melt-drawn films after melt recrystallization

Ultrathin films of isotactic poly(1-butene) (iPBu) with highly oriented form I fibril crystals have been prepared by a melt-draw technique. The melt recrystallization of these films after vacuum evaporation of a thin carbon layer on their surfaces has been conducted and highly oriented films with form II chain fold lamellar structure have been obtained. Therefore, the spontaneous II-I phase transition of thus prepared iPBu films has been studied and compared with their non-oriented counterparts either with or without carbon-coating. The results show that surface carbon decoration slows down the II-I phase transition of the non-oriented films with respect to the non-carbon-coated ones. In strong contrast, the II-I phase transition of oriented films with carbon-coating has been tremendously accelerated. This is attributed to the fixing effect of coated carbon layer on the extended iPBu molecular chains initially packed in the crystalline unit cell of the fibrils. These extended molecular chains pass through multiple crystalline lamellae and consequently generate external stresses between the lamellae, which have been confirmed to promote the II-I phase conversion. Moreover, the recrystallization temperature shows evident influence on the II-I transformation. The higher the recrystallization temperature, the faster the II-I transition, which has been associated to the increased external stresses originating from tightly entangled loops caused by thickening of the lamellae at higher crystallization temperature.

Sb‐Se‐based electrical switching device with fast transition speed and minimized performance degradation due to stable mid‐gap states

Sb‐Se‐based electrical switching device with fast transition speed and minimized performance degradation due to stable mid‐gap states

Room-Temperature Near-Infrared Phosphorescence from C64 Nanographene Tetraimide by π-Stacking Complexation with Platinum Porphyrin.

Near-Infrared (NIR) phosphorescence at room temperature is challenging to achieve for organic molecules due to negligible spin-orbit coupling and a low energy gap leading to fast non-radiative transitions. Here, we show a supramolecular host-guest strategy to harvest the energy from the low-lying triplet state of C64 nanographene tetraimide 1. 1H NMR and X-ray analysis confirmed the 1 : 2 stoichiometric binding of a Pt(II) porphyrin on the two π-surfaces of 1. While the free 1 does not show emission in the NIR, the host-guest complex solution shows NIR phosphorescence at 77 K. Further, between 860-1100 nm, room temperature NIR phosphorescence (λmax=900 nm, τavg=142 μs) was observed for a solid-state sample drop-casted from a preformed complex in solution. Theoretical calculations reveal a non-zero spin-orbit coupling between isoenergetic S1 and T3 of π-stacked [1 ⋅ Pt(II) porphyrin] complex. External heavy-atom-induced spin-orbit coupling along with rigidification and protection from oxygen in the solid-state promotes both the intersystem crossing from the first excited singlet state into the triplet manifold and the NIR phosphorescence from the lowest triplet state of 1.

Experimental and numerical study of different mode-locking techniques in holmium fiber laser with a ring cavity.

Experimental and numerical study has been performed for three techniques of mode-locking in all-fiber Holmium laser. We have compared the fundamental repetition rate pulsed generation for mode-locking based on: nonlinear polarization evolution, polymer-free single-walled carbon nanotubes, and hybrid mode-locking. Experimental and numerical simulation results demonstrated the shortest pulse duration and maximum spectrum width for mode-locking based on the nonlinear polarization evolution: 1.3 ps, 4.2 nm and 1.3 ps, 4.1 nm, respectively. The self-starting mode in this case can vary depending on external conditions in the experiment. In Ho-doped fiber laser with polymer-free single-walled carbon nanotubes mode-locking, the small modulation depth of saturable absorption leads to a long time period of stationary single-pulse lasing development (about 104 cavity roundtrips in simulation, and ≈5 s in the experiment). Both experimental and numerical studies have indicated that a Ho-doped fiber laser with hybrid mode-locking provides optimal generation, enabling self-starting and a relatively fast transition to stable single-pulse lasing (less than 1.5 × 103 cavity roundtrips in simulation, and ≈3 s in experiment). This study presents the first employment of polymer-free single-walled carbon nanotubes for hybrid mode-locking in a Ho-doped fiber laser.

A fast transition: A case study of patients' experiences during the diagnostic and surgical treatment phase of an accelerated brain cancer pathway.

Patients receiving a brain cancer diagnosis may face cognitive decline and a poor prognosis. In addition, they suffer from a high symptom burden in a complex cancer pathway. The aim of this study was to investigate the early hospital experiences of brain tumour patients during the diagnostic and surgical treatment phase. A descriptive longitudinal single-case study design was used, and data were analysed via systematic text condensation. The patients' experiences of being diagnosed with and treated for brain cancer were interpreted in terms of the central theme: a fast transition into an unknown journey. This theme consisted of the following subthemes: emotionally overwhelmed, putting life on hold and an unfamiliar dependency. Patients diagnosed with brain cancer struggle with overwhelming emotions due to this sudden life-threatening diagnosis, their fear of brain surgery and their progressing dependence. Patients did not voice their feelings, fears or needs, so these may easily be overlooked and unmet. A proactive and continuous care approach throughout the diagnostic phase is needed to support these patients.

Gravitational wave signals from early matter domination: interpolating between fast and slow transitions

An epoch of matter domination in the early universe can enhance the primordial stochastic gravitational wave signal, potentially making it detectable to upcoming gravitational wave experiments. However, the resulting gravitational wave signal is quite sensitive to the end of the early matter-dominated epoch. If matter domination ends gradually, a cancellation results in an extremely suppressed signal, while in the limit of an instantaneous transition, there is a resonant-like enhancement. The end of the matter dominated epoch cannot be instantaneous, however, and previous analyses have used a Gaussian smoothing technique to account for this, and consider only a limited regime around the fast transition limit. In this work, we present a study of the enhanced gravitational wave signal from early matter domination without making either approximation and show how the signal smoothly evolves from the strongly suppressed to strongly enhanced regimes.

Chip-Scale Watt-Range Terahertz Generation Based on Fast Transition in Nanoplasma Switches

Chip-Scale Watt-Range Terahertz Generation Based on Fast Transition in Nanoplasma Switches

Competition between biodetoxification fungus and lactic acid bacterium in the biorefinery processing chain for production of cellulosic L-lactic acid

Biodetoxification fungus selectively degrades toxic inhibitors generated from pretreatment of lignocellulose without consuming fermentable sugars. However, one barrier for practical application is the sustained cell viability in the consequent fermentation step to compete the fermentable sugars with fermenting strains, resulting in sugar loss and reduced target product yield. This study investigated the competitive growth property between the biodetoxification fungus Paecilomyces variotii FN89 and the L-lactic acid bacterium Pediococcus acidilactici ZY271 under varying temperature and lactic acid osmatic stress. The results show that the L-lactic acid bacterium Ped. acidilactici ZY271 showed less thermotolerance to Pae. variotii FN89 at high temperature of 45 °C to 50 °C in both synthetic medium and wheat straw hydrolysate. In the higher temperature environment, the growth of the biodetoxification strian failed to compete with the lactic acid fermentation strain and was quickly eliminated from the fermentation system. The high temperature fermentation facilitated a fast transition from the detoxification stage to the fermentation stage for higher production of L-lactic acid.

Understanding the microstructure evolution of carbon-doped Sb2Te3 phase change material for high thermal stability memory application

The Sb2Te3 phase change material shows a growth-dominated crystallization mechanism with fast phase transition but poor thermal stability of the amorphous state. This work investigated the effects of carbon doping on the thermal stability, microstructure, and electrical properties of the Sb2Te3 material. The 10-year data retention temperature of the material increased to ∼147.3 °C and the size of the grains was limited to ∼10 nm by carbon doping. The formation of the C cluster upon crystallization was found at the grain boundaries, which was accelerated as the temperature increased due to the break of the Sb–C bonds. The memory device based on the carbon-doped Sb2Te3 material exhibited a switching speed of 15 ns and an endurance of ∼105 cycles with a resistance ratio of more than two orders of magnitude. This work suggests that the carbon-doped Sb2Te3 material is a promising candidate for memory applications that require high thermal stability, fast speed, and high endurance.

Growth of β-Ga2O3 nanostructures by thermal oxidation of GaN-on-sapphire for optoelectronic devices applications

Heterostructures of wide-bandgap semiconductors, like β-Ga2O3/ GaN, are being used in many high-power, high-frequency electronic and optoelectronic devices. This paper presents the growth of β-Ga2O3 thin film and nanostructures by thermally oxidizing (at 1000 °C) the planar and nano-structured GaN surfaces respectively. The nano-structures of GaN (having 300–500 nm long vertical nano-kinks) are fabricated by metal-assisted chemical etching of GaN surface for 1–2 hours. The thermally grown β-Ga2O3 samples are polycrystalline. The chemical analysis of the samples using X-ray photoelectron spectroscopy (XPS) showed enhancement of Ga-O peak intensity (at 20.21–20.3 eV) at the expense of the Ga-N peak intensity (at 19.2–19.7 eV) in the thermal oxidation process. The O1s XPS spectra of the oxidized samples exhibited prominent signature of O2- ions (530.7–530.9 eV) representing the formation of Ga2O3 with presence of adsorbed hydroxyl group at the surface (532.2 – 532.4 eV). The valance band XPS spectra disclosed the formation of an additional Ga(4 s)–O(2p) hybridization energy state, and the valence band maxima increased from 2.3 eV to 3.25 eV. The Raman spectra of the oxidized samples exhibited multiple Ag and Bg vibrational modes of β-Ga2O3 along with intense E2(high), A1(LO) modes of GaN. The time-resolved photoluminescence spectra of the samples demonstrated fast transition of charge carriers from excited state to ground state with 460–820 pico-seconds average career lifetime.

Experimental study of the vacuum arc motion-diffuse transition in cup-shaped transverse magnetic field contacts

The arc in transverse magnetic field (TMF) contacts transitions to diffusion mode before current zero, affecting arc morphology and motion. TMF-generated force competes with local overheating's stagnation effect, impacting contact surface ablation. Cup-shaped TMF contacts exhibit slow, fast, and unstable transitions. Arc voltage declines gently, rapidly, or in repeated steps. Peak current, contact diameter, contact piece structure, and iron core influence transition characteristics. Transition energy increases linearly with peak current. Larger contact diameter and iron cores make transition constant earlier and transition current higher. Compared to circular contacts, annular contacts delay transition constant and widen transition current range. Scanning electron microscope (SEM) images showed that the ablation cathode surfaces exhibited five morphologies: melting pit, periphery, lamellar, particle, and pore. Energy dispersive spectrum (EDS) analyses show that the periphery has a higher Cu content than the interior, suggesting less Cu loss during fracture and less droplet splashing. The peripheral Cu content is comparable between the two contacts, 62.94 % vs. 62.37 %. However, the interior Cu content of contact NO.4 is higher than NO.6 at 60.54 % vs. 56.26 %. This indicates that the difference in the effect of fast and slow transitions on the cathode surface activity is mainly in the interior region.

A Review on Automatic Toll Collection System

One of the most crucial elements for any country's development is logistics, or transportation. Since India is one of the world's largest nations, road transportation plays a vital role in the country's economy. For any government, having fast road transit becomes essential, and toll plazas are essential to this. The most commonly used toll systems in India at the moment are the manual toll collection and FASTag systems. Toll plaza processing times rise as a result of their need for a toll collector or attendant. The Automatic Toll Collection System, or ATCS, is a tool used to automatically collect taxes. Here, radio frequency is used to help in identification. An RFID tag will be attached to a car. This tag is nothing more than an allocated unique identification number. The RTO, or traffic controlling body, will assign this. We shall keep all of his basic data and the amount he has paid in advance for the TOLL collection in line with this number. At the toll collection facility, the reader will be positioned strategically. His prepaid balance will be reduced by the tax amount each time the car passes the toll collection center. This essay discusses several automated toll collection systems that are intended to improve overall transportation efficiency, ease toll payment procedures, and lessen traffic congestion. The suggested method computes toll fees automatically by utilizing cutting-edge technology including mobile communication, GPS, and RFID (Radio Frequency Identification).

Transition probabilities of diabetic retinopathy and death in an Asian population with diabetes

PurposeTo evaluate the dynamic transitions in diabetic retinopathy (DR) severity over time and associated risk factors in an Asian population with diabetes. DesignLongitudinal cohort study MethodsWe analyzed data from 9481 adults in the Singapore Integrated Diabetic Retinopathy Screening Program (2010–2015) with linkage to death registry. A multistate Markov model adjusted for age, sex, systolic blood pressure (SBP), diabetes duration, HbA1c, and body mass index (BMI) was applied to estimate annual transition probabilities between four DR states (no, mild, moderate, and severe/proliferative) and death, and the mean sojourn time in each state. ResultsThe median assessment interval was 12 months, with most patients having 3 assessments. Annual probabilities for DR progression (no-to-mild, mild-to-moderate and moderate-to-severe/proliferative) were 6.1 %, 7.0 % and 19.3 %, respectively; and for regression (mild-to-no, moderate-to-mild and severe-to-moderate) were 55.4 %, 17.3 % and 4.4 %, respectively. Annual mortality rates from each DR state were 1.2 %, 2.0 %, 18.7 %, and 30.0 %. The sojourn time in each state were 8.2, 0.8, 0.8 and 2.2 years. Higher HbA1c and SBP levels were associated with progression of no-mild and mild-moderate DR, and diabetes duration with no-to-mild and moderate-to-severe/proliferative DR. Lower HbA1c levels were associated with regression from mild-to-no and moderate-to-mild, and higher BMI with mild-to-no DR. ConclusionsOur results suggest a prolonged duration (∼8 years) in developing mild DR, with faster transitions (within a year) from mild or moderate states. Moderate/above DR greatly increases the probability of progression and death as compared to mild DR/below. HbA1c was associated with both progression as well as regression.

Effects of carbon concentration on the local atomic structure of amorphous GST.

Ge-Sb-Te (GST) alloys are leading phase-change materials for data storage due to the fast phase transition between amorphous and crystalline states. Ongoing research aims at improving the stability of the amorphous phase to improve retention. This can be accomplished by the introduction of carbon as a dopant to Ge2Sb2Te5, which is known to alter the short- and mid-range structure of the amorphous phase and form covalently bonded C clusters, both of which hinder crystallization. The relative importance of these processes as a function of C concentration is not known. We used molecular dynamics simulation based on density functional theory to study how carbon doping affects the atomic structure of GST-C. Carbon doping results in an increase in tetrahedral coordination, especially of Ge atoms, and this is known to stabilize the amorphous phase. We observe an unexpected, non-monotonous trend in the number of tetrahedral bonded Ge with the amount of carbon doping. Our simulations show an increase in the number of tetrahedral bonded Ge up to 5 at.% C, after which the number saturates and begins to decrease above 14 at.% C. The carbon atoms aggregate into clusters, mostly in the form of chains and graphene flakes, leaving less carbon to disrupt the GST matrix at higher carbon concentrations. Different degrees of carbon clustering can explain divergent experimental results for recrystallization temperature for carbon doped GST.