Decay Pattern Research Articles

Conservation-oriented integrated approach for structural stability assessment of complex historic masonry structures

The paper presents a multidisciplinary approach for diagnosing the structural stability of the Takiyya of Ibrahim al-Gulshani in Historic Cairo using geometric and architectural documentation, field survey, laboratory tests, and numerical analyses under static and seismic conditions. The Takiyya, built during the Mamluk period, is an important medieval architectural complex in Egypt and has undergone multiple renovations. The field-testing includes geotechnical and geophysical investigations to evaluate the properties of the bearing soil beneath the monument. A 3D survey using Terrestrial Laser Scanning was employed to record Takiyya’s geometry. Terrestrial photogrammetry and high-resolution images accompanied by an in-situ damage survey were used to document cracking levels, stone weathering, and identification of decay patterns. Laboratory tests were conducted to assess the mineral composition, physical and mechanical properties of the construction materials to enable structural assessments. Data appraisal and integration into architectural drawings was used for mapping degradation patterns and the preservation state of the building. The documentation procedures combined with experiments were then employed to develop a model for structural analysis. Three-dimensional finite element numerical simulations employing macro-modelling approaches were performed for the Takiyya structures under various loading conditions, including modelling the bearing soil, resulting in good agreement with in-situ recorded structure damage patterns. The static and seismic nonlinear analyses helped identify the causes and effects of the current structural deficiencies. The adopted methodologies provided large amounts of information, permitting an improved understanding of existing damage and the assessment of the preservation state of the masonry structure. This project exists thanks to the Egyptian Ministry of Tourism and Antiquities (MoTA) and is funded by World Monument Fund (WMF) through various donors.

Ho3+ -doped BaGd2 ZnO5 green-emitting phosphor for solid-state lighting: synthesis, characterization, and photoluminescence properties.

In this work, we present the synthesis of a green-emitting series of BaGd2 ZnO5 :xHo3+ (0.5-3mol%) phosphors using a high-temperature solid-state reaction method. Phase purity and crystal structure information were evaluated through X-ray powder diffraction patterns. Optical properties were examined through diffuse reflectance spectra, revealing that the prepared phosphor exhibited a band gap of 4.65 eV. The effect of Ho3+ doping on the morphology and ion distribution on the surface was assessed using scanning electron microscopy and time-of-flight secondary ion mass spectrometry techniques, respectively. The excitation spectra of the synthesized phosphor exhibited a charge transfer band and strong absorption transitions. The emission spectra displayed typical holmium emission characteristics, featuring a strong green emission band associated with f-f transitions from 5 F4 + 2 S2 → 5 I8 . Decay dynamics of the synthesized phosphor exhibited a single-exponential decay pattern, with lifetimes ranging from 0.103 to 0.053 ms. The intrinsic radiative lifetime, calculated through Auzel's fitting was determined to be 0.14 ms. Using the emission spectra, colorimetric behaviour was analyzed, revealing that the Commission Internationale de l'éclairage (CIE) coordinates exclusively lay within the green region at (0.285, 0.705), with an impressive colour purity of 99.6%. Given these marked properties, the synthesized phosphor exhibits great potential for a wide range of green-emitting applications, including displays, white light-emitting diodes, and security signage.

A Study of Shock-Induced Transient Jets: The Impact of Exit Conditions on Mach Disk and Vortex Ring

Abstract We investigate the effect of exit pressure history on the flow characteristics of underexpanded transient jets. Using both experiments and numerical simulations, we study the dynamics of shock-cell and vortex structures within these jets. A shock tube with an open-ended configuration allows us to generate transient jets by adjusting the diaphragm pressure ratio and the length of the driver section. Our results indicate that when the shock Mach number exceeds 1.6, a Mach disk forms, indicating a highly underexpanded transient jet at the exit of the shock tube. A distinguishing feature of this jet is the emergence of counter-rotating vortex rings (CRVRs) alongside the initial primary vortex ring. Our findings reveal a substantial influence of both the amplitude and duration of the peak exit pressure on the characteristics of the Mach disk and vortex ring. Notably, the characteristics of the primary vortex ring exhibit significant sensitivity to the formation and evolution of CRVRs. In cases of continuously decreasing exit pressure, the Mach disk follows a consistent self-similar decay pattern, regardless of the peak exit pressure magnitude. Finally, we present an empirical relationship between exit pressure and the characteristics of the Mach disk. In summary, this research provides insight into the complex interaction between the exit pressure history and the flow characteristics in underexpanded transient jets.

Complex magnetic interactions and critical behavior analysis in quaternary CoFeV0.8Mn0.2Si Heusler alloy

We investigate the magnetic behavior and critical exponents of quaternary CoFeV0.8Mn0.2Si Heusler alloy to understand the interactions across the Curie temperature (TC). The Rietveld refinement of the x-ray diffraction pattern with the space group F4¯3m confirms a single-phase cubic Y-type crystal structure. The magnetic susceptibility χ(T) data show a ferromagnetic nature with a second-order phase transition from paramagnetic to ferromagnetic at 446±1 K. The saturation magnetization at 5 K is found to be 2.2 μB/f.u., which is close to the Slater–Pauling rule and indicates its half-metallic nature. The values of asymptotic critical exponents (β, γ, and δ) and the TC are extracted through detailed analytical analysis including the modified Arrott plot, the Kouvel–Fisher (K–F) method, and the Widom scaling relation. Interestingly, the estimated values of β=0.369 and γ=1.445 closely approximate the theoretical values of the 3D Heisenberg model across the TC and validate the second-order thermodynamic phase transition. The obtained exponents lead to the collapse of renormalized isotherms, represented by the relationship between the magnetization (m) and the applied magnetic field (h), into two distinct branches above and below the TC, which validates the reliability of the analysis. Furthermore, these exponents suggest that the spin interaction follows a decay pattern of J(r)∼r−4.99, indicating a short-range magnetic ordering, akin to the itinerant-electron 3D Heisenberg model.

On-Shelf and Operational Decay Dynamics of Self-Healing Quasi-Two-Dimensional Perovskite Light-Emitting Devices.

Currently, the external quantum efficiency (EQE) performance of perovskite light-emitting diodes (PeLEDs) is approaching its theoretical limit. The main drawback of PeLEDs is their stability. Ion migration in the perovskite layer is one of the main causes of the operational decomposition of PeLEDs. Here, we find that butylammonium-based quasi-two-dimensional (quasi-2D) PeLEDs show self-healing ability, revealing the existence of ion migration in the fabricated perovskite layer. Then, on the basis of the analysis of ∼170 operational decay EQE curves, patterns of on-shelf and operational decay in self-healing quasi-2D PeLEDs have been identified. The uneven distributions of resistance on the perovskite film surface are proposed to cause secondary electric fields. The electroluminescent scintillation in certain regions results in fluctuating electroluminescence of PeLEDs, further proving the existence of microcosmic steric ion movement under secondary electric fields. Our work explores the decay patterns of self-healing PeLEDs and highlights the impact of steric ion movements on the decay processes of PeLEDs.

Stretched exponential to power-law: crossover of relaxation in a kinetically constrained model

The autocorrelation function in many complex systems shows a crossover in the form of its decay: from a stretched exponential relaxation (SER) at short times to a power law at long times. Studies of the mechanisms leading to such multiple relaxation patterns are rare. Additionally, the inherent complexity of these systems makes it hard to understand the underlying mechanism leading to the crossover. Here we develop a simple one-dimensional spin model, which we call a domain wall (DW) to doublon model, that shows such a crossover as the nature of the excitations governing the relaxation dynamics changes with temperature and time. The relevant excitations are DWs and bound pairs of DWs, which we term ‘doublons’. The diffusive motion of the DWs governs the relaxation at short times, whereas the diffusive motion of the doublons yields the long-time decay. This change of excitations and their relaxation leads to a crossover from SER to a power law in the decay pattern of the autocorrelation function. We augment our numerical results with simple physical arguments and analytic derivations.

Comparative analysis of inbound tourist flows of different groups: the case of Japan

ABSTRACT Analyzing the tourism mobility characteristics and preferences of different tourist groups helps develop corresponding tourism strategies and targeted tourism planning. This study applied Social Network Analysis and GIS mapping to comprehensively deconstruct the structural characteristics of inbound tourist flow networks of different tourist groups in Japan. The results show that there are significant differences in the structural characteristics and nodal role functions of tourist flow networks from different regions, with Tokyo, Kyoto, Osaka, and Aichi being stable core nodes. The distance decay patterns of tourist flows from each region vary, with a significant influence from length of stay. There are four distribution patterns for tourist flow networks under the influence of spatial–temporal distance: short-stay with double-core pattern, short and medium stay with multi-core pattern, medium-stay with triangle core pattern, and long-stay with a regional pattern. Lastly, the mobility preferences of different inbound tourist groups are summarized.

Machine Learning Bolsters Evidence That D1, Nef, and Tat Influence HIV Reservoir Dynamics.

The primary hurdle to curing HIV is due to the establishment of a reservoir early in infection. In an effort to find new treatment strategies, we and others have focused on understanding the selection pressures exerted on the reservoir by studying how proviral sequences change over time. To gain insights into the dynamics of the HIV reservoir we analyzed longitudinal near full-length sequences from 7 people living with HIV between 1 and 20 years following the initiation of antiretroviral treatment. We used this data to employ Bayesian mixed effects models to characterize the decay of the reservoir using single-phase and multiphasic decay models based on near full-length sequencing. In addition, we developed a machine-learning approach utilizing logistic regression to identify elements within the HIV genome most associated with proviral decay and persistence. By systematically analyzing proviruses that are deleted for a specific element, we gain insights into their role in reservoir contraction and expansion. Our analyses indicate that biphasic decay models of intact reservoir dynamics were better than single-phase models with a stronger statistical fit. Based on the biphasic decay pattern of the intact reservoir, we estimated the half-lives of the first and second phases of decay to be 18.2 (17.3 to 19.2, 95%CI) and 433 (227 to 6400, 95%CI) months, respectively.In contrast, the dynamics of defective proviruses differed favoring neither model definitively, with an estimated half-life of 87.3 (78.1 to 98.8, 95% CI) months during the first phase of the biphasic model. Machine-learning analysis of HIV genomes at the nucleotide level revealed that the presence of the splice donor site D1 was the principal genomic element associated with contraction. This role of D1 was then validated in an in vitro system. Using the same approach, we additionally found supporting evidence that HIV nef may confer a protective advantage for latently infected T cells while tat was associated with clonal expansion. The nature of intact reservoir decay suggests that the long-lived HIV reservoir contains at least 2 distinct compartments. The first compartment decays faster than the second compartment. Our machine-learning analysis of HIV proviral sequences reveals specific genomic elements are associated with contraction while others are associated with persistence and expansion. Together, these opposing forces shape the reservoir over time.

Rates of species turnover across elevation vary with vertical stratum in rainforest ant assemblages

Climatic variation at local scales can influence both exposure and sensitivity of organisms and thereby scale up to influence population persistence and community composition across broader geographic extents. Tropical forest canopies are more climatically dynamic than the understorey. Consequently, the niche space of forest canopies has higher overlap in thermal conditions along elevation gradients, which imposes less of a climatic barrier to arboreal species than their ground‐dwelling counterparts. We use ant communities of the Australian Wet Tropics to test the prediction that ground communities should have higher rates of species turnover over elevation compared to arboreal communities. We sampled ground and arboreal ants along elevation gradients at a bioregional scale that includes four mountain sub‐regions. We assessed community composition at three spatial resolutions (regional, elevation, vertical) and then calculated beta diversity (species turnover) over elevation for ground and arboreal communities using null modelling procedures to compare different sized species pools. Vertical niche affinity was a strong contributor to overall biogeographic patterns; indicated by a strong interaction between vertical niche and elevation in beta diversity models. On average, the ground community exhibited a pronounced elevational distance–decay pattern while the arboreal community showed no pattern. Mean species turnover was 36% higher in ground than arboreal communities. Our findings suggest that the vertical niche has a pronounced effect on biogeographic patterns which has important implications for understanding the role of local scale climate conditions in shaping communities and for potential responses to future climate change.

Coupled multiphase flow and viscoelastic mechanics modeling of gas injection in a compacted bentonite buffer

Bentonite is chosen as a suitable buffer material for a deep geologic repository for radioactive waste. Thus, understanding the behavior of gas migration in the buffer layer is key to the safety assessment and functioning of such a repository. Based on the gas-injection experiments performed by the British Geological Survey (BGS), the modeling of gas migration in a compacted bentonite is carried out by the multi-phase-flow module (H) coupled with the viscous-elastic geomechanics module (M) of a fully coupled model, called THMC 7.1. Two laboratory scenarios for gas injection into compacted and saturated bentonite confined in a pressure vessel are considered in this simulation study. Injected gas (Helium) accumulates, entering the saturated bentonite after reaching a critical pressure to be detected by the gas filters to show the timing of the “breakthrough”. It is found in the experiments that the total stress reaches the maximum value right after breakthrough but does not exceed the gas injection pressure. It is found that our simulation results can capture the peak lab-test values of total stress and porewater pressure as well as the lab-test timing of breakthrough. Moreover, the decay patterns of both total stress and porewater pressure are well described in the simulations. A comparison of the simulation results with the experimental data shows that our HM coupled modeling can qualitatively and quantitatively model the gas migration behavior and its mechanical contribution to the buffer response. According to the presented simulations, the further improvement of the viscous-elastic geomechanical modelling is also discussed.

Double-gluon charmonium hybrid states with various exotic quantum numbers

We study the double-gluon charmonium hybrid states with various quantum numbers, each of which is composed of one valence charm quark and one valence charm antiquark as well as two valence gluons. We concentrate on the exotic quantum numbers JPC=0−−/0+−/1−+/2+−/3−+ that the conventional q¯q mesons cannot reach. We apply the QCD sum rule method to calculate their masses to be 7.28−0.43+0.38, 5.19−0.46+0.36, 5.46−0.62+0.41, 4.48−0.31+0.25, and 5.54−0.43+0.35 GeV, respectively. We study their possible decay patterns and propose to search for the JPC=2+−/3−+ states in the D*D¯(*)/Ds*D¯s(*)/Σc*Σ¯c(*)/Ξc*Ξ¯c(′,*) channels. Experimental investigations on these states and decay channels can be useful in classifying the nature of the hybrid state, thus serving as a direct test of QCD in the low energy sector. Published by the American Physical Society 2024

Australian Summer Monsoon Bursts: A Moist Static Energy Budget Perspective

AbstractThe Australian monsoon's wet season is associated with sequences of wet and dry conditions known as bursts and breaks, which usually have timescales of a week or two. There are several hypotheses for the physical processes involved in monsoon bursts, ranging from the effects of the Madden‐Julian Oscillation to extratropical influences. We analyze rainfall bursts in Northern Australia using a moist static energy (MSE) budget framework. We separate the bursts into three types and further separate them into pre‐monsoon, active monsoon, and post‐monsoon. We then apply ERA5 data to calculate the MSE budget for each burst and construct composite bursts for each of the three types. We find that the horizontal advection of MSE over the tropical northern Australian convergence zone is the most critical term in the budget for the day‐to‐day precipitation variation. MSE‐related gross moist stability analysis reveals that each type has distinct characteristics. The burst type associated with active monsoon bursts displays convective growth and decay patterns both before and after the precipitation peak, which is typical of oceanic convection. A low‐rainfall burst type, which is often seen before monsoon onset, is linked to coastal convection and has minimal rainfall decay after the burst. Finally, a sustained high‐rainfall burst type, mostly observed at the end or after the monsoon retreat, has growth characteristics similar to the typical monsoon burst but does not decay, maintaining very high rainfall for at least a week due to a rearrangement of the circulation and local thermodynamic structure of the atmosphere.

Mapping cognitive place associations within the United Kingdom through online discussion on Reddit

AbstractThis paper explores cognitive place associations; conceptualised as a place‐based mental model that derives subconscious links between geographic locations. Utilising a large corpus of online discussion data from the social media website Reddit, we experiment on the extraction of such geographic knowledge from unstructured text. First we construct a system to identify place names found in Reddit comments, disambiguating each to a set of coordinates where possible. Following this, we build a collective picture of cognitive place associations in the United Kingdom, linking locations that co‐occur in user comments and evaluating the effect of distance on the strength of these associations. Exploring these geographies nationally, associations were shown to be typically weaker over greater distances. This distance decay is also highly regional, rural areas typically have greater levels of distance decay, particularly in Wales and Scotland. When comparing major cities across the UK, we observe distinct distance decay patterns, influenced primarily by proximity to other cities.

Faster photoswitching and amplified NBE emission from mg doped sol-gel derived ZnO thin films

ABSTRACT Photoconductivity and photoluminescence of highly transparent predominantly c-axis oriented hexagonal wurtzite nanocrystalline Mg doped zinc oxide thin films are reported here. These films prepared by sol-gel spin coating are useful for switching and UV detector applications. The increase in dopant concentration tunes the optical band-gap from 3.15 to 3.41 eV. Amplified NBE emission with low defect emission is obtained in appropriately doped sample along with high suitability for switching applications since the photocurrent sharply falls to a very low value as the illumination is put off and the rise and decay pattern is reproducible for several consecutive cycles. The films have crystallite size less than 16 nm and rod-like structures of diameter 50 to 100 nm are seen to grow out of spherical granular background. Doping reduces the size of grains and rods as well as the surface roughness.

Research on the vibration mechanism of compressor complex exhaust pipeline based on transient flow

The periodic exhaust of the compressor often induces gas flow fluctuations within the pipeline, leading to vibrations. Excessive vibration can lead to fatigue, cracks, loosening of components, and resulting in local leakage, which may easily lead to fire, explosion, and secondary hazards. Therefore, in this paper, a computational model for the transient flow field of the compressor exhaust pipeline was established, using the pulse excitation method and Fluent software, the natural frequencies of the gas column in the pipeline were calculated, and the patterns of oscillation decay of the gas column wave propagating back and forth within three exhaust pipes were researched. The mechanism behind the pipeline pressure pulsation and the influence of pipeline structural parameters on the natural frequencies of the gas column were explored. The calculation results show that the first-order natural frequency of the gas column is very close to the double frequency of the compressor excitation frequency at 3.33Hz, and the second-order natural frequency of the gas column is very close to the quadruple frequency of the compressor excitation frequency at 3.33Hz, which may cause significant pipeline vibrations. Altering the pipeline structure, especially when influenced by airflow branching after a tee junction, results in complex changes in the natural frequencies of the gas column. Furthermore, the structural natural frequencies of the pipeline were obtained through the finite element. It has been observed that resonance phenomena exist among the structural natural frequencies and their harmonics of the pipeline and the natural frequencies of the gas column and their harmonics, as well as multiples of the excitation frequency. These results lay the foundation for understanding the vibration mechanism of the pipeline and finding ways to reduce vibration.

Field Measurement of Dust Concentration on Open-pit Coal Mine Truck Transportation Roads and Numerical Simulation of Dust Patterns

Dust generated by open-pit coal truck transportation is one of the main sources of pollution, adversely affecting road visibility and the surrounding air quality during transportation operations. To investigate the distribution patterns of transport dust on coal quality roads in open-pit coal mines, we conducted on-site measurements of transport dust pollution in a coal mine in Xinjiang, China. We also used numerical simulation software to simulate the distribution patterns of dust under different truck speeds. The results indicate that dust pollution on the coal quality road surfaces within the open-pit coal mine exceeds national standards. The concentration of dust behind the trucks at different speeds can be categorized into the following zones: vortex zone, rapid descent zone, and stable zone. The peak dust concentration occurs around 1.5 meters behind the rear of the trucks. Furthermore, the dust concentration behind the trucks follows an exponential decay pattern with increasing height and longitudinal distance.

Angiosperm fossil woods from the Upper Cretaceous (Cardiel Formation) of Argentinean Patagonia

Abstract We describe nine angiosperm fossil woods from sediments of the Cardiel Formation (Upper Cretaceous) near the Cardiel Lake, Santa Cruz Province, Argentinian Patagonia. On the basis of the characteristics of the anatomy, the specimens were placed in three fossil species: Weinmannioxylon trichospermoides related to the Cunoniaceae, Burseroxylon panzai sp. nov. possibly related to the Anacardiaceae or Burseraceae, and a new taxon with unknown affinity, Tortorellixylon oligoporosum gen. et sp. nov. Angiosperms are 15% of the assemblage and conifers 85%, which is consistent with previous studies of fossil woods from the Late Cretaceous of Patagonia. Most specimens show poorly distinct growth ring boundaries that suggest a weakly marked annual seasonality during the deposition of the Cardiel Formation. In addition, the specimens’ size and the rings’ curvature are consistent with large trees. Decay patterns similar to those produced by modern xylophagous fungi are also recognized in most specimens. The identification of three species in an assemblage of nine fossil woods suggests a significant taxonomic richness of angiosperms, and the taxonomic composition suggests a Late Cretaceous age for the Cardiel Formation (probably Campanian–Maastrichtian). These new records allow a better understanding of the composition of the fossil forests of the Late Cretaceous of Patagonia, in which the tree canopy was apparently dominated by conifers.

Fast and portable fluorescence lifetime analysis for early warning detection of micro- and nanoplastics in water

The presence of plastic fragments in aquatic environments, particularly at the micro- and nano-scale, has become a significant global concern. However, current detection methods are limited in their ability to reveal the presence of such particles in liquid samples. In this study, we propose the use of a fluorescence lifetime analysis system for the detection of micro- and nanoplastics in water. This approach relies on the inherent endogenous fluorescence of plastic materials and involves the collection of single photons emitted by plastic fragments upon exposure to a pulsed laser beam. Briefly, a pulsed laser beam (repetition frequency = 40 MHz) shines onto a sample solution, and the emitted light is filtered, collected, and used to trace the time distributions of the photons with high temporal resolution. Finally, the fluorescence lifetime was measured using fitting procedures and a phasor analysis. Phasor analysis is a fit-free method that allows the measurement of the fluorescence lifetime of a sample without any assumptions or prior knowledge of the sample decay pattern. The developed instrument was tested using fluorescence references and validated using unlabelled micro- and nano-scale particles. Our system successfully detected polystyrene particles in water, achieving a remarkable sensitivity with a detection limit of 0.01 mg/mL, without the need for sample pre-treatment or visual inspection. Although further studies are necessary to enhance the detection limit of the technique and distinguish between different plastic materials, this proof-of-concept study suggests the potential of the fluorescence lifetime-based approach as a rapid, robust, and cost-effective method for early warning detection and identification of plastic contaminants in aquatic environments.

Degradation behavior and ageing mechanism of E-glass fiber reinforced epoxy resin composite pipes under accelerated thermal ageing conditions

In this work, accelerated ageing experiments with circulating air and simulated oilfield water were carried out at 95 °C on aromatic amine-cured GFRP pipes used in oilfield environments, with effective ageing times of 5000 h and 3000 h respectively. The differences in ageing behavior and ageing mechanisms of the GFRP tubes at different times under the two conditions were then analyzed and discussed. The changes in the apparent morphology and microstructure of the samples after thermal ageing were first observed using optical microscopy and scanning electron microscopy, and the results demonstrated that the thermal oxygen environment triggered more drastic color changes and obvious oxidation layers. The resin matrix manifests a large number of nano-scale micropores and modest matrix shrinkage pores in the micron size range, this is accompanied by damage to the fiber cross-section. Hydrothermal ageing causes further dissolution of the surface resin and dissolution of the exposed fibers. ATR-FTIR analysis verifies the increase in CO bonding of the ester group during thermal oxidation and the decreasing strength of the C–O–C and C–H bonds, while the behavior of ageing water absorption and glass fiber hydrolysis is illustrated by changes in the intensity of the –OH and Si–O characteristic bands. NMR hydrogen spectroscopy verified the formation of amides, methyl ethers and carboxylic acids in the thermal oxidation products of epoxy resins. Furthermore, the decay pattern of the circumferential tensile strength indicates that the hydrothermal environment has a more significant effect on the mechanical properties of GFRP pipes, which is attributed to the physical dissolution of the surface resin, significant hydrolytic damage to the surface exposed fibers, and the combined damage to the resin-fiber interfacial bonding by chloride ions in simulated oilfield water.

Degradation of pharmaceuticals in UV/H2O2 process: EEM-based kinetic model, transformation products and corresponding toxicity evaluation

Advanced oxidation process (AOP) by UV/H2O2 presented excellent performance on removing trace pharmaceuticals in wastewater. Monitoring the removal efficiency of pharmaceuticals rapidly can evaluate the effectiveness of UV/H2O2 process. And evaluating the potential risks of this technology is essential to facilitate its engineering application. In this study, diclofenac, ibuprofen, naproxen, carbamazepine and citalopram, which have potential biological effect to ecological environment, were degraded by UV/H2O2 in wastewater. Results suggested that UV/H2O2 could degrade 5 pharmaceuticals effectively. An EEM-based degradation kinetic model was constructed by combining pseudo first-order kinetic patterns of pharmaceuticals degradation and multiple exponential decay pattern of fluorescence degradation. This model could estimate the removal of pharmaceuticals rapidly and exhibited excellent predictive capability (R2 values > 0.90). Based on suspect and untargeted screening, 40 transformation products (TPs) were identified, with hydroxylation, (de)methylation and decarboxylation being the dominant pathways. Among them, 20 TPs were newly discovered. Furthermore, the predicted toxicity results from Ecological Structure-Activity Relationship (ECOSAR) model suggested that 37.5%− 42.5% of TPs exhibited higher toxicity than parent compounds. The increased toxicity of TPs of DCF and IBP could be attributed to decarboxylation. This study provides a promising and rapid method for monitoring the degradation of pharmaceuticals and estimating the toxicity of TPs. These findings facilitate further evaluation of the practicality and risks associated with the UV/H2O2 process for pharmaceutical removal in wastewater.