Probe Measurements Research Articles

In-Line Chemical Composition Monitoring for the Injection Molding Process of Biodegradable Polymer Blends Using Simultaneous Measurement of Near-Infrared Diffuse Reflectance and Transmission Spectra.

In the processing of polymer blends and composites, in-line near-infrared (NIR) spectroscopy enables monitoring of the composition and its composite uniformity and contributes to rapid process development and quality control. However, in the injection molding process, the study of the composition of polymer materials has been delayed due to high-pressure conditions. Our research group developed NIR probes for transmission and diffuse reflectance measurements that can withstand high-pressure and temperature conditions up to 130 MPa and 200 °C. In this research, transmission and diffuse reflectance spectra were measured inline during the injection molding process of polymer blends of poly(lactic acid) and polybutylene succinate adipate. The intensity of each polymer band in the second-derivative spectra exhibited a monotonic increase or decrease in response to changes in the blend ratio. Using transmission and diffuse reflectance spectra as explanatory variables of the partial least squares regression model simultaneously, the model showed high estimation accuracy for the entire region of the blend ratio. Finally, this model was applied to monitor the polymer changeover operation, and the change in the blend ratio in the molded product was successfully estimated in line.

Characterizing the Unsteady Flow Field in Low-Flow Turbine Operation

Abstract Current operational considerations require steam turbines to operate in a more flexible way, with more frequent and faster start-up and an increasing part-load operation. For very low mass flowrates, the interaction of highly separated flow with the high-speed rotor blades causes windage flow. This type of flow is characterized by increased temperature and highly unsteady flow, which forms vortex structures that rotate at a fraction of the rotor speed. If their magnitude is sufficiently high and the frequency is close to the blade eigenfrequency, non-synchronous vibration (NSV) can be induced. In this paper, low-flow turbine operation is investigated using a three-stage turbine rig that features an instrumentation concept focused on capturing aerodynamic and aeroelastic phenomena. Extensive steady probe, unsteady pressure, and tip-timing measurements are utilized. The experimental scope covers a wide range of operating points in terms of rotational speed and mass flowrates. Low-flow regimes are detected by a reversal in torque and increase in temperature. Unsteady measurements during transient operation identified large-scale vortical flow structures rotating along the circumference, so-called rotating instabilities (RIs). The onset, growth, and breakdown regimes of RI are characterized for different low-flow conditions. The quantitative characteristics of RI with regard to nodal diameter and rotational speed are derived by a cross-correlation of multiple unsteady sensors. The blade vibration measurements show a moderate structural response from unsteady aerodynamic excitation, indicating no significant NSV occurring in the present experimental setup. Later in the study, an acoustic excitation system has been applied to trigger a locked-in NSV without interrupting the coherent flow structures. From that, significant blade response has been observed, revealing a high degree of mistuning and damping of the rotor blading.

Comparison of detachment in Ohmic plasmas with positive and negative triangularity

In recent years, negative triangularity (NT) has emerged as a potential high-confinement L-mode reactor solution. In this work, detachment is investigated using core density ramps in lower single null Ohmic L-mode plasmas across a wide range of upper, lower, and average triangularity (the mean of upper and lower triangularity: δ) in the TCV tokamak. It is universally found that detachment is more difficult to access for NT shaping. The outer divertor leg of discharges with δ≈−0.3 could not be cooled to below 5 eV through core density ramps alone. The behavior of the upstream plasma and geometrical divertor effects (e.g. a reduced connection length with negative lower triangularity) do not fully explain the challenges in detaching NT plasmas. Langmuir probe measurements of the target heat flux widths (λ q ) were constant to within 30% across an upper triangularity scan, while the spreading factor S was lower by up to 50% for NT, indicating a generally lower integral scrape-off layer width, λ int. The line-averaged core density was typically higher for NT discharges for a given fuelling rate, possibly linked to higher particle confinement in NT. Conversely, the divertor neutral pressure and integrated particle fluxes to the targets were typically lower for the same line-averaged density, indicating that NT configurations may be closer to the sheath-limited regime than their PT counterparts, which may explain why NT is more challenging to detach.

Treatment of an Infrabony Defect of a Maxillary Canine Tooth Using Enamel Matrix Derivatives with Allogeneic Bone Augmentation in a Dog.

A 5-year-old Miniature Dachshund was presented having an infrabony pocket on the palatal aspect of the right maxillary canine tooth. The bony defect had worsened despite previous closed root planing and administration of a perioceutic agent. A second surgery using an allogeneic cancellous bone augmentation with an enamel matrix derivative was performed in the infrabony defect following open root planing. Eight months after the periodontal surgery, the osseous defect showed healing by improved periodontal probing measurements and increased radiopacity using dental radiography and computed tomography.

Characterisation of the scrape-off layer in JET-ILW deuterium and helium low-confinement mode plasmas

Langmuir probe measurements in neutral beam injection (NBI) heated, low-confinement mode plasmas in JET ITER-like wall showed that the current to the divertor targets, Idiv, in helium (He) plasmas was up to 70% lower on the low-field side (LFS) than in otherwise identical deuterium (D) plasmas. The edge plasma density at which the rollover of Idiv occurred i.e. the onset of detachment, was 10% higher in He plasmas on both the LFS and high-field side (HFS). The density of Idiv rollover increases by 25% for He when the NBI power increases 1MW to 5MW. The total radiated power was similar in He and D plasmas for densities below the Idiv rollover. At densities above the Idiv rollover density, the total radiated power and power from within the separatrix are higher in He, reducing the power across the separatrix and subsequently Idiv,LFS. In He plasmas, the peak radiated power was observed within the confined region above the X-point in tomographic reconstructions from bolometry.

Electron ITB formation in EAST high poloidal beta plasmas under dominant electron heating

Plasma confinement and transport in tokamaks play a crucial role in the development of high poloidal beta steady-state operation scenarios. Therefore, it is very important to study the relevant mechanism of internal transport barriers (ITBs), which can help plasmas to obtain better confinement in order to achieve higher fusion gain. This paper mainly introduces the analysis of the characteristics of electron heat transport of discharges with ITB in high βP operation regime in Experimental Advanced Superconducting Tokamak (EAST). Based on the statistical analysis of stable discharges with βP > 1.5, it is found that there is an obvious bifurcation of the normalised electron temperature gradient (ETG) ( R/LTe ) in the range of βP = 2–2.2. Then the discharges of lower βP ( βP < 2, where the value of βP is below the bifurcation threshold) and of higher βP ( βP > 2.2, where the value of βP is above the threshold) were selected for analysis. The diagnostic data provided by Thomson scattering, x-ray crystal spectrometry and charge exchange recombination spectroscopy are used to provide reliable parameter profiles and then combined with the data of external magnetic probe measurements and the polarisation interferometer diagnosis system to fully reconstruct the balance. A relevant plasma current calculation model is used to calculate and analyse the current density profiles and power deposition, and then the transport analysis is carried out. Interestingly, in the higher βP discharges, it is found that the turbulence intensity provided by the CO2 laser collective scattering system gradually decreases and the normalised ETG R/LTe gradually increases. It is also found that the electron heat transport coefficient decreases in the discharge with higher βP and the growth rate of the electron-scale turbulence calculated by transport gyro-Landau fluid (TGLF) is significantly reduced. Meanwhile, similar conclusions are also obtained in the discharges when the βP is further increased.

Parametric characterization of arcs in semi-sealed splitter plate DC circuit breakers

Precisely assessing plasma parameters holds paramount importance in investigating the arc extinguishing mechanism of semi-sealed splitter plate DC circuit breakers, refining the configuration of splitter plates, and optimizing the overall structural design of circuit breakers. Based on the principle of the Langmuir probe, a double probe diagnostic method is proposed to investigate the air arc plasma in the opening process of a DC circuit breaker. The diagnostic circuit of the probes is designed, and three sets of double probes are arranged to trace the evolution of the plasma density during the opening process. The research reveals that the plasma center density, measured by the diagnostic system during the opening process of the DC circuit breaker, is about 1022 m−3–1023 m−3. This density is compared with the diagnostic results obtained by other methods, confirming the accuracy of the Langmuir double probe for plasma measurements in the DC circuit breaker. The study also revealed an exponential decay behavior of electron density along the radial direction of the arc. A mathematical model was employed to describe this phenomenon, establishing a relationship between the distribution of electron density and arc current.

Remote inductively coupled plasmas in Ar/N2 mixtures and implications for plasma enhanced ALD

Plasma enhanced atomic layer deposition (PEALD) is a cyclic atomic layer deposition (ALD) process that incorporates plasma-generated species into one of the cycle substeps. The addition of plasma is advantageous as it generally provides unique reactants and a substantially reduced growth temperature compared to thermal approaches. However, the inclusion of plasma, coupled with the increasing variety of plasma sources used in PEALD, can make these systems challenging to understand and control. This work focuses on the use of plasma diagnostics to examine the plasma characteristics of a remote inductively coupled plasma (ICP) source, a type of plasma source that is commonly used for PEALD. Ultraviolet to near-infrared spectroscopy and spatially resolved Langmuir probe measurements are employed to characterize a remote ICP system using nitrogen-based gas chemistries typical for III-nitride growth processes. Spectroscopy is used to characterize the relative concentrations of important reactive and energetic neutral species generated in the remote ICP as a function of gas flow rate, Ar/N2 flow fraction, and gas pressure. In addition, the plasma potential and plasma density for the same process parameters are examined using an RF compensated Langmuir probe downstream from the ICP source. The results are also discussed in terms of their impact on materials growth.

Probe chip nanofabrication enabled reverse tip sample scanning probe microscopy concept and measurements

We introduce a new scanning probe microscopy (SPM) concept called reverse tip sample scanning probe microscopy (RTS SPM), where the tip and sample positions are reversed as compared to traditional SPM. The main benefit of RTS SPM over the standard SPM configuration is that it allows for simple and fast tip changes. This overcomes two major limitations of SPM which are slow data acquisition and a strong dependency of the data on the tip condition. A probe chip with thousands of sharp integrated tips is the basis of our concept. We have developed a nanofabrication protocol for Si based probe chips and their functionalization with metal and diamond coatings, evaluated our probe chips for various RTS SPM applications (multi-tip imaging, SPM tomography, and correlative SPM), and showed the high potential of the RTS SPM concept.

Photophysical and cellular studies of pH-sensitive boron-functionalised far-red fluorophores

Two novel chromenylium-based probes were developed by functionalisation of the 5-position of the xanthene core with either a para-N-methyldiaminoacetic acid (MIDA) boronate ester (CRpMD) or closo‑1,7-carborane (CRmCB). CRpMD revealed near-infrared emission at 655 nm, demonstrating a bathochromic shift compared to the analogous phenyl derivative (CRPh). Both boron-containing probes were found to be sensitive to changes in acidic pH, with CRpMD also displaying a dual fluorescence response at alkaline pH (pKa1 = 2.40 and pKa2 = 9.16). CRmCB showed a ca. 3-fold increase in fluorescence intensity at 638 nm from pH 7.01 to 2.00, with a pKa = 2.08. Moreover, CRpMD and CRmCB were successfully taken up by A549 lung cancer cells to assess their intracellular biodistributions, thereby showcasing the future potential of these probes for time-resolved pH measurements using confocal microscopy.

A comparison of function lumen imaging probe measurements of anal sphincter function in fecal incontinence.

The functional lumen imaging probe (FLIP) is a test of anal sphincter distensibility under evaluation by specialist centers. Two measurement protocols termed "stepwise" and "ramp" are used, risking a lack of standardization. This study aims to compare the performance of these protocols to establish if there are differences between them. Patients with fecal incontinence were recruited and underwent measurement with both protocols at a tertiary pelvic floor referral unit. Differences in minimum diameter, FLIP bag pressure, and distensibility index (DI) at rest and during squeeze were calculated at various FLIP bag volumes. Twenty patients (19 female, mean age 61 [range: 38-78]) were included. The resting minimum diameter at 30 and 40 mL bag volumes were less in the stepwise protocol (mean bias: -0.55 mm and -1.18 mm, p < 0.05) along with the DI at the same bag volumes (mean bias: -0.37 mm2/mmHg and -0.55 mm2/mmHg, p < 0.05). There was also a trend towards greater bag pressures at 30 mL (mean bias: +2.08 mmHg, p = 0.114) and 40 mL (mean bias: +2.81 mmHg, p = 0.129) volumes in the stepwise protocol. There were no differences between protocols in measurements of minimum diameter, maximum bag pressure, or DI during voluntary squeeze (p > 0.05). There are differences between the two commonly described FLIP measurement protocols at rest, although there are no differences in the assessment of squeeze function. Consensus agreement is required to agree the most appropriate FLIP measurement protocol in assessing anal sphincter function.

Fabrication of CsPbBr3 nanocrystal/POSS-based copolymer films for non-contact temperature probes

Fluorescence-based non-contact temperature measurement has been attested a widely-used technique for temperature aware in rotating mechanical equipment, electrical devices, and other fields. Inspired by the thermal sensitivity of perovskite nanocrystals, we prepared a CsPbBr3/polyhedral oligomeric silsesquioxane (POSS)-based composite film with outstanding temperature-photoluminescence (PL) dependence, high reversibility, and high hydrophobicity. Perovskites nanocrystals with controllable nanocubic and nanoplate morphologies were synthesized by adjusting the temperature. Various CsPbBr3/POSS-based composite films with different CsPbBr3 morphologies and ratios were fabricated. The CsPbBr3 nanocubic and nanoplate based films possessed high hydrophobicity, UV stability, and thermal stability. Temperature dependence experiments revealed that PL spectral parameters of CsPbBr3/POSS-based composite films had obvious temperature change characteristics attributable to the CsPbBr3 morphology. The PL intensity and full width at half maximum (FWHM) of the CsPbBr3 nanoplate based film exhibited poor regularity with temperature. In contrast, the PL intensity of the CsPbBr3 nanocubic based film was related to temperature exponentially, and the FWHM had a strong linear relationship with temperature. Moreover, temperature dependence reversibility was realized for the CsPbBr3 nanocubic based film. Furthermore, the applicability of a CsPbBr3 nanocubic based temperature probe was verified by monitoring the temperature of a bearing cage on a spindle-bearing test platform. The CsPbBr3/POSS-based composites can be applied as temperature probes for non-contact temperature measurement of rotating components of mechanical equipment.

Investigation of the directional Faraday cup and improvement of the comparison between direct and indirect thrust measurements of a magnetic nozzle ECR thruster

The thrust of an electric propulsion device estimated from electrostatic probe measurements may be different from direct thrust measurements. In order to reduce this discrepancy for electron cyclotron resonance thrusters (ECRT), a new diagnostic is presented: the directional Faraday cup (FCDi). Thanks to a peculiar design, it assesses the angular distribution of ion current density in the plume of plasma thrusters. First, a theoretical model of the angular selectivity of the FCDi is introduced. It is validated with both simulations and experiments. Guidelines are given to use the FCDi in the plume of ECRT. Second, the observed discrepancies between direct thrust measurements made on a thrust stand and indirect ones are reduced when using the FCDi instead of a planar Faraday probe with a guard ring (FPGR). Relative errors come down to 10% with the FCDi, which are compared to 20%–30% observed with the FPGR. An analysis demonstrates that it is not due to the effect of local ion trajectories but comes from the magnitude of the ion current measured. A large sheath in front of the negatively biased FPGR seems to be the cause of this phenomenon. The grounded opening of the FCDi reduces this phenomenon and improves the ion flux measurement accuracy. This new probe, with angular selectivity characteristics, allows for the comparison of the ion flux ejection direction with the magnetic field line and contributes to a better description of ion population dynamic in the magnetic nozzle of the thruster.

Modeling Geomagnetically Induced Currents in the Alberta Power Network: Comparison and Validation Using Hall Probe Measurements During a Magnetic Storm

AbstractDuring space weather events, geomagnetic disturbances (GMDs) induce geoelectric fields which drive geomagnetically induced currents (GICs) through electrically‐grounded power transmission lines. Alberta, Canada—located near the auroral zone and thus prone to large GMDs—has a dense network of magnetometer stations and surface impedance measurements to better characterize the GMD and ground conductivity, respectively. GIC monitoring devices were recently installed at five substation transformer neutrals, providing a unique opportunity to compare data to modeled GICs. GICs are modeled across the &gt;240 kV provincial power transmission network during a moderate GMD event on 24 April 2023. GIC monitoring devices measured larger neutral‐to‐ground currents than expected up to 117 Amps during peak storm time, providing unequivocal evidence linking network GICs with GMDs. The model performs reasonably well (correlation coefficients &gt;0.5; performance parameter &gt;0.15) at four of five substations, but generally underestimates peak GIC values (sometimes by a factor &gt;2), suggesting that the present model underrepresents overall network risk. The model performs poorly at one of the five substations (correlation = 0.46; performance parameter = 0.10), the reasons for which may be due to simplifications and/or unknowns in network parameters. Despite these underestimates, during this GMD, the model predicts the largest GIC at substations located in the northeastern part of the province (240 kV) or around Edmonton (500 kV)—regions which have significant electrical and industrial infrastructure. Further refinement of the network model with transformer resistances, more line and earthing resistances, and/or including lower voltage levels is necessary to improve data fit.

Application of helium line intensity ratio spectroscopy to xenon plasma in E × B Penning discharge

We propose the application of helium line intensity ratio spectroscopy in a low-pressure (0.3 mTorr) xenon E × B discharge with an electron temperature of ∼2 eV and a density of 1010−1011cm−3 . We successfully identified the helium atom line emissions at 388.9, 447.1, 501.6, 504.8, and 706.5 nm with helium pressures of up to ∼20 mTorr. The measured electron temperature, density, and I−V characteristics of the discharge remained almost constant in all helium pressures in the present experiment, indicating the suitability of the helium gas as a diagnostic gas. The results of helium line intensity ratio spectroscopy using the line emissions at 388.9, 447.1, and 504.8 nm showed fair agreement with the Langmuir probe measurement. Considering the trade-off relationship between the disturbance introduced by the helium gas and the signal-to-noise ratio, we conclude that a helium pressure of approximately 4 mTorr (approximately 13 times the partial pressure of xenon) represents the optimal pressure range for the application of the helium line emission intensity ratio method to this xenon plasma. It is found that the use of the line emissions at 501.6 and 706.5 nm result in a significant disturbance in the helium line intensity ratio method due to the radiation trapping effect.

Modular slot-die coater for in situ grazing-incidence x-ray scattering experiments on thin films.

Multimodal in situ experiments during slot-die coating of thin films pioneer the way to kinetic studies on thin-film formation. They establish a powerful tool to understand and optimize the formation and properties of thin-film devices, e.g., solar cells, sensors, or LED films. Thin-film research benefits from time-resolved grazing-incidence wide- and small-angle x-ray scattering (GIWAXS/GISAXS) with a sub-second resolution to reveal the evolution of crystal structure, texture, and morphology during the deposition process. Simultaneously investigating optical properties by in situ photoluminescence measurements complements in-depth kinetic studies focusing on a comprehensive understanding of the triangular interdependency of processing, structure, and function for a roll-to-roll compatible, scalable thin-film deposition process. Here, we introduce a modular slot-die coater specially designed for in situ GIWAXS/GISAXS measurements and applicable to various ink systems. With a design for quick assembly, the slot-die coater permits the reproducible and comparable fabrication of thin films in the lab and at the synchrotron using the very same hardware components, as demonstrated in this work by experiments performed at Deutsches Elektronen-Synchrotron (DESY). Simultaneous to GIWAXS/GISAXS, photoluminescence measurements probe optoelectronic properties in situ during thin-film formation. An environmental chamber allows to control the atmosphere inside the coater. Modular construction and lightweight design make the coater mobile, easy to transport, quickly extendable, and adaptable to new beamline environments.

Wake Formation Flow Physics and Boundary Layer Analysis on the Sides of the Isosceles Triangular Cylinder with Apex Pointing Downstream

Boundary layer interaction with downstream flow structures was numerically studied to find the region of inactivity behind an 75° isosceles triangular cylinder with apex pointing downstream at intermediate Reynolds numbers (Re = 520, 640, 840 and 1040). The Standard k-ε model in OpenFOAM was used in the study. Numerical results were validated against Particle Image Velocimetry data. Results revealed the stable region of inactivity characterized by low turbulent kinetic energy and vorticity. The onset of secondary vortex and separation point, independent of Reynolds number, was identified. The onset of the secondary vortex was located at (x = 2 mm) from the base and (y = 1.5 mm) from the apex on either side of the cylinder. The ratio of modulus of absolute primary z-component of vorticity, |ω_z^1 |, to the modulus of secondary z-component of vorticity, |ω_z^2 |, was found to be approximately equal to 1.2. This ratio is invariant of the Reynolds number of the study. These findings have practical implications. The unique properties of the inactivity region forms an ideal location that can be used for injecting fluid, placing measurement probe, active flow control and drag reduction. The research problem is formulated in the introduction. Literature is reviewed next providing the background. Details about the range of parameters, governing equations, numerical study details and software used are given in the methodology section. The results section gives the numerical results, verified by mesh refinement test and validated against experimental results. The results are finally discussed in the next section.

Advances in Aeroengine Cooling Hole Measurement: A Comprehensive Review.

Film cooling technology is of great significance to enhance the performance of aero-engines and extend service life. With the increasing requirements for film cooling efficiency, researchers and engineers have carried out a lot of work on the precision and digital measurement of cooling holes. Based on the above, this paper outlines the importance and principles of film cooling technology and reviews the evolution of cooling holes. Also, this paper details the traditional measurement methods of the cooling hole used in current engineering scenarios with their limitations and categorizes digital measurement methods into five main types, including probing measurement technology, optical measurement technology, infrared imaging technology, computer tomography (CT) scanning technology, and composite measurement technology. The five types of methods and integrated automated measurement platforms are also analyzed. Finally, through a generalize and analysis of cooling hole measurement methods, this paper points out technical challenges and future trends, providing a reference and guidance for forward researches.

Intraparenchymal near-infrared spectroscopy for detection of delayed cerebral ischemia in poor-grade aneurysmal subarachnoid hemorrhage

ObjectiveDetection of delayed cerebral ischemia (DCI) is challenging in comatose patients with poor-grade aneurysmal subarachnoid hemorrhage (aSAH). Brain tissue oxygen pressure (PbtO2) monitoring may allow early detection of its occurrence. Recently, a probe for combined measurement of intracranial pressure (ICP) and intraparenchymal near-infrared spectroscopy (NIRS) has become available. In this pilot study, the parameters PbtO2, Hboxy, Hbdeoxy, Hbtotal and rSO2 were measured in parallel and evaluated for their potential to detect perfusion deficits or cerebral infarction. MethodsIn patients undergoing multimodal neuromonitoring due to poor neurological condition after aSAH, Clark oxygen probes, microdialysis and NIRS-ICP probes were applied. DCI was suspected when the measured parameters in neuromonitoring deteriorated. Thus, perfusion CT scan was performed as follow up, and DCI was confirmed as perfusion deficit. Median values for PbtO2, Hboxy, Hbdeoxy, Hbtotal and rSO2 in patients with perfusion deficit (Tmax > 6 s in at least 1 vascular territory) and/or already demarked infarcts were compared in 24- and 48-hour time frames before imaging. ResultsData from 19 patients (14 University Hospital Zurich, 5 Charité Universitätsmedizin Berlin) were prospectively collected and analyzed. In patients with perfusion deficits, the median values for Hbtotal and Hboxy in both time frames were significantly lower. With perfusion deficits, the median values for Hboxy and Hbtotal in the 24 h time frame were 46,3 [39.6, 51.8] µmol/l (no perfusion deficits 53 [45.9, 55.4] µmol/l, p = 0.019) and 69,3 [61.9, 73.6] µmol/l (no perfusion deficits 74,6 [70.1, 79.6] µmol/l, p = 0.010), in the 48 h time frame 45,9 [39.4, 51.5] µmol/l (no perfusion deficits 52,9 [48.1, 55.1] µmol/l, p = 0.011) and 69,5 [62.4, 74.3] µmol/l (no perfusion deficits 75 [70,80] µmol/l, p = 0.008), respectively. In patients with perfusion deficits, PbtO2 showed no differences in both time frames. PbtO2 was significantly lower in patients with infarctions in both time frames. The median PbtO2 was 17,3 [8,25] mmHg (with no infarctions 29 [22.5, 36] mmHg, p = 0.006) in the 24 h time frame and 21,6 [11.1, 26.4] mmHg (with no infarctions 31 [22,35] mmHg, p = 0.042) in the 48 h time frame. In patients with infarctions, the median values of parameters measured by NIRS showed no significant differences. ConclusionsThe combined NIRS-ICP probe may be useful for early detection of cerebral perfusion deficits and impending DCI. Validation in larger patient collectives is needed.

Parallel additions of molybdenum and copper particles for boosted peroxydisulfate activation process: Performance, mechanism, and application

Molybdenum (Mo) has been certified as a benign cocatalyst in homogenous Fenton/Fenton-like reactions. To improve zero-valent copper (Cu) induced peroxydisulfate (PDS) reaction, Mo and Cu were parallelly added to enhance the activation of (PDS for metronidazole (MTZ) degradation in this work. The efficient MTZ elimination (96.01 %) was reached after 20 min by Cu/Mo/PDS process in terms of 0.10 g⋅L−1 PDS, 0.08 g⋅L−1 Cu, 0.30 g⋅L−1 Mo, and initial pH 6.5. This ternary system presented a broad pH adaptive capacity (pH 3.5–9.5) and well cycling effect (above 80 % after three cycles). The addition of Mo enhanced Cu(II)/Cu(I) circulation and PDS decomposition, and electrochemical test testified that could be attributed to the electron migration between Cu and Mo. The cycle of Cu(II)/Cu(I) triggered by the conversion of Mo0 and Mo4+ was further proved by X-ray photoelectron spectroscopy result. Singlet oxygen and sulfate radicals were identified as the dominant reactive substances by scavenger test, probe measurement, and electron paramagnetic resonance spectroscopy. By density functional theory calculation and mass spectrometry analyses, two possible decomposed pathways of MTZ were raised. At last, Mo and Cu powders were immobilized together by a simple physical mixing with methacrylate, which also showed the integrated catalytic property and good reusability. This work could advance the development of Cu-catalyzed Fenton-like reaction with inorganic co-catalysis in water purification.