Quality Factor Research Articles

Noncontact excitation of multi-GHz lithium niobate electromechanical resonators

The demand for high-performance electromechanical resonators is ever-growing across diverse applications, ranging from sensing and time-keeping to advanced communication devices. Among the electromechanical materials being explored, thin-film lithium niobate stands out due to its strong piezoelectric properties and low acoustic loss. However, in nearly all existing lithium niobate electromechanical devices, the configuration is such that the electrodes are in direct contact with the mechanical resonator. This configuration introduces an undesirable mass-loading effect, producing spurious modes and additional damping. Here, we present an electromechanical platform that mitigates this challenge by leveraging a flip-chip bonding technique to separate the electrodes from the mechanical resonator. By offloading the electrodes from the resonator, our approach yields a substantial increase in the quality factor of these resonators, paving the way for enhanced performance and reliability for their device applications.

Controllable dual resonances of Fano and EIT in a graphene-loaded all-dielectric GaAs metasurface and its sensing and slow-light applications

Abstract Active nanophotonic metasurfaces have attracted considerable attention for their promise to develop compact, tunable optical metadevices with advanced functions. In this work, we theoretically demonstrated the dynamically controllable dual resonances of Fano and electromagnetically induced transparency (EIT) using a graphene-loaded all-dielectric metasurface with U-shaped gallium arsenide (GaAs) nanobars operating in the near-infrared region. The destructive interference between a subradiant mode (i.e., a dark mode) supported by two vertical GaAs bars and two radiative modes (i.e., two bright modes) supported by a horizontal GaAs nanobar gives rise to a Fano resonance and an EIT window with high transmission and a large quality factor (Q-factor) in the transmission spectrum. Importantly, the transmission amplitudes can be flexibly modulated by adjusting the graphene Fermi levels without rebuilding the nanostructures. This modulation results from the controllable light absorption by the loaded graphene monolayer due to its interband losses in the near-infrared spectrum. Furthermore, the peak wavelengths of the Fano resonance and EIT window with high Q-factors are highly sensitive to variations in the refractive index (RI) of the surrounding medium, giving the proposed metasurface a relatively good sensitivity of ~700 nm/RIU and a high figure of merit (FOM) of 280, making it an effective RI sensor. Additionally, the metasurface features an adjustable slow light effect, indicated by the adjusted group delay time ranging from 0.12 ps to 0.38 ps. Therefore, the metasurface system proposed in this work offers a viable platform for advanced multi-band optical sensing, low-loss slow light devices, switches, and potential applications in nonlinear optical fields.

Giant enhancement of nonlinear harmonics of an optical-tweezer phonon laser

Phonon lasers, as mechanical analogues of optical lasers, are unique tools for not only fundamental studies of the emerging field of phononics but also diverse applications such as deep-ocean monitoring, force sensing, and biomedical ultrasonics. Recently, nonlinear phonon-lasing effects were observed in an opto-levitated micro-sphere, i.e., the spontaneous emerging of weak signals of high-order phonon harmonics in the phonon lasing regime. However, both the strengths and the quality factors of the emerging phonon harmonics are very poor, thus severely hindering their potential applications in making and utilizing nonlinear phonon-laser devices. Here we show that, by applying a single-colour electronic injection to this levitated system, giant enhancement can be achieved for all higher-order phonon harmonics, with more than 3 orders enhanced brightness and 5 orders narrowed linewidth. Such an electronically-enhanced phonon laser is also far more stable, with frequency stability extended from a dozen of minutes to over 1 h. More importantly, higher-order phonon correlations, as an essential lasing feature, are confirmed to be enhanced by the electronic injection as well, which as far as we know, has not been reported in previous works using this technique. This work, providing much stronger and better-quality signals of coherent phonon harmonics, is a key step towards controlling and utilizing nonlinear phonon lasers for applications such as phonon frequency combs, broadband phonon sensors, and ultrasonic bio-medical diagnosis.

Roles of science and research in vocational teacher preparation: A case study from a Norwegian VET teacher programme

Bridging vocational skills and scientific principles can pose challenges in vocational education and training (VET) teacher programmes. This study aims to enhance such programmes by exploring the potential of reflective practices among students and educators on the nature of science and research in VET contexts. Engaging VET teacher students with multidisciplinary backgrounds in a learning community, the study explores how to further develop research-based teacher training by ‘nudging’ student cooperation. A pedagogical course designed to appreciate students’ prior experiences aimed at preparing them to reflect upon their own professional development from a scientific perspective. Using five focus group interviews with 19 first-year students, the study identifies and explains four key factors for quality in VET teacher training: relevance of pedagogical theory, the value of a multidisciplinary approach, recognition of students’ VET backgrounds, and the importance of community in learning. The findings emphasise the significance of creating coherence between research, vocational skills, educational theory, and real-world applications to develop quality in VET teacher training. This study has implications for educators and policymakers, underlining the need for a comprehensive approach to research-based VET teacher competence that integrates personal, academic, and professional elements.

Service Quality Variables and Customer Satisfaction at A Nepalese Commercial Bank

Customer satisfaction is a critical component of banking strategy, which reflects customer sentiment towards an organization's offerings, emphasizing emotional attachment over mere satisfaction. This research investigates customer satisfaction in commercial banks of Kathmandu Valley in Nepal. The study conducted a descriptive cross-sectional study using a quantitative research design, explicitly targeting 380 general customers of commercial banks in Kathmandu Valley through convenience sampling. Participants received a semi-structured questionnaire via email in Google Forms, encompassing inquiries on demographics, banking habits, and customer satisfaction. Data analysis was performed using SPSS version 20, and a p-value below 0.05 was considered statistically significant. The investigation found that the study population appears to be young, as 46.6% of the participants are in the 18–30 age range and predominantly male (56.6%). Most respondents (88.4%) hold accounts with private banks. Among those experiencing ATM service-related problems, 45.5% encountered them most frequently. Despite this, overall customer satisfaction remains high. Customers are notably content with the bank's reliability, including timely service and accurate record-keeping. Conversely, dissatisfaction mainly stems from communication issues, particularly regarding timely interest rates and service updates. Customer satisfaction is significantly influenced by service quality factors such as reliability, responsiveness, empathy, assurance, and communication. These findings highlight the necessity of addressing service challenges to enhance customer satisfaction and service quality within Nepal's banking sector.

Tailor-made ammonia nitrogen risk management with machine learning models for aquatic environments in the Mainland of China

Efficient management of pollutant risks in water bodies is crucial for public health and aquatic ecosystem sustainability. However, the toxicities of pollutants, such as ammonia nitrogen (NH3-N), are often affected by multiple water quality factors, including the pH and water temperature. Extensive spatial and temporal variability in these factors hinders tailor-made management of risk. This study used high-frequency monitoring data collected over 1 year to evaluate the long-term NH3-N risk in China’s aquatic ecosystems. High accuracy and interpretability were achieved by decomposing NH3-N risk into the contributions of key influencing factors using random forest models and Shapley Additive Explanations. Two distinct types of NH3-N risk hotspots were identified across 18 cities: 15 cities with high NH3-N concentrations and 3 cities with low environmental carrying capacity due to high pH levels or elevated water temperatures. For the former, rapid NH3-N abatement measures are necessary to bring NH3-N concentrations back below the environmental capacity. For the latter, it is recommended that NH3-N related industries are relocated to regions with high environmental capacities because fragile environments are not suitable for such industries. Importantly, this study investigated methods for attributing pollutant risks in the context of non-linear influencing factors, and the risk of NH3-N was predicted to increase by 6.1 % by the end of 2100 in the context of increasing temperatures under the SSP 2–4.5 scenario. The methodology is also adaptable and suitable for integration into global ecosystem risk management efforts to balance development and aquatic ecological sustainability.

Enhancing phase modulation and group delay in reflective Huygens metasurfaces via a Fabry-Perot cavity

Huygens metasurfaces exhibit excellent optical properties such as 2π phase modulation and slow light effects. However, they face challenges including wide bandwidth and low group delay due to their high radiation losses. Here, we propose a reflective Huygens metasurface coupled with an F-P cavity. We demonstrate that F-P resonance modes can couple with magnetic-quasi-bound-state (M-QBIC) and electric-quasi-bound-state (E-QBIC) in the Huygens metasurface through constructive interference, significantly enhancing the quality factors of both QBICs. Through structural parameter optimization, our reflective Huygens metasurface achieves 4π phase modulation and a high group delay of up to 166 ps. Compared to the non-coupled Huygens metasurface with the same structural asymmetry, the group delay of the F-P coupled reflective Huygens metasurface is enhanced by up to 30 times. Our design reduces the fabrication precision requirements for Huygens metasurfaces, enabling similar group delays to be achieved in low-symmetry coupling structures as in highly symmetric non-coupling structures. Additionally, the performance of this metasurface shows robustness to changes in incident light polarization. This design highlights the potential for achieving high-quality factors, large phase modulation, and large group delay, offering new avenues for the design of highly sensitive tunable devices, efficient nonlinear optical devices, and narrowband slow light devices.

Searching for tidal orbital decay in hot Jupiters

Abstract We study transits of several ‘hot Jupiter’ systems – including WASP-12 b, WASP-43 b, WASP-103 b, HAT-P-23 b, KELT-16 b, WD 1856+534 b, and WTS-2 b – with the goal of detecting tidal orbital decay and extending the baselines of transit times. We find no evidence of orbital decay in any of the observed systems except for that of the extensively studied WASP-12 b. Although the orbit of WASP-12 b is unequivocally decaying, we find no evidence for acceleration of said orbital decay, with measured $\ddot{P} = (-7 \pm 8) \times 10^{-14} \rm ~s^{-1}$, against the expected acceleration decay of $\ddot{P} \approx -10^{-23} \rm ~s^{-1}$. In the case of WD 1856+534 b, there is a tentative detection of orbital growth with $\dot{P} = (5.0 \pm 1.5) \times 10^{-10}$. While statistically significant, we err on the side of caution and wait for longer follow-up observations to consider the measured $\dot{P}$ real. For most systems, we provide a 95%-confidence lower limit on the tidal quality factor, $Q_\star ^{\prime }$. The possibility of detecting orbital decay in hot Jupiters via long-term radial velocity (RV) measurements is also explored. We find that $\sim 1 \rm ~m~s^{-1}$ precision in RVs will be required to detect orbital decay of WASP-12 b with only 3 yr of observations. Currently available RV measurements and precision are unable to detect orbital decay in any of the systems studied here.

Neuromorphic alternating current sensing using piezoelectric resonators and physical reservoir computing

Non-contact current sensors are valuable because they can safely measure alternating current without interrupting the circuit. However, current sensors utilizing Hall elements or coils are only available for single wires, and piezoelectric resonator-based sensors have difficulty achieving both high sensitivity and linearity. To address this issue, we propose a novel approach, that is, the use of piezoelectric current sensors as nodes for physical reservoir computing (physical RC), allowing us to utilize nonlinear regions. To improve the sensitivity and short-term memory required by physical RC, a piezoelectric resonator with a quality factor of 75 was realized by employing a tuning fork structure. Nonlinearities were also introduced by analog circuits. The results of the benchmark tests indicate that the device worked as a physical RC and that it successfully predicted unknown current values from the results of training at three levels of current.

Nonequilibrium quasiparticle distribution in superconducting resonators: Effect of pair-breaking photons

Many superconducting devices rely on the finite gap in the excitation spectrum of a superconductor: thanks to this gap, at temperatures much smaller than the critical one the number of excitations (quasiparticles) that can impact the device’s behavior is exponentially small. Nevertheless, experiments at low temperature usually find a finite, non-negligible density of quasiparticles whose origin has been attributed to various non-equilibrium phenomena. Here, we investigate the role of photons with energy exceeding the pair-breaking threshold 2\Delta2Δ as a possible source for these quasiparticles in superconducting resonators. Modeling the interacting system of quasiparticles, phonons, sub-gap and pair-breaking photons using a kinetic equation approach, we find analytical expressions for the quasiparticles’ density and their energy distribution. Applying our theory to measurements of quality factor as function of temperature and for various readout powers, we find they could be explained by assuming a small number of photons above the pair-breaking threshold. We also show that frequency shift data can give evidence of quasiparticle heating.

Effects of air damping on quality factors of different probes in tapping mode atomic force microscopy

Abstract The AFM probe in tapping mode is a continuous process of energy dissipation, from moving away from to intermittent contact with the sample surfaces. At present, studies regarding the energy dissipation mechanism of this continuous process have only been reported sporadically, and there are no systematic explanations or experimental verifications of the energy dissipation mechanism in each stage of the continuous process. The quality factors can be used to characterize the energy dissipation in TM-AFM systems. In this study, the vibration model of the microcantilever beam was established, coupling the vibration and damping effects of the microcantilever beam. The quality factor of the vibrating microcantilever beam under damping was derived, and the air viscous damping when the probe is away from the sample and the air squeeze film damping when the probe is close to the sample were calculated. In addition, the mechanism of the damping effects of different shapes of probes at different tip–sample distances was analyzed. The accuracy of the theoretical simplified model was verified using both experimental and simulation methods. A clearer understanding of the kinetic characteristics and damping mechanism of the TM-AFM was achieved by examining the air damping dissipation mechanism of AFM probes in the tapping mode, which was very important for improving both the quality factor and the imaging quality of the TM-AFM system. This study’s research findings also provided theoretical references and experimental methods for the future study of the energy dissipation mechanism of micro-nano-electromechanical systems.

Long-Term Monitoring and Analysis of Key Driving Factors in Environmental Quality: A Case Study of Fujian Province

Ecological environment quality reflects the overall condition and health of the environment. Analyzing the spatiotemporal dynamics and driving factors of ecological environment quality across large regions is crucial for environmental protection and policy-making. This study utilized the Google Earth Engine (GEE) platform to efficiently process large-scale remote sensing data and construct a multi-scale Remote Sensing Ecological Index (RSEI) based on Landsat and Sentinel data. This approach overcomes the limitations of traditional single-scale analyses, enabling a comprehensive assessment of ecological environment quality changes across provincial, municipal, and county levels in Fujian Province. Through the Mann–Kendall mutation test and Sen + Mann–Kendall trend analysis, the study identified significant change points in the RSEI for Fujian Province and revealed the temporal dynamics of ecological quality from 1987 to 2023. Additionally, Moran’s I statistic and Geodetector were employed to explore the spatial correlation and driving factors of ecological quality, with a particular focus on the complex interactions between natural factors. The results indicated that: (1) the integration of Landsat and Sentinel data significantly improved the accuracy of RSEI construction; (2) the RSEI showed a consistent upward trend across different scales, validating the effectiveness of the multi-scale analysis approach; (3) the ecological environment quality in Fujian Province experienced significant changes over the past 37 years, showing a trend of initial decline followed by recovery; (4) Moran’s I analysis demonstrated strong spatial clustering of ecological environment quality in Fujian Province, closely linked to human activities; and (5) the interaction between topography and natural factors had a significant impact on the spatial patterns of RSEI, especially in areas with complex terrain. This study not only provides new insights into the dynamic changes in ecological environment quality in Fujian Province over the past 37 years, but also offers a scientific basis for future environmental restoration and management strategies in coastal areas. By leveraging the efficient data processing capabilities of the GEE platform and constructing multi-scale RSEIs, this study significantly enhances the precision and depth of ecological quality assessment, providing robust technical support for long-term monitoring and policy-making in complex ecosystems.

Q-enhancement of piezoelectric micro-oven controlled MEMS resonators using honeycomb lattice phononic crystals

In this paper, a two-dimensional (2-D) honeycomb lattice phononic crystal (PnC) based micro-oven with large bandgap is introduced to be integrated with piezoelectric microelectromechanical systems (MEMS) resonator to reduce anchor loss for timing applications. Finite element method (FEM) analysis and experimental measurement were performed to verify that the proposed PnC micro-oven design gives advantage in quality factor (Q). The measurement results demonstrate that the resonator with 2-D honeycomb lattice PnC micro-oven shows a repeatable 1.7 times improvement of average Q compared with the bare one. The resonator with micro-oven control was further measured for frequency stability. The proposed piezoelectric micro-oven controlled MEMS resonator achieves a frequency stability of less than ±10 ppb in a stable environment, which indicates promising potential for application in high-end timing field.

In-situ deposited anti-aging TiN capping layer for Nb superconducting quantum circuits

Abstract The performance of Nb superconducting quantum devices is predominantly limited by dielectric loss at the metal–air interface, where Nb2O5 is considered the main loss source. Here, we suppress the formation of native oxides by in-situ deposition of a TiN capping layer on the Nb film. With TiN capping layers, no Nb2O5 forms on the surface of the Nb film. The quality factor Q i of the Nb resonator increases from 5.6 × 105 to 7.9 × 105 at low input power and from 6.8 × 106 to 1.1 × 107 at high input power. Furthermore, the TiN capping layer also shows good aging resistance in Nb resonator devices, with no significant performance fluctuations after one month of aging. These findings highlight the effectiveness of TiN capping layers in enhancing the performance and longevity of Nb superconducting quantum devices.

On the viscoelastic-electromagnetic-gravitational analogy

The analogy between electromagnetism and gravitation was achieved by linearizing the tensorial gravitational equations of general relativity and converting them into a vector form corresponding to Maxwell’s electromagnetic equations. On this basis, we use the equivalence with viscoelasticity and propose a theory of gravitational waves. We add a damping term to the differential equations, which is equivalent to Ohm’s law in electromagnetism and Maxwell’s viscosity in viscoelasticity, to describe the attenuation of the waves. The differential equations in viscoelasticity are those of cross-plane shear waves, commonly referred to as SH waves. A plane-wave analysis gives the phase velocity, the energy velocity, the quality factor and the attenuation factor of the field as well as the energy balance. To obtain these properties, we use the analogy with viscoelasticity; the properties of electromagnetic and gravitational waves are similar to those of shear waves. The presence of attenuation means that the transient field is generally a composition of inhomogeneous (non-uniform) plane waves, where the propagation and attenuation vectors do not point in the same direction and the phase velocity vector and the energy flux (energy velocity) are not collinear. The polarization of cross-plane field is linear and perpendicular to the propagation-attenuation plane, while the polarization of the field within the plane is elliptical. Transient wave fields in the space–time domain are analyzed with the Green function (in homogeneous media) and with a grid method (in heterogeneous media) based on the Fourier pseudospectral method for calculating the spatial derivatives and a Runge–Kutta scheme of order 4 for the time stepping. In the examples, wave propagation at the Sun-Earth and Earth-Moon distances using quadrupole sources is considered in comparison to viscoelastic waves. The Green and grid solutions are compared to test the latter algorithm. Finally, an example of propagation in heterogeneous media is presented.

ISM band CPW-fed antenna for detection of skin cancer

A CPW-fed antenna sensor with high quality factor is designed to identify the skin cancer. The proposed antenna operates in the ISM band at 2.47 GHz frequency. The proposed antenna aims to exploit the variations in dielectric constants of skin, fat, and muscle tissues to enable non-invasive and early detection of skin cancer. The antenna design process involves considerations for achieving a high frequency shift and quality factor to discern subtle variations in dielectric properties. Electromagnetic simulations, utilizing advanced numerical techniques are employed to analyze the antenna's performance in different tissue environments. The proposed antenna design is optimized for enhancing its sensitivity to changes in the dielectric constants associated with healthy and cancerous skin tissues. To validate the antenna's effectiveness, experimental setups using tissue-mimicking phantoms are utilized. This research not only emphasizes the technical aspects of antenna design but also underscores the potential clinical applications for non-invasive skin cancer detection.

Amino functionalized zeolitic imidazolate framework-8 coated cellulose aerogel for enhanced air purification

Human activities generate large quantities of air pollutants, and particulate matter (PM) in the air poses a serious threat to public health. Nanofiber filters with surface-loaded metal–organic frameworks (MOFs) are promising materials for the capture of PM. Herein, this work creatively fabricated an air filter by anchoring amino-functionalized ZIF-8 on the surface of cellulose aerogel (NZCA) by in situ growth approach. The excellent compatibility between ZIF and cellulose was demonstrated by XRD, FT-IR, SEM and XPS characterization techniques. The functionalized ligand introduces –NH2, and the polar –NH2 group enhances the electrostatic interaction between ZIF-8-NH2 and PM, resulting in NZCA with superior PM filtration performance (filtration efficiency and quality factor: PM2.5: 92%, 0.054; PM10: 96%, 0.068) compared to ZCA without sacrificing the pressure drop. Furthermore, ZIF-8-NH2 modified cellulose filters were easy to regenerate and exhibited excellent reusability. This work paves the way for the rational design of ligand-modified MOF/cellulose filters for the efficient removal of PM from air, which has important implications for solving environmental problems and energy crises.

An UHF band planar resonator temperature sensor constructed from high-performance titanium dioxide system microwave dielectric ceramics: Toward integrated ceramic-based sensor devices

With the rapid fusion of temperature sensing technology and microwave technology, microwave temperature sensors have become the protagonist of competing research. We propose a planar resonator temperature sensor that combines substrate material modifications with sensor structure design. To realize this concept, high-performance TiO2-xwt. % ZnO (0 ≤ x ≤ 3) microwave dielectric ceramics are prepared. The various factors influencing dielectric properties, including crystal structure, phase composition, Raman vibration, microstructure, element valence, and oxygen vacancy, are completely investigated. The TiO2-0.7 wt. % ZnO ceramic exhibiting exceptional properties (εr = 106.6, Qf = 46 000 GHz, τf = 426.0 ppm/°C) is selected for substrate fabrication. The frequency and temperature dependence of εr and tan δ are analyzed at 2–4.5 GHz from −50 to 100 °C, revealing a good linearity between εr and temperature. A CSRR temperature sensor employing this substrate material is designed, simulated, fabricated, and validated from −50 to 90 °C. This sensor generates two resonance frequencies (around 0.5 and 1.4 GHz) in the UHF band, demonstrating sensitivities of 2.2 MHz/10 °C and 6.3 MHz/10 °C at the first and second resonance frequencies, along with an outstanding normalized sensitivity of approximately 0.045. Through a comprehensive analysis of the physical mechanisms affecting the sensor's sensitivity and quality factor, the design of the sensor is strengthened from the perspective of optimizing the performance of microwave dielectric ceramics. The regulation mechanism of dielectric characteristics is enriched and clarified, thereby achieving a synergistic improvement in sensor performance. This work expands the application scope of microwave dielectric ceramics and provides an innovative approach to environmental monitoring.

Mitigating rim bending in fused silica micro shell resonators by a chamfered mold

In this work, we addressed the bending of a micro shell resonator’s rim toward the stem during glass-blowing process. This phenomenon occurs due to increased heat loss at the mold’s edge and reduced heat flux at the side of the Gaussian heat source. To mitigate rim bending and the subsequent reduction in capacitance between the rim and 3D electrodes, which can degrade performance in micro glass-blown shell resonators for gyroscopes, we propose two potential mold solutions, using short-stem mold and chamfered mold. To quantitatively compare resonators created by these two types of molds, we calculated the noise factor for predicting its gyroscope performance. From these calculations, we find out that using the chamfered mold enables us to increase in the resonator’s effective mass, eigenfrequency, angular gain, and quality factor, consequently reducing the noise factor compared to using the short-stem mold. We also demonstrated these results by manufacturing shell resonators and measuring its vibrational characteristics. After metalization of the glass shell resonator, Q factor and eigen frequency of n = 2 vibration mode along the primary (secondary) axis were measured to 622,466 ± 6,427 (619,793 ± 6,402) and 4,343 ± 40 Hz (4,350 ± 40 Hz), respectively. This simulation process will assist us in getting insight into understanding a shell resonator as a gyroscope, designing a mold and determining experimental conditions.

Optimization of the use of Moringa oleifera in wastewater treatment by rotational central composite design

Textile effluents have a complex waste composition due to the various compounds present and their resistance to degradation. Given the harmful effects of these pollutants on aquatic ecosystems, adequate treatment before disposal is essential, usually involving chemical processes such as coagulation and flocculation. This study optimizes textile wastewater treatment using Moringa oleifera as a natural coagulant through Rotational Central Composite Design (RCCD), a type of Response Surface Methodology (RSM), aiming to improve color removal, a key factor for effluent quality. By exploring Moringa oleifera as a sustainable alternative, the research provides new insights into environmentally friendly coagulant use and treatment optimization. The treatment’s effectiveness depends on the coagulant dosage, the energy applied, and the pollutant concentration. Dye removal was evaluated using spectrophotometry, and the evaluated factors in the optimization process were slow and fast mixing times, coagulant dosage, and pollutant concentration. The study identified pollutant concentration and slow mixing time as the most influential factors in treatment effectiveness. The model achieved a coefficient of determination (R²) of 87.9 %, and maximum dye removal reached 80.2 % under optimal conditions: 30 mL of coagulant, 20 min of slow mixing, 2 min of fast mixing, and a pollutant concentration of 300 mg ∙ L−1. The average removal efficiency was 47.86 %, indicating that natural coagulants offer a viable alternative for textile effluent treatment.