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Advanced Oxidation of Pesticide-Containing Wastewater Using an Ozonation Column System Under Optimized Conditions
No full textWastewater containing pesticides is characterized by refractory organic pollutants and suspended solids that pose significant challenges to conventional biological and physicochemical treatment methods. This study evaluated the efficiency of ozonation as an advanced oxidation process for degrading organic contaminants in such wastewater and optimized key operational parameters to enhance treatment performance. Using a Box-Behnken design combined with Response Surface Methodology (RSM), the effects of pH, ozone dosage, and ozone gas flow rate were systematically investigated. The optimal conditions were identified at pH 9, an ozone dosage of 500 g/m3, and a gas flow rate of 0.75 L/min, achieving a maximum COD removal efficiency of more than 70%, compared with only 47–55% under acidic or near-neutral conditions. Continuous-flow experiments further demonstrated that hydraulic retention time (HRT) strongly influences ozonation performance, with COD removal increasing from 50.4% at 10 minutes to 69.2% at 100 minutes. However, the practical optimal range was 30-60 minutes, where removal stabilized between 63% and 66%. Ozonation alone exhibited limited capacity for suspended solids removal, with TSS reduction remaining below 19% even at extended HRTs, indicating the need for integration with coagulation, sedimentation, or filtration processes. Overall, the findings confirm that ozonation is an effective sludge-free oxidation technology for treating wastewater containing pesticides and provide valuable operational parameters for future scale-up and industrial application
Experimental Work on Shear Behaviour of Masonry Wall Using Local Mortar and Traditional Solid Clay Brick
No full textIndonesia is located in a high seismic zone, making the shear performance of masonry walls a key factor in the safety of simple buildings. The characteristics of bricks and mortar vary between regions in Indonesia due to differences in materials, production processes, and local practices. This study aims to assess shear performance of masonry walls made with brick units from local traditional manufacturers and local mortar in Aceh, western Indonesia. The evaluation was conducted experimentally using diagonal compression tests and direct triplet specimen tests in accordance with standards. In this regard, 3 types of mortar ratios are being used, namely 1:3, 1:4, and 1:5 (binder-sand ratio). It is found that the bricks produced in Aceh (western Indonesia) have lower compressive strength than the locally used mortar. This research concludes that shear capacity for masonry walls can be determined using either the triplet test or the diagonal tension test, and both methods typically yield comparable shear strength values. The mortar in all cases governs the masonry failure mechanism under shear loading for triplet and diagonal tension specimens. It was also observed that higher cement proportions in mortar lead to greater compressive and shear strength
Decoding Telemedicine Adoption: The Roles of Digital Skills, Trust Dynamics, and Facilitating Conditions Among Outpatients
No full textThe proposed study will explore the interconnection of digital literacy, trust in technology, and the presence of facilitating conditions in the process of telemedicine acceptance of outpatients at a Regional General Hospital. The rationale for the laboratory is the sudden great need for digital health services after the pandemic, besides the hospital's difficulties in providing quick, efficient, and accessible services to the community. A quantitative explanatory research design was adopted for this study with 150 participants who either used or were acquainted with the telemedicine services drawn into the research. The participants were picked based on purposive sampling, and a structured questionnaire containing a five-point Likert scale were used for data collection. The research instrument was affirmed through validity and reliability tests which included Cronbach's Alpha and classical assumption tests that were conducted pre-analysis by multiple linear regression. The analysis of data produced each of the independent variable's presence leading to the positive and significant influence on the adoption of telemedicine. The value of the R2 which is the coefficient of determination showed that the model accounted for 67% of the variation in telemedicine adoption. The research also portrays management recommendations on the need for upgrading patients' digital literacy as well as the security and reliability of technology and the ensuring and promotion of the right conditions for telemedicine use which will be optimal and sustainable
Hybrid Evaluation of Water Distribution System Using Epanet and Statistical Indices
No full textEfficient management of water distribution systems is essential to ensure reliable and sustainable water supply. This study focuses on the performance evaluation and reliability assessment of a water distribution system using a combination of Epanet, Mean Bias Error (MBE), and Nash-Sutcliffe Efficiency (NSE). The main objective is to evaluate the system's hydraulic performance in terms of pressure and flow distribution, and to assess its reliability under varying demand conditions. The methodology involved developing a detailed hydraulic model in EPANET using actual network data such as pipe diameters, lengths, nodal elevations, and water demands. Field measurements of pressure and flow were collected for calibration and validation of the simulated results. Statistical techniques—MBE and NSE—were applied to quantify the model's accuracy and pipes. Statistical validation techniques, including Root Mean Square Error (RMSE) and Scatter Index - were used to evaluate the model's accuracy and reliability. Results indicate a strong agreement between simulated and observed values, confirming the model's adequacy for system analysis and decision-making. The calibrated EPS model enables the identification of low-pressure zones, high headloss areas, and potential operational inefficiencies under varying demand conditions. This research demonstrates that WaterGEMS is an effective tool for improving network performance assessment, aiding in the optimization of water distribution system planning, operation, and management to ensure sustainable and reliable water supply. Results revealed that the simulated pressures and flows closely matched the observed data, with low MBE values and NSE coefficients approaching unity, indicating a high level of model reliability. Conclusively, the integrated approach proved effective in evaluating system performance and identifying potential problem areas. It is recommended that the calibrated Epanet model be used for future planning, operational optimization, and maintenance strategies to enhance the overall efficiency and sustainability of the water distribution system
A kinetic model for polyatomic gas with quasi-resonant collisions leading to bi-temperature relaxation processes
No full textIn this article, we extend the Boltzmann framework for polyatomic gases by introducing quasi-resonant kernels, which relax resonant interactions, for which kinetic and internal energies are separately conserved and lead to equilibrium states with two temperatures. We establish an H-theorem and analyze the quasi-resonant model's asymptotic behaviour, demonstrating a two-phase relaxation process: an initial convergence towards a two-temperature Maxwellian state followed by gradual relaxation of the two temperatures towards each other. Numerical simulations validate our theoretical predictions. The notion of quasi-resonance provides the first rigorous framework of a Boltzmann dynamics for which the distribution is at all times close to a multi-temperature Maxwellian, relaxing towards a one-temperature Maxwellian
Gaseous reference standard for breath analysis
No full textAn increasing amount of research is going into detecting volatile organic compounds (VOCs) in exhaled breath to detect diseases and personalize treatment for patients: recently, these analytes has risen as potential biomarkers. The present work aims to examine different multi-component gas mixtures suitable for breath gas analysis. In addition, also the stability of these mixtures was investigated. The number of components tested were 31, divided in two gas mixtures A and B. These components are aldehydes, acetate compounds, aromatics compounds: the lists are available in the article. Gas components of mixture A and B were prepared in different concentration from 1 µmol/mol to 10 nmol/mol. All the mixtures were analytically verified and the expected analytical relative uncertainty is 10-15% for 10 nmol/mol mixture. The stability check is also performed after 1 year and 2 years. The mixtures demonstrated good stability, and tests are still on going
Reducing helium dependency in gas chromatography for natural gas blends with hydrogen
No full textThe transition toward blending hydrogen in natural gas networks requires a new generation of gas chromatographs, capable of accurately measuring hydrogen. At the same time, the ongoing helium shortage highlights the need to reduce helium consumption in gas chromatography. This research evaluates the analytical performance of the DynamiQ-X NG2220 micro gas chromatograph using three carrier gas combinations: helium-argon, hydrogen-argon and argon alone. Ten natural gas blends containing up to 20% hydrogen were measured to assess calorific value accuracy, limits of detection, and overall performance in accordance with OIML R140 and ISO 10723. All carrier gas combinations produced calorific values within the limits of OIML R140 accuracy class A. Operation with argon as the only carrier gas showed lower detector response and therefore higher limits of detection but remained suitable for fiscal metering ranges. Carrier gas consumption was low for all methods, and replacing helium with a hydrogen or argon can save approximately 19.2 litres of helium per day during continuous operation. Overall, the DynamiQ-X NG2220 demonstrated reliable performance with all tested carrier gases without needing any hardware changes, supporting the use of hydrogen or argon as viable alternatives to helium for online monitoring of natural gas blends with hydrogen
The CON-quasar stage of IRAS 07251−0248 E
No full textALMA continuum measurements of the local ultra-luminous galaxy IRAS 07251−0248 E at 667 μm reveal an extremely compact (R ≲ 27 pc) and bright (TB ≳ 200 K) nucleus with an absorbing foreground envelope and a surrounding (R ∼ 75 pc) disk or torus seen nearly face-on. The bright and unresolved nuclear emission implies large optical depths (τ667 μm ≳ 0.5, corresponding to NH ≳ 1025 cm−2) of hot dust at ≳500 K. In addition, JWST observations of the source show strong mid-infrared (mid-IR) absorption in the ro-vibrational bands of H2O ν2 = 1 − 0 (5 − 7 μm) and of other species including CO, HCN, C2H2, CH4, and CO2, and Herschel/PACS observations exhibit strong and saturated absorption due to OH, H2O, CH+, and CH. We propose a model in which the unresolved ALMA submillimeter and JWST mid-IR continua trace the same nuclear source, the former penetrating deep into the nucleus and the latter probing the nuclear photosphere. The continuum model, which includes trapping of photons (the “greenhouse” effect), indicates that the nuclear (Rh ≈ 13 pc) luminosity and luminosity surface density are ∼1012 L⊙ and Σbol ≈ 5 × 108 L⊙ pc−2, arising from an active galactic nucleus (AGN) so buried that high-ionization lines are completely obscured. The observed mid-IR gas-phase molecular bands probe outflowing gas with velocities of ∼160 km s−1 and are reproduced with the predicted Tdust profile, while the far-IR molecular absorption lines are generated in the surrounding thick disk or torus with τ100 μm ∼ 10. We conclude that IRAS 07251−0248 harbors a compact obscured nucleus (CON) that hides an AGN currently emitting at quasar luminosity. While the observed outflow could be driven by radiation pressure, we favor the scenario of a (partially) energy-conserving hot bubble caught in a very early phase of the expulsion of the highly concentrated gas at the galactic nucleus
Galaxy And Mass Assembly (GAMA): Deconstructing the galaxy stellar mass function by star formation and environment
No full textUsing the equatorial Galaxy and Mass Assembly (GAMA) dataset, we investigate how the low-redshift galaxy stellar mass function (GSMF) varies across different galaxy populations and as a function of halo mass. We find that: (i) the GSMF of passive and star-forming galaxies are well described by a double and a single Schechter function, respectively, although the inclusion of a second component for the star-forming population yields a more accurate description. Furthermore, star-forming galaxies dominate the low-mass end of the total GSMF, whereas passive galaxies mainly shape the intermediate-to-high-mass regime; (ii) the GSMF of central galaxies dominates the high-mass end, whereas satellites and ungrouped galaxies shape the intermediate-to-low-mass regime. Additionally, we find a relative increase in the abundance of low-mass galaxies moving from dense group environments to isolated systems; (iii) more massive halos host more massive galaxies, have a higher fraction of passive systems, and show a steeper decline in the number of intermediate-mass galaxies. Finally, our results reveal larger differences between passive and star-forming GSMFs than predicted by a phenomenological quenching model, but generally confirm the environmental quenching trends for central and satellite galaxies reported in other works
A distance measurement for blazar TXS 0506+056 using its radio variability and very long baseline interferometry images
No full textAims. We present the results of constraining the angular diameter distance to blazar TXS 0506+056 (z = 0.3365), a radio-bright active galactic nucleus (AGN) whose jet is aligned with the line of sight.
Methods. We used data obtained with the 15 GHz Very Long Baseline Array (VLBA) from MJD 54838 to MJD 60262 (15 years) and data from the 15 GHz Owens Valley Radio Observatory (OVRO) 40 m single dish (SD) telescope from MJD 54474 to MJD 59023 (12 years). We used a variability timescale and a causality argument of a linear size (taking the Doppler factor and a cosmological redshift into account) to measure the angular diameter distance to the source. To constrain the Doppler factor, we applied the relation between the rest-frame brightness temperature of the emission region and the observed brightness temperature. To calculate the observed brightness temperature, the angular size and flux density variation of the emission region are required. The angular size of the emission region (i.e., the VLBA core) was obtained from a full width at half maximum, which is a circular Gaussian model-fitting parameter that ranges from 0.048–0.228 mas, and its uncertainty is determined to be 1.8–13%. Using the OVRO SD light curve, we obtained a variability timescale of days and a peak flux density of Jy for the largest flare that peaked on MJD . We assumed a disk brightness morphology, equipartition brightness temperature (Tb, int = 5 × 1010 K), and perfect radius.
Results. By fitting the circular Gaussian model to the VLBA images, we found that the variability in the VLBA core drives the multiple flares. Based on the timescales and peak flux densities for the flares, we calculated the angular diameter distance. Using the VLBA core sizes obtained near the flare peaks, we found consistent distance measurement results with the ΛCDM model within 1σ uncertainties.
Conclusions. We suggest that the best distance from the source is Mpc, which is comparable with the ΛCDM distance of 948.2 ± 13.5 Mpc. The distance measurement should indeed be taken at the peak of a flare. We found that the decomposed timescale allowed us to obtain consistent distances with the ΛCDM. We strongly suggest to decompose light curves when the variability timescales are to be obtained properly