HPU2 Journal of Science: Natural Sciences and Technology

One-loop gauge boson contributions to decays \(h\to e_a e_b\) in the general gauge \(\text{R}_\xi\)

2026-04-28T09:24:30+07:00

Analytic formulas to express one-loop contributions to lepton flavor violating decays of the Standard Model-like Higgs boson \(h\to e^\pm_a e^\mp_b\) are calculated in the general gauge \(\text{R}_\xi\) for the general seesaw version of the Standard Model. The calculation is performed using the Passarino-Veltman functions, which include various well-known relations useful for analytic transformations. This calculation also requires precise forms of the couplings of the Goldstone boson of \(\text{W}^\pm\), which are model-dependent. We demonstrate analytically that the final result is gauge-independent, namely, the free unphysical parameter \(\xi\) of the \(\text{R}_\xi\) gauge vanishes completely. Moreover, the resulting decay amplitude is consistent with those previously calculated in different gauges, including the unitary gauge.

Trends in applying artificial intelligence in agricultural cultivation and some orientations for Vietnam

2026-04-28T09:24:28+07:00

This study examines the pivotal role of Artificial Intelligence (AI) in transforming agricultural biotechnology, especially amid the pressing challenges of climate change and the escalating global demand for food. AI has demonstrated considerable potential in optimizing agricultural processes through big data analytics, predictive modeling, and the development of novel crop varieties with enhanced resilience, improved resource efficiency, and reduced environmental impact. In precision agriculture, AI enables optimized use of water, fertilizers, and pesticides, and provides accurate forecasts for planting and harvesting schedules. Such capabilities substantially enhance productivity and mitigate production risks for farmers. AI applications for detecting pests and diseases have opened new ways to monitor and manage crops, thereby improving production quality and efficiency. AI also plays a key role in adapting agriculture to climate change, from smart irrigation management to adjusting farming practices based on weather conditions. However, for AI to reach its full potential in Vietnam, attention needs to be paid to factors such as digital infrastructure, training and awareness raising, cost and accessibility, integration with traditional methods, data security and adaptability to local conditions. These factors not only ensure effective AI deployment but also help bring sustainable benefits to Vietnam’s agricultural sector in the digital age.

Non-uniform lagrange interpolation in B-mode ultrasound image reconstruction

2026-04-28T09:24:27+07:00

This study introduces a signal-processing framework based on non-uniform Lagrange interpolation for improving spatial sampling consistency in ultrasound imaging. The proposed method adaptively adjusts pixel coordinates to make the effective sampling density across the reconstructed image more uniform, thereby mitigating the geometric distortion commonly observed in conventional B-mode ultrasound data. To experimentally validate the approach, a compact B-mode ultrasound acquisition system was developed using an Arduino-based transmitter–receiver module interfaced with a personal computer. The measured echo amplitudes reliably captured key acoustic characteristics of the examined medium, including transmission behavior, reflection properties, and attenuation effects. Following the acquisition, the signals were processed in MATLAB using the implemented non-uniform Lagrange interpolation algorithm. The results demonstrate that the method enables accurate and stable reconstruction of B-mode ultrasound images from the non-uniformly sampled echo data.

Removal of Cr(VI) from aqueous solutions using MnFe₂O₄–Coffee husk activated carbon composite

2026-04-28T09:24:23+07:00

This work reports the fabrication of MnFe₂O₄-based composite adsorbents (MFO@CF) derived from HNO₃-activated coffee husk biochar via a combination of co-precipitation and hydrothermal methods. The structural and chemical characteristics of the prepared nanocomposites were analyzed using Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). Batch adsorption experiments were conducted to evaluate the Cr(VI) removal performance under various operational conditions, including solution pH (2÷8), contact time (10÷120 min), and initial Cr(VI) concentration (5÷30 mg·L⁻¹). The findings indicate that the MFO@CF composite exhibited effective Cr(VI) removal, which can be attributed to electrostatic interactions and the presence of functional groups on the composite surface. According to the Langmuir isotherm model, the maximum adsorption capacity of MFO@CF reached 30.45 mg·g⁻¹, demonstrating its potential as an adsorbent for Cr(VI) removal in wastewater treatment applications. The adsorption kinetics followed a pseudo-second-order model, suggesting that chemisorption may be involved in the adsorption process.

Complexation of polyhydroxy-nitroso dyes with \(\text{Co}^{2+}\), \(\text{Ni}^{2+}\), and \(\text{Cr}^{3+}\): characteristics, chemisorption behavior, and application in electroplating wastewater treatment

2026-04-28T09:24:20+07:00

Polyhydroxy–nitroso dyes are multifunctional compounds with strong chemisorption capabilities for heavy metal ions, making them promising candidates for wastewater treatment. In this study, the complexation behavior of two phloroglucinol-based polyhydroxy–nitroso dyes with Co²⁺, Ni²⁺, and Cr³⁺ was systematically investigated using UV–Vis, FT-IR, EDX, and EPR spectroscopy. The equilibria of the complexation reactions were examined by spectrophotometric titration, and the stoichiometry and stability constants of the resulting complexes in solution were subsequently determined. The chemisorption performance and potential application of these dyes for treating electroplating wastewater were further evaluated under various pH conditions. The results demonstrated that both polyhydroxy–nitroso dyes form stable complexes with metal cations, primarily of ML and ML₂ types. The synthesized compounds efficiently precipitated selected metal ions from acidic solutions, indicating their suitability as metal-adsorbent materials. When applied to electroplating wastewater, the dyes reduced the concentrations of Co²⁺, Ni²⁺, and Cr³⁺ by more than 85%.

Sustainable development of the global dyeing industry in the future

2026-04-28T09:24:21+07:00

The dyeing stage plays an important role within the textile production chain, as it contributes significantly to the aesthetics and commercial value of the product. Moreover, it is the step that can detect mistakes from previous stages and find an appropriate solution. However, the dyeing sector in Vietnam remains a weak stage compared to other segments of the textile chain. Additionally, dyeing is characterized by high consumption of energy, chemicals, and water, leading to environmental pollution. In the context of a global shift towards sustainable development, the dyeing industry must change to meet environmental protection standards, conserve resources, and ensure labor safety.

This article introduces new sustainable development directions of the dyeing industry, such as the adoption of eco-friendly dyeing technologies, the use of natural dyes, the reuse of wastewater, and the optimization of production processes. These are also emerging research directions that have attracted considerable attention in recent years.

Constructing waveform of P, Q, R, S, and T waves in ECG signals for cardiovascular disease diagnosis

2026-04-28T09:24:31+07:00

This study presents the development of an electrocardiogram (ECG) signal acquisition and analysis system based on Arduino hardware and a personal computer. The recorded ECG signals were processed in MATLAB to extract key diagnostic parameters, including sinus rhythm, the amplitude and width of the P, S, and T waves, as well as the slope of the ST segment. These features were subsequently transformed into Time-domain representations, enabling clinicians to simultaneously examine hundreds of cardiac cycles. By providing a comprehensive view of ECG variability, the proposed waveform effectively reduces the influence of artifacts caused by technical errors or transient physiological and emotional fluctuations. Consequently, the integration of s enhances diagnostic precision and reliability compared to conventional visual inspection methods currently used in clinical practice.

Some applications of directional subdifferentials at infinity to vector optimization problems

2026-04-28T09:24:25+07:00

This paper presents a comprehensive investigation into several advanced applications of variational analysis, with a particular focus on the roles of special normal cones and directional subdifferentials at infinity. By extending classical tools of nonsmooth and variational analysis to unbounded settings, we establish directional optimality conditions at infinity and derive sufficient conditions ensuring the existence and compactness of global solution sets for vector optimization problems. The theoretical results obtained contribute to a deeper understanding of optimization behavior in asymptotic regimes. Furthermore, illustrative examples are provided to demonstrate the validity and applicability of the proposed results, highlighting their potential use in future research on infinite-dimensional and unbounded optimization problems.

Using coconut water for polyphenol extraction from Artocarpus altilis

2026-04-28T09:24:18+07:00

This study investigates the potential of coconut water for the extraction of polyphenolic compounds from the leaves and branches of Artocarpus altilis. The objective is to identify a green and clean solvent as an alternative to environmentally harmful organic solvents. Two extraction methods were used: hot extraction (reflux) and cold extraction (maceration), with three types of coconut water (Malaysian dwaft, green Siamese, and strawberry coconuts) employed as solvents. The results indicated that the total polyphenol content in the extracts obtained with coconut water and an acetate buffer (pH 3.6) was higher than that of aqueous extracts (18.8–48.0 and 15–28.0 mg GAE/g, respectively). Furthermore, 6/24 extracts exhibited significant antioxidant activity, with IC₅₀ values below 50 µg/mL in the DPPH free radical scavenging assay. Based on MPI (mobile phase performance index) values, the optimal solvent system identified was a combination of Malaysian dwarf or strawberry coconut water with a 0.5 M acetate buffer (pH 3.6) at a 1:1 ratio, which yielded high polyphenolic content and antioxidant activity from A. altilis leaves and branches.