Search Results (210)

The management of effluents and their treatment is a fundamental issue in water management, the removal of different types of contaminants is another relevant issue for public health and the environment. Bacteria are one of the main types of contaminants in untreated water discharged to receiving bodies. The objective of this research was to evaluate the removal efficiency of pathogenic bacteria in a horizontal feeding subsurface artificial wetland that treats wastewater originated from the Boca de Río Technological Institute, Veracruz, Mexico. A hybrid system composed of seven cells with three types of substrates and ornamental type vegetation was designed; the indicators evaluated were the concentration of total and fecal coliforms and the efficiency of bacterial removal in the stages of the system. The artificial wetland system demonstrated a significant reduction (p < 0.05) between the different cells of the system. The values of pathogenic bacteria removal obtained in the wetland were higher than 99% in the cells of the system and times. In conclusion, it was identified that the interaction of the components of this system and its operation under the climatic seasons of the site influenced the removal efficiency of pathogenic bacteria, allowing optimal removal efficiency. Full article

The glymphatic system is a newly discovered waste-clearing system that is analogous to the lymphatic system in our central nervous system. Furthermore, disruption in the glymphatic system has also been associated with many neurodegenerative disorders (e.g., Alzheimer’s disease), traumatic brain injury, and subarachnoid hemorrhage. Thus, understanding the function and structure of this system can play a key role in researching the progression and prognoses of these diseases. In this review article, we discuss the current ways to map the glymphatic system and address the advances being made in preclinical mapping. As mentioned, the concept of the glymphatic system is relatively new, and thus, more research needs to be conducted in order to therapeutically intervene via this system. Full article

This paper is aimed at eliciting consistency conditions for the existence of unsteady incompressible axisymmetric swirling viscous Beltrami vortices and explicitly constructing solutions that obey the conditions as well as the Navier–Stokes equations. By Beltrami flow, it is meant that vorticity, i.e., the curl of velocity, is proportional to velocity at any local point in space and time. The consistency conditions are derived for the proportionality coefficient, the velocity field and external force. The coefficient, whose dimension is of [length⁻¹], is either constant or nonconstant. In the former case, the well-known exact nondivergent three-dimensional unsteady vortex solutions are obtained by solving the evolution equations for the stream function directly. In the latter case, the consistency conditions are given by nonlinear equations of the stream function, one of which corresponds to the Bragg–Hawthorne equation for steady inviscid flow. Solutions of a novel type are found by numerically solving the nonlinear constraint equation at a fixed time. Time dependence is recovered by taking advantage of the linearity of the evolution equation of the stream function. The proportionality coefficient is found to depend on space and time. A phenomenon of partial restoration of the broken scaling invariance is observed at short distances. Full article

In this paper, we studied the Picard–Fuchs systems and equations which appear in the theory of Gauss–Manin systems and connections associated with deformations of isolated singularities. Among other things, we describe some interesting properties of such systems and relationships between them. Then we show how to calculate the fundamental solutions to the Gauss–Manin system for $A_{\mu }$-singularities and to the corresponding generalized Legendre equations in terms of the multidimensional Horn’s hypergeometric functions. In conclusion, some important questions concerning basic properties of the local and global Picard–Fuchs systems of Pfaffian type, involving integrability conditions and commuting relations, are discussed in some detail. Full article

Vegetation indices (VIs) have long been a crucial tool for monitoring plant growth and health, assessing the impact of environmental factors on vegetation, and supporting decision-making processes in agriculture and forestry. Traditionally, these mathematical formulations, leveraging the spectral response of plants to sunlight, have been instrumental in assessing vegetation health. However, emerging research suggests some unconventional applications that extend the scope of VIs. This article surveys the traditional and novel uses of VIs in various fields, including other applications such as climate change studies, disaster management, or microorganism assessment. It underscores the value of VIs, such as the normalized difference vegetation index (NDVI), or the enhanced vegetation index (EVI), in tracking climate-related shifts, mitigating the impact of disasters, assessing microbial terroir, organic production, and even aiding the wine industry. Nonetheless, despite their promise, the practical application of VIs also presents interpretational and technical challenges that need to be addressed. Hence, while the vast potential of VIs is underscored in this article, it also calls for continued technological advancements and research efforts to fully harness their benefits, ultimately aiding in the sustainable management of our environment. The objective of this review is not only to reflect on the current situation, but also to explore innovative and unconventional applications of vegetation indices. This involves anticipating the potential of this dynamic and rapidly advancing scientific tool, rather than solely following mainstream approaches. Full article

Having access to a unique quantum circuit that one wants to protect against use by others is a very likely scenario in industrial computing. However, currently, users rely on classical computer security schemes, which have known shortcomings. In this paper, we introduce a novel protection scheme along with a survey of other known methods to protect quantum information. In particular, we review physically unclonable functions (PUFs), obfuscation, and introduce quantum logic locking (QLL). The latter technique provisions end users to protect their circuit from an adversary through the use of a secret key. Full article

Unmanned network robotics is a new multidisciplinary field that involves many fields of computer networks, multi-agent systems, control theory, 5G and 6G Internet, computer security, and wireless quantum communications. Efficient conjugation of such technologies needs to design new data verification schemes for robotic agents using the advantages of quantum key distribution lines. For such schemes the joint use of known fuzzy logic parametrical $T$-gates and discrete multiple-valued logic models simplifies the application of quantum quasi-random keys. Namely, the separate regulating parameter in $T$-gates is the most convenient tool to use quantum keys in comparatively simple classical control and verification procedures that do not involve quantum logic gates. Full article

High-speed health trains have the advantages of large rescue volume, strong continuous operation capability, and medical treatment on the way. It is the best transport platform for large-scale medical transfer tasks. To solve the problem of space limitations and the vehicle formation of high-speed health trains, a new method of space layout design and evaluation of high-speed health trains based on improved systematic layout planning (SLP) was proposed. First, SLP was improved, and the relationship between functional carriages was reasonably marshaled using the improved SLP. Then, according to the space constraints of high-speed trains and the requirements of the man–machine environment, the space layout of the vehicles was designed, and 3ds MAX software was used to visualize the designed layout structure. Finally, the static and dynamic simulation effects and adaptability of the design scheme were evaluated using the digital virtual simulation software JACK. The design scheme can meet the requirements of human–computer interaction efficiency. Compared with previous studies, the results of this study reflect the superiority and rationality of the design in functional configuration, space utilization, medical treatment, and injury-carrying capacity. The results of this study can provide theoretical support for the formation of high-speed health trains, and provide a reference for the research and development of such trains. It has certain practical application value. Full article

The sugarcane industry has a high environmental impact. In countries such as Mexico, cultivation and harvesting practices consume and pollute many ecological resources. However, quantifying these impacts is difficult due to their diverse nature and different units of measurement. In this study, an approach with two focuses was taken to assess the environmental costs of the sugarcane industry in San Luis Potosí, México. The first focus is human health costs related to air pollution (black carbon) and the second one is a lifecycle assessment applied to the production phase. In the first case, four scenarios, with different concentrations and populations, were projected. Costs of 516.8 thousand USD were estimated for a scenario in which black carbon concentrations exceeded the WHO reference by one unit for the total population. In the second case, costs of 642 million USD were estimated for the impairment of seven ecosystem-based services. These estimates may vary due to the source and specificity of the information provided, but nevertheless are considered an appropriate approximation of the cost of environmental damage. It is recommended that first-hand information be collected and systematized to improve the certainty of the estimates and that changes to sugarcane agrifood systems be considered to reduce environmental costs. Full article

In this review, the authors conducted benchmarks for three thermodynamic models to analyze PSA-based medical oxygen concentrator (MOC) systems to allow for optimization and operational flexibility. PSA oxygen generator plants are good medical-grade oxygen sources, a crucial tool in healthcare from the primary to the tertiary level. However, they must be designed accordingly and properly operated, considering key design goals such as improving adsorbent productivity, improving oxygen recovery, and innovating to reduce unit size and weight. The importance of mapping the performance of various design and operating requirements or designs themselves on outlet product specifications and production effectiveness is outlined. Emphasizing optimal PSA design and operation, the authors suggest considering simulation-based optimization frameworks or high-fidelity modeling for the optimal layout and operation conditions of adsorption-based MOC systems. Notwithstanding, a simplified first-principles-based model with additional assumptions and simplifications generates a large volume of scenarios faster. Therefore, it represents a good approach for a feasibility study dealing with many options and designs or even the real-time monitoring of PSA operating conditions. All this paved the way for efficient translation into machine learning models and even deep learning networks that might be better suited to simulate the complex PSA process. The conclusion outlines that PSA-based plants can be flexible and effective units using any of the three models when properly optimized. Full article

The multiple steady states of Ag/Bi2212-composite high-$T_c$ superconducting leads modeling current delivery to a superconducting magnet have been numerically calculated. The model is based on longitudinal conduction combined with convective heat dissipation from a helium gas stream along the conductor. Because of the nonlinearities introduced by the voltage–current relationship and the temperature-dependent material properties, up to three solutions have been identified within the range of parameters considered. Linear stability analysis reveals that two of them are stable, i.e., the superconducting and the normal branches, while the remaining one is unstable. The limit points separating the stable from the unstable steady states form the blow-up threshold, beyond which any further increase in the operating current results in a thermal runway. Interesting findings are that for low filling ratios no bounded solution exists when the length of the lead exceeds the lower limit point, while very high maximum temperatures may be encountered along the normal solution branch. The effect of various parameters such as the conduction–convection parameter, the applied current, and the reduction in coolant flow (LOFA) on the bifurcation structure and their stabilization effect on the blow-up threshold are also evaluated. Apart from the steady and unsteady operating modes, the multiplicity analysis is also used to identify the range of the design and operating variables where safe operation, with a sufficient margin from the onset of instabilities, may be established, thus facilitating the protection of the leads and the device connected to it. Full article

In the controlled source radiomagnetotelluric (CSRMT) sounding method, a horizontal magnetic dipole, HMD (vertical loop) or a horizontal electric dipole, and HED (grounded line) are used as sources. When working with HMD, the source is usually tuned to resonance to increase the current in the loop. However, the disadvantage of this approach is the narrow frequency range realized in the CSRMT method (1–12 kHz) and the short operating distance from the source (600–800 m). The need to tune the source to resonance at each selected frequency reduces the efficiency of the survey. In the case of using HED for sounding, measurements are performed in a wider frequency range of 1 to 1000 kHz, and along with the signal of the base frequency, its subharmonics are measured. In this case, emitted signal measurements are possible at a distance of up to 3–4 km from the source. At the same time, the disadvantage of using HED is that it requires grounding, the arrangement of which requires additional time when working on frozen ground or dry stony soil. We consider the possibilities of generation and registration of signals of subharmonics of base frequencies when applying the CSRMT method with loop sources—HMD and VMD (horizontal loop). A matching unit (MU) based on a step-up transformer was developed, which increases the output voltage of the CSRMT transmitter. In a field test with base frequencies of 20, 40, and 80 kHz, the signal amplitudes increased by a factor of two to four for subharmonics at frequencies of 60–200 kHz and by up to 10–13 times for subharmonics at frequencies of 200–500 kHz due to transformation of signal spectrum provided by MU. The possibility of using odd subharmonics of base frequencies for inversion has been demonstrated in the results of field experiments with different sources (HED, HMD, and VMD). This expands the frequency range of the method when working with loop sources and increases the survey’s effectiveness. The use of loop sources in the CSRMT method is especially advantageous for winter work in Arctic regions. Full article

Urbanization has led to the degradation of green areas and natural resources, which are critical for preserving biodiversity and natural benefits. Sustainable urban development (SUD) practices aim to balance urbanization with preserving and protecting green land and natural resources to achieve greater sustainability. This study evaluated land suitability for SUD in the Nabatiyeh area of Lebanon using a multi-criteria decision analysis technique, the analytical hierarchy process, combined with a geographic information system. The elevations and slopes were the most important criteria, followed by the distances from urban agglomeration and industrial areas, accessibility, and land cover types, with corresponding weights of 34% and 36%, 12%, 9%, 6%, and 3%, respectively. The study created a suitability map for future SUD. This identification assists urban planners and policymakers in making informed decisions regarding the development of urban areas. The study’s findings highlight the efficiency of combining multi-criteria decision analysis with geospatial techniques for urban planning and environmental management in promoting sustainable development and protecting the environment. Future research could explore the possibility of integrating administrative reforms to promote SUD, including improving governance, enhancing the efficiency of governmental agencies responsible for urban development, building scientific capacities, and increasing officials’ accountability. Full article

The spectrophotometric methods of determination of the active pharmaceutical ingredients meloxicam and nimesulide were reviewed and a simple UV-spectrophotometric method for the determination of these active pharmaceutical ingredients in industrial equipment cleaning validation samples was proposed. The methods were based on extraction of the residual quantities of meloxicam and nimesulide from the manufacturing equipment surface by the concentrated sodium carbonate solution and the subsequent UV-spectrophotometric determination of the basic forms of the drugs at the wavelength of 362 nm for meloxicam and at 397 nm for nimesulide. The calibration graphs were linear in the range from 5 to 25 mg/L of both nimesulide and meloxicam, the molar attenuation coefficients were 6100 m²/mol for nimesulide and 9100 m²/mol for meloxicam, the limit of detection was 0.8 mg/L for nimesulide and 1.9 mg/L for meloxicam and the limit of quantification was 2.5 mg/L for nimesulide and 5.8 mg/L for meloxicam. The methods were selective with respect to the common excipients, showed a good accuracy (the relative uncertainty did not exceed 7%) and precision (the relative standard deviation did not exceed 4%), did not require lengthy sample preparation or sophisticated laboratory equipment and were suitable for the routine analysis of cleaning validation samples. Full article

The COVID-19 pandemic, caused by the coronavirus SARS-CoV-2, has generated a renewed interest in the larger family of Coronaviridae, which causes a variety of different respiratory infections in a variety of different hosts. Understanding the mechanisms behind the ability of a family of viruses to spill over into different hosts is an ongoing study. In this work, we studied the relationship between specific amino acid sites and the solvent accessibility of the surface (or spike) protein of different Coronaviridae. Since host specificity hinges on the portion(s) of the protein that interfaces with the host cell membrane, there could be a relationship between information gain in specific amino acid sites and solvent accessibility. We found a connection between sites with high information gain and solvent accessibility within several major subgenera of Coronaviridae. Such a connection could be used to study other lesser-known families of viruses, which is desirable because information gain is much easier to compute when the number of sequences is large, as we show. Finally, we produced a visualization of the sequences within each major subgenus and discussed several regions of interest, as well as focused on some pairs of Coronaviridae hosts of interest. Full article