Search Results (33,643)

Surface acoustic wave-based (SAW) sensors are of great interest due to their high sensibility and fast and stable responses. They can be obtained at an overall low cost and with an intuitive and easy-to-use method. The chemical sensitization of a piezoelectric transducer plays a key role in defining the properties of SAW sensors. In this study, we investigate the structural and adhesion properties of a new class of coating material based on polyurethane polymeric composites. We used dark-field microscopy (DFM) and scanning electron microscopy (SEM) to observe the microstructure of polyurethane composite coatings on piezoelectric sensor elements and to analyze the effects of the chemical resistance and adhesion test (CAT) on the coating layers obtained with the polyurethane polymeric composites. The results of the microscopy showed that all polyurethane composite coatings exhibited excellent uniformity and stability after chemical adherence testing (CAT). All of the observations were correlated with the results of the ultrasonic analysis, which demonstrated the role of polyurethane as a binder to form the stable structure of the composites and, at the same time, as an adhesion promoter, increasing the chemical resistance and the adherence of the coating layer to the complex surface of the piezoelectric sensor element. Full article

Dopamine is a neurotransmitter which is classified as a catecholamine. It is also one of the main metabolites produced by some tumor types (such as paragangliomas and neoblastomas). As such, determining and monitoring the level of dopamine is of the utmost importance, ideally using analytical techniques that are sensitive, simple, and low in cost. Due to this, we have developed a non-enzymatic dopamine sensor that is highly sensitive, selective, and rapidly detects the presence of dopamine in the body. A hybrid material fabricated with NiO and ZnO, based on date fruit extract, was synthesized by hydrothermal methods and using NiO as a precursor material. This paper discusses the role of date fruit extracts in improving NiO’s catalytic performance with reference to ZnO and the role that they play in this process. An X-ray powder diffraction study, a scanning electron microscope study, and a Fourier transform infrared spectroscopy study were performed in order to investigate the structure of the samples. It was found that, in the composite NiO/ZnO, NiO exhibited a cubic phase and ZnO exhibited a hexagonal phase, both of which exhibited well-oriented aggregated cluster shapes in the composite. A hybrid material containing NiO and ZnO has been found to be highly electro-catalytically active in the advanced oxidation of dopamine in a phosphate buffer solution at a pH of 7.3. It has been found that this can be accomplished without the use of enzymes, and the range of oxidation used here was between 0.01 mM and 4 mM. The detection limit of non-enzymatic sensors is estimated to be 0.036 μM. Several properties of the non-enzymatic sensor presented here have been demonstrated, including its repeatability, selectivity, and reproducibility. A test was conducted on Sample 2 for the detection of banana peel and wheat grass, and the results were highly encouraging and indicated that biomass waste may be useful for the manufacture of medicines to treat chronic diseases. It is thought that date fruit extracts would prove to be valuable resources for the development of next-generation electrode materials for use in clinical settings, for energy conversion, and for energy storage. Full article

Novel and practical methods are always sought across all disciplines; within bioaerosol research, portable, lightweight, and low-cost sampling pumps are few and far between. Fungal spores, key components of bioaerosols, have attracted attention due to their negative effects on human populations, agricultural systems, and ubiquitous nature. In terms of spatial scales, fungal spores across vertical gradients are frequently overlooked and in cases where atmospheric samples are collected, they are often a large distance away from the ground, occurring hundreds or thousands of meters into the atmosphere, which also requires substantial expenses for specialist apparatus. Here, we have utilized a drone and low-cost equipment to produce a new sampling method that can efficiently collect fungal spores and bridge the gap between ground sampling and atmospheric sampling, and sample in areas such as forest canopies or at building rooftop heights, in which planes, helicopters, or other UAVs may not be able to safely or practically maneuver. Additionally, we have created a novel approach to utilizing a drone for bioaerosol sampling during rain events, which, to our knowledge, is the first of its kind, opening up the possibilities for much needed comparisons of fungal spores in varying weather conditions. Full article

Background/Objectives: Shrimp surimi-based products (SSPs) are composed of minced shrimp meat and are highly susceptible to food fraud as fish surimi. This study employed a double-gene metabarcoding approach to authenticate SSPs sold on Chinese e-commerce platforms. Methods: 16S rRNA and 12S rRNA genes were amplified and sequenced from 24 SSPs. Mislabeling was evaluated based on the correspondence between the ingredients (only those of animal origin) reported on the products’ labels and the molecular results. Results: Overall, 87.50% of SSPs (21/24) were found to be mislabeled. The replacement of Penaeus vannamei with other shrimp species was particularly noteworthy. Interestingly, in some SSPs, the primary species detected in terms of sequence abundance were not shrimp but fish, pork, chicken, and cephalopods, raising concerns regarding both health risks and ethical issues related to SSP consumption. The 12S rRNA sequencing results revealed that fish species like Gadus chalcogrammus, Evynnis tumifrons, and Priacanthus arenatus were added to some SSPs in significant proportions, with certain products relying on fish priced from “Low” to “High” levels to substitute higher-cost shrimp. Notably, many fish species in SSPs were highly vulnerable to fishing, raising sustainability concerns. Overall, the high mislabeling rate in SSPs, as well as the detection of endangered fish species (Pangasianodon hypophthalmus), underscores significant quality control issues. Conclusions: DNA metabarcoding has proven to be an effective tool for ingredient authentication in processed seafood. Full article

With their cost-effective manufacturing process, hybrid stepper motors (HSMs) are a popular choice for position control in low-power industrial applications. These versatile motors offer a compelling solution for reducing system costs and size since at standstill/low speeds, HSMs typically have higher torque density with respect to low-power permanent magnet (PM) motors. This higher torque density determines a reduced use of rare-earth PMs and, therefore, a lower environmental footprint. In practical applications, the commonly used microstepping control faces low efficiency, low dynamic performance, vibrations, and a variable maximum continuous torque depending on the working point. In this paper, the operating region of an HSM is extended in the field-weakening (FW) region, showing how field-oriented control (FOC) with FW allows one to strongly increase the drive performance with a slight cost increase thanks to the availability of low-cost magnetic encoders. Due to the fact that FOC provides only the requested current, the HSM faces lower temperatures, lower insulation degradation, and lower permanent magnet demagnetization issues. An experimental evaluation comparing the commonly used microstepping and the proposed FOC with FW is performed on four commercial HSMs with different DC voltage power supplies using an industrial test bench. In particular, the experimental campaign has a focus on steady-state conditions in the case of the maximum continuous torque, showing the advantages of FOC with FW because the advantages in transient conditions are well known. Full article

Carbon nitrides are polymeric materials with a broad range of applications, including photocatalysis. Among them, graphitic carbon nitride (g-C₃N₄), a low-cost material, is an excellent photocatalyst under visible light irradiation owing to its features such as correct band positions, high stability and non-toxicity. g-C₃N₄ is a metal-free material that is easily synthesized by polymerizing nitrogen-rich compounds and is an efficient heterogeneous catalyst for many reaction procedures due to its distinctive electronic structure and the benefits of the mesoporous texture. In addition, in situ or post-modification of g-C₃N₄ can further improve catalytic performance or expand its application for remediating environmental pollution. Water pollution from organic compounds such as pesticides and pharmaceuticals is increasing dramatically and is becoming a serious problem around the world. These pollutants enter water supplies in a variety of ways, including industrial and hospital wastewater, agricultural runoff, and chemical use. To solve this problem, photocatalysis is a promising technology. Without the use of other oxidative chemicals, g-C₃N₄ uses renewable solar energy to transform harmful pollutants into harmless products. As a result, much recent research has focused on the photocatalytic activity of g-C₃N₄ for wastewater treatment. For this reason, the main objective of this paper is to contribute a chronological overview of the bibliometrics on g-C₃N₄ for the removal of pesticides and pharmaceuticals from water using the tools BibExcel, Bibliometrix and R-Studio IDE. A bibliometric analysis was performed using the Science Citation Index Expanded (WoS^©) database to analyze the scientific literature published in the field over the last 10 years. The results were used to identify limitations and guide future research. Full article

Tuberculosis (TB) induces a hypercoagulable state characterized by systemic inflammation, endothelial dysfunction, and alterations in the coagulation and fibrinolytic pathways. This review explores the pathophysiological mechanisms underlying hypercoagulability in TB, including increased pro-inflammatory cytokine release, endothelial damage, platelet activation, and reduced anticoagulant and fibrinolytic activity. These factors contribute to an elevated risk of venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), which complicate TB prognosis and treatment. The potential role of adjunctive anti-inflammatory therapies, such as vitamin D, NSAIDs, corticosteroids, and anti-platelet agents, is highlighted as a strategy to mitigate systemic inflammation and reduce thrombotic risks in patients with TB. The challenges of anticoagulation therapy, particularly in managing the interactions between anti-TB medications and traditional anticoagulants, are discussed, along with the potential of novel oral anticoagulants (NOAs) as alternatives. We also address therapy of hypercoagulability in TB within resource-limited settings which requires low-cost diagnostics, accessible anticoagulation options, adjunctive therapies, and preventive strategies integrated into existing healthcare systems. Effective risk stratification and individualized management strategies are vital for reducing the morbidity and mortality associated with thrombotic complications in TB. Full article

Low-cost technology devices, such as smartphones (SPs) and smart watches (SWs), are widely used today to monitor various health effects and environmental risk factors associated with them. However, the efficacy of using these devices as monitoring tools is largely unknown. The present study attempts to narrow this knowledge gap by reviewing recent studies in which low-cost technological tools were used to monitor sleep and associated environmental risk factors. The study focuses on peer-refereed articles that appear in three major scientific databases, Web of Science, Scopus, and ScienceDirect, and were published between 2002 and 2022. Of the 15,000+ records retrieved from these databases by the systematic literature review (PRISMA) search, 15 studies were identified as the most relevant and consequently analyzed. The analysis shows that nighttime light pollution and noise are environmental factors that are most commonly monitored by low-cost technology tools (eight studies), followed by temperature monitoring (seven studies), humidity monitoring (seven studies), and CO₂ monitoring (four studies). In eight studies, tandems of SPs and SWs were used to monitor sleep, while in six studies, data obtained from SPs and SWs were compared with records obtained from conventional monitoring devices. In general, SP and SW measurements were found to be fairly accurate for monitoring sleep and light pollution and less accurate for monitoring noise. At the same time, no studies conducted to date and analyzed in this review demonstrated the effectiveness of SPs and SWs in monitoring ambient temperature, humidity, and air pressure. Our general conclusion is that although SPs and SWs often lack the precision of professional instruments, they can nevertheless be used for large-scale field research and citizen science initiatives, while their feasibility and effectiveness for monitoring several environmental attributes have yet to be determined. Full article

Aqueous zinc ion batteries are considered one of the most promising energy storage devices due to their high safety, low cost, and ease of fabrication. However, the growth of anode dendrites and continuous side reactions during cycling limit the practical application of zinc ion batteries. In this paper, sodium dodecyl sulfate (SDS) was used as an aqueous electrolyte additive to improve the surface deposition of Zn²⁺. The experimental results show that the SDS electrolyte additive forms a protective layer on the anode surface through electrostatic action and inhibits the growth of dendritic protruding dendrites by increasing the zinc deposition overpotential, as well as by limiting the two-dimensional diffusion of Zn²⁺ on the negative electrode surface of the aqueous zinc ion battery. As a result, adding SDS improves the discharge specific capacity of NVP/Zn batteries at high voltages and results in improved capacity retention. The cycling stability of NVP/Zn batteries was greatly enhanced by using a battery containing 1% SDS that still had a discharge specific capacity of 71 mAh/g after 100 cycles at a charging current density of 1 C, with a capacity retention rate of 89%. This work provides a simple and feasible solution to the anode problem of aqueous zinc ion batteries. Full article

The yield of photovoltaic hydrogen production systems is influenced by a number of factors, including weather conditions, the cleanliness of photovoltaic modules, and operational efficiency. Temporal variations in weather conditions have been shown to significantly impact the output of photovoltaic systems, thereby influencing hydrogen production. To address the inaccuracies in hydrogen production capacity predictions due to weather-related temporal variations in different regions, this study develops a method for predicting photovoltaic hydrogen production capacity using the long short-term memory (LSTM) neural network model. The proposed method integrates meteorological parameters, including temperature, wind speed, precipitation, and humidity into a neural network model to estimate the daily solar radiation intensity. This approach is then integrated with a photovoltaic hydrogen production prediction model to estimate the region’s hydrogen production capacity. To validate the accuracy and feasibility of this method, meteorological data from Lanzhou, China, from 2013 to 2022 were used to train the model and test its performance. The results show that the predicted hydrogen production agrees well with the actual values, with a low mean absolute percentage error (MAPE) and a high coefficient of determination (R²). The predicted hydrogen production in winter has a MAPE of 0.55% and an R² of 0.985, while the predicted hydrogen production in summer has a slightly higher MAPE of 0.61% and a lower R² of 0.968, due to higher irradiance levels and weather fluctuations. The present model captures long-term dependencies in the time series data, significantly improving prediction accuracy compared to conventional methods. This approach offers a cost-effective and practical solution for predicting photovoltaic hydrogen production, demonstrating significant potential for the optimization of the operation of photovoltaic hydrogen production systems in diverse environments. Full article

Due to their diverse properties and functionalities, cost-effective transition metal-based nanomaterials have been rigorously studied for electrochemical applications. Ultrathin nanosheets have been identified as the most effective electrodes for catalyzing water-splitting reactions in both acidic and alkaline environments. Here, we reported ZnWO₄, a member of the tungstate family, as an effective electrocatalyst for promoting the electrochemical hydrogen evolution reaction. The Zn⁺²-stabilized tungstate showed a remarkable cathodic reaction during the water-splitting reaction with low overpotential (136 mV at 10 mA cm⁻²) and small HER kinetics (Tafel Slope = 75.3 mV dec⁻¹) and long-term cyclic durability. The high-valence tungsten stabilized with divalent Zn⁺² promotes electron transfer during the reaction, making it an advanced electrocatalyst for green hydrogen production. Full article

The use of renewable energy sources (RESs) together with energy storage systems (ESSs) allows for smoothing power variations, thus improving power backup capabilities and power quality in the electric power grid. These applications require power converters to transfer energy between the renewable generator or energy storage and the power grid. In any case, the control algorithm of the power converter requires the synchronization method to provide a correct estimation of the instantaneous voltage of the power grid. This work provides engineers and researchers with an accessible platform at a low cost (less than USD 100) and a methodology for the experimental validation of digital synchronization algorithms as a step before their implementation in grid-connected equipment. The methodology evaluates the performance of the digital algorithms when there are variations in amplitude, frequency, phase, and harmonic content in the emulated three-phase power grid, as well as the execution times (t_ex), while a digital platform emulates the electrical signals and generates reference signals for the evaluation. To illustrate this proposal, two synchronization algorithms—SRF-PLL and DSOGI-PLL with a low-pass filter—are implemented in a digital controller and tested. The evaluation tool confirms the algorithms’ performance and shows that the execution time of DSOGI-PLL is 91% longer than that of SRF-PLL, which is well known in the literature. Full article

This study sheds light on the performance of the common high-precision electromagnetic sensor TEROS 10 to estimate volumetric soil water content (θ) from dry to saturation across three different substrates, six different soil types having three different levels of electrical conductivity of soil solutions (EC_w), and in liquids with increasing salinity level under laboratory conditions, by using low-cost but accurate experimental IoT hardware arrangements. This performance was evaluated using statistical analysis metrics such as Root Mean Square Error (RMSE). It was found that TEROS 10 performance did not conform to the manufacturer’s specifications throughout the full scale range, although in some cases good water content estimation was provided. Some inconsistencies were identified by applying the manufacturer’s calibration equations, and thus recommendations for improvements are provided, aiming to enhance the sensor’s overall performance. TEROS 10 performance across all six soils and three substrates was improved on average from an RMSE of 0.052 and 0.078 cm³ cm⁻³, respectively, by using factory-derived calibration, to 0.031 and 0.031 cm³ cm⁻³ by using the multipoint calibration method (CAL). Furthermore, a linear calibration formula, using Raw output as the predictor variable, was tested and resulted in an RMSE of 0.026 and 0.046 cm³ cm⁻³ for soils and substrates, respectively. Full article

Background: Obesity is constantly growing worldwide, representing a serious concern also for healthcare costs. Current anti-obesity pharmacological strategies, although effective, represent a significant cost for the patient. Similarly, very low energy ketogenic therapy (VLEKT) protocols with replacement meals also have high costs. Objectives: The objective of this study was to estimate the average costs of a VLEKT protocol with replacement meals compared with those of isocaloric diets with fresh foods. Methods: VLEKTs with replacement meals and fresh foods were developed considering an ideal young woman and man with grade II obesity (BMI ≥ 35.0 kg/m²). The costs of the individual fresh foods were extrapolated from official Italian databases. The costs of replacement meals were obtained by consulting the catalogs of three companies specialized in VLEKTs operating in Italy. Results: On a monthly basis, VLEKT with fresh food had an average cost of EUR 253.44 and EUR 295.67, while VLEKT with replacement meals had an average cost of EUR 434.91 and EUR 535.99, for the woman and man, respectively. Conclusions: Although more expensive than a common diet, VLEKT should be seen not only as a dietary method for losing weight, but as a non-pharmacological, medicalized nutritional therapy, useful for managing various conditions, even those not directly related to obesity. Like a drug therapy, VLEKT requires the use of specific products that entail a higher cost, to be borne by the patient, but whose benefits should be emphasized, which go beyond weight loss and concern general health, thus considering them as a targeted nutritional strategy. Full article

In the aerospace industry, low-density quartz fiber/phenolic resin composites offer advantages such as low cost, low density, high thermal insulation, and excellent thermal resistance, making them a promising candidate when exposed to a long-term low–medium heat flow environment. However, there is currently a lack of understanding regarding the ablation evolution and mechanisms of these materials under this environment, which hampers the enhancement of material performance. Additionally, there is insufficient quantification of their pyrolysis processes, which is detrimental to the development of subsequent mathematical models for ablation thermal response. Therefore, this work focuses on the study of the ablation process of low-density needled quartz felt/phenolic resin (PR/NQF) under long-term low–medium heat flow. Ablation samples of PR/NQF with varying densities were obtained by treating them with a quartz lamp at different temperatures. The differences in the carbonization of the PR/NQF ablation surface were analyzed through SEM, microCT, FTIR, XRD, and XPS experiments, revealing the influence of ablation temperature and composite density. Subsequently, the pyrolysis mechanism of PR/NQF was analyzed using Py-GC-MS, resulting in insights into the evolution and component ratio of pyrolysis gases and their temperature correlations. To further describe the pyrolysis process of low-density PR/NQF, a pyrolysis kinetics model was developed based on the TGA experimental results, and the consistency between the fitted results and theoretical values was validated. The conclusions of this study provide support for analyzing the ablation mechanisms and evolution processes of low-density PR/NQF under long-term low–medium heat flow. Furthermore, the conclusions offered a certain degree of basic data support of mathematical models for ablation processes and the development of new thermal protection materials. Full article