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With the increasing demand for compact, lightweight, cost‐effective, and high‐performance radiofrequency (RF) devices, the development of low‐profile antennas becomes crucial. This article presents a study of a novel carbon–cellulose‐based paste intended for screen printing RF devices. The investigation specifically explores the application of high‐reactivity carbon mixture (HRCM) particles as conductive fillers. The results demonstrate that optimal electrical conductivity values and discrete electromagnetic dipole performances can be achieved at lower concentrations of solid conductive material compared to conventional pastes, for similar applications. This offers benefits in terms of total cost, material consumption, and environmental impact. The paste formulation showcases a complex non‐Newtonian behavior, where yielding flow and thixotropicity are found to be independent and dependent on preshear conditions, respectively. This behavior can be attributed to the network orientation and rearrangement of filler structures within the paste system, which in turn are responsible for filler pattern uniformity and overall printing quality. Compared to traditional conductive materials, HRCM pastes are proven to be a viable alternative for RF devices fabrication, including printed Wi‐Fi antennas. [ABSTRACT FROM AUTHOR]

The development of efficient photocatalysts is crucial in addressing water pollution concerns, specifically in the removal of organic dyes from wastewater. In this context, the use of silver nanoparticles (Ag NPs) might represent a method to achieve high dye degradation efficiencies. On the other hand, the classical Ag NP production process involves several reactants and operating conditions, which make it poorly sustainable. In the present work, Ag NPs were synthesized according to a new sustainable process involving the use of natural extracts of Spirulina platensis and milder operating conditions. The material was also calcined to determine the influence of organic content on the properties of Ag NPs. The X-ray diffraction (XRD) analysis displayed the AgCl and Ag phases with a crystalline size of 11.79 nm before calcination. After calcination, only the Ag phase was present with an increased crystalline size of 24.60 nm. Fourier Transform Infrared Spectroscopy (FTIR) confirmed the capping role of the metabolites from the extract. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) revealed the spherical or quasi-spherical morphologies with agglomeration due to the calcination. Energy-dispersive X-ray spectroscopy (EDX) and Thermogravimetric (TGA) analyses further confirmed the involvement of metabolites in the synthesis of Ag NPs. The optical changes in the products were observed in a UV-Vis analysis. The Ag NPs were tested for their photocatalytic activity against the laboratory dye brilliant blue r in visible light in various conditions. The highest degradation efficiency of 81.9%, with a kapp value of 0.00595 min−1, was observed in alkaline medium after 90 min of light irradiation. [ABSTRACT FROM AUTHOR]

Carasau bread is a typical Sardinian baking product, with great commercial potential, due to its long shelf life. Nowadays, its production is performed, in most cases, in small or medium size factories, where the working conditions and quality properties of the product are set on an empirical basis. Thus, the processing know-how lacks quantitative information, and the product is still far from standardization. As a result, industrial-scale manufacturing is hindered. The literature presents some studies devoted to better explaining the effect of semolina doughs' main constituents (gluten, starch, etc.) on their rheological properties or to infer the latter through in-line measurement. However, it is still necessary to understand the role of each working parameter in conditioning the dough rheology. This work investigated the role of five working parameters: yeast amount, salt amount, water temperature, kneading time, and leavening time. The water amount was kept constant to avoid covering other effects because its role can be predominant in most cases. A Design of Experiments (DOE) was performed, in order to plan the experimental campaign. First, the dough samples were tested through a parallel plate rheometer (Anton Paar, model MCR 102), applying both creep and frequency sweep tests. Moreover, the same samples were subjected to Texture Profile Analysis (TPA) to highlight possible correlations between theoretical rheological model parameters and TPA ones, which can be obtained in shorter times, so being more suitable for process monitoring purposes. [ABSTRACT FROM AUTHOR]

The present case study reports a shear rheological characterization in the temperature domain of inks and pastes loaded with conductive High Reactivity Carbonaceous Material (HRCM) consisting mainly of few-layers graphene sheets. The combined effect of filler concentration and applied shear rate is investigated in terms of the shear viscosity response as a function of testing temperature. The non-Newtonian features of shear flow ramps at constant temperature are reported to depend on both the HRCM load and the testing temperature. Moreover, temperature ramps at a constant shear rate reveal a different viscosity–temperature dependence from what is observed in shear flow ramps while maintaining the same filler concentration. An apparent departure from the well-known Vogel–Fulcher–Tamman relationship as a function of the applied shear rate is also reported. [ABSTRACT FROM AUTHOR]

Different physicochemical phenomena are involved in breadmaking, which produce perceptible changes in the rheological properties of dough. In this regard, the kneading phase is crucial for the assessment of the quality of the final product. Indeed, the determination of the optimal time in the mixing process allows to optimize the rheological properties of the dough and the energy consumption. In this work, torque measurements were carried out on durum wheat commercial semolina using a Brabender Mixer 350 (Brabender® GmbH, Duisburg, D) where semolina was mixed with water in different amounts (from 40% to 60% of semolina weight). Each sample was mixed for 20 minutes. The salt effect was instead investigated by adding a variable amount of salt (from 0% to 2.5% of semolina weight). The optimal mixing time value, which occurs at the maximum torque value, was determined and studied with respect to salt and water quantity. Additionally, spectrograms of the torque time series data were computed in order to provide the magnitude (and frequency) of the torque oscillations with time. The results showed a significant influence of water amount on the torque maximum value and on the mixing time, with the latter that linearly depends on water amount. Also, the amplitude oscillations resulted to be related to the water amount, as their amplitude decreases when the water amount increases. On the other hand, the salt effect is less evident but an influence on optimal mixing time is however detected. [ABSTRACT FROM AUTHOR]

Bound and free water within dough strongly affect its rheological behavior and processability, as well as its gluten network. Depending on its total content and on the characteristics of flour constituents, water can be both bound to components and free in the dough. The equilibrium between bound and free water directly impacts the elasticity and extensibility of dough and therefore controls the texture of final products. In this study, Nuclear Magnetic Resonance (NMR) was used to assess the relaxation behavior with the focus on water. The proton spin-spin relaxation measurements were carried out at 20 MHz with a Bruker Minispec mq20 NMR spectrometer (Bruker, Rheinstetten, Germany). The transverse relaxation time in a spin locking field (T1?) was determined at 25°C following the Carr-Purcell-Meiboom-Gill (CPMG) sequence. The data were analyzed by the continuous distribution model. The dough was prepared with commercial semolina, which was mixed with water in a Brabender Mixer 350 (Brabender® GmbH, Duisburg, Germany) to reach three different levels of water content (30, 50, and 70%, based on semolina weight) and to study the water distribution as a function of the water total content. The dough characterization was carried out also comparing the T1? distribution of semolina dough with that of starch-water and gluten-water mixtures and also of pure starch and gluten to assess the role of each flour component. Additionally, the semolina dough sample was compared with a sample prepared with pastry flour, with a lower content of proteins, to investigate the different behavior as a function of the gluten amount. It was found that the dough presents three relaxation processes: one, very fast, is related to crystalline starch, while the other two are characteristic of two water populations, water in intragranular and in extragranular regions of starch, respectively. The comparison with pastry flour showed that the dough prepared with the latter one was less homogenous than the semolina one, with a clear distinction between free and bound water, while the semolina dough seemed to contain several water populations differently bounded, that were responsible for a broader peak at medium water content (around 50%). [ABSTRACT FROM AUTHOR]

The thermal properties of doughs with a different relative amount of ingredients were investigated using Thermogravimetric Analysis (TGA). The doughs were prepared to mix water, semolina, yeast, and salt in different proportions. The gelatinized flour fraction plays an important role in the thermal properties' definition, while the water amount influences the development of the dough network and consequently the starch gelatinization phenomena. The amount of yeast and salt influences the dough network force and consequently, the thermal properties. In such a way, it was possible to find some information on the relationship between the dough characteristics and the thermogravimetric analysis outputs. The study is devoted to acquiring deeper knowledge about the thermophysical characteristics of doughs in the breadmaking industrial processes, and about their changes during the different process steps, when the relative amount of ingredients changes. This could help to improve the controllability of the breadmaking plants and their energetic performances, and in particular the efficiency of "pani carasau" manufacturing, a typical toasted and high-quality Sardinian bread. Currently, in industrial productions, large amounts of it are lost because off-specification and it is not possible to prevent this, since the bread characteristics can be verified after baking, which is high energy consuming. Consequently, a deeper knowledge of the dough properties could help to decrease the amounts of offspecification products, resulting in a much more energy efficient and sustainable process. [ABSTRACT FROM AUTHOR]

Microwave heating is a more efficient alternative to conventional heating in the chemical reactions field due to its positive effects on conversion and reaction kinetics. Dielectric properties of substances and mixtures are important for the optimization of microwave heating processes; notwithstanding this, specific databases are poor and far from being complete, and in the scientific literature only a few data regarding these properties can be found. Dielectric properties are represented by permittivity, which is a complex measure of a substance behaviour in the presence of an electromagnetic field and depends on the field frequency, as well as on the temperature and composition of the chemical system under study. In this work, some real and imaginary parts of permittivity measurements were carried out using a specially designed measurement system. The apparatus was tested in the estimation of permittivity values in water-ethanol mixtures, varying their composition. The results were compared to literature data and fitted with available literature models to verify their trend as a function of composition. The permittivity real part values increase with reducing the molar fraction of ethanol, whereas the imaginary part decreases, according to the values of water and ethanol permittivity reported in the literature. The regressions carried out to describe the permittivity dependence on composition prove that the measured values can be well described by the models taken into account. [ABSTRACT FROM AUTHOR]

In the present study, the rheological properties of doughs, prepared by mixing semolina with water, yeast and salt, were investigated with different relative amounts of the ingredients. The rheological measurements were carried out by an Anton Paar MCR 102 rheometer, equipped with a plate-plate fixture. In more detail, frequency sweep tests were performed. Indeed, frequency sweep measurements showed to be informative about the force and extension of the gluten network that, in turn, demonstrated to depend on the relative amount of ingredients. The oscillatory experiments were analyzed by means of the "weak gel model", whose parameters are directly related to such physical properties. It was found that doughs obtained with different amounts of ingredients showed significant differences in the rheological responses. The addition of yeast led to a significant viscosity and force network decrease, whilst the presence of salt produced an improve of the three-dimensional gluten network characteristics and, consequently, to the machinability of the dough. The study aims at contributing to a more efficient controllability in the industrial production of flour and semolina dough based foods, and in particular to that of "pani carasau", a typical high quality and valuable Sardinian bread, since this process is high energy consuming (mainly in the baking step), in order to decrease the amount of off-specification products, and so making the processes more energy efficient and sustainable. [ABSTRACT FROM AUTHOR]

The agricultural neediness of cost-effective, environmental friendly and chemical-free methods for farmlands disinfection led to the development of microwave-based solutions, an efficient way of directly conveying energy to the target. Harmful agents such as weeds pests, fungi and bacteria can be suppressed heating the contaminated soil up to pasteurization or sterilization temperatures by irradiating electromagnetic energy by an antenna. The treatment can be carefully devised and designed optimizing the temperature distribution and calibrating the exposure time depending on the soil characteristics, and on the environmental and boundary conditions. In this work a computational model to solve the non-linear multi-physic dielectric heating phenomenon is presented, so taking into account the temperature dependence of the dielectric and thermal soil properties, in order to demonstrate the possibility of properly tuning the microwave application depending on the external heat transfer conditions. It was found that, in the specific conditions here analyzed, an increase of the external convection heat transfer coefficient up to 50 W·m-2·K-1, despite being a possible critic condition for the surface, brings to the possibility of treating a soil layer of higher thickness, up to 20 cm. On the other hand, doubling the microwave power from 12 to 24 kW·m-2 generally reduces the treatment time to less than half, with overall energy savings. [ABSTRACT FROM AUTHOR]

In the present study, the rheological properties of doughs obtained from semolina produced by milling different wheat varieties of durum grains (Cappelli and Alemanno) were investigated. The dough was prepared by mixing the semolina with water in a mixograph. Rheological frequency sweep measurements were carried out by considering different mixing times and water amounts. The experimental data were analyzed by means of the weak gel model, whose parameters may be directly related to the force and the extension of the gluten network, that is developing during the mixing operation. It was found that the doughs obtained from the different wheat varieties showed a not trivial rheological behavior with the mixing time, that depends on the wheat variety. It was also found that the network force and extension appear to be negatively correlated to the water content, and doughs with higher water content present lower viscosities. The weak gel parameters were modelled as a function of mixing time using an exponential law which demonstrates to adequately describe and quantify the influence of kneading time and water content on the rheological properties of dough. [ABSTRACT FROM AUTHOR]

The thermal properties of different kinds of dough were investigated after different kneading times by means of Thermogravimetric Analysis (TGA). Two varieties of durum wheat semolina were used in this study: Alemanno and Cappelli. The doughs were prepared using a mixograph. The gelatinized flour fraction plays an important role on the thermal properties' definition, while the mixing time influences the dough network building and consequently the starch gelatinization phenomena. Also, the amount of free water in the dough could be influenced by the mixing time. Thus, the TGA technique was applied in order to evidence the mass loss as a function of the increasing temperature and, from this, the free water content, the residual weight (related to the protein kind and content), and the weight loss rate, i.e. the peaks of the first derivative of the thermogravimetric curve (DTG), which appear at different temperatures and present different heights and positions, depending on the dough network force and extension. In such a way, it was possible to find some correlations between the dough characteristics, like the semolina composition (e.g. the gluten content and quality) and the mixing time, and the thermogravimetric analysis outputs. The results showed that the ratio between free and bond water is strongly dependent on both the mixing time and the semolina variety, and a clear evidence of the protein content in the dough is found because of the position and the size of the peaks in the DTG curve, in combination with the residual mass at fixed temperatures. [ABSTRACT FROM AUTHOR]

The present work reports the effects of low power microwaves in the frequency range of 2.20-2.50 GHz with an incident power range of 0-400 mW on the growth rate of the bacterial species Pseudomonas aeruginosa and Staphylococcus aureus. Since culture temperatures were maintained constant (37°C) during irradiation, these effects can be considered as non-thermal. A continuous recirculating experimental structure was used for the purpose. It is very difficult to find a mathematical correlation between the observed effects and radiation power or frequency. [ABSTRACT FROM AUTHOR]

This work aims to compare different processes for treating biomass of arboreous origin to produce electric energy. The work is preliminary to the realization of a pyrolitic plant with three electricity generation units with a rated load of 1.4 MWe each. The plant will be located in the industrial area of the town of Cagliari (Italy) and will treat biomass of agricultural origin. The comparison is made with four different technologies able to produce electric energy from biomass; three main parameters are taken into account: the total capital cost, the unit cost of electricity production and net plant system efficiency. This comparison demonstrated that the proposed pyrolysis process showed the best performance with respect to the other competitive processes examined. [ABSTRACT FROM AUTHOR]

The article presents a study which used a plug flow reactor, which permits the growth of bacteria in a microwave environment, to analyze the effect of microwave radiation at the frequency of 2.45 Gigahertz and at 37 degrees Celsius on the growth rate of three bacterial species, namely, Bacillus clausii, Pseudomonas aeruginosa, and Staphylococcus aureus. Results show that the proposed apparatus can be used for studying the evolution of a biological process without any contamination from the external environment.

Several studies have shown the presence of fluoride levels much higher than the 1.5 mg/L threshold concentration recommended by WHO in the spring waters and wells of the Ethiopian Rift Valley. Available defluoridation techniques can be costly, present complicated technical aspects, and show limited effectiveness. Therefore, it is necessary to devise innovative, sustainable, and effective solutions. This study proposes an alternative method of intervention to the known techniques for removing fluoride from water, particularly suitable for smaller rural communities. In particular, in this work, the possibility to use electromagnetic fields as a physical method for removing the excess fluoride was investigated. The study was carried out by developing a multiphysics model used for studying and envisaging the design of a device. In this framework, the combination of this approach with the use of highly reactive smectite clay was numerically studied. The results obtained, although preliminary, indicate that the proposed system could significantly impoverish the waters of the Rift Valley from fluoride, with the consequence of obtaining a resource suitable for human consumption, in particular for rural communities. However, further theoretical investigations and experimental phases will be necessary to achieve the desired results. [ABSTRACT FROM AUTHOR]