In this work, paper disks were made of paper, the written paper was shredded and chips with a length of 50 mm and a width of 5 mm were obtained, these chips were moistened and then pressed, obtaining disks with diameters of 60 mm and thicknesses of 20 mm and 5 mm respectively. The obtained discs were processed in a high-frequency electromagnetic field and analyzed thermally, the bio-oil resulting from the pyrolysis process was analyzed. Also the water collected after wetting and pressing of the written paper chips was not neglected, and a microscopic analysis of its content was performed. The paper disks from samples 1 and 3 were left to dry and then processed, while the written paper disks from samples 2 and 4 were processed immediately after pressing, with a moisture content of $\mathbf{3 1. 6 \%}$.

The main challenge in many countries is how to deal with climate change, particularly reducing CO2 emissions which is the most crucial aspect. Therefore, this paper focuses on adopting renewable energy in a fuel cell microgrid connected with hybrid energy storage systems. A control management approach based on state machines is introduced to regulate the combined renewable generation with hybrid energy storage systems. The operational performance of the microgrid has been evaluated under various conditions, including different weather patterns and the energy needs of local villagers. The key contribution of this work is aimed at addressing the region's unique issues in rural electrification and climate change mitigation. The results of microgrid stability in energy supply, mainly in off-grid scenarios affirm the system's practical viability and reliability.

A very important category of applications of the high-frequency electromagnetic field concerns the direct action of the microwave field on materials capable of absorbing some of the received energy and converting it into heat. The use of microwave energy (MW) can be considered as a controlled heating source, which can also be used in combination with other heating methods. The great advantage of this type of heating is that the power is distributed throughout the load mass. Based on these considerations, the present work aims to analyze the electric field distribution on the surface of a dielectric whose dielectric loss and loss angle tangent correspond to those of office paper, simulated for different humidity values. The results on the electromagnetic field distribution in the dielectric are emphasized by the complex electric field component which were obtained with a specific software. It is known that the existence of such software reduces the workload but if we pursue the optimization of the installations, it increases the number of simulations required.

Apples represent a category of products frequently consumed by people, owing both to their beneficial effects on human health and to their antioxidant effects. Microwave (MW) treatment is a simple and fast method that can be used successfully in the food industry to obtain dry apple slices, rich in bioactive compounds and with a pleasant aspect. This study presents the effect of applying microwave treating to apple slices from two cultivars (Golden Delicious and Idared), for three, four, and five minutes, respectively, at a power of 450 W, in order to reduce the browning effect. For this purpose, the browning index (BI), chromatic parameters (CIE L*a*b*), total phenolic content (Folin-Ciocâlteu method), and antioxidant capacity (by Ferric Reducing Antioxidant Power (FRAP assay) were evaluated in the case of apple slices before and after MW treatment. Based on the results obtained, it can be argued that the microwave treatment results in a significant increase in the total phenolic content and enhances antioxidant capacity in the case of both apple cultivars. Apples from the Idared cultivar have a higher total phenolic content than apples from the Golden cultivar, and this concentration increased by 56.14% and 48.9%, respectively, after MW treatment. In terms of antioxidant capacity, Idared apples also recorded a higher value compared to Golden cultivars. According to the results of the multivariate analysis, there are variations between the two apple categories with regard to the phenolic content and the browning process; browning was inhibited at the five-minute exposure to microwaves. The apple processing domain may use our findings in order to produce high-quality finished products, with a pleasant aspect, which retain the bioactive compounds of the fruit.

In this study, the microwave pyrolysis process was used to carbonize wheat and oat straws for energy use. The charring effect was studied by varying the microwave power level (160–800 W) and biomass moisture content (6-60%). During the pyrolysis process, the time and temperature level were monitored until the wheat and oat straws reached the charcoal stage. By looking at the power it was possible to see that the processing time is inversely proportional, when the power level is low, the processing time increases. When it comes to the temperature level, when we have a higher power the temperature of the straws increases in a relatively shorter time than when we have a lower power and a longer time for the temperature of the straws to rise. During the pyrolysis process to reach the carbonization of wheat and oat straw, it was found that the temperature of the straw must reach over 200°C. The charcoal resulting from the microwave pyrolysis of the two investigated biomasses is intended to be used in the production of thermal energy.

High frequency electromagnetic field pyrolysis process has been used on waste office paper and stationery to obtain bio-oil and bio-char. The composition of crude bio-oil in the organic phase was explored and the coal was energetically analyzed. During the experiments, in order to find out the shortest processing time, the moisture content of the biomass was varied, while the power level of the microwaves remained constant. The resulting bio-oil was analyzed and found to contain carbon and tar, resulting from the carbonization of paper. The purpose of this study was to observe the interactions between biomass materials and microwave energy in obtaining bio-oil and charcoal.

Microwave extraction is becoming a popular option in many fields, especially for bioactive compounds from medicinal plants. This paper addresses the application of microwaves in the process of extracting bioactive compounds (phenols, flavonoids, chlorophyll) from peppermint with antioxidant capacity in order to highlight the influence of the microwave field on the quality of the final product in comparison with the control samples. The Mentha piperita L. is a rich source of phenols. The total phenol content after applying the MW treatments significant increased and varied between 25.000 ± 1.992 and 391.687 ± 20.537 mg GAE/100 g dw compared to the untreated sample (8.089 ± 2.745 mg GAE/100 g dw). The same trend was also recorded in the case of the flavonoid and pigment content in peppermint leaves following the application of microwave treatments. The obtained results were investigated using chemometric multivariate analysis. The main purpose of our research was to compare the possibilities of total or partial substitution of conventional extraction technologies with the microwave extraction technology, and also to highlight the existing differences in the amount of total phenols and flavonoids extracted from peppermint plants in different processing conditions. Through microwave processing, a significant increase in polyphenolic compounds is obtained.

The new environmental friendly microwave technologies represents an important concern in the environmental policies. The use of microwave energy for the processing of different agricultural products presents the advantage of a green technology which allow a uniform distribution of electromagnetic and thermal field with a short relatively time of the process. In the paper is studied the microwave drying technology used in the drying process of oat seeds. In this sense the experiments were carried out for different working conditions of the equipment with respect to applied microwave power and obtained temperatures. A numerical model associated to the problem and solved by the means of finite element method is used. These allows us to obtain the electromagnetic field distribution through simulation inside the microwave dryer. The simulations were performed in order to obtain good quality products that may be used for seeding and food industry. The approached method is flexible so as it can be applied to all cereals.

The paper investigates the relationships between agricultural productivity, efficiency and farm's competitiveness, trying to find out to what extend the farm's activity is both efficient and competitive? The research starts from the assumption that a farm can be economically inefficient but competitive, and, reciprocally, an economically efficient farm is not necessarily competitive. A case study of a farm from North-West Romania has been considered. It was found that, although the overall activity of the farm is inefficient in some agricultural years, for certain crops, the farm is competitive in those regarding prices and yields. The analysis goes deeper to compare crops between them and proposes solutions for increasing farm's efficiency by replacing inefficient crops to efficient ones, using the method of balance of gains and losses. The results of the research are useful in helping farmers making their decisions regarding the structure of production.

Construction and demolition projects are large waste generators, being a sensitive issue for any EU country that has to comply with Directive 2008/98 / EC, recycling of which is a subject of global interest. In this work demolition waste resulted from both civilian and industrial residential complexes was considered. The most important milestone was the identification of waste (wood, concrete, masonry, gypsum, granular waste (ballast, sand), iron etc.) in order to focus on recycling. The experiments performed showed that, in the demolition stages, concrete wastes are the most important and have the largest volume accounting for 57.3% of the total waste of a building. Identifying methods for reducing waste resulting from construction through recovery, reuse and recycling will increase the percentage of green buildings and give a boost to the stagnant construction market since the last global crisis. In this work, a series of laboratory tests were performed using the high frequency electromagnetic field to determine the performance properties of the identified materials to assess their potential use.

In this paper a series of laboratory tests were made using the high-frequency electromagnetic field to decontaminate, dry and sterilize of demolition materials as well as to determine physical properties and performance of demolition materials to see their potential use. This article examines the use of materials resulting from the demolition of concrete waste byproducts as a new source of building materials used in road construction. The amount of construction waste grows each year, while natural rocks are becoming more and more expensive. Recycled concrete from various sources, such as construction and demolition waste, is a good option that can be used as a foundation for road construction. The experimental results demonstrate that the materials in the selected concrete waste are suitable for use as base layers and flexible pavement substrates in road construction.

Materials like alumina and silicon carbide, sensitive to high frequency electromagnetic field are very useful for processing other materials in the high frequency electromagnetic field. The use of these sensitive materials can enhance a more uniform temperature alignment over a hot material in a high frequency electromagnetic field. These silicon carbide composites will be loaded with enriched cement. In this article, we will also discuss the factors that influence the heating rate of composed materials. These factors depend on the size of the silicon carbide particles, the percentage of silicon carbide in the volume of the composite material, the treatment atmosphere and the maximum experimental temperature. The heating rate of the composite materials was determined as the amount of silicon carbide increased while the heating rate increased. The size of the silicon carbide particles also influenced the heating rate of the composite material, which has been demonstrated experimentally. Mathematical model has shown that the effect of particle size is a geometric one dependent on a non-perfect thermal contact between the silicon carbide particle and the cement patern. The size of the silicon carbide particles also affected the filtration threshold of the composite materials. The heating rate of the composite materials grew when the calcium carbonate in the cement was pyrolyzed to form calcium oxide due to an growth in thermal conductivity.

The paper presents the possibility of using susceptible ceramics made of silicon carbide in industrial applications. In this sense it is showed that is possible to achieve very fast high temperature by using susceptible ceramics in microwave aplications. The experiments were carried out on two types of ceramic susceptors made from silicon carbide mixed with kaolin and different binders, in order to point out there behavior in microwave field. A mathematical model used to predict its behavior in high frequency field is also presented.

The use of electro thermal technologies based on microwave energy represents an important step in the development of new innovative solutions. The numerical modelling allows to study the influence of the high frequency electromagnetic and thermal field on the dielectric materials during the drying process before achieving practical installation. So, when is developed the experimental model will be already known some of the phenomena that characterize the system, being eliminated a number of unknown issues. This paper describes experiments conducted to gather data on production parameters in order to improve the stored corn seed quality. The interpretation and dissemination of results triggers the description of "recipes" for drying corn seeds. The described method is flexible and can be applied to near any agricultural seeds in further researches.

The purpose of these experiments was to find optimum conditions based on the influence of microwave / hot air heating on barley seeds with high humidity. Parameters variation, temperature, humidity, power in the drying process were analyzed. The effects of microwaves on the drying characteristics were studied in two cases: the first case uses a constant microwave power and hot air jet at 55°C±10%, without taking into account the maximum allowable temperature in the seedbed, and in the second situation, variable power is used to ensure that the temperature does not exceed 65°C. The experiments were carried out on barley seeds, the Thuringia variety. To see and study the influence microwaves have on microwave field treated seeds, in the two above-mentioned cases, barley grains were germinated and the daily progression of the germination process was followed.

The paper presents a method of extracting essential oils from chili pepper by using the energy of the microwave field. The main objective of this work it is to highlight the possibilities of substitution of all or a part of the current extraction technology with the extraction technology that's uses the microwave energy, and to highlight the existence differences in quality of the extracted oils, in function of chili pepper used.

Carrot root has been used for medicinal purposes from ancient times, being well known its beneficial properties as follow: anti-inflammatory, anti-diabetic, antioxidant, hypoglycemic oil of carrot. The paper presents a study regarding an extraction method of volatile oil from carrot root using microwave energy and ethyl alcohol as a solvent. The yield of extraction was examined in a series of experiments in order to determine the effect of process parameters - initial temperature, the temperature of extraction and the particle size of carrot used. The experiments conducted for the extraction of beta-carotene from carrots were performed in various conditions involving different temperatures and processing of the samples using ethanol as solvent. The samples used for the extraction were tested at 40°C, 50°C, 60°C and 80°C. It was observed that the solubility and the yield of carotene from carrots depends on the temperature and time of extraction. It has been shown that the most efficient extraction was performed with samples dried, using a temperature range of 65° ÷ 75°C for a period of 4-5 hours. At higher temperatures the sample was destroyed.

The main objective of this work is to highlight the possibilities of substitution of all or a part of the current extraction technology with the microwave extraction technology, and to highlight the differences between the two type of the extraction solvents used. The work also presents the importance of the solvent used in the extraction process of volatile oils from parsley leaves, in terms of its quality and the microwave energy applied to the sample.

The paper deals with numerical computation methods for solving the quasistationary electromagnetic field for ferromagnetic semi-finished parts placed into industrial inductor. Finite element method is used for eddy current problem solution initially for fixed ferromagnetic parts. The coupled question electromagnetic field and thermal field during induction heating process is solved. Power density as a function of amplitude and frequency of exciting current is evaluated. Thermal field distribution inside the semi-finished part is also quantified. These results are an essential phase in the design optimization of industrial induction equipment and the heating process.

This paper present aspects regarding the numerical modelling of the electromagnetic field in microwave drying systems. The numerical method used to solve this application will involve the use of 3D finite element method to point out the process parameters in high frequency electromagnetic field of the dielectric materials with losses, situated in an applicator, excited with energy through a wave guide. It has the character of an applicative research, the obtained results being of practical use, with the main purpose of optimizing the functioning of some heating.