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Vending machines are a convenient source of food and drinks, but they can also be a significant source of energy consumption in public buildings. To reduce energy waste and improve energy efficiency, a low-cost sensor network was used to monitor the energy usage of vending machines. The sensor network consists of small, wireless sensors that are placed inside the vending machines, and a central hub that is connected to the internet via Wi-Fi. The sensors are able to collect data on the energy usage of the vending machines, including when they are idle, in use, or in a standby mode. This data is then transmitted to the central hub, where it is processed and made available to users through a web-based interface or mobile app. With this information, users can identify patterns in energy usage and make changes to reduce overall energy consumption. In a university in southern Spain, 53 vending machines of three types were monitored: snack, cold drinks, and hot drinks. The average monthly consumptions of these types of vending machines were snack (250 kWh), cold drinks (200 kWh), and hot drinks (100 kWh). By using a sensor network to monitor the energy usage of vending machines, it is possible to identify areas where energy is being wasted and make adjustments to reduce this waste. This can help to reduce the environmental impact of the vending machines, by reducing the amount of energy that is consumed and the associated greenhouse gas emissions. Additionally, by making the vending machines more energy efficient, it is possible to improve their overall productivity and cost-effectiveness. Overall, the use of a low-cost sensor network to monitor vending machines energy usage can be seen as a form of cleaner production, because it promotes the use of more sustainable and efficient industrial processes.

Jordan faces pressing energy challenges, characterized by a substantial dependence on imported resources. This paper addresses these challenges by examining the potential integration of solar thermal energy systems into poultry slaughterhouses, using a representative case study. The study starts by providing a brief background on Jordan's energy challenges and the rationale for exploring solar thermal applications in the poultry industry. The methodology involves a meticulous analysis of existing processes in the slaughterhouse, followed by the necessary calculations for integrating a solar thermal flat plate collector. Validation is performed through T*SOL and Polysun simulations, accompanied by a comprehensive economic analysis. The proposed flat plate collector-based system demonstrates the capacity to cover approximately 72% of the facility's annual energy requirements, resulting in substantial savings of 1,926,396 kWh per year, equivalent to 330,318 L of diesel. Simulation results indicate a concise payback period of 3.8 years and net profits approximately 6.6 times the initial investment over a 25-year span. Beyond economic benefits, the adoption of solar technology leads to an 84% reduction in annual CO2 emissions, underscoring its environmental advantages. The study also sheds light on a notable lack of awareness about solar thermal technology, emphasizing the need for knowledge dissemination to foster global renewable energy adoption.

The application of a fair tariff for electricity pricing is aimed at controlling demand and promoting sustainability by motivating homeowners to use household appliances as well as heating and cooling systems that offer increased energy efficiency. It is possible to structure the price levels such that customers (typically those who have increased demands for electricity) are encouraged to lower their overall demand. The reorganisation of electrical subsidies within the residential sector has considerable importance for the country’s economy as well as for more effective management of the consumption of electricity and the resulting effects on the environment, which lays the foundation for more sustainable development. In the current research, data from 260,000 regular customers paying standard electricity tariffs were gathered and the energy usage of in excess of 1,000 energy-subsidised District Electricity Distribution Company (IDECO) members of staff was recorded over a period of two years (2017 and 2018). A comparison was made between the two aforementioned groups to investigate the outcomes of energy subsidies on energy usage as well as consumption patterns within the residential sector. The results of the analysis indicated that on average, normal homeowners used approximately 297 kWh/month, whereas customers whose electricity was subsidised consumed approximately 615 kWh/month. In both winter and summer, there was an increase in the amount of energy consumed, particularly among those receiving subsidies, as the demand for heating and cooling was raised. The application of electricity tariffs (with no subsidisation) provides a means of controlling the demand profile that is particularly effective. The structure of tariffs can motivate customers (typically those electricity consumption levels are high) to lower their overall consumption in addition to peak demand (which has the consequence of limiting the strain on the grid and power stations) by requiring them to pay for electricity at maximum prices.

This research aimed to evaluate the thermal performance of rooftop PV as a shading element on uninsulated roof-related HVAC energy consumption of buildings in a moderate dry–warm climate zone. A transient-state 3D distributed thermal model was developed of the PV-added rooftop components. Photovoltaic (PV) solar rooftops as shading devices were constructed using Integrated Environmental Solution-Virtual Environment Software to predict the reduction and increase in heating and cooling loads connected with the roof floor each month. The impact of rooftop PV systems on a building’s roof-related energy burden was quantified about a low-rise residential building in a moderate dry–warm climate zone represented by the city of Amman in Jordan. The results indicated that PV roof structure reduced heat gain by 10.87% during the summer and increased heat loss by 3.8% during the winter. In the summer season, the electricity demand for indoor cooling declined, but the demand for indoor heating increased slightly. The investigation focused on a middle-income home in Jordan’s capital, Amman. The limitations imposed by building rooftops on the use of PV were also investigated in this research and the findings validate the importance of providing environmental authorities, the construction industry, and ordinary individuals with important guidelines on the use of renewable energy to heat and cool buildings. Consequently, this analysis enhances awareness of a building’s overall energy needs, which are crucial for the future design of sustainable buildings.

In the context of the global energy sector’s increasing reliance on fossil fuels and escalating environmental concerns, there is an urgent need for advancements in energy monitoring and optimization. Addressing this challenge, the present study introduces the Open Multi Power Meter, a novel open hardware solution designed for efficient and precise electrical measurements. This device is engineered around a single microcontroller architecture, featuring a comprehensive suite of measurement modules interconnected via an RS485 bus, which ensures high accuracy and scalability. A significant aspect of this development is the integration with the Non-Intrusive Load Monitoring Toolkit, which utilizes advanced algorithms for energy disaggregation, including Combinatorial Optimization and the Finite Hidden Markov Model. Comparative analyses were performed using public datasets alongside commercial and open hardware monitors to validate the design and capabilities of this device. These studies demonstrate the device’s notable effectiveness, characterized by its simplicity, flexibility, and adaptability in various energy monitoring scenarios. The introduction of this cost-effective and scalable tool marks a contribution to the field of energy research, enhancing energy efficiency practices. This research provides a practical solution for energy management and opens advancements in the field, highlighting its potential impact on academic research and real-world applications.

During the COVID-19 pandemic, the energy consumption profile has been changed in several facilities as a response to the lockdown and other precautionary measures. Lockdown has reduced the electrical load consumption in commercial buildings. Accordingly, the energy cost savings have been reflected in the energy bills. However, such savings were not due to improvement of energy performance and equipment efficiency, but because of changes that occurred in the operating conditions and parameters. As a result, it was complicated to identify the real energy savings in the energy retrofit projects during this period. For the energy conservation and refurbishment projects, a challenge was faced to calculate an accurate energy savings amount and to track the energy pattern and performance during these lockdown months.This study discusses the energy behavior of retrofitted buildings that follows the energy performance contracting. It shows the improvement of energy consumption for one year for 30 studied buildings. It discusses the strategy to follow in the calculation of the energy savings during a full lockdown period. This article addresses the approach to be taken into consideration and its consequences to monitor the energy profile as per the International Performance Measurement and Verification Protocol.

The negative consequences of toxic emissions from internal combustion engines, energy security, climate change, and energy costs have led to a growing demand for clean power sources in the automotive industry. The development of eco-friendly vehicle technologies, such as electric and hydrogen vehicles, has increased. This article investigates whether hydrogen vehicles will replace electric vehicles in the future. The results showed that fuel-cell cars are unlikely to compete with electric cars. This is due to the advancements in electric vehicles and charging infrastructure, which are becoming more cost-effective and efficient. Additionally, the technical progress in battery electric vehicles (BEVs) is expected to reduce the market share of fuel-cell electric vehicles (FCEVs) in passenger vehicles. However, significant investments have been made in hydrogen cars. Many ongoing investments seem to follow the sunk cost fallacy, where decision-makers continue to invest in an unprofitable project due to their already invested resources. Furthermore, even with megawatt charging, fuel-cell trucks cost more than battery-powered electric trucks. The use cases for fuel-cell electric trucks are also much more limited, as their running expenses are higher compared to electric cars. Hydrogen vehicles may be beneficial for heavy transport in remote areas. However, it remains to be seen if niche markets are large enough to support fuel-cell electric truck commercialization and economies of scale. In summary, we believe that hydrogen vehicles will not replace electric cars and trucks, at least before 2050.

This study analyzed fifty years of severe malaria research worldwide. Malaria is a parasitic disease that continues to have a significant impact on global health, particularly in sub-Saharan Africa. Severe malaria, a severe and often fatal form of the disease, is a major public health concern. The study used different bibliometric indicators such as the number of publications, citations, authorship, and keywords to analyze the research trends, patterns, and progress made in the field of severe malaria. The study covers the period from 1974 to 2021 and includes articles from Scopus. The results of the study indicated that there has been a steady increase in the number of publications on severe malaria over the past fifty years, with a particular increase in the last decade. The study also showed that most of the publications are from USA and Europe, while the disease occurs in Africa, South-East Asia, and the Americas. The study also identified the most frequent keywords used in the publications, and the most influential journals and authors in the field. In conclusion, this bibliometric study provides a comprehensive overview of the research trends and patterns in the field of severe malaria over the past fifty years and highlights the areas that need more attention and research efforts.

Inventions are new, unique, and useful creations or solutions to problems that have been developed through the process of invention [...]

The production of crops in greenhouses will ensure the demand for food for the world’s population in the coming decades. Precision agriculture is an important tool for this purpose, supported among other things, by the technology of wireless sensor networks (WSN) in the monitoring of agronomic parameters. Therefore, prior planning of the deployment of WSN nodes is relevant because their coverage decreases when the radio waves are attenuated by the foliage of the plantation. In that sense, the method proposed in this study applies Deep Learning to develop an empirical model of radio wave attenuation when it crosses vegetation that includes height and distance between the transceivers of the WSN nodes. The model quality is expressed via the parameters cross-validation, R2 of 0.966, while its generalized error is 0.920 verifying the reliability of the empirical model.

Many developing countries subsidise energy (petroleum fuel products, natural gas and electricity), which was reflected in an extra pressure on the national budget, and this will support inefficient use of energy. In this study, the effects of electrical energy subsidies on the total electrical energy consumption in the residential sector were examined. Data on more than 260,000 Jordanian ordinary customers were collected, and the energy consumption of more than 1000 energy-extra subsidised Irbid District Electricity Distribution Company (IDECO) staff members was recorded over a 2-year period (2017 and 2018). These two groups were compared to examine the consequences of subsidising energy on the energy consumption and the consumption behaviour in the residential sector. The analysis revealed that ordinary householders consume around 296 kWh/month, while for the subsidised group 615 kWh/month was noted. Energy consumption increased during the summer and winter months, especially in the subsidised group, due to the heavy reliance on mechanical systems for cooling and heating. Electricity full price (without any subsidies) can be a very effective way to control the demand profile. It can be structured to encourage customers (generally those that have significant electricity demand) to reduce their total usage as well as peak demand (thus reducing the pressure on the grid and the power plant) by charging them full electricity prices.

Renewable energy sources are increasingly being integrated into small-scale production systems, so plants with multiple supply sources are becoming more common. This improvement in technology added to a greater social awareness of energy saving and resource usage, which makes flexible systems to manage these facilities necessary. Modern energy management can be more accessible to the interested public if it is located in universities, making it available to teachers and students alike. Furthermore, as it is a developing field of study, its location on campus facilitates research, maintenance, and financing. In this scenario, a SCADA system is proposed, capable of monitoring and centrally storing the values of the most important production and consumption parameters. In addition, by using this system, it is possible to control the state of the different energy sources in a centralized way, as well as their distribution in the plant where it is implemented. This study focuses on the management of a flexible, modern, and accessible solution to the advances in electrical systems because of technological development in this field, which broadens the experience of university teachers and students in their engineering careers. The systems have been put into practice in the facilities of a research and teaching laboratory at the University of Almeria, which integrates renewable and conventional energy resources.

The journal retracts the article “A Critical Review on Recycling Composite Waste Using Pyrolysis for Sustainable Development” Energies 2021, 14(18), 5748 [...]

The growing global demand for food and the environmental impact caused by agriculture have made this activity increasingly dependent on electronics, information technology, and telecommunications technologies. In Colombia, agriculture is of great importance not only as a commercial activity, but also as a source of food and employment. However, the concept of smart agriculture has not been widely applied in this country, resulting in the high production of various types of crops due to the planting of large areas of land, rather than optimization of the processes involved in the activity. Due to its technical characteristics and the radio spectrum considered in its deployment, 5G can be seen as one of the technologies that could generate the greatest benefits for the Colombian agricultural sector, especially in the most remote rural areas, which currently lack mobile network coverage. This article provides an overview of the current 5G technology landscape in Colombia and presents examples of possible 5G/IoT applications that could be developed in Colombian fields. The results show that 5G could facilitate the implementation of the smart farm in Colombia, improving current production and efficiency. It is useful when designing 5G implementation plans and strategies, since it categorizes crops by regions and products. This is based on budget availability, population density, and regional development plans, among others.

The importance of the quality and continuity of electricity supply is increasingly evident given the dependence of the world economy on its daily and instantaneous operation. In turn, the network is made up of power transmission lines. This study has been carried out based on the Scopus database, where all the publications, over 5000 documents, related to the topic of the power transmission lines have been analyzed up to the year 2022. This manuscript aims to highlight the main global research trends in power transmission lines and to detect which are the emerging areas. This manuscript cover three main aspects: First, the main scientific categories of these publications and their temporal trends. Second, the countries and affiliations that contribute to the research and their main research topics. Third, identification of the main trends in the field using the detection of scientific communities by means of the clustering method. The three main scientific categories found were Engineering, Energy and Computer Science. This research is most strongly developed in China, as the top 10 institutions are from this country, followed by USA and in third place by Russia. Twelve lines of research have been detected: Line Inspection, Leakage Current, Magnetic Fields, Fault Location, Icing, Lines Design, Natural Disasters, Temperature, Half-wave, Arc Flash, Pattern Recognition, and Artificial Intelligence. This research will open new perspectives for future research on power transmission lines.

This Special Issue has focused on symmetry in renewable energy and energy systems II—including wind energy and fluid power [...]

The performance of photovoltaic (PV) solar panels is dependent on certain factors, such as dust effects. Even though Palestine’s energy issues are well-known, no research has been undertaken on the soiling effect on solar energy generation in Palestine’s climatic circumstances. The study’s findings can aid Palestine’s efforts to achieve long-term energy sustainability and solar energy use. Outdoor research was conducted in Tulkarm, Palestine, to explore the impact of dust on PV systems. The current study examined the impact of dust accumulation based on the Mediterranean climate. To accomplish this, a one-year experiment was conducted from 1 January to 31 December 2021. An 85-kW PV power plant at Tulkarm was utilized in the study. Knowing the efficiency reduction over time will aid in minimizing cleaning expenses by selecting the most appropriate cleaning interval. The results concluded that in January, February, November, and December, there will be a two-month cleaning period, monthly cleaning in March and October, as well as two weeks of cleaning in April and May. It may also be concluded that the plant should be cleaned weekly throughout the months of June, July, August, and September. This recommendation is necessary to maintain the PV panel plant operating at peak efficiency.

Inventions have been the technological advances of mankind [...]

Countries with limited natural resources and high energy prices, such as Jordan, face significant challenges concerning energy consumption and energy efficiency, particularly in the context of climate change. Residential buildings are the most energy-consuming sector in Jordan. Photovoltaic (PV) systems on the rooftops of residential buildings can solve the problem of increasing electricity demands and address the need for more sustainable energy systems. This study calculated the potential electricity production from PV systems installed on the available rooftops of residential buildings and compared this production with current and future electricity consumption for residential households. A simulation tool using PV*SOL 2021 was used to estimate electricity production and a comparative method was used to compare electricity production and consumption. The results indicated that electricity production from PV systems installed on single houses and villas can cover, depending on the tilt angle and location of the properties, three to eight times their estimated future and current electricity use. PV installation on apartment buildings can cover 0.65 to 1.3 times their future and current electricity use. The surplus electricity produced can be used to mitigate urban energy demands and achieve energy sustainability.

The discovery of a Roman mosaic from the 2nd century AD in Cantillana (Seville) generated interest and the need for exhaustive documentation, so that it could be recreated with real measurements in a 3D model, not only to obtain an exact replica, but with the intention of analyzing and studying the behavior of two main geomatics techniques. Thus, the objective of this study was the comparative analysis of both techniques: near object photogrammetry by SfM and terrestrial laser scanner or TLS. The aim of this comparison was to assess the use of both techniques in archaeological excavations. Special attention was paid to the accuracy and precision of measurements and models, especially in altimetry. Mosaics are frequently relocated from their original location to be exhibited in museums or for restoration work, after which they are returned to their original place. Therefore, the altimetric situation is of special relevance. To analyze the accuracy and errors of each technique, a total station was used to establish the real values of the ground control points (GCP) on which the comparisons of both methods were to be made. It can be concluded that the SfM technique was the most accurate and least limiting for use in semi-buried archaeological excavations. This manuscript opens new perspectives for the use of SfM-based photogrammetry in archaeological excavations.

Despite the wealth of studies on bilingual education, there is a dearth of meta-research on the worldwide development and trends of this area of investigation over the past few decades. The occupation of this gap allows scholars to take stock of current states of research, get overviews of the contributions made to the field, foresee future research trends, and identify research needs and gaps that may be addressed in future investigation. This study analyses the evolution and trends of bilingual education research during a 50-year period (1969–2018) from a bibliometric perspective. The results show a steady increase in the number of publications, and was exponential in the last decade, mainly in the form of research articles, which makes bilingual education a truly consolidated and increasingly evolving research field. The US is the leading country with respect to the number of publications, affiliations, and sponsors, followed, primarily, by some other North American (e.g., Canada), European (e.g., UK and Spain), and Asian (e.g., China) countries, as well as Australia. There is a large research network cluster led by the US involving intercontinental interaction among institutions from Europe, Asia, and, to a lesser extent, South America. However, a scant level of internationalisation of scholars publishing works on bilingual education was observed, with most author collaboration being limited to different US institutions. The most influential authors belong to institutions from the US, Canada, Spain, and Israel, and, to a lesser extent, Australia. The main research topics in the field depend on the contexts and include regulations of language institutions, bilingual education models, language skills, pedagogical strategies, education levels, and ages, among others. These results may contribute to the identification of new research needs and therefore, to the development of future directions in bilingual education research.

Agriculture has the large challenge of providing food for a continuously growing world population, while natural resources remain the same. This great challenge is certainly supported in the future by Agronomy, which brings together practical knowledge and scientifically based techniques and applies them to agricultural productivity. Research in agronomy at a global level must reflect global interests, while considering the particular conditions of each country or region. One of the main objectives of this Special Issue is to contribute studies that help to identify the global research trends in agronomy, especially if they have an approach related to sustainability.

Based on recent developments and the predicted future advancement of lighting technologies, researchers are now questioning the extent to which daylight is effective in lowering the overall energy consumption of buildings. As light-emitting diode (LED) luminaires are highly energy efficient, the amount of power consumed for lighting purposes can be reduced, even in situations where the lighting system is at its full power. It has already been demonstrated that LED-lighting technologies can facilitate significant energy savings through minimizing window size (the main source of heat loss in buildings), and there is considerable potential for developing the LEDs’ source efficacy and lighting-product efficiency to ultimately achieve levels of efficacy of approximately 350 lumens per Watt (lm/W). For building designs to be sustainable in the future, it is critical that the windows-to-wall ratio (WWR) is optimized to minimize both heating and cooling loads, as well as the total energy consumed by the building for lighting, according to the efficiency of the LED, while still maintaining a suitable lighting level for occupants. This research examines the influence of the WWR on the total amount of energy consumed by standard buildings in Jordan using various LED luminaires (existing and projected efficiencies). DesignBuilder software was utilized to analyze the effect of LED-technology development on optimizing the WWR for a typical residential structure in Jordan. The research presents beneficial recommendations with respect to optimizing the WWR for primary decision-makers in the design of residential buildings with enhanced energy efficiency, considering the losses and gains associated with solar heat and light to capitalize on solar energy with no adverse impacts by windows size. The outcomes suggest a WWR of 17% could be achieved by typical residential buildings in Jordan that have extremely efficient LED lighting systems (350 lm/W), which is more than 50% less than the existing level of 40% recommended by multiple standards. Additionally, this study highlighted that when the efficiency of LED technologies increases, the energy demand of the building will be reduced because of lower energy usage combined with heat gain resulting from the LED efficiency.

The rising usage of carbon and glass fibers has raised awareness of scrap management options. Every year, tons of composite scrap containing precious carbon and glass fibers accumulate from numerous sectors. It is necessary to recycle them efficiently, without harming the environment. Pyrolysis seems to be a realistic and promising approach, not only for efficient recovery, but also for high-quality fiber production. In this paper, the essential characteristics of the pyrolysis process, their influence on fiber characteristics, and the use of recovered fibers in the creation of a new composite are highlighted. Pyrolysis, like any other recycling process, has several drawbacks, the most problematic of which is the probability of char development on the resultant fiber surface. Due to the char, the mechanical characteristics of the recovered fibers may decrease substantially. Chemically treating and post-heating the fibers both help to reduce char formation, but only to a limited degree. Thus, it was important to identify the material cost reductions that may be achieved using recovered carbon fibers as structural reinforcement, as well as the manufacture of high-value products using recycled carbon fibers on a large scale. Recycled fibers are cheaper than virgin fibers, but they inherently vary from them as well. This has hampered the entry of recycled fiber into the virgin fiber industry. Based on cost and performance, the task of the current study was to modify the material in such a way that virgin fiber was replaced with recycled fiber. In order to successfully modify the recycling process, a regulated optimum temperature and residence duration in post-pyrolysis were advantageous.

Energy savings gained through natural lighting could be offset by the loss of energy through windows; therefore, the target of this study is to examine the effects of enhancing the efficiency of lighting systems on the optimum window-to-wall ratio (WWR) of Jordanian residential structures. This research proposes the hypothesis that the WWR of residential structures that contain artificial lighting systems with increased efficiency will be lower than buildings in which solar lighting is provided. The energy simulation tool, DesignBuilder (DesignBuilder Software Ltd, Stroud, UK) was used to simulate an intricate model showing a standard Jordanian residential building with a size of 130 m2. The study offers useful guidance regarding the optimum WWR for key decisionmakers when designing energy-efficient residential structures in the context of Jordan. By considering the balance between gains and losses in solar heat and light gain to exploit energy from solar sources with no reverse effects, while making comparisons between different WWR situations, the findings indicate that the typical WWR for residential structures in Jordan that have efficient Light Emitting Diode (LED) systems of lighting installed could be between 25% and 30%, which is lower than the highest WWR stipulated by the ASHRAE standards.

Any building’s design should sustain thermal comfort for occupants and promote less energy usage during its lifetime using accurate building retrofits to convert existing buildings into low-energy buildings so that the heating and cooling loads can be minimized. Regarding the methodology adopted in this research, an energy model of an educational building located at the German Jordanian University in Jordan was constructed utilizing DesignBuilder computer software. In addition, it was calibrated utilizing real energy consumption data for a 12-month simulation of energy performance. Subsequently, a computerized evaluation of the roles of building envelope retrofits or the adaptive thermal comfort limits in the reduction of the overall building energy consumption was analyzed. The results of the study show that the current building’s external wall insulation, roof insulation, glazing, windows, and external shading devices are relatively energy-efficient but with high cost, resulting in significant financial losses, even though they achieved noticeable energy savings. For instance, equipping the building’s ventilation system with an economizer culminated in the highest financial profit, contributing to an annual energy savings of 155 MWh. On the other hand, in an occupant-centered approach, applying the adaptive thermal comfort model in wider ranges by adding 1 °C, 2 °C, and 3 °C to the existing operating temperatures would save a significant amount of energy with the least cost (while maintaining indoor thermal comfort), taking over any retrofit option. Using different adaptive thermal comfort scenarios (1 °C, 2 °C, and 3 °C) led to significant savings of around 5%, 12%, and 21%, respectively. However, using different retrofits techniques proved to be costly, with minimum energy savings compared to the adaptive approach.

Agriculture as an economic activity and agronomy as a science must provide food for a constantly growing population. Research in this field is therefore becoming increasingly essential. Much of the research is carried out in academic institutions and then developed in the private sector. Patents do not have to be issued through scientific institutions. Patents from scientific institutions are intended to have a certain economic return on the investment made in research when the patent is transferred to industry. A bibliometric analysis was carried out using the Scopus and SciVal databases. This study analyses all the research carried out in the field of agronomy and related sciences (Agricultural and Biological Sciences category of Scopus database) by EU-27 countries, which has been cited in at least one international patent. The data show that out of about 1 million published works only about 28,000 have been used as a source of patents. This study highlights the main countries and institutions in terms of this transfer. Among these, Germany, France and Spain stand out in absolute terms, but considering the degree of specialization. Regarding their specialization the institution ranking is led by Swedish University of Agricultural Sciences (58%), AgroParisTech (52%), Wageningen University & Research (48%), and INRAE (38%). It also analyses which journals used for this transfer are most important. For these publications more than 90% of the articles have had a higher-than-expected citation level for the year of publication, the type of publication and the discipline in which they are categorized. The most-obtained research fields can be distinguished as those related to genetics or mo-lecular biology, those related to specific foods, such as cheeses, milk, breads or oils, and, thirdly, the group covering food-related constituents such as caseins, probiotics, glutens, or starch.

The combustion process of power generation plants originates particulates. There are different technologies to collecting particulate such as electrostatic precipitators (ESPs) or fabric filters. Currently, these ESPs take 25 or 35 years in service and if the performance expectations of their Plants are positives, improving investments required which can adapt to the new particulate emission limits becoming more stringent. This paper analyzes an alternative means great savings in investment costs; Conversion of the existing ESP casing to a Pulse Jet fabric filter. This study also presents a real case, implementing this conversion with good results in unit of 660 MW power plants of Italy.

With the growing demand for clean and economically feasible renewable energy, solar photovoltaic (PV) system usage has increased. Among many factors, the tilt and azimuth angles are of great importance and influence in determining the photovoltaic panel’s efficiency to generate electricity. Although much research was conducted related to solar PV panels’ performance, this work critically determined the tilt and azimuth angles for PV panels in all countries worldwide. The optimum tilt and azimuth angles are estimated worldwide by the photovoltaic geographic information system (PVGIS). Also, annual and average daily solar irradiation incident on the tilted and oriented plate optimally (AR1 and DR1) are calculated. Besides, annual and average daily solar irradiation incident on plate tilt optimally and oriented because of the south in the northern hemisphere and because of the north in the southern hemisphere (AR2 and DR2) are estimated. PVGIS is also used to calculate the annual and average daily solar irradiation incident on the horizontal plate (AR3 and DR3). The data collected from PVGIS are used to develop an efficient and accurate artificial neural network model based on feed-forward neural network approach. This model is an essential subpart that can be used in an embedded system or an online system for further PV system analysis and optimization. The developed neural model reflected very high accuracy in predicting the PV panels’ optimal tilt and azimuth angles worldwide. The benefit of tilting is generally increased by increasing the latitude. As the latitude increases, the tilt factor (F) increases because of the increase in the optimum tilt angle by increasing the latitude. The optimal orientation is due to the north in the southern hemisphere and due to the south in the northern hemisphere for most cities worldwide. In sum, it can be concluded that the optimum tilt angle is equal to or greater than the latitude until the latitude 30°. The optimum tilt angle becomes less than the latitude, and the difference is increased until it reaches more than 20°. Hence in this study the aim is to develop a simple neural network model which can accurately predict the annual radiation and optimum tilt and azimuth angle in any region of the world and can be easily implemented in a low-cost microcontroller.

Energy efficiency and management is certainly one of the key drivers of human progress. Thus, the trends in the energy research are a topic of interest for the scientific community. The aim of this study is to highlight global research trends in this field through the analysis of a scientific journal indexed exclusively in the energy and fuels category. For this purpose, a journal has been selected that is in the center of the category considering its impact factor, which is only indexed in this category and of open access, Energies of the publisher MDPI. Therefore, a bibliometric analysis of all the contents of the journal between 2008 and 2020, 13,740 documents published, has been carried out. Analyzing the articles that are linked to each other by their citations, 14 clusters or research topics have been detected: smart grids; climate change–electric energy community; energy storage; bioenergy sources; prediction algorithms applied to power; optimization of the grid link for renewable energy; wind power; sustainability of power systems; hydrocarbon improvements; conversion of thermal/electrical energy; electric motor advancements; marine renewable energy; hydropower and energy storage; and preventive techniques in power transformers. The main keywords found were electric vehicle, renewable energy, microgrid, smart grid, and energy efficiency. In short, energy research remains necessary to meet the future challenge of sustainable energy with high efficiency and the exploration of new renewable resources, all for increasingly sustainable cities.

Background: The more than 4100 species of phytoparasitic nematodes are responsible for an estimated economic loss in the agricultural sector of nearly $125 billion annually. Knowing the main lines of research and concerns about nematodes that affect plants is fundamental. Methods: For this reason, an analysis using bibliometric data has been carried out, with the aim of tracing the state of world research in this field, as well as knowing the main lines of work, their priorities, and their evolution. Results: This will allow us to establish strategic lines for the future development of this research. Conclusions: The analysis has allowed us to detect that the interest in nematodes affecting plants has not stopped growing in the last decades, and that tomato, soybean, and potato crops are the ones that generate the most interest, as well as nematodes of the genus Meloidogyne and Globodera. Likewise, we have detected that the main lines of research in this field are focused on biological control and host–parasite interaction.

Symmetry can be understood in two different ways: as a property or as a principle. As Plato said, the symmetry that can be seen in nature is not random in itself, because it is a result of the symmetries of the physical laws. Thus, the principles of symmetry have been used to solve mechanical problems since antiquity. Today, these principles are still being researched; for example, in chemical engineering, the spatial symmetry properties of crystal lattices are being studied, or in electrical engineering, the temporal symmetry of the periodic processes of oscillators can be observed. This Special Issue is dedicated to symmetry in engineering sciences (electrical, mechanical, civil, and others) and aims to cover both engineering solutions related to symmetry and the search for patterns to understand the phenomena observed.

The use of renewable energies, energy saving, and efficiency are needs of global society. According to the latest estimates, global energy demand could triple by 2050 and, by then, 70% of the world’s population will live in cities. Cities are currently responsible for 80% of greenhouse gas emissions, so they have a key role to play in shifting towards a sustainable energy future. Cities are threatened not only by overcrowding, but also by rising energy demand, obsolete infrastructure, volatile energy markets, and the effects of climate change. This Special Issue aims to advance the contribution of energy saving and the use of renewable energies in order to achieve more sustainable cities.

The accurate assessment of tree crowns is important for agriculture, for example, to adjust spraying rates, to adjust irrigation rates or even to estimate biomass. Among the available methodologies, there are the traditional methods that estimate with a three-dimensional approximation figure, the HDS (High Definition Survey), or TLS (Terrestrial Laser Scanning) based on LiDAR technology, the aerial photogrammetry that has re-emerged with unmanned aerial vehicles (UAVs), as they are considered low cost. There are situations where either the cost or location does not allow for modern methods and prices such as HDS or the use of UAVs. This study proposes, as an alternative methodology, the evaluation of images extracted from Google Maps (GM) for the calculation of tree crown volume. For this purpose, measurements were taken on orange trees in the south of Spain using the four methods mentioned above to evaluate the suitability, accuracy, and limitations of GM. Using the HDS method as a reference, the photogrammetric method with UAV images has shown an average error of 10%, GM has obtained approximately 50%, while the traditional methods, in our case considering ellipsoids, have obtained 100% error. Therefore, the results with GM are encouraging and open new perspectives for the estimation of tree crown volumes at low cost compared to HDS, and without geographical flight restrictions like those of UAVs.

The first industrial-scale pyrolysis plant for solid tire wastes has been installed in Jenin, northern of the West Bank in Palestine, to dispose of the enormous solid tire wastes in the north of West Bank. The disposable process is an environmentally friendly process and it converts tires into useful products, which could reduce the fuel crisis in Palestine. The gravimetric analysis of tire waste pyrolysis products from the pyrolysis plant working at the optimum conditions is: tire pyrolysis oil (TPO): 45%, pyrolysis carbon black (PCB): 35%, pyrolysis gas (Pyro-Gas): 10% and steel wire: 10%. These results are depending on the tire type and size. It has been found that the produced pyrolysis oil has a High Heating Value (HHV), with a range of 42 − 43 ( MJ / kg ) , which could make it useful as a replacement for conventional liquid fuels. The main disadvantage of using the TPO as fuel is its strong acrid smell and its low flash point, as compared with the other conventional liquid fuels. The produced pyrolysis carbon black also has a High Heating Value (HHV) of about 29 (MJ/kg), which could also encourage its usage as a solid fuel. Carbon black could also be used as activated carbon, printers’ ink, etc. The pyrolysis gas (Pyro-Gas) obtained from waste tires mainly consist of light hydrocarbons. The concentration of H2 has a range of 30% to 40% in volume and it has a high calorific value (approximately 31 MJ / m 3 ), which can meet the process requirement of energy. On the other hand, it is necessary to clean gas before the burning process to remove H2S from Pyro-Gas, and hence, reduce the acid rain problem. However, for the current plant, some recommendations should be followed for more comfortable operation and safer environment work conditions.

It is essential to address research into low-cost technologies, as those employed on a wide scale demand a great amount of resources. The main goal of this work was to analyze the research on low cost technologies worldwide by studying the scientific output recorded in the Scopus database. This analysis makes it possible to determine the evolution of research into low cost technologies. In particular, we analyzed the distribution of this research by the different scientific categories, the categories’ evolution over time, the types of publications, the geographical distribution throughout different countries, the main institutions in each scientific category, and the areas of research identified through the main keywords indexed in the publications. A remarkable finding of this work has been that the universities that are most active in low-cost technologies are those in the most technologically advanced countries. There is only one exception to the above statement and it is in the field of medicine, where the most technologically developed countries are not always the most interested in this field. Given the trends observed in recent years, there is a need for a major change and for low-cost technologies to become an area of interest in countries with emerging economies.

The optimum tilt angle of solar panels or collectors is crucial when determining parameters that affect the performance of those panels. A mathematical model is used for determining the optimum tilt angle and for calculating the solar radiation on a south-facing surface on a daily, monthly, seasonal, semi-annual, and annual basis. Photovoltaic Geographical Information System (PVGIS) and Photovoltaic Software (PVWatts) is developed by the NREL (US National Renewable Energy Laboratory) are also used to calculate the optimum monthly, seasonal, semi-annual, and annual tilt angles and to compare these results with the results obtained from the mathematical model. The results are very similar. PVGIS and PVWatts are used to estimate the solar radiation on south-facing surfaces with different tilt angles. A case study of a mono-crystalline module with 5 kWP of peak power is used to find out the amount of increased energy (gains) obtained by adjusting the Photovoltaic (PV) tilt angles based on yearly, semi-annual, seasonal, and monthly tilt angles. The results show that monthly adjustments of the solar panels in the main Palestinian cities can generate about 17% more solar energy than the case of solar panels fixed on a horizontal surface. Seasonal and semi-annual adjustments can generate about 15% more energy (i.e., it is worth changing the solar panels 12 times a year (monthly) or at least 2 times a year (semi-annually). The yearly optimum tilt angle for most Palestinian cities is about 29°, which yields an increase of about 10% energy gain compared to a solar panel fixed on a horizontal surface.

Renewable energy today is no longer just an affordable alternative, but a requirement for mitigating global environmental problems such as climate change. Among renewable energies, the use of solar energy is one of the most widespread. Concentrating Solar Power (CSP) systems, however, is not yet fully widespread despite having demonstrated great efficiency, mainly thanks to parabolic-trough collector (PTC) technology, both on a large scale and on a small scale for heating water in industry. One of the main drawbacks to this energy solution is the large size of the facilities. For this purpose, several models have been developed to avoid shadowing between the PTC lines as much as possible. In this study, the classic shadowing models between the PTC rows are reviewed. One of the major challenges is that they are studied geometrically as a fixed installation, while they are moving facilities, as they have a tracking movement of the sun. In this work, a new model is proposed to avoid shadowing by taking into account the movement of the facilities depending on their latitude. Secondly, the model is tested to an existing facility as a real case study located in southern Spain. The model is applied to the main existing installations in the northern hemisphere, thus showing the usefulness of the model for any PTC installation in the world. The shadow projected by a standard, the PTC (S) has been obtained by means of a polynomial approximation as a function of the latitude (Lat) given by S = 0.001 − Lat2 + 0.0121 − Lat + 10.9 with R2 of 99.8%. Finally, the model has been simplified to obtain in the standard case the shadows in the running time of a PTC facility.

Most offshore wind farms built thus far are based on waters below 30 m deep, either using big diameter steel monopiles or a gravity base. Now, offshore windfarms are starting to be installed in deeper waters and the use of these structures—used for oil and gas like jackets and tripods—is becoming more competitive. Setting aside these calls for direct or fixed foundations, and thinking of water depths beyond 50 m, there is a completely new line of investigation focused on the usage of floating structures; TLP (tension leg platform), Spar (large deep craft cylindrical floating caisson), and semisubmersible are the most studied. We analyze these in detail at the end of this document. Nevertheless, it is foreseen that we must still wait sometime before these solutions, based on floating structures, can become truth from a commercial point of view, due to the higher cost, rather than direct or fixed foundations. In addition, it is more likely that some technical modifications in the wind turbines will have to be implemented to improve their function. Regarding wind farm connections to grid, it can be found from traditional designs such as radial, star or ring. On the other hand, for wind generator modeling, classifications can be established, modeling the wind turbine and modeling the wind farm. Finally, for the wind generator control, the main strategies are: passive stall, active stall, and pitch control; and when it is based on wind generation zone: fixed speed and variable speed. Lastly, the trend is to use strategies based on synchronous machines, as the permanent magnet synchronous generator (PMSG) and the wound rotor synchronous generator (WRSG).

The demand for improved food quality has been accompanied by a technological boost. This fact enhances the possibility of improving the quality of horticultural products, leading towards healthier consumption of fruits and vegetables. A better electrical characterization of the dielectric properties of fruits and vegetables is required for this purpose. Moreover, a focused study of dielectric spectroscopy and advanced dielectric sensing is a highly interesting topic. This review explains the dielectric property basics and classifies the dielectric spectroscopy measurement techniques. It comprehensively and chronologically covers the dielectric experiments explored for fruits and vegetables, along with their appropriate sensing instrumentation, analytical modelling methods and conclusions. An in-depth definition of dielectric spectroscopy and its usefulness in the electric characterization of food materials is presented, along with the various sensor techniques used for dielectric measurements. The collective data are tabulated in a summary of the dielectric findings in horticultural field investigations, which will facilitate more advanced and focused explorations in the future.

Hallar nuevas fuentes de energía es uno de los retos que trajo consigo el siglo XXI. En este tr abajo se hace un análisis sobre la energía de las olas, la cual presenta varia s ventajas significativas con r especto a otras fuentes de energ ías basadas en combustibles fós iles e, inclusive, otras fuentes renovables de energía. De entre estas ventajas de stacan el bajo impacto ambiental y su alta densidad energética, respectivamente. La energía de las olas del mar se considera ca da vez en más países como un recurso renovable importante y sob re todo prometedor. El objetivo de este trabajo es la evaluación del po tencial energético de las olas en la costa sur del Golfo de Méx ico; en él se observó el comportamiento del olea je y se obtuvo que la potenci a media anual disponible es de 55.91 W/m. Adicionalmente, se de staca el comportamiento estacional de las olas en la región; pues, en es te punto, la estación más energética es otoño y la menos energé tica es primavera, lo cual difiere de la tendencia mundial, en la que i nvierno y verano son la más y la menos energética, respectivamente.

En este trabajo se evalúan los métodos de obtención de curvas IDF para México: Wencel modificado, Chen, Chen modificado, Témez y Témez modificado. Los datos proceden de 63 estaciones automáticas (EMAS), distribuidas por todo el país, con registros cada 10 minutos y durante siete años como mínimo. Para el análisis se han diferenciado estaciones de costa cuando están a 50 km o menos de esa zona, y las demás como de interior. Se han valorado para cada una de las estaciones, todos los parámetros de los métodos de cálculo de curvas IDF mencionados, para duraciones entre 10 minutos y 24 horas, y para periodos de retorno de 2 a 500 años. Se ha comprobado que cuando se tienen registros de lluvia cada 10 minutos o menos, se recomienda el método de Wencel; cuando se tienen registros de lluvia horarios, se aconseja el método de Chen; cuando los datos de lluvia son diarios, para duraciones menores de 2 h, se necesita el método de Témez modificado; para duraciones de más de 2 h, el mejor es el de Chen modificado para las zonas del interior y Témez modificados para las zonas costeras.

La agricultura del sureste español ha experimentado uno de los cambios más importantes que se han producido en los últimos años gracias a los cultivos de invernadero. En este tipo de cultivos es muy importante la utilización de técnicas avanzadas y tecnologías novedosas para mejorar el rendimiento de los cultivos. Este trabajo presenta un sistema avanzado para la monitorización de variables aplicadas a la agricultura intensiva. El sistema usa una red de sensores inalámbricos (WSN) que funciona con 6LoWPAN y RPL como el protocolo de enrutamiento, mide humedad, temperatura, luz y el contenido volumétrico de agua en el suelo. La WSN envía los datos recolectados a un dispositivo embebido que almacena la información en una base de datos a fin de visualizar de forma gráfica y en tiempo real los valores obtenidos en los cultivos. El sistema desarrollado permite una gran flexibilidad de instalación y de adaptación a cualquier invernadero, ya que se basa en tecnología inalámbrica, que los nodos pueden establecer las rutas de los enlaces entre ellos automáticamente, y tienen implementada una función de ahorro de energía que le permite alargar la vida útil de las baterías lo suficiente para una campaña agrícola sin necesidad de mantenimiento.

The arches were a great advance in construction with respect to the rigid Greek linteled architecture. Its development came from the hand of the great Roman constructions, especially with the semicircular arch. In successive historical periods, different types of arches have been emerging, which in addition to their structural function was taking aesthetic characteristics that are used today to define the architectural style. When, in the construction of a bow, the rise is less than half the springing line, the semicircular arch is no longer used and the segmental arch is used, and then on to another more efficient and aesthetic arch, the basket-handle arch. This study examines the classic geometry of the basket-handle arch also called the three-centered arch. A solution is proposed from a constructive and aesthetic point of view, and this is approached both geometrically and analytically, where the relationship between the radius of the central arch and the radius of the lateral arch is minimized. The solution achieved allows the maximum springing line or clear span to be saved with the minimum rise that preserves the aesthetic point of view, since the horizontal thrust of a bow is greater than the relationship between the springing line of the arch and the rise. This solution has been programmed and the resulting software has made it possible to analyse existing arches in historic buildings or constructions to check if their solutions were close or not from both points of view. Thus, it has been possible to verify that in most of the existing arches analyzed, the proposed solution is reached.

Grain cereals such as wheat, barley, rice, and maize are the nutritional basis of humans and animals worldwide. Thus, these crop plants are essential in terms of global food security. We conducted a bibliometric assessment of scientific documents and patents related to wheat and barley through the Scopus database. The number of documents published per year, their affiliation and corresponding scientific areas, the publishing journals, document types and languages were metricized. The main keywords included in research publications concerning these crops were also analysed globally and clustered in thematic groups. In the case of keywords related to agronomy or genetics and molecular biology, we considered documents dated up to 1999, and from 2000 to 2018, separately. Comparison of the results obtained for wheat and barley revealed some remarkable different trends, for which the underlying reasons are further discussed.

The symmetry concept is mainly used in two senses. The first from the aesthetic point of view of proportionality or harmony, since human beings seek symmetry in nature. Or the second, from an engineering point of view to attend to geometric regularities or to explain a repetition process or pattern in a given phenomenon. This special issue dedicated to geometry in engineering deals with this last concept, which aims to collect both the aspects of geometric solutions in engineering, which may even have a certain aesthetic character, and the aspect of the use of patterns that explain observed phenomena.

Continuous advances in computer hardware and software are enabling researchers to address optimization solutions using computational resources, as can be seen in the large number of optimization approaches that have been applied to the energy field [...]

Gothic art was developed in western Europe from the second half of the 12th century to the end of the 15th century. The most characteristic Gothic building is the cathedral. Gothic architecture uses well-carved stone ashlars, and its essential elements include the arch. The thrust is transferred by means of external arches (flying buttresses) to external buttresses that end in pinnacles, which accentuates the verticality. The evolution of the flying buttresses should not only be considered as an aesthetic consideration, but also from a constructive point of view as an element of transmission of forces or loads. Thus, one evolves from a beam-type buttress to a simple arch, and finally to a rampant arch. In this work, we study the geometry of the rampant arch to determine which is the optimum from the constructive point of view. The optimum rampant arch obtained is the one with the common tangent to the two arches parallel to the slope line. A computer program was created to determine this optimal rampant arch by means of a numerical or graphical input. It was applied to several well-known and representative cases of Gothic art in France (church of Saint Urbain de Troyes) and Spain (Cathedral of Palma de Mallorca), establishing if they were designs of optimal rampant arches or not.

Concern about everything related to energy is increasingly latent in the world and therefore the use of energy saving concepts has been increasing over the past several years. The interest in the subject has allowed a conceptual evolution in the scientific community regarding the understanding of the adequate use of energy. The objective of this work is to determine the contribution made by international institutions to the specialized publications in the area of energy-saving from 1939 to 2018, using Scopus Database API Interface. The methodology followed in this research was to perform a bibliometric analysis of the whole scientific production indexed in Scopus. The world’s scientific production has been analysed in the following domains: First the trend over time, types of publications and countries, second, the main subjects and keywords, third, main institutions and their main topics, and fourth, the main journals and proceedings that publish on this topic. Then, these data are presented using community detection algorithms and graph visualization software. With these techniques, it is possible to determine the main areas of research activity as well as to identify the structures of the collaboration network in the field of renewable energy. The results of the work show that the literature in this field have substantially increased during the last 10 years.