Environmentally friendly amino-acid salt solutions are used for the absorption of carbon dioxide from concentrated flue-gas streams via chemical absorption. Process intensification reduces operating and capital costs by combining chemical reactions and separation operations. Here, we present a new process-intensification approach that combines the CO2 capture and the amino-acid regeneration steps into a single process carried out in a slurry three-phase reactor. The absorbed CO2 precipitates as a solid carbonated guanidine compound. The cycle is completed by separation of the solid precipitate to strip the CO2 and regenerate the guanidine compound, while the liquid solution is recycled to the slurry reactor. The process was studied by modifying a model developed by the authors for a gas-liquid bubble column without the presence of the guanidine compound. The guanidine precipitation reaction was accounted for using kinetic parameters calculated by the authors in another study. The propo... [more]

The stability problem for load frequency control (LFC) of power systems with two time-varying communication delays is studied in this paper. The one-area and two-area LFC systems are considered, respectively, which are modeled as corresponding linear systems with additive time-varying delays. An improved stability criterion is proposed via a modified Lyapunov-Krasovskii functional (LKF) approach. Firstly, an augmented LKF consisting of delay-dependent matrices and some single-integral items containing time-varying delay information in two different delay subintervals is constructed, which makes full use of the coupling information between the system states and time-varying delays. Secondly, the novel negative definite inequality equivalent transformation lemma is used to transform the nonlinear inequality to the linear matrix inequality (LMI) equivalently, which can be easily solved by the MATLAB LMI-Toolbox. Finally, some numerical examples are presented to show the improvement of the... [more]

Ion transport is a significant concept that underlies a variety of technologies including membrane technology, energy storages, optical, chemical, and biological sensors and ion-mobility exploration techniques. These applications are based on the concepts of capacitance and ion transport, so a prior understanding of capacitance and ion transport phenomena is crucial. In this review, the principles of capacitance and ion transport are described from a theoretical and practical point of view. The review covers the concepts of Helmholtz capacitance, diffuse layer capacitance and space charge capacitance, which is also referred to as quantum capacitance in low-dimensional materials. These concepts are attributed to applications in the electrochemical technologies such as energy storage and excitable ion sieving in membranes. This review also focuses on the characteristic role of channel heights (from micrometer to angstrom scales) in ion transport. Ion transport technologies can also be us... [more]

The phosphate industry generates a large amount of waste called phosphogypsum (PG). Generally, this waste is discharged without any treatment, and it causes considerable environmental problems. Hence, the objective of this study is the treatment of phosphate waste using thermal plasma technology. First, the waste is characterized using different techniques, such as X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and inductively coupled plasma (ICP). Such characterization shows that the waste contains different toxic elements, such as heavy metals, fluorine, chlorine, sulfur, and phosphorus. For this reason, a plasma reactor is used to separate toxic elements from metals, such as silicon, aluminum, and magnesium, with a pyrolysis/combustion plasma system. In this work, the influence of different parameters, such as time of treatment and plasma current, on the volatility of toxic elements is studied. The obtained results show that... [more]

In this study, a demanded power point tracking (DPPT) control algorithm was designed for the application of multiple-input multiple-output (MIMO) modern control algorithms. The proposed DPPT control algorithm has been newly implemented as a multiple reference trajectory method for applying an MIMO control algorithm without mode switches. Dynamic simulations and wind tunnel experiments were performed using a scaled wind turbine to validate the proposed control algorithm. The wind speeds were 4.6 and 7.3 m/s, the average wind speeds corresponding to region 2 and region 3, respectively, with a turbulence intensity of 10%. Both sets of results demonstrated satisfactory performance for tracking the power commands transmitted from the wind farm controller. Furthermore, the proposed control algorithm was compared and validated with a DPPT control algorithm proposed in previous studies, and its improved control performance and validity were confirmed.

Presently, Internet of Things (IoT) protocols are at the heart of Machine-to-Machine (M2M) communication. Irrespective of the radio technologies used for deploying an IoT/M2M network, all independent data generated by IoT devices (sensors and actuators) rely heavily on the special messaging protocols used for M2M communication in IoT applications. As the demand for IoT services is growing, the need for reduced power consumption of IoT devices and services is also growing to ensure a sustainable environment for future generations. The Message-Queuing Telemetry Transport or in short MQTT is a widely used IoT protocol. It is a low-resource-consuming messaging solution based on the publish−subscribe type communication model. This paper aims to assess the performance of several MQTT broker implementations (also known as MQTT servers) using stress testing, and to analyze their relationship with system design. The evaluation of the brokers is performed by a realistic test scenario, and the an... [more]

One of the measures to fight against the current energy situation and reduce the energy consumption at an industrial process is to recover waste heat and transform it into electric power. Thermoelectric generators can be used for that purpose but there is a lack of experimental studies that can bring this technology closer to reality. This work presents the design, optimizations and development of two devices that are experimented and compared under the same working conditions. The hot side heat exchanger of both generators has been designed using a computational fluid dynamics software and for the cold side of the generators two technologies have been analysed: a finned dissipater that uses a fan and free convection biphasic thermosyphon. The results obtained show a maximum net generation of 6.9W in the thermoelectric generator with the finned dissipater; and 10.6W of power output in the generator with the biphasic thermosyphon. These results remark the importance of a proper design o... [more]

Two experimental simulations of underground coal gasification (UCG) processes, using large bulk samples of lignites, were conducted in a surface laboratory setup. Two different lignite samples were used for the oxygen-blown experiments, i.e., “Velenje” meta-lignite (Slovenia) and “Oltenia” ortho-lignite (Romania). The average moisture content of the samples was 31.6wt.% and 45.6wt.% for the Velenje and Oltenia samples, respectively. The main aim of the study was to assess the suitability of the tested lignites for the underground coal gasification process. The gas composition and its production rates, as well as the temperatures in the artificial seams, were continuously monitored during the experiments. The average calorific value of gas produced during the Velenje lignite experiment (6.4 MJ/Nm3) was much higher compared to the result obtained for the experiment with Oltenia lignite (4.8 MJ/Nm3). The Velenje lignite test was also characterized by significantly higher energy efficiency... [more]

An intelligent control strategy is proposed in this paper which suggests the Optimum Power Quality Enhancement (OPQE) of grid-connected hybrid power systems with solar photovoltaic, wind turbines, and battery storage. Unified Power Quality Conditioner with Active and Reactive power (UPQC-PQ) is designed with Atom Search Optimization (ASO) based Fractional-order Proportional Integral Derivative (FOPID) controller in the proposed Hybrid Renewable Energy Sources (HRES) system. The main aim is to regulate voltage while reducing power loss and reducing Total Harmonic Distortion (THD). UPQC-PQ is used to mitigate the Power Quality (PQ) problems such as sag, swell, interruptions, real power, reactive power and THD reductions related to voltage/current by using ASO based FOPID controller. The developed technique is demonstrated in various modes: simultaneous to improve PQ reinforcement and RES power injection, PRES > 0, PRES = 0. The results are then compared to those obtained using previous l... [more]

These days, various national and international research organizations are working on the development of low NOx combustors. The present work describes the experimental and numerical characterization of flow dynamics and combustion characteristics in a rectangular burner. A ring-needle type plasma actuator was developed and driven by a high voltage nanosecond pulsed generator under atmospheric conditions. Smoke flow visualizations and Proper Orthogonal Decomposition (POD) were carried out to identify the relevant flow structures. Electrical characterization of the non-reactive flow was carried out to predict the electrical power and the optimum value of the reduced electric field (EN), which is useful for the implementation of a numerical model for the study of plasma-assisted ignition. A detailed plasma kinetic mechanism integrated with all excited species was considered and validated with experimental studies. Numerical modeling of plasma ignition has been performed by coupling ZDPlas... [more]

Process planning in manufacturing today focuses on optimizing the conflicting targets of cost, quality, and time. Due to increasing social awareness and subsequent governmental regulation, environmental impact becomes a fourth major aspect. Eventually, sustainability in manufacturing ensures future competitiveness. In this paper, a framework for the planning of sustainable manufacturing is proposed. It is based on the abstraction and generalization of manufacturing resources and part descriptions, which are matched and ranked using a multi-criteria decision analysis method. Manufacturing resources provide values for cost, quality, time and environmental impacts, which multiply with their usage within a manufacturing task for a specific part. The framework is validated with a detailed modeling of a laser machine as a resource revealing benefits and optimization potential of the underlying data model. Finally, the framework is applied to a use case of a flange part with two different man... [more]

Entrepreneurs have long been convinced about the power and possibilities of the Internet. Nowadays, the Internet is an integral tool for the functioning of a company, not only as an alternative distribution channel, but also as a channel of information and communication flow, a means of interaction with the environment. The increasing use of the Internet, and especially of social media, made it possible to escalate the activity of various social groups in various areas of the company’s activity, including innovation, leading to the development of crowdsourcing. Crowdsourcing has redefined the existing production rules and ways of using labor resources. Its potential lies in openness, partnership, resource sharing and global action. There are already many studies on crowdsourcing and innovation, but little attention is paid to the relationship between crowdsourcing and the determinants of innovation activity. Thus, the aim of this research is examining whether the use of crowdsourcing w... [more]

Chlorine demand as a disinfectant for water utility impacts on unintended energy consumption from electrolysis manufacture; thus, diminishing the chlorine consumption also reduces the environmental impact and energy consumption. Problems of disinfectant distribution and uniformity in Water Distribution Networks (WDN) are associated with the exponential urban growth and the physical and biochemical difficulties within the network. This study optimizes Chlorine Booster Stations (CBS) location on a network with two main objectives; (1) to deliver minimal Free Residual Chlorine (FRC) throughout all demand nodes according to country regulations, and (2) to reduce day chlorine mass concentration supplied in the system by applying an hour time pattern in CBS, consequently associated economic, energy and environmental impacts complying with regulatory standards. The application is demonstrated on a real-world WDN modeled from Guanajuato, Mexico. The resulting optimal location and disinfectant... [more]

Wheel flat can cause a large impact between the wheel and rail and excites a forced vibration in the locomotive and track structure systems. The working conditions and fatigue life of the motor bearings are significantly affected by the intensified wheel−rail interaction via the transmission path of the gear mesh. In this study, a fatigue life prediction method of the traction motor bearings in a locomotive is proposed. Based on the L−P theory or ISO 281 combined with the Miner linear damage theory and vehicle−track coupled dynamics, the irregular loads induced by the track random irregularity and gear mesh are considered in this proposed method. It can greatly increase the accuracy of predictions compared with the traditional prediction models of a rolling bearing life whose bearing loads are assumed to be constant. The results indicate that the periodic impact forces and larger mesh forces caused by the wheel flat will reduce the fatigue life of the motor bearings, especially when th... [more]

Lightning discharge becomes a serious source of interference and damage for electronic and electrical power systems. Safe and reliable operation of railway traffic control systems requires proper protection against the effects of lightning. However, the current standards on lightning protection, PN-EN/EN/IEC 62305, do not cover railway objects. Moreover, there are no other standards or recommendations dedicated to the railway. The paper is an attempt to apply the procedure of lightning risk management according to PN-EN 62305-2 to select the proper protection measures in railway objects. A case study for the signal box with installed relaying and digital stations of the railway traffic control system is analyzed. The analysis comprises calculations based on the current standard PN-EN 62305-2:2012 but including the issues specific to railway traffic control. The risks of lightning losses have been calculated for two cases: without lightning protection measures and with protection measur... [more]

Several carbon sequestration technologies have been proposed to utilize carbon dioxide (CO2) to produce energy and chemical compounds. However, feasible technologies have not been adopted due to the low efficiency conversion rate and high-energy requirements. Process intensification increases the process productivity and efficiency by combining chemical reactions and separation operations. In this work, we present a model of a chemical-electrochemical cyclical process that can capture carbon dioxide as a bicarbonate salt. The proposed process also produces hydrogen and electrical energy. Carbon capture is enhanced by the reaction at the cathode that displaces the equilibrium into bicarbonate production. Literature data show that the cyclic process can produce stable operation for long times by preserving ionic balance using a suitable ionic membrane that regulates ionic flows between the two half-cells. Numerical simulations have validated the proof of concept. The proposed process cou... [more]

Climate change has a major impact on the urban built environment, both with respect to the heating and cooling energy requirements, but also regarding the higher probability of confronting extreme events such as heatwaves. In parallel, the ongoing urbanization, the urban microclimate and the formation of the urban heat island effect, compounding the ongoing climate change, is also a considerable determinant of the building’s energy behavior and the outdoor thermal environment. To evaluate the magnitude of the complex phenomenon, the current research investigates the effect of climate change and urban heat island on heating and cooling energy needs of an urban building unit in Thessaloniki, Greece. The study comparatively evaluates different tools for the generation of future weather datasets, considering both statistical and dynamical downscaling methods, with the latter involving the use of a regional climate model. Based on the output of the regional climate model, another future wea... [more]

In the quest to achieve sustainable pipeline operations and improve pipeline safety, effective corrosion control and improved maintenance paradigms are required. For underground pipelines, external corrosion prevention mechanisms include either a pipeline coating or impressed current cathodic protection (ICCP). For extensive pipeline networks, time-based preventative maintenance of ICCP units can degrade the CP system’s integrity between maintenance intervals since it can result in an undetected loss of CP (forced corrosion) or excessive supply of CP (pipeline wrapping disbondment). A conformance evaluation determines the CP system effectiveness to the CP pipe potentials criteria in the NACE SP0169-2013 CP standard for steel pipelines (as per intervals specified in the 49 CFR Part 192 statute). This paper presents a predictive maintenance framework based on the core function of the ICCP system (i.e., regulating the CP pipe potential according to the NACE SP0169-2013 operating window).... [more]

The further development of electric mobility requires major scientific efforts to obtain reliable data for vehicle and drive development. Practical experience has repeatedly shown that vehicle data sheets do not contain realistic consumption and range figures. Since the fear of low range is a significant obstacle to the acceptance of electric mobility, a reliable database can provide developers with additional insights and create confidence among vehicle users. This study presents a detailed, yet easy-to-implement and modular physical model for both passenger and commercial battery electric vehicles. The model takes consumption-relevant parameters, such as seasonal influences, terrain character, and driving behavior, into account. Without any a posteriori parameter adjustments, an excellent agreement with known field data and other experimental observations is achieved. This validation conveys much credibility to model predictions regarding the real-world impact on energy consumption a... [more]

The reference characteristics of complex permittivity of the transformers insulation solid component were determined for use in the precise diagnostics of the power transformers insulation state. The solid component is a composite of cellulose, insulating oil and water nanoparticles. Measurements were made in the frequency range from 10−4 Hz to 5000 Hz at temperatures from 293.15 to 333.15 K. Uncertainty of temperature measurements was less than ±0.01 K. Pressboard impregnated with insulating oil with a water content of (5.0 ± 0.2) by weight moistened in a manner maximally similar to the moistening process in power transformers was investigated. It was found that there are two stages of changes in permittivity and imaginary permittivity components, occurring for low and high frequency. As the temperature increases, the frequency dependencies of the permittivity and imaginary permittivity component shifts to the higher frequency region. This phenomenon is related to the change of relaxa... [more]

The development of energy from renewable sources is one of the most important aspects of today’s energy industry. The level of this development (production of green energy) is determined by the use of a variety of methods, e.g., the methods of multicriteria and multivariate analysis. The effectiveness of these methods is affected by many factors, and one of them is the appearance of non-typical objects (outliers). This paper investigates the effectiveness of selected methods (TOPSIS, VIKOR, VMCM) in terms of computational robustness to outlier objects. The most effective method in this respect (VMCM) is then applied to study the level of development of renewable energy sources in European countries. The presented research provides the opportunity to carry out a dynamic analysis (for selected base years) of the level of energy generation from diverse renewable sources in reference to the adopted patterns and anti-patterns (European countries). The obtained results are discussed, thus co... [more]

Future office buildings are expected to be integrated with energy intensive, inherently DC components such as photovoltaic panels (PV), electric vehicles (EV), LED lighting, and battery storage. This paper conceptualizes the interconnection of these components through a 750 V DC nanogrid as against a conventional three-phase 400 V AC system. The factors influencing the performance of a DC-based nanogrid are identified and a comparative analysis with respect to a conventional AC nanogrid is presented in terms of efficiency, stability, and protection. It is proved how the minimization of grid energy exchange through power management is a vital system design choice. Secondly, the trade-off between stability, protection, and cost for sizing of the DC buffer capacitors is explored. The transient system response to different fault conditions for both AC and DC nanogrid is investigated. Finally the differences between the two systems in terms of various safety aspects are highlighted.

Efforts to increase the power output of wind turbines include Diffuser Augmented Wind Turbines (DAWT) or a shroud for the rotor of a wind turbine. The selected duct has three main components: a nozzle, a diffuser, and a flange. The combined effect of these components results in enriched upstream velocity for the rotor installed in the throat of the duct. To obtain the maximum velocity in the throat of the duct, the optimum angles of the three parts have been analyzed. A code was developed to allow all the numerical steps including changing the geometries, generating the meshes, and setting up the numerical solver simultaneously. Finally, the optimum geometry of the duct has been established that allows a doubling of the flow velocity. The flow characteristics inside the duct have also been analyzed in detail. An H-Darrieus Vertical Axis Wind Turbine (VAWT) has been simulated inside the optimized duct. The results show that the power coefficient of the DAWT can be enhanced up to 2.9 tim... [more]

Opening deeper coal seams requires constructing underground mine roadways in difficult geological conditions. Supporting of such roadways is subjected to a very high load from the rock mass. The types of roof supports used so far do not provide immediate support for the rock mass, which tends to converge the roadway, allowing for a rapid build-up of stresses in the surrounding rock mass. The article presents a new type of frame roadway support. This is a yielding support (consecutive arches are connected in a helical pattern), enabling the successive arches to be provided with initial load-bearing capacity already at the construction stage. The so-called unscrewing of the helix enables the arches to be pressed against the surface of the developed roadway with a controlled force. The introduction discusses the types of yielding roof supports used in the Polish mining industry and indicates their characteristic features. Further along in the article, the assumptions adopted for the const... [more]

Ignition delay times of small alkenes are a valuable constraint for the refinement of the core kinetic mechanism of hydrocarbons used in representing combustion properties of real fuels. Moreover, the chemical reactivity comparison of those small alkenes provides a reference in object-oriented fuel design and logical combustion utilization. In this study, the ignition delay times of C2−C4 alkenes (ethylene, propene and 1-butene) were measured behind reflected shock waves first, with a fixed oxygen concentration (XO2 = 6%) and equivalence ratio (φ = 1.0) at various pressures of 1.2, 4.0 and 16.0 atm, in order to facilitate the comparison. Three chemical-based-Arrhenius-type correlations covering a wide range of temperature, pressure, equivalence ratio, and dilution were proposed. The simplified reaction network for pyrolysis and oxidation of 1-alkenes was depicted relying on the reaction classes of alkenes. Nine generally accepted mechanisms were used to simulate the ignition delay time... [more]