A new networking paradigm, Vehicular Edge Computing (VEC), has been introduced in recent years to the vehicular network to augment its computing capacity. The ultimate challenge to fulfill the ...requirements of both communication and computation is increasingly prominent, with the advent of ever-growing modern vehicular applications. With the breakthrough of VEC, service providers directly host services in close proximity to smart vehicles for reducing latency and improving quality of service (QoS). This paper illustrates the VEC architecture, coupled with the concept of the smart vehicle, its services, communication, and applications. Moreover, we categorized all the technical issues in the VEC architecture and reviewed all the relevant and latest solutions. We also shed some light and pinpoint future research challenges. This article not only enables naive readers to get a better understanding of this latest research field but also gives new directions in the field of VEC to the other researchers.
Worldwide demand for oil, coal, and natural gas has increased recently because of odd weather patterns and economies recovering from the pandemic. By using these fuels at an astonishing rate, their ...reserves are running low with each passing decade. Increased reliance on these sources is contributing significantly to both global warming and power shortage problems. It is vital to highlight and focus on using renewable energy sources for power production and storage. This review aims to discuss one of the cutting-edge technologies, metal-air batteries, which are currently being researched for energy storage applications. A battery that employs an external cathode of ambient air and an anode constructed of pure metal in which an electrolyte can be aqueous or aprotic electrolyte is termed as a metal-air battery (MAB). Due to their reportedly higher energy density, MABs are frequently hailed as the electrochemical energy storage of the future for applications like grid storage or electric car energy storage. The demand of the upcoming energy storage technologies can be satisfied by these MABs. The usage of metal-organic frameworks (MOFs) in metal-air batteries as a bi-functional electrocatalyst has been widely studied in the last decade. Metal ions or arrays bound to organic ligands to create one, two, or three-dimensional structures make up the family of molecules known as MOFs. They are a subclass of coordination polymers; metal nodes and organic linkers form different classes of these porous materials. Because of their modular design, they offer excellent synthetic tunability, enabling precise chemical and structural control that is highly desirable in electrode materials of MABs.
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IJS, KILJ, NUK, UL, UM, UPUK
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•RF, SVM were applied and compared to predict pyrolytic gas yield and compositions.•Feature reduction was applied to improve performances (R2 > 0.85, RMSE < 5.7%).•The importance of ...features for different targets was identified.•Partial dependence analysis provided new insights for pyrolysis process.
This study aimed to utilize machine learning algorithems combined with feature reduction for predicting pyrolytic gas yield and compositions based on pyrolysis conditions and biomass characteristics. To this end, random forest (RF) and support vector machine (SVM) was introduced and compared. The results suggested that six features were adequate to accurately forecast (R2 > 0.85, RMSE < 5.7%) the yield while the compositions only required three. Moreover, the profound information behind the models was extracted. The relative contribution of pyrolysis conditions was higher than that of biomass characteristics for yield (55%), CO2 (73%), and H2 (81%), which was inverse for CO (12%) and CH4 (38%). Furthermore, partial dependence analysis quantified the effects of both reduced features and their interactions exerted on pyrolysis process. This study provided references for pyrolytic gas production and upgrading in a more convenient manner with fewer features and extended the knowledge into the biomass pyrolysis process.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Hydrogen is a zero-emission green fuel containing sufficient energy potentially suitable for electricity generation. Currently, large quantities of hydrogen are produced using classical fossil fuels. ...Nevertheless, the finite quantities of these resources have compelled the global community to look into using more sustainable and environmentally friendly resources such as bio-based waste. There are several approaches, to convert biomass to hydrogen, among which the thermochemical and biological processes are considered as the most important ones. The aim of this review paper is twofold, namely, (a) to evaluate hydrogen production and biomass processing methods to give a better insight into their potential merits and identify gaps for sustainable hydrogen generation, and (b) to evaluate current and future opportunities in membrane technology for hydrogen separation and purification from biomass processing. By fulfilling these gaps, the objectives of economical, sustainable, and environmentally-friendly resources for hydrogen production and separation can be recommended.
•Thermochemical conversion technologies for hydrogen production.•Gasification technologies review for hydrogen production.•Biological routes for hydrogen production.•Potential of membrane applications for hydrogen separation from syngas.•Prospective of hydrogen as future of energy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Thrive for the COx-free hydrogen production via methane decomposition has gained much interest owing to its feasibility and environmental friendliness. Herein, ahydrotalcite based Nickel catalyst was ...synthesized via co-precipitation method by varying the amount of Nickel concentration and tested for methane decomposition reaction in a fixed bed reactor. In addition, the effect of calcination temperature in the development of the spinel-like structure of as-developed catalyst was comprehensively discussed. It was found that the hydrotalcite based Nickel catalyst prepared at 40% Nickel concentration has the highest performance of above 80% conversion for 7 h of methane decomposition which was owing to its effective diffusion of carbon particles and its spinel-like structure, evidently from the XRD and FESEM analysis. The profound performance monitored here was attributed to the formation of carbon nanofibers (CNFs) on the surface of the catalyst which levitates the active Niospecies on its tips, results in more available active sites for the chemisorptions of the methane molecules. Nevertheless, the excessive of Nickel concentration leads to the detrimental methane decomposition performance, hencepromotes the formation of large particle size and successive development of bulk NiO phases during the reduction process, consequently abnegate the overall methane decomposition reaction. The aforementionedfindingsshow that the spinel-like structure is the key factor in the growth of long uniform CNFs and elevation of active sites on the fibre tips.
•A novel hydrotalcite based Nickel catalyst was synthesized via co-precipitation method.•Hydrotalcite based Nickel catalyst prepared at 40% Nickel concentration has the highest performance.•The overall conversion of methane to hydrogen is directly related to the presence of spinel-like structures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Vehicular edge computing (VEC) is a promising paradigm to offload resource-intensive tasks at the network edge. Owing to time-sensitive and computation-intensive vehicular applications and high ...mobility scenarios, cost-efficient task offloading in the vehicular environment is still a challenging problem. In this paper, we study the partial task offloading problem in vehicular edge computing in an urban scenario. Where the vehicle computes some part of a task locally, and offload the remaining task to a nearby vehicle and to VEC server subject to the maximum tolerable delay and vehicle’s stay time. To make it cost-efficient, including the cost of the required communication and computing resources, we consider to fully exploit the vehicular available resources. We estimate the transmission rates for the vehicle to vehicle and vehicle to infrastructure communication based on practical assumptions. Moreover, we present a mobility-aware partial task offloading algorithm, taking into account the task allocation ratio among the three parts given by the communication environment conditions. Simulation results validate the efficient performance of the proposed scheme that not only enhances the exploitation of vehicular computation resources but also minimizes the overall system cost in comparison to baseline schemes.
The co-torrefaction of several biomasses may be a viable solution in the study area, as it produces biofuels and addresses waste-treatment concerns. This review evaluates biomass through ultimate, ...proximate, and FTIR analyses, and the mechanism of the co-torrefaction process is observed for product quality with a synergistic effect. Furthermore, the parameters of co-torrefaction, including temperature, reaction time, mass yield, energy yield, and the composition of the H/C and O/C ratio of the co-torrefied materials, are similar to those for coal composition. Different reactor types, such as fixed-bed, fluidized-bed, microwave, and batch reactors, are used for co-torrefaction, in which biomass blends with optimized blend ratios. The co-torrefaction process increases the bio-solid yield and heating value, the capacity to adsorb carbon dioxide, and the renewable fuel used for gasification. One of the objectives of this study is to adopt a process that must be viable, green, and sustainable without generating pollution. For this reason, microwave co-torrefaction (MCT) has been used in many recent studies to transform waste and biomass materials into an alternative fuel using a microwave reactor.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The disposal of used vehicle tires at the end of their life time, is a significant environmental concern. There is need for specific legislative framework, regulating their disposal, after these are ...replaced, however, there are several options for further processing. In the framework of circular economy, recovery methods and new applications for the material are available. This paper examines the life cycle environmental impacts of the pyrolysis of End of Life (EoL) tires and the use of the produced Tire Pyrolysis Oil (TPO) for generation, presenting a Life Cycle Assessment (LCA) for a 17.8 MW designed generation unit in Cyprus. The boundaries of the system under study start from the receipt of shredded used tyres, and include the pyrolysis process, the electricity generation and the management of by-products, pollutants and waste for a case study about a unit designed to operate in Cyprus. Two Functional Units (FU) are used, 1 Kg of TPO and 1 MWh of produced electricity. A detailed Life Cycle Inventory (LCI) is presented and moreover, by applying the CML 2001 impact characterization method, the magnitude of a number of characterization factors are calculated for both of them. These results are compared to the respective of Light Fuel Oil (LFO) and of Cyprus grid electricity as alternatives. While, the TPO found to have lower environmental impact than LFO for all the impact categories, the production of electricity at the unit cause higher potential of depletion of abiotic resources – elements and marine aquatic ecotoxicity potential than the grid electricity. Specifically, the first, for 1 MWh produced in the unit under study, is 0.00026 kg antimony eq. and the second 171666.4 kg 1,4-dichlorobenzene eq., while for 1 MWh of Cyprus grid electricity they are 0.00013 kg antimony eq. and 136095.2 kg 1,4-dichlorobenzene eq., respectively. A contribution analysis, for these two impact categories is presented, showing that the use of urea and the production of solid waste to the unit contributes the most to both plus the exhaust gases to the second, therefore specific suggestions to minimize the contribution are formulated, available to be exploited for similar units. Moreover, concluding that the TPO use for generation could be an advantageous environmental option, recommendations for its strategic adoption are also made.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Application of advanced pyrolysis processes to agricultural waste for liquid production is gaining great attention, especially when it is applied to an economic crop like tobacco. In this work, ...tobacco residues were pyrolyzed in an ablative reactor under vacuum. The maximum bio-oil yield of 55% w/w was obtained at 600°C with a particle size of 10 mm at a blade rotation speed of 10 rpm. The physical properties of the products showed that the oil produced was of high quality with high carbon, hydrogen, and calorific value. Two-dimensional gas chromatography/time-of-flight mass spectrometric analysis results indicated that the oils were complex mixtures of alkanes, benzene derivative groups, and nitrogen-containing compounds. In addition, 13C NMR results confirmed that long aliphatic chain alkanes were evident. The alkanes were likely converted from furans that were decomposed from hemicelluloses. Ablative pyrolysis under vacuum proved to be a promising option for generating useful amount of bio-oils from tobacco residues.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
Hydrogen and oxygen evolution through electrochemical water splitting is essential for effective and inexpensive production of hydrogen and oxygen, which depends on the development of ...economical, and extremely active electrocatalysts. Two‐dimensional (2D) nano‐laminated materials are imperious as electrocatalysts due to their phenomenal properties and extensive scope of applications. In this work, we report a greener way of synthesizing MXene without hydrofluoric acid (HF) treatment and demonstrated its excellent electrochemical characteristics as an overall water‐splitting catalyst. Cl‐terminated MXenes (Ti3C2Cl2) were synthesized via a molten salt approach, in which the MAX phase (Ti3AlC2) was reacted with copper chloride (CuCl2) salt followed by thermal treatment at a temperature of 550°C for 5 hours. The resulting Cl‐terminated MXene was characterized by scanning electron microscopy, X‐ray diffraction, transmission electron microscope, Raman, Fourier transform infrared spectroscopy, energy dispersive X‐ray analysis, X‐ray photoelectron spectroscopy, and electrochemical testing was performed in the alkaline media for oxygen evolution reactions (OER) and hydrogen evolution reactions (HER). For OER in 1 M KOH, Cl‐terminated MXene achieves a benchmark of 30 mA cm−2 current density at an overpotential of 330 mV and a Tafel slope of 48 mV dec−1, while HF‐MXene exhibits an overpotential of 390 mV and a Tafel slope of 136 mV dec−1. For HER, Cl‐MXene attains an overpotential of 259 mV, and a Tafel slope of 92 mV dec−1 to achieve the 10 mA cm−2 current density, on the other hand, HF‐MXene achieves an overpotential of 444 mV and a Tafel slope of 311 mV dec−1. Furthermore, the electrocatalyst exhibited excellent long‐term stability of 0.7 V at 100 mA cm−2 current density for 36 hours. The synthesis methodology for greener Cl‐terminated MXene coupled with an outstanding electrocatalytic activity is set to open new avenues of catalyst design for water splitting.
Cl‐MXene successfully synthesized by greener route via molten salt method. Cl‐MXene synthesized electrocatalyst demonstrated enhanced OER and HER performances as compared to traditional HF‐MXenes. The improved overall electrochemical activity is credited to the interface engineering of MXenes.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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