This review provides the hydration and volume expansion mechanism of expansive materials, with the goal of utilizing them in the development of sustainable mining methods. The main focus of the review will be the newly developed non-destructible rock fragmentation method, slow releasing energy material agent (SREMA), which is a modified soundless chemical demolition agent (SCDA). The review aims to address one of the main gaps in studies related to SREMA, by presenting a thorough understanding of the components of SREMA and their mechanisms of action, leading to volume expansion. Thus, this review would act as a guide for researchers working on using expansive materials for rock breaking. As many literatures have not been published regarding the recently discovered SREMA, studies on cements, expansive cements, and soundless chemical demolition agents (SCDA) were mainly considered. The chemical reactions and volume expansive processes of these materials have been studied and incorporate... [more]

The physicochemical and electrochemical performance of electrolytes prepared with different grades of V2O5 raw materials were investigated systematically for a vanadium redox flow battery. Physicochemical tests showed that the conductivity of electrolytes prepared with lower grades of V2O5 raw materials obviously decreased, while the viscosity increased. The results of electrochemical experiments showed that the electrochemical activity and reversibility of electrolytes decreased, and the solution resistance increased obviously, as the grade of V2O5 raw materials gradually decreased. In addition, the battery efficiency and charge−discharge capacity were negatively affected by impurities in the lower grade V2O5 raw materials, due to an increase of polarization on the charge−discharge voltage. Moreover, the performance of electrolytes was related to the total concentration of impurities in the electrolyte, and Na, K impurity ions were the main factors that adversely affected the electroc... [more]

In recent years, perovskite solar cells (PSCs), often referred to as the third generation, have rapidly proliferated. Their most prominent deficiencies are their low efficiency and poor stability. To enhance their productivity, a combination of silicon and perovskite is employed. Here, we present a 3D simulation analysis of various electrical and optical properties of PSCs using the SILVACO simulation software. Using the inverted planar method with inorganic transport materials and the proper selection of anti-reflective coatings with a back contact layer increases the efficiency of PSCs to 28.064%, and enhances their stability without using silicone composites. Several materials, including CaF2, SiO2, and Al2O3, with various thicknesses have been employed to investigate the effect of anti-reflective coatings, and to improve the efficiency of the simulated PSC. The best thickness of the absorbent layer is 500 nm, using a CaF2 anti-reflective coating with an optimal thickness of 110 nm.... [more]

Large amounts of lignin residue is expected in the future when biorefineries for producing biofuels and bio-products will increase in numbers. It is, therefore, valuable to find solutions for using this resource for the sustained production of useful bioenergy or bio-products. Anaerobic digestion could potentially be an option for converting the biorefinery lignin into a valuable energy product. However, lignin is recalcitrant to biodegradation under anaerobic conditions unless the structure is modified. Wet oxidation followed by steam explosion (wet explosion) was previously found to make significant changes to the lignin structure allowing for biodegradation under anaerobic conditions. In this study, we examine the effect of wet explosion pretreatment for anaerobic digestion of wheat straw lignin under mesophilic (37 °C) conditions. Besides the biorefinery lignin produced from wheat straw, untreated lignin was further tested as feed material for anaerobic digestion. Our results showe... [more]

The current paper presents the development and characterization of polyvinylidene fluoride (PVDF)-Zn2GeO4 (ZGO) fine fiber mats. ZGO nanorods (NRs) were synthesized using a hydrothermal method and incorporated in a PVDF solution to produce fine fiber mats. The fiber mats were prepared by varying the concentration of ZGO NRs (1.25−10 wt %) using the Forcespinning® method. The developed mats showed long, continuous, and homogeneous fibers, with average fiber diameters varying from 0.7 to 1 µm, depending on the ZGO concentration. X-ray diffraction spectra depicted a positive correlation among concentration of ZGO NRs and strengthening of the beta phase within the PVDF fibers. The composite system containing 1.25 wt % of ZGO displayed the highest piezoelectric response of 172 V. This fine fiber composite system has promising potential applications for energy harvesting and the powering of wearable and portable electronics.

Thermal management is the most vital element of electric vehicles (EV) to control the maximum temperature of module/pack for safety reasons. This paper presents a novel passive thermal management system (TMS) composed of a heat sink (HS) and phase change materials (PCM) for lithium-ion capacitor (LiC) technology under the premise that the cell is cycled with a continuous 150 A fast charge/discharge current rate. The experiments are validated against numerical analysis through a computational fluid dynamics (CFD) model. For this purpose, a comprehensive electro-thermal model based on an equivalent circuit model (ECM) is designed. The designed electro-thermal model combines the ECM model with the thermal model since the performance of the LiC cell highly depends on the temperature. Then, the robustness of the model is evaluated using a precise second-order ECM. The extracted parameters of the electro-thermal model are verified by the experimental results in which the voltage and temperat... [more]

In this work, the impact of chemical additions, especially nano-particles (NPs), was quantitatively analyzed using our constructed artificial neural networks (ANNs)-response surface methodology (RSM) algorithm. Fe-based and Ni-based NPs and ions, including Mg2+, Cu2+, Na+, NH4+, and K+, behave differently towards the response of hydrogen yield (HY) and hydrogen evolution rate (HER). Manipulating the size and concentration of NPs was found to be effective in enhancing the HY for Fe-based NPs and ions, but not for Ni-based NPs and ions. An optimal range of particle size (86−120 nm) and Ni-ion/NP concentration (81−120 mg L−1) existed for HER. Meanwhile, the manipulation of the size and concentration of NPs was found to be ineffective for both iron and nickel for the improvement of HER. In fact, the variation in size of NPs for the enhancement of HY and HER demonstrated an appreciable difference. The smaller (less than 42 nm) NPs were found to definitely improve the HY, whereas for the HER... [more]

The analysis of the soil behavior when the pile is driving into the seabed in offshore wind platforms is one of the major problems associated with this new form of clean energy generation. At present, there are no scaled studies carried out analyzing the mechanical and deformational behavior of both the material of the pile supporting the engine (large steel hollow piles with a diameter of 8 m and a thickness of 15−20 cm) and the soil where the pile is driven. Usually, these elements are installed on sands with a very small grain size displaced from the limits of dry−wet beach (water limit) toward the offshore limits, which prevents them from returning to their previous location in a natural way. This paper presents results obtained from scale tests in a steel pool to analyze the behavior of the sand where the piles were installed. First, the California Bearing Ratio (CBR) test was carried out to estimate the soil behavior in similar conditions to the steel pool. The scale tests consis... [more]

Ternary low melting point mixtures with the addition of LiNO3 and Ca(NO3)2 have been presented as direct system candidates for CSP technologies due to having better physical and chemical properties than those of Solar Salt. In this study, thermal, physical and chemical properties are measured as is the corrosive behavior of stainless alloy VM12 (Cr 12%) when in contact with Solar Salt, 60% NaNO3-40% KNO3 (wt.%) and ternary 46% NaNO3-19% Ca(NO3)2-35% LiNO3 (wt.%). Gravimetric weight change measurements were performed on the test specimens, which were tested under accelerated fluid conditions (0.2 m s−1) at 500 °C for 2000 h. This research confirms the potential of this novel formulation as a thermal storage medium and validates the suitability of ferritic VM12-SHC stainless steel as a structural material for CSP technology with Solar Salt. Meanwhile, the results obtained by scanning electron microscopy and X-ray diffraction indicate a reduction in the protective character of the oxide l... [more]

In this study, three types of silicone rubbers, namely, insulative silicone rubber, conductive silicone rubber and silicone rubber with conductive as well as insulative layers are investigated for their compatibility with mineral oil. Mineral oil with different silicone rubber samples is thermally aged at 130 °C for 360 h, 720 h and 1080 h and at 23 °C, 98 °C and 130 °C for 360 h. At the end of each ageing interval, mineral oil and oil-impregnated silicone rubbers are investigated for their dielectric properties. Aged mineral oil samples are investigated for their moisture content, breakdown voltage, colour number, dissolved gases and total acid number, whereas solid insulation samples are investigated for their moisture content. Additionally, pressboard samples in mineral oil and mineral oil without any solid insulation materials are also aged under the same conditions and are investigated for their dielectric properties. From the obtained results, it can be assessed that the presence... [more]

The need to increase the use of renewable biomasses for energy supply, such as fuel pellets is significant. However, different types of biomasses have different mechanical properties to be pelletized, which entails a limitation in available raw materials for pellet producers. Within this study eleven different pure substances from biomasses were separately mixed with European beech and Scots pine, to identify its impact on the densification process. Beech and pine pellets were used as control materials against their corresponding pellets mixed with substances representing: cellulose, hemicelluloses, other polysaccharides, lignin, protein, and extractives. The mechanical properties were investigated as well as FT-IR and SEM analyses on the pellets. The results showed that the addition of the substances xylan and galactan created the hardest pellets for both pine and beech and that adding extractives to wood affects pine more than beech in relation to hardness. The FT-IR data could not p... [more]

The production of fuel hydrocarbons from CO2-neutral raw materials is a promising task at present. The thermal dissolution of biochar obtained by the method of hydrothermal carbonization of sawdust was studied. The dissolution of biochar in tetralin (hydrogen donor solvent) was studied at different temperatures (350−450 °C) and with two types of dilution of the mixture with tetralin: 1/3 and 1/4. The process proceeded without a catalyst. It was found that the samples subjected to thermal dissolution at temperatures of 425−450 °C had the highest conversion and yield of liquid products. The reaction temperature also had a significant effect on the composition of liquid products. It was found that an increase in the reaction temperature led to a significant increase in benzenes, both in the direct and in the hexane fraction. A benzene yield of more than 50% was observed for both fractions at a temperature of 450 °C. It was also suggested that the possible positive effect of abietates on t... [more]

The article presents an analysis of the influence of selected operating environment parameters on the operation of a technological system in a mine and examines the profitability of exploiting a deposit of low quality. A model based on a cyclical transportation system in a surface limestone mine, developed in the Haulsim software, served to evaluate—from an economic perspective—several material transportation scenarios depending on the quality of the deposit. A discrete simulation of machine operation allowed a detailed analysis of the technological, operating and economic parameters for selected solutions. The results may be the basis for a decision to begin or to resign from mineral extraction. The simulation results demonstrate that maintaining the operating environment in good technical condition positively influences machine operating cycle times, the required total time of the transportation task and the operating costs. The analysis was performed for the production period of one... [more]

The growing interest in using low-cost methods that use natural sources makes the study of adsorption processes increasingly frequent and common. Thus, the use of uçá crab shell (Ucides cordatus) in the adsorption of reactive dye (reactive blue 222) was studied in two systems (S1 and S2) in a finite bath, with a scale-up of 12 times and considering different forms of agitation. The biosorbent material was previously characterized from FTIR and EDX spectroscopies, SEM, physical adsorption of N2, and point of zero charge. The kinetic study allowed modeling the experimental data and defining the equilibrium time for the S1 system as 400 min, and the S2 system as 360 min. The equilibrium adsorption capacities are 3.623 mg·g−1 (S1) and 4.191 mg·g−1 (S2). The pseudo-second-order (PSO) model best described the experimental data. The favorable multilayer adsorption was confirmed for the isothermal analysis, and the Freundlich and Sips models represented the experimental data of S1 and S2, resp... [more]

With the rapid development of society, the number of hydropower projects has increased. During the construction of these projects, due to excavation-induced unloading, the high sidewalls of the hydropower station are often subject to splitting failure, which produces many adverse effects on the construction of the cavern. In order to reveal the formation mechanism of splitting failure of hydropower stations, based on the strain gradient theory and elasto-plastic damage theory, we proposed an elasto-plastic damage softening model. Using the ODE45 program in MATLAB, we solved the numerical solution of displacement and stress of circular cavern based on our proposed elastoplastic damage model. Then, we apply the complex function method and use the Schwarz−Christoffel integral formula to obtain the mapping function from the outer domain of the high sidewall cavern to the outer domain of the unit circle. Finally, the elastic-plastic region and displacement distribution of the high sidewall... [more]

The work presented in this paper studies the potential of cylindrical piezoelectric transducers for harvesting high-frequency acoustic energy. The cylinder was made of a modified PZT (lead zirconate titanate) and had the shape of a squared cylinder with a side length of 4 cm and a wall thickness of 1 mm. The study used open-circuit measurements to study the relationship between the sound wavelength and the cylinder size and its effect on the performance of energy harvesting. The cylinder was found to give the best performance at a frequency of 20 kHz. In addition to open-circuit measurements, closed-circuit measurements were performed to demonstrate the ability to dissipate energy harvested from 20 kHz sound waves across an electric load. The load was designed in a series of experimental steps that aimed at optimizing an impedance-matched energy harvester. Finally, the cylinder was tested at the optimized load conditions, and it was possible to harvest and store energy with a power of... [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]

This study investigates the impact behaviour and post-impact performance of polyamide-6 glass fibre reinforced composites, manufactured by thermoplastic resin transfer moulding. Impact test samples were extracted from quasi-isotropic laminates using two different glass fibre sizings, both with a fibre volume fraction of approximately 52%. A previous study showed that one of these sizings enhanced the interfacial strength and Mode I fracture toughness; however, the effects of the sizing on out-of-plane impact is of greater significance in terms of automotive applications. A drop-weight impact tester was used to determine out-of-plane impact performance for both sizings in terms of impact load-induced and energy returned from the striker. High-speed video of the impact response was simultaneously captured. Testing was carried out at three impact energy levels: two sub-penetration and one full penetration. The impact damage area was observed, and the post-damage compression properties of... [more]

Fly ash cement is used to solidify marine clay to prepare marine-clay-based cemented paste backfill (MCCPB) to fill the underground goaf of mines, which not only utilizes solid waste such as fly ash and marine clay, but also controls surface subsidence and protects the environment. To simulate the complex underground mine water environment of the filling body, a dry-wet cycle aquatic environment test under different material ratios and curing ages was designed. The water absorption and unconfined compression strength (UCS) of MCCPB with curing ages of 7 and 28 days under the action of 0, 1, 3, and 7 dry-wet cycles were investigated. The results indicate as the number of dry-wet cycles increases, the surface of MCCPB becomes significantly rougher, and the water content and the solid mass decrease accordingly. Different ratios and curing ages of MCCPB in dry-wet cycles of the UCS tend first to increase, then decrease. Meanwhile, the stress-strain curve of the specimen shows that the tren... [more]

Hydrogen energy is a very attractive option in dealing with the existing energy crisis. For the development of a hydrogen energy economy, hydrogen storage technology must be improved to over the storage limitations. Compared with traditional hydrogen storage technology, the prospect of hydrogen storage materials is broader. Among all types of hydrogen storage materials, solid hydrogen storage materials are most promising and have the most safety security. Solid hydrogen storage materials include high surface area physical adsorption materials and interstitial and non-interstitial hydrides. Among them, interstitial hydrides, also called intermetallic hydrides, are hydrides formed by transition metals or their alloys. The main alloy types are A2B, AB, AB2, AB3, A2B7, AB5, and BCC. A is a hydride that easily forms metal (such as Ti, V, Zr, and Y), while B is a non-hydride forming metal (such as Cr, Mn, and Fe). The development of intermetallic compounds as hydrogen storage materials is ve... [more]

Due to the high light absorption and the possibility of localizing boiling to the interior of the receiver, nanoparticles are promising for solar-driven desalination. The paper presents an experimental study of the nanoparticle-based photothermal boiling of water with sea salt. The experiments were carried out using a laboratory-scale system with a transparent photothermal receiver of light and a closed condensate cycle. In this study, we tested three types of nanoparticles: multiwall carbon nanotubes with two main sizes of 49 nm and 72 nm, 110 nm iron oxide particles Fe3O4, and a commercial paste based on carbon nanotubes. The concentration of nanoparticles was varied up to 10% wt. We found that the nanoparticles enhance the steam generation by 23%, relative to a conventional desalinator with a black-body receiver. The best result was obtained for the 5% wt. concentration of carbon nanotubes.

The adsorption characteristics of H2 molecules on the surface of Pd-doped and Pd-decorated graphene (G) have been investigated using density functional theory (DFT) calculations to explore the sensing capabilities of Pd-doped/decorated graphene. In this analysis, electrostatic potential, atomic charge distribution, 2D and 3D electron density contouring, and electron localization function projection, were investigated. Studies have demonstrated the sensing potential of both Pd-doped and Pd-decorated graphene to H2 molecules and have found that the gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), i.e., the HOMO-LUMO gap (HLG), decreases to 0.488 eV and 0.477eV for Pd-doped and Pd-decorated graphene, respectively. When H2 is adsorbed on these structures, electrical conductivity increases for both conditions. Furthermore, chemical activity and electrical conductivity are higher for Pd-decorated G than Pd-doped G, whereas the char... [more]

We propose an evaluation system to choose appropriate materials for solar cells. A fuzzy DEMATEL information procedure was used for decision-making to gather information and analyze the casual relationship. These data acquired were partitioned into causal and impact bunches, empowering users to gather an improved understanding of the intelligent relationship among them, as well as making recommendations for changes to upgrade their general execution. The proposed approach can deliver a compelling fabric choice assessment with satisfactory criteria that fit the respondent’s discernment designs; particularly, these evaluation dimensions are interlaced. Recommendations are given to assist government authorities to plan a Taiwan solar cell industry approach and for industries to develop commerce techniques for improvement in the solar cell field.

Although many advanced insulation materials have been recently developed, very few are eco-friendly and their production requires a substantial amount of energy and complex manufacturing processes. To address this issue, a bio-based thermal insulation material was developed using short- and long-grained puffed rice. A set of experiments was subsequently carried out to identify the best rice type and the optimal range for the most influential parameters (sample amount, temperature, and moisture level). Our findings revealed that short-grained rice exhibited greater puffing ability and was thus adopted in further material optimization experiments. These assessments indicated that the most optimal thermal conductivity of the insulation material and the highest puffing ratio was attained at 12−15% moisture, 260−270 °C temperature, and 15−18 g sample weight. The thermal properties, including thermal conductivity and fire reaction, and thermal performance of samples obtained using these para... [more]