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Mesopores and silanol nests are known two technological keys that essentially control the catalytic performance of ZSM-5 zeolite. However, designing and controlling them without using chemicals so that the produced ZSM-5 can have strongly enhanced catalytic properties and more importantly can be applied at industrial scale have still been a big challenge up to now. The present study employed the 10 MeV electron beam (EB) generated from an industrial linear accelerator to introduce both the O-vacancy rich mesopores and stable triad-silanol nests in ZSM-5. The structural modification of irradiated ZSM-5 samples was explored by using SEM and FTIR combined with positron annihilation spectroscopy (PAS) including positron annihilation lifetime (PAL), Doppler broadening (DB) of electron–positron annihilation energy and electron momentum distribution (EMD). Obtained results indicated that EB irradiation could recover the defective-crystal structure as well as intensively modify the structures of ZSM-5. In particular, the mechanism for the solid-state crystallization and the formation of the O-vacancy rich mesopores (maximum size of ∼4.5 nm) in ZSM-5 under the combined EB irradiation (10−110 kGy) and calcination (600 °C) was, for the first time, proposed. The mechanism for the formation of stable triad-silanol nests in the channels of irradiated and calcined ZSM-5 zeolites was also explored. The present study, therefore, opens a new research path of applying both EB irradiation and calcination to produce ZSM-5 with novel features for industrial catalytic application at large-production scale.

The optical properties of MoS2 and WS2 monolayers are significantly influenced by fabrication methods, especially with respect to the behavior of excitons at the K−point of the Brillouin zone. Using spectroscopic ellipsometry, we obtain the complex dielectric functions of monolayers of these materials from cryogenic to room temperatures over the energy range 1.5 to 6.0 eV. The excitonic structure of each sample is analyzed meticulously by fitting the data to a standard analytical function to extract the energy positions of the excitons at each temperature. At low temperatures, excitonic structures are blue-shifted and sharpened due to the reduction in phonon noise and lattice distance. The excitons of monolayers fabricated by MOCVD separate into sub-structures at low temperatures, while monolayers grown by LPCVD and APCVD remain a single peak. The origin of these peaks as charged or neutral excitons follows from their temperature dependences. [ABSTRACT FROM AUTHOR]

The conductivity for half-filled disordered Hubbard model in different interaction regimes is studied using a typical medium dynamical mean-field theory. The Kubo formula with the geometrically averaged Green function is used to calculate the optical and dc conductivity of the system. The dependence of the conductivities in the model on the random potential and temperature in the weak and intermediate interaction regimes is investigated numerically. It is shown that in the weak interaction regime at a fixed temperature the optical conductivity at low frequencies as well as the dc conductivity get decreased as disorder strength increases. Whereas in the intermediate interaction regime, the results show a reentrant effect of the insulating phases. Our dc conductivity of a non-interacting disordered system is consistent with those known in the literature and our other results are in agreement with the phase diagram obtained by using typical medium theory with different impurity solvers. [ABSTRACT FROM AUTHOR]

A partial cooling supercritical carbon dioxide cycle is used in this study for the application of a solar power tower. Additionally, the organic Rankine cycle (ORC) is considered as a bottoming cycle in the process of recovering wasted heat. Moreover, fluids with zero ozone depletion potential and low global warming potential are considered as operating fluids for bottoming ORC. Exergy, energy and exergoenvironmental analyses were performed in order to evaluate the usefulness of the proposed system to generate electrical power and driven by solar energy. The effect of various independent parameters on system performance is investigated. It is concluded that as direct normal irradiation (DNI) changes from 0.4 to 0.95 kW m−2, the combined cycle's thermal efficiency, exergy efficiency, and power output increase from 35.16% to 55.43%, 37.73% to 59.42%, and 188 kW to 298.5 kW, respectively for R1224yd(Z) fluid. However, exergoenvironmental impact index falls by 58.79% as DNI rises, while the exergetic stability factor rises by 57.79%. The system's optimized thermal efficiency is found to be 53.45%. Furthermore, the performance of the combined system can be improved by decreasing the incidence angle of the sun while simultaneously increasing the concentration ratio. The fluid R1224yd(Z) is recommended as the best-performing fluid as compared to the other fluids due to its superior thermal performance. [ABSTRACT FROM AUTHOR]

Flexible electronics have recently gained considerable attention due to their potential to provide new and innovative solutions to a wide range of challenges in various electronic fields. These electronics require specific material properties and performance because they need to be integrated into a variety of surfaces or folded and rolled for newly formatted electronics. Two-dimensional (2D) materials have emerged as promising candidates for flexible electronics due to their unique mechanical, electrical, and optical properties, as well as their compatibility with other materials, enabling the creation of various flexible electronic devices. This article provides a comprehensive review of the progress made in developing flexible electronic devices using 2D materials. In addition, it highlights the key aspects of materials, scalable material production, and device fabrication processes for flexible applications, along with important examples of demonstrations that achieved breakthroughs in various flexible and wearable electronic applications. Finally, we discuss the opportunities, current challenges, potential solutions, and future investigative directions about this field. [ABSTRACT FROM AUTHOR]

P‐values that are derived from continuously distributed test statistics are typically uniformly distributed on (0,1) under least favorable parameter configurations (LFCs) in the null hypothesis. Conservativeness of a p‐value P (meaning that P is under the null hypothesis stochastically larger than uniform on (0,1)) can occur if the test statistic from which P is derived is discrete, or if the true parameter value under the null is not an LFC. To deal with both of these sources of conservativeness, we present two approaches utilizing randomized p‐values. We illustrate their effectiveness for testing a composite null hypothesis under a binomial model. We also give an example of how the proposed p‐values can be used to test a composite null in group testing designs. We find that the proposed randomized p‐values are less conservative compared to nonrandomized p‐values under the null hypothesis, but that they are stochastically not smaller under the alternative. The problem of establishing the validity of randomized p‐values has received attention in previous literature. We show that our proposed randomized p‐values are valid under various discrete statistical models, which are such that the distribution of the corresponding test statistic belongs to an exponential family. The behavior of the power function for the tests based on the proposed randomized p‐values as a function of the sample size is also investigated. Simulations and a real data example are used to compare the different considered p‐values. [ABSTRACT FROM AUTHOR]

This research encompasses the numerical analysis of trioxymethylene dimethyl ether (OME3) e-fuel on an industrial compression ignition engine, as a viable replacement for diesel fuel. The performed simulations examined single injection and multi-injection operating conditions of OME3, varying injection rates and timing. The combustion process is modeled employing two approaches: three-dimensional extended coherent flame model (ECFM-3Z) and general gas phase reactions (GGPR) with a reduced chemical kinetic mechanism. ECFM-3Z gives a faster convergence, where pretabulated autoignition and laminar flame speed databases are integrated into the model to decrease computational time. The GGPR approach is validated on the experimental values for mean pressure, temperature, and rate of released heat in the same engine with diesel fuel and then again employed on an OME3. Both approaches confirmed that a higher amount of OME3 and a prolonged injection time is needed to achieve the same released heat per cycle as diesel fuel since OME3 has a lower net calorific value. It is established that combusting OME3, a 15% higher mean pressure peak can be achieved in multi-injection case compared to the diesel fuel, by adapting the injection timing. Additionally, nitrogen oxides emissions for OME3 are also compared to the diesel case for both combustion modeling approaches. Under the context of multi-injection, the OME3 fuel results show equivalent or lesser nitrogen oxides emissions than those of diesel fuel. The outcomes yielded by the GGPR model utilizing the Lin mechanism revealed decreased temperatures, leading to correspondingly diminished concentrations of nitrogen oxide emissions in comparison with the ECFM-3Z model. [ABSTRACT FROM AUTHOR]

Xử lý chất thải rắn thông qua viên nén nhiên liệu RDF cho phép thu hồi triệt để tài nguyên, nâng cao hiệu suất chuyển hóa năng lượng và giảm phát thải ô nhiễm môi trường. Mô phỏng quá trình cháy của viên RDF trong khí quyển cung cấp các thông tin cần thiết để thực hiện mô phỏng quá trình tạo syngas trong lò khí hóa. Khi hệ số không khí dư ER tăng thì nhiệt độ cực đại của ngọn lửa tăng. Nhiệt độ cực đại đạt 1110K, 1154K, 1227K và 1338K lần lượt tương ứng với ER 0,3; 0,45; 0,65 và 0,95. Khi ER giảm thì nồng độ các chất CO, CH4, H2 tăng lên dẫn đến tăng nhiệt trị syngas Qsyn. Khi ER=0,32 thì Qsyn thu được từ quá trình cháy RDF-Trấu, RDF-Chất thải rắn và RDF-Gỗ vụn lần lượt là 5,3; 5,5 và 5,9 MJ/kg.

Ammonia plays a key role in the renewable hydrogen economy nowadays, thus, the efficiency of ammonia decomposition for hydrogen production becomes an important research topic. In this study, a numerical model was built to study the performance of ammonia decomposition using a membrane reactor and Ru/Al 2 O 3 catalyst under various operating conditions such as feed NH 3 temperature and volume flow rate as well as retentate side pressure. The reactor performance was characterized by ammonia conversion, hydrogen recovery, and recovered hydrogen flow rate. Pre-exponential factor and activation energy of ammonia reaction rate were obtained by equilibrium conversion and two-step parametric sweeping. It was found that ammonia conversion can be increased by about 33% compared to a conventional fixed-bed reactor under the same operating conditions. H 2 recovery can be enhanced when the reactant inlet temperature and the pressure difference between the retentate and permeate sides increase. The increase in feed NH 3 flow rate (gas hourly space velocity, GHSV) decreased the ammonia conversion and H 2 recovery. An optimum GHSV that results in a maximum recovered H 2 flow rate can be found. Finally, optimum operation conditions for maximizing the hydrogen recovery and recovered hydrogen flow rate were analyzed using the multi-objective Non-dominated sorting genetic algorithm-II (NSGA-II). It was found that maximum H 2 recovery with a value of 79.7% can be obtained under the conditions of inlet temperature of 336 °C, GHSV of 900 h−1, and retentate side pressure of 9.9875 bar. The maximum recovered hydrogen flow rate with a value of 9.55 × 10 − 14 (mol · s − 1) can be obtained under the conditions of an inlet temperature of 394 °C, GHSV of 1315 h−1, and retentate side pressure of 9.9879 bar. • A novel two-step parametric sweeping is employed to obtain parameters in reaction rate. • Increasing reaction pressure produces more significant enhancement than temperature. • An optimum GHSV for recovered H 2 flow rate is found due to the change in residential time. • Optimum operating conditions for H 2 recovery and recovered H 2 flow are found using NSGA-II. [ABSTRACT FROM AUTHOR]

This present study showed a comprehensive analysis of energy, exergy, performance, and emission characteristics of a spark-ignition engine powered by blends of gasoline-isoamyl alcohol-ethanol at volume proportions (100_0_0)% (P0E0), (90_5_5)% (P5E5), (80_5_15)% (P5E15), and (70_5_25)% (P5E25) at various engine speeds and compression ratios (CR). The outcomes of thermodynamic analyses revealed that the highest exergy and energy efficiency were 28.92 % (P0E0, 2600 rpm, CR of 9:1) and 31.01 % (P0E0, 2600 rpm, CR of 9:1), respectively. In addition, the average brake power and brake thermal efficiency for P0E0, P5E5, P5E15, and P5E25 increased by (30.36 %, 27 %, 26.74 %, 27.84 %) and (0.34 %, 0.07 %, 0.35 %, 0.33 %) respectively, while brake specific fuel consumption decreased by (2.5 %, 0.64 %, 3.62 %, 6.33 %) in the engine speed range of 2600–3200 rpm. Compared to gasoline, the maximum reduction of carbon monoxide emissions was 6.13 %, 8.81 %, and 9.96 %, while unburnt hydrocarbon emissions exhibited the maximum decrement by 5.8 %, 10.75 %, 12.58 % for P5E5, P5E15, and P5E25, respectively. However, nitrogen oxide (NOx) emissions for P5E25 tended to increase significantly compared to P0E0, while the difference in NOx emissions for P5E15 and P0E0 was marginal. Overall, P5E15 could be considered as the potential alternative fuel for spark-ignition engines towards the goal of sustainable energy conversion. [Display omitted] • Gasoline and ethanol blends with 5 % of isoamyl alcohol were used for all tests. • Energy, exergy, performance, and emission analysis were conducted in an SI engine. • The highest exergy and energy efficiency for blends exhibited at 3000 rpm. • Addition of ethanol and isoamyl alcohol to gasoline lowered pollutant emissions. [ABSTRACT FROM AUTHOR]

Electrostatic capacitors are foundational components of advanced electronics and high-power electrical systems owing to their ultrafast charging-discharging capability. Ferroelectric materials offer high maximum polarization, but high remnant polarization has hindered their effective deployment in energy storage applications. Previous methodologies have encountered problems because of the deteriorated crystallinity of the ferroelectric materials. We introduce an approach to control the relaxation time using two-dimensional (2D) materials while minimizing energy loss by using 2D/3D/2D heterostructures and preserving the crystallinity of ferroelectric 3D materials. Using this approach, we were able to achieve an energy density of 191.7 joules per cubic centimeter with an efficiency greater than 90%. This precise control over relaxation time holds promise for a wide array of applications and has the potential to accelerate the development of highly efficient energy storage systems.

Strain engineering has been employed as a crucial technique to enhance the electrical properties of semiconductors, especially in Si transistor technologies. Recent theoretical investigations have suggested that strain engineering can also markedly enhance the carrier mobility of two-dimensional (2D) transition-metal dichalcogenides (TMDs). The conventional methods used in strain engineering for Si and other bulk semiconductors are difficult to adapt to ultrathin 2D TMDs. Here, we report a strain engineering approach to apply the biaxial tensile strain to MoS 2 . Metal-organic chemical vapour deposition (MOCVD)-grown large-area MoS 2 films were transferred onto SiO 2 /Si substrate, followed by the selective removal of the underneath Si. The release of compressive residual stress in the oxide layer induces strain in MoS 2 on top of the SiO 2 layer. The amount of strain can be precisely controlled by the thickness of oxide stressors. After the transistors were fabricated with strained MoS 2 films, the array of strained transistors was transferred onto plastic substrates. This process ensured that the MoS 2 channels maintained a consistent tensile strain value across a large area.

The uniform deposition of perovskite light-emitting diodes (PeLEDs) and their integration with backplane thin-film transistors (TFTs) remain challenging for large-area display applications. Herein, an active-matrix PeLED display fabricated via the heterogeneous integration of cesium lead bromide LEDs and molybdenum disulfide (MoS 2 )-based TFTs is presented. The single-source evaporation method enables the deposition of highly uniform perovskite thin films over large areas. PeLEDs are integrated with MoS 2 TFTs to fabricate an active-matrix PeLED display with an 8 × 8 array, which exhibits excellent brightness control capability and high switching speed. This study demonstrates the potential of PeLEDs as candidates for next-generation displays and presents a novel approach for fabricating optoelectronic devices via the heterogeneous integration of 2D materials and perovskites, thereby paving the way toward the fabrication of practical future optoelectronic systems., (© 2023 Wiley-VCH GmbH.)