Considering the feasibility of geothermal wells employed worldwide in the energy sector, this study was motivated to examine a novel multi-generation system devised to enhance the feasibility of ...flash-binary geothermal systems through innovative heat recovery in five stages. Accordingly, the main system consists of a flash-binary geothermal cycle, an ejector refrigeration cycle, a Kalina cycle integrated with another ejector refrigeration cycle, a humidification dehumidification desalination unit, and a low-temperature electrolyzer. Due to the five stages of innovative heat recovery, this system achieved a cost-effective and efficient design framework, introducing it as a high-quality alternative for stand-alone flash-binary geothermal cycles. To study the feasibility of the proposed system, a sensitivity analysis based on energy, exergy, and exergoeconomic concepts was employed. Moreover, the genetic algorithm in different multi-objective optimization scenarios was implemented to reach stable and high-efficiency products. According to the obtained results, the capability of the system to produce electricity, cooling, freshwater, and hydrogen are calculated to be 782 kW, 881.6 kW, 0.286 kg/s, and 0.181 kg/h, respectively. Also, in the exergy-cost optimization scenario, the system's optimum exergy efficiency and sum unit cost of products were obtained to be 46.44% and 3.98 $/GJ, respectively based on LINMAP decision-making method.
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•A novel multi-generation system devised based on a flash-binary geothermal system.•Five stages of heat recovery are considered for uttermost utilization of energy.•Energy, exergy, and exergoeconomic analyses were considered for system evaluation.•The system yielded 0.286 kg/s and 0.181 kg/h of freshwater and hydrogen, respectively.•In the exergy-cost optimization scenario, the optimum exergy efficiency was 46.44%.
Sodium‐based layered oxides are among the leading cathode candidates for sodium‐ion batteries, toward potential grid energy storage, having large specific capacity, good ionic conductivity, and ...feasible synthesis. Despite their excellent prospects, the performance of layered intercalation materials is affected by both a phase transition induced by the gliding of the transition metal slabs and air‐exposure degradation within the Na layers. Here, this problem is significantly mitigated by selecting two ions with very different MO bond energies to construct a highly ordered Ni6‐ring superstructure within the transition metal layers in a model compound (NaNi2/3Sb1/3O2). By virtue of substitution of 1/3 nickel with antimony in NaNiO2, the existence of these ordered Ni6‐rings with super‐exchange interaction to form a symmetric atomic configuration and degenerate electronic orbital in layered oxides can not only largely enhance their air stability and thermal stability, but also increase the redox potential and simplify the phase‐transition process during battery cycling. The findings reveal that the ordered Ni6‐ring superstructure is beneficial for constructing highly stable layered cathodes and calls for new paradigms for better design of layered materials.
Two ions with very different MO bond energy are selected to construct a highly ordered Ni6‐ring superstructure within transition metal layers in a model compound (NaNi2/3Sb1/3O2). The formed Ni6‐rings with super‐exchange interaction by Ni/Sb ordering can greatly enhance the air stability and thermal stability of layered cathodes, increase the redox potential, and simplify the phase‐transition process during battery cycling.
The frequency regulation service (FRS) is playing an increasingly important role in maintaining the power balance between generation and consumption. Moreover, the recent progress in information and ...communication technologies has enabled residential customers to participate in FRS through direct control over appliances, such as inverter air conditioners (ACs), whose market share is growing rapidly and has made up a large fraction of electricity consumption. Inverter ACs can change compressor's speed continuously to adjust operating power and provide FRS for the system operation. In this paper, the thermal model of a room and the electrical model of an inverter AC for providing FRS are developed. The model of the inverter AC is equivalent to a generator. In this manner, the aggregation of inverter ACs can be controlled just as traditional generators. Besides, a stochastic allocation method of the regulation sequence among inverter ACs is proposed to reduce the effect of FRS on customers. A hybrid control strategy by taking into account the dead band control and the hysteresis control is also developed to reduce the frequency fluctuations of power systems. The effectiveness of the proposed models and control strategies is illustrated in the numerical studies.
Precise positioning using smartphones has been a topic of interest especially after Google decided to provide raw GNSS measurement through their Android platform. Currently, the greatest limitations ...in precise positioning with smartphone Global Navigation Satellite System (GNSS) sensors are the quality and availability of satellite-to-smartphone ranging measurements. Many papers have assessed the quality of GNSS pseudorange and carrier-phase measurements in various environments. In addition, there is growing research in the inclusion of a priori information to model signal blockage, multipath, etc. In this contribution, numerical estimation of actual range errors in smartphone GNSS precise positioning in realistic environments is performed using a geodetic receiver as a reference. The range errors are analyzed under various environments and by placing smartphones on car dashboards and roofs. The distribution of range errors and their correlation to prefit residuals is studied in detail. In addition, a comparison of range errors between different constellations is provided, aiming to provide insight into the quantitative understanding of measurement behavior. This information can be used to further improve measurement quality control, and optimize stochastic modeling and position estimation processes.
Objectives
Microscopic tympanoplasty has been the standard surgery for repairing perforated tympanic membranes since the 1950s, but endoscopic tympanoplasty has been increasingly practiced since the ...late 1990s. In this study, we compared the efficacies of endoscopic and microscopic tympanoplasty.
Data Sources
PubMed, Embase, MEDLINE, and the Clinical Trial Register.
Review Methods
We conducted a systematic review and meta‐analysis following the Preferred Reporting Items for Systematic Reviews and Meta‐Analysis statement. We included clinical studies that compared the efficacies of endoscopic and microscopic tympanoplasty. We assessed the risk of bias and calculated the pooled relative risk (RR) estimates with 95% confidence interval (CI).
Results
We identified four studies (involving 266 patients in total) that met the inclusion criteria. The pooled tympanic membrane closure rates and hearing results of endoscopic and microscopic tympanoplasty were comparable (85.1% vs. 86.4%, respectively; RR: 0.98; 95% CI: 0.85 to 1.11; I2 = 0) (mean difference of improvements of air‐bone gaps: −2.73; 95% CI: −6.73 to 1.28; I2 = 80%). The pooled canalplasty rate of endoscopic tympanoplasty was significantly lower than that of microscopic tympanoplasty. Patients receiving endoscopic tympanoplasty had a more desirable cosmetic result than did those receiving microscopic tympanoplasty.
Conclusions
Our up‐to‐date review evidences the comparable tympanic membrane closure rates and hearing results for endoscopic and microscopic tympanoplasty. Patients receiving endoscopic tympanoplasty have a lower canalplasty rate and more desirable cosmetic result than do those receiving microscopic tympanoplasty. Laryngoscope, 127:1890–1896, 2017
Abstract
N-doping plays an irreplaceable role in controlling the electron concentration of organic semiconductors thus to improve performance of organic semiconductor devices. However, compared with ...many mature p-doping methods, n-doping of organic semiconductor is still of challenges. In particular, dopant stability/processability, counterion-semiconductor immiscibility and doping induced microstructure non-uniformity have restricted the application of n-doping in high-performance devices. Here, we report a computer-assisted screening approach to rationally design of a triaminomethane-type dopant, which exhibit extremely high stability and strong hydride donating property due to its thermally activated doping mechanism. This triaminomethane derivative shows excellent counterion-semiconductor miscibility (counter cations stay with the polymer side chains), high doping efficiency and uniformity. By using triaminomethane, we realize a record n-type conductivity of up to 21 S cm
−1
and power factors as high as 51 μW m
−1
K
−2
even in films with thicknesses over 10 μm, and we demonstrate the first reported all-polymer thermoelectric generator.
Alcohol use disorder (AUD) is an important brain disease. It alters the brain structure. Recently, scholars tend to use computer vision based techniques to detect AUD. We collected 235 subjects, 114 ...alcoholic and 121 non-alcoholic. Among the 235 image, 100 images were used as training set, and data augmentation method was used. The rest 135 images were used as test set. Further, we chose the latest powerful technique—convolutional neural network (CNN) based on convolutional layer, rectified linear unit layer, pooling layer, fully connected layer, and softmax layer. We also compared three different pooling techniques: max pooling, average pooling, and stochastic pooling. The results showed that our method achieved a sensitivity of 96.88%, a specificity of 97.18%, and an accuracy of 97.04%. Our method was better than three state-of-the-art approaches. Besides, stochastic pooling performed better than other max pooling and average pooling. We validated CNN with five convolution layers and two fully connected layers performed the best. The GPU yielded a 149× acceleration in training and a 166× acceleration in test, compared to CPU.
Spinal cord injury (SCI) is the most common disabling spinal injury, and the complex pathological process can eventually lead to severe neurological dysfunction. Many studies have reported that the ...mammalian target of rapamycin (mTOR) signaling pathway plays an important role in synaptogenesis, neuron growth, differentiation, and survival after central nervous system injury. It is also involved in various traumatic and central nervous system diseases, including traumatic brain injury, neonatal hypoxic-ischemic brain injury, Alzheimer's disease, Parkinson's disease, and cerebral apoplexy. mTOR has also been reported to play an important regulatory role in various pathophysiological processes following SCI. Activation of mTOR signals after SCI can regulate physiological and pathological processes, such as proliferation and differentiation of neural stem cells, regeneration of nerve axons, neuroinflammation, and glial scar formation, through various pathways. Inhibition of mTOR activity has been confirmed to promote repair in SCI. At present, many studies have reported that Chinese herbal medicine can inhibit the SCI-activated mTOR pathway to improve the microenvironment and promote nerve repair after SCI. Due to the role of the mTOR pathway in SCI, it may be a potential therapeutic target for SCI. This review is focused on the pathophysiological process of SCI, characteristics of the mTOR pathway, role of the mTOR pathway in SCI, role of inhibition of mTOR on SCI, and role and significance of inhibition of mTOR by related Chinese herbal medicine inhibitors in SCI. In addition, the review discusses the deficiencies and solutions to mTOR and SCI research shortcomings. This study hopes to provide reference for mTOR and SCI research and a theoretical basis for SCI biotherapy.
•This paper reviews the recent literature on mTOR signaling pathway and spinal cord injury.•According to the role of mTOR pathway in spinal cord injury, the role of mTOR pathway on spinal cord injury field was summarized.•It is concluded that mTOR pathway may be a potential therapeutic target for spinal cord injury.•This review is valuable to all who are engaged in this field.
Charge transport of conjugated polymers in functional devices closely relates to their density of states (DOS) distributions. However, systemic DOS engineering for conjugated polymers is challenging ...due to the lack of modulated methods and the unclear relationship between DOS and electrical properties. Here, the DOS distribution of conjugated polymers is engineered to enhance their electrical performances. The DOS distributions of polymer films are tailored using three processing solvents with different Hansen solubility parameters. The highest n‐type electrical conductivity (39 ± 3 S cm−1), the highest power factor (63 ± 11 µW m−1 K−2), and the highest Hall mobility (0.14 ± 0.02 cm2 V−1 s−1) of the polymer (FBDPPV‐OEG) are obtained in three films with three various DOS distributions, respectively. Through theoretical and experimental exploration, it is revealed that the carrier concentration and transport property of conjugated polymers can be efficiently controlled by DOS engineering, paving the way for rationally fabricating organic semiconductors.
The charge transport properties of conjugated polymers relate closely to their density of states (DOS) distributions. This work enables DOS engineering of conjugated polymer by using different processing solvents to improve three electronic parameters in one polymer system: electrical conductivity, power factor, and Hall mobility. It is suggested that DOS engineering is crucial for the refinement of conjugated polymers for different electrical performances.
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