In this paper, vanadium oxide (VO x ) was chosen for the resistive switching layer in a typical resistive random access memory (RRAM) structure. During negative forming bias, we found an initial ...selector property. This indicates the presence of metal-insulator-transition characteristics in the VO x layer even without an annealing process. In order to study this phenomenon, material analyses were conducted, with results indicating that there are V-O stretching bonds and an oxide/vanadium ratio of nearly 2.2 (<inline-formula> <tex-math notation="LaTeX">{O}/{V} = {2.2} </tex-math></inline-formula>). In addition, the experimental results of the dc sweeping test indicated that off-state current gradually decreased after each cycle, meaning that the selectivity characteristics in the VO x selector could be improved. Endurance performance of our experimental devices reached 10 8 , sufficient for integration with RRAM devices in a 1S1R array. To further investigate this special phenomenon, current fitting analysis and simulation analyses were conducted. The results of the fitting analysis indicated that the conduction mechanism for off-state current was Schottky emission and the Schottky distance increased with increasing numbers of cycles. In other words, oxide ions migrate toward the filament at low negative voltage during dc sweeping, causing the formation of VO x . Furthermore, the results of thermal field simulation analysis indicated that there is a thermal concentration effect in and around the filament. Thus, oxide ions more easily migrate toward the vanadium filament when a stronger electrical field is present around the filament during dc sweeping cycles. Finally, stable vanadium selector characteristics are obtained and a conduction filament behavior model is proposed.
The storage of electrical energy in a rechargeable battery is subject to the limitations of reversible chemical reactions in an electrochemical cell. The limiting constraints on the design of a ...rechargeable battery also depend on the application of the battery. Of particular interest for a sustainable modern society are (1) powering electric vehicles that can compete with cars powered by the internal combustion engine and (2) stationary storage of electrical energy from renewable energy sources that can compete with energy stored in fossil fuels. Existing design strategies for the rechargeable battery have enabled the wireless revolution and the plug-in hybrid electric car, but they show little promise of providing safe, adequate capacity with an acceptable shelf and cycle life to compete in cost and convenience with the chemical energy stored in fossil fuels. Electric vehicles that are charged overnight (plug-in vehicles) offer a distributed energy storage, but larger battery packs are needed for stationary storage of electrical energy generated from wind or solar farms and for stand-by power. This paper outlines the limitations of existing commercial strategies and some developing strategies that may overcome these limitations.
Oxide/polymer separator membranes allow alternative strategies for Li-ion and Na-ion batteries storing electrical energy for the grid.
•In this manuscript, MLGK-TDCNN is proposed for the detection of ECG arrhythmia.•Here, the input ECG signals are taken from two datasets: (i) AFDB (ii) MBDB.•These datasets are balanced using ...Improved fuzzy c-means method.•Moreover, the de-noised ECG signals are given to the MLGK.•Then, the MLGK features given to the TDCNN classifier for detecting AF and NSR.
In this manuscript, Multiscale Laplacian graph kernel features combined with Tree Deep Convolutional Neural Network (MLGK-TDCNN) is proposed for the detection of Electrocardiogram (ECG) arrhythmia. Here, the input ECG signals are taken from two datasets: (i) MIT-BIH AF database (AFDB) (ii) MIT-BIH arrhythmia database (MBDB). These datasets are fully unbalanced dataset, and these datasets are balanced using Improved fuzzy c-means method for unbalanced dataset. Moreover, the de-noised ECG signals are given to the MLGK. The proposed MLGK is to combine the Multiscale kernel features from the Preprocessed ECG signals. The combined Multiscale kernel features given to the TDCNN classifier for the detection of AF with raw normal sinus rhythm (NSR). The proposed approach is activated in MATLAB platform, then the efficiency is analyzed with existing approaches. The experimental outcomes demonstrate that the proposed FFREWT-MLGK-TDCNN approach is compared with two databases. From the analysis, the accuracy of AFDB shows 9.40%, 16.44% and 23.20% better than the existing approaches, the accuracy of MBDB shows 14.67%, 21.42% and 7.54% better than the existing approaches, like novel intelligent approach depending on multi-scale convolution kernel (MCK) and Squeeze-and-Excitation network (SENet) for AF detection, automatic arrhythmia classification strategy using the optimization-based deep convolutional neural network (CNN-BaROA), deep learning method for classifying arrhythmia by using 2-second segments of 2D recurrence plot images of ECG signals (2D-CNN) respectively.
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Reversal learning deficits following reward and punishment processing are observed across disruptive behaviors (DB) and attention-deficit/hyperactivity disorder (ADHD), and have been associated with ...callous-unemotional (CU) traits. However, it remains unknown to what extent these altered reinforcement sensitivities are linked to the co-occurrence of oppositional traits, ADHD symptoms, and CU traits. Reward and punishment sensitivity and perseverative behavior were therefore derived from a probabilistic reversal learning task to investigate reinforcement sensitivity in participants with DB (n=183, ODD=62, CD=10, combined=57, age-range 8-18), ADHD (n=144, age-range 11-28), and controls (n=191, age-range 8-26). The SNAP-IV and Conners rating scales were used to assess oppositional and ADHD traits. The Inventory of CU traits was used to assess CU traits. Decreased reward sensitivity was associated with ADHD symptom severity (p=0.018) if corrected for oppositional symptoms. ADHD symptomatology interacted with oppositional behavior on perseveration (p=0.019), with the former aggravating the effect of oppositional behavior on perseveration and vice versa. Within a pooled sample, reversal learning alterations were associated with the severity of ADHD symptoms, underpinned by hyposensitivity to reward and increased perseveration. These results show ADHD traits, as opposed to oppositional behavior and CU traits, is associated with decreased reward-based learning in adolescents and adults.
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•Review of SFE literature on vegetable matrices from 2000 to 2013.•Critical analysis of a compilation of almost 600 papers.•Trends on raw materials, products, modes of operation, and closeness of SFE ...to industrial application.•Current modeling, optimization, economic analysis, and scale-up approaches.•Remarks and perspectives for the upcoming research on SFE of vegetable biomass.
Along more than a decade, R&D on supercritical fluid extraction (SFE) of vegetable matrices has been increasingly reported in the literature. Aiming at portraying the current state of this field and its evolution in terms of raw materials, products, modes of operation, optimization, modeling techniques, and closeness to industrial application, a large compilation of almost 600 essays from 2000 to 2013 has been deeply analyzed in order to unveil those indicators and their trends. Furthermore, strengths and weaknesses are identified, and some remarks that may drive upcoming research are provided.
Globally, more than 300 species are reported in the literature, with prevalence of the extraction of seeds (28% of works) and leaves (17%). The main families of extracted compounds, cosolvents and operating conditions adopted are critically examined, being possible to conclude that researchers investigate many times working regions far from the optimum due to practical limitations or absence of experimental optimization. Current phenomenological, statistical and semi-empirical approaches are reviewed, along with scale-up studies, and economic analysis. In the whole, the most comprehensive picture over SFE of vegetable matrices is provided in this review, highlighting pertinent aspects and opportunities that may further consolidate the convincing route of this technology for the next years.
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This community service activity aims to improve the logical thinking abilities of SMAN 4 Parepare students by teaching the application of mathematical logic in compiling computer instructions based ...on MIT App Inventor. The method for implementing this service was problem-based learning training by taking the example of the traditional game of rock-paper-scissors as a learning case. Next, create a rock-paper-scissors game program using MIT App Inventor as a student learning experience in applying mathematical logic concepts. The evaluation instrument employed was a questionnaire to collect pre-test and post-test results, which were then analyzed using descriptive statistics and paired sample t-tests. The results of this service showed an increase in the average participant score on the post-test results, where the average pre-test score was 7.24 out of 15, while the average post-test score was 9.17 out of 15.
Biobutanol has demonstrated to be a superior alternative biofuel in internal combustion engine (ICEs). Acetone-butanol-ethanol (ABE) fermentation engineering is a typical technique for biobutanol ...production. However, the high costs and extra energy consumption in recovery process of biobutanol from intermediate fermentation solvent (i.e. ABE mixture) has obstructed its large-scale application. It is gaining increasing attention to investigate ABE as a potential alternative biofuel. ABE production and ABE combustion in ICEs have been widely studied, but these studies are rarely reviewed to favor understanding and popularization for ABE so far. In this work, the updated progress of ABE fermentation techniques is first summarized from the aspects: (i) selection of suitable strain; (ii) availability of cheaper substrates; (iii) development of fermentation engineering. Then, the research on ABE combustion in ICEs are concluded from the aspects: (i) physicochemicalproperties and tests in ICEs of ABE components; (ii) substitute for diesel in compression ignition engines; (iii) substitute for gasoline in spark ignition engines. These studies demonstrate that ABE is a better alternative for gasoline or diesel fuel due to the environmentally benign manufacturing process and the potential to improve energy efficiency and reduce pollutant emissions. However, ABE has not been intensively studied when compared to conventional alternative fuels (e.g. ethanol, butanol, biodiesel, etc.), for which considerable numbers of reports are available. Therefore, some challenges and future research directions are outlined in the end. This review is helpful for finding opportunities to make ABE as a feasible alternative biofuel in near future.
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•Propanol, n-butanol and 1-pentanol were added diesel–biodiesel blends.•Cold flow properties of the diesel–biodiesel blends were improved by adding higher alcohols.•Engine ...characteristics of higher alcohol blends were reported and compared to diesel–biodiesel blend.•There were different results in terms of HC emissions as a result of higher alcohol addition to diesel–biodiesel.•All higher alcohol blends increased CO emissions, while they reduced NOx emissions as compared to diesel–biodiesel blend.
Higher alcohols are important alternative fuel resources for use in internal combustion engines promising positive economical and environmental outcomes. Moreover, higher alcohols are advantageous over lower alcohols due to their better blending capabilities, hydrophobic properties, higher cetane numbers and calorific value. The aim of this work is to investigate and compare the basic fuel properties of the ternary blends of diesel (D), waste oil methyl ester (biodiesel (B)) and the higher alcohols of propanol (Pro), n-butanol (nB) and 1-pentanol (Pn), and their effects on engine performance and exhaust emissions of a diesel engine. As test fuels four different blends were prepared by volume: 50%D–50%B (D50B50), 40%D–40%B–20%Pro (D40B40Pro20), 20%nB (D40B40nB20) and 20%Pn (D40B40Pn20). Addition of higher alcohols to diesel–biodiesel blend improved especially the cloud point (CP) and cold filter plugging point (CFPP), while slightly decreased density, lower heating value, kinematic viscosity, cetane number and flash point. In order to determine engine performance and exhaust emissions, tests were performed at four engine loads (1, 3, 6, 9kW) with a constant engine speed (1800rpm). Based on the engine performance and exhaust emissions, D40B40Pro20 had higher brake specific fuel consumption (BSFC) values than the ternary blends of D40B40nB20 and D40B40Pn20 at all engine loads. The exhaust gas temperatures (EGT) of D40B40Pro20, D40B40nB20 and D40B40Pn20 were higher than that of the diesel–biodiesel blend. All blends of the higher alcohols reduced oxides of nitrogen (NOx) emissions as 1-pentanol, n-butanol and propanol were the most to least effective alcohols respectively. However, carbon monoxide (CO) emissions were increased with the addition of the alcohols to the blends. When the effects of higher alcohols on hydrocarbon (HC) emissions are compared in terms of emission reduction, the order from best to worst was as follows: D40B40Pn20, D40B40nB20.
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This paper overviews our present understanding of the fundamentals behind Electrolytic Plasma Technology (EPT) in view of the experimental results and theoretical predictions. EPT is an effective ...surface engineering tool that combines cleaning and coating of metals. During EPT processing, DC voltage is applied to the electrodes in the aqueous electrolyte, which produces plasma at the surface of the work piece. Thermal, chemical, electrical and mechanical effects imparted by EPT to the work piece create unique surface characteristics. The mechanism and metallurgical aspects of the effects are discussed in detail. EPT is under development for industrial applications in specific processes and is being explored for other potential commercial applications. Both of the aspects are presented. The experimental and industrial tests to date demonstrate that EPT is an emerging surface engineering technique with economical commercial applications in the field of surface engineering.
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This review paper covers potential alternative fuels for automotive engine application for both spark ignition (SI) and compression ignition (CI) engines. It also includes applications of alternative ...fuels in advanced combustion research applications. The representative alternative fuels for SI engines include compressed natural gas (CNG), hydrogen (H2) liquefied petroleum gas (LPG), and alcohol fuels (methanol and ethanol); while for CI engines, they include biodiesel, di-methyl ether (DME), and jet propellent-8 (JP-8). Naphtha is introduced as an alternative fuel for advanced combustion in premixed charge compression ignition. The production, storage, and the supply chain of each alternative fuel are briefly summarized, and are followed by discussions on the main research motivations for such alternative fuels. Literature surveys are presented that investigate the relative advantages and disadvantages of these alternative fuels for application to engine combustion. The contents of engine combustion basically consist of the combustion process from spray development, air–fuel mixing characteristics, to the final combustion product formation process, which is analyzed for each alternative fuel. An overview is provided for alternative fuels together with summaries of engine combustion characteristics for each fuel, in addition to its current distribution status and future prospects.
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