Miracle-dz/UniFAR-FTUs huggingface dataset:
Nitrogen and sulfur co-doped graphene aerogels as an efficient metal-free catalyst for oxygen reduction reaction in an alkaline solution

Nitrogen and sulfur dual-doped three dimensional (3D) graphene aerogels (N–S-GAs) are firstly prepared through pyrolyzing poly[5-amino-1,3,4-thiadiazole-2-thiol] coated graphene aerogels (PATT-GAs) as a metal-free oxygen reduction reaction (ORR) catalyst. 3D structures of N–S-GAs have been reserved after high temperature pyrolyzing, and N and S atoms are successfully doped into graphene frameworks. The catalytic performance of the fabricated N–S-GAs towards the ORR is assessed by electrochemical test techniques. The effects of pyrolyzing temperature on catalytic activity are also studied. The binding states of N and S atoms have a great influence on the electrocatalytic activity for the ORR. The N–S-GAs gained after pyrolysis at 900 °C (N–S-GAs 900) demonstrate higher electrocatalytic activity and diffusion-limiting current density, better stability and methanol tolerance. The excellent performance for the ORR on N–S-GAs is attributed to the interconnected porous network, conductive multiplexed pathways of N–S-GAs, greater electrocatalytically active site exposure and the synergistic effect originating from the doped N and S in the graphene sheets.
Effect of Forest Canopy Structure on Wintertime Land Surface Albedo: Evaluating CLM5 Simulations With In‐Situ Measurements

Land Surface Albedo (LSA) of forested environments continues to be a source of uncertainty in land surface modeling, especially across seasonally snow covered domains. Assessment and improvement of global scale model performance has been hampered by the contrasting spatial scales of model resolution and in‐situ LSA measurements. In this study, point‐scale simulations of the Community Land Model 5.0 (CLM5) were evaluated across a large range of forest structures and solar angles at two climatically different locations. LSA measurements, using an uncrewed aerial vehicle with up and down‐looking shortwave radiation sensors, showed canopy structural shading of the snow surface exerted a primary control on LSA. Diurnal patterns of measured LSA revealed strong effects of both azimuth and zenith angles, neither of which were adequately represented in simulations. In sparse forest environments, LSA were overestimated by up to 66%. Further analysis revealed a lack of correlation between Plant Area Index (PAI), the primary canopy descriptor in CLM5, and measured LSA. Instead, measured LSA showed considerable correlation with the fraction of snow visible in the sensor's field of view, a correlation which increased further when only considering the sunlit fraction of visible snow. The use of effective PAI values as a simple first‐order correction for the discrepancy between measured and simulated LSA in sparse forest environments substantially improved model results (64%–76% RMSE reduction). However, the large biases suggest the need for a more generic solution, for example, by introducing a canopy metric that represents canopy gap fraction rather than assuming a spatially homogeneous canopy.
Construction of appropriate model for Enrolment Projection of India

Article History: Received: 10 November 2020; Revised: 12 January 2021; Accepted: 27 January 2021; Published online: 05 April 2021 Abstract: There are different models used for enrolment projection in the education system. Of them ARIMA, double exponential, logistic curve method, reconstructive cohort, and regression model, method are commonly used. Every model has its suitability under certain conditions and with prior assumptions. In India, no attempt was made to estimate enrolment except in 1996. The logistic curve method was adopted to estimate enrolment between 1996 – 2001. In the present situation, an attempt has been made to estimate school enrolment for the next years. The present paper discusses fitting the best model for estimating enrolment for the next few years.
Modeling Formation and Oxidation of Soot in Nonpremixed Flames

A detailed kinetic mechanism of aromatic growth, particulate formation, and oxidation is presented and is tested in nonpremixed laminar flames of methane and ethylene at atmospheric pressure. Model development is refined in strict connection with new experimental data on the formation and oxidation of high molecular mass compounds and incipient particles. Reaction pathways leading to the formation of incipient particles, their transformation to soot, their oxidation, and the oxidation-induced fragmentation of particles and aggregates have been included by using a multisectional approach for the particle process. Predictions within a factor of 2–3 are obtained for major oxidation and pyrolysis products as well as trace aromatic species and particulate concentrations. The newly developed model predicts the concentration of the particles, their sizes, morphology, and chemical properties in nonpremixed flames of methane and ethylene with a wide range of particle formation without any condition-dependent adjus.
The changes in Alkaline, Neutral and Acid Protease Activities of Artemia Enriched with Commercial Emulsion and Different Additive Combinations

The biochemical compositions and the changes observed in alkaline, neutral and acid protease activities of Artemia enriched with commercial emulsion and different additive combinations were determined. Artemia nauplii (ArtN), GroBiotic-A (GA), Red Algamac (RA), Red Algamac:GroBiotic-A (50:50) (RA:GA (50:50)), Spirulina (SP), Spirulina:Red Algamac (50:50) (SP:RA (50:50)), Spirulina:GroBiotic-A (50:50) (SP:GA (50:50)) and Spirulina:Red Algamac:GroBiotic-A (33:33:33) (SP:RA:GA (33:33:33)) were tested in the study. The lowest and highest protein contents after the enrichment of Artemia were 40.74±1.02% (RA) and 55.03±1.26% (SP:RA:GA (33:33:33)), respectively. The lowest lipid contents of tested groups were found in 5.63±0.47% (GA) and 5.63±0.84% (RA:GA (50:50)). The highest lipid value after the enrichment were observed in 16.98±1.15 % (RA). The lowest and highest ash values observed after the enrichment were 4.51±0.27% (SP:GA (50:50)) and 6.07±0.35% (RA) (p<0.05). The lowest and highest protease activities of the pH=3, pH=4, pH=5, pH=6, pH=7 and pH=8.5 values were 18.18±0.37 U/mg protein (GA), 31.04±0.38 U/mg protein (RA), 9.1±0.32 U/ mg protein (SP), 9.66±0.19 U/mg protein (SP), 16.94±0.61 U/mg protein (SP), 63.09±0.75 U/mg protein (SP) and 33.77±0.59 U/mg protein (RA:GA (50:50)), 57,54±0.34 U/mg protein (RA:GA (50:50)), 23.75±0.28 U/mg protein (GA), 40.82±0.49 U/mg protein (GA), 69.94±0.65 U/mg protein (GA), and 286.14±8.2 U/mg protein (GA) (p<0.05). In conclusion, GA and SP:RA:GA (33:33:33) enrichment combinations are recommended as an alternative to enrichment products. On the other hand, SP and RA should not be used alone due to the disadvantages such as the biochemical composition and proteolytic enzyme activities of Artemia observed in the present study.
Lake and Land Breezes at a Mediterranean Artificial Lake: Observations in Alqueva Reservoir, Portugal

The Alqueva reservoir, in the Southeast of Portugal, has significantly changed the landscape of the region, with impacts also on the local climate, as documented in this manuscript, namely the thermal circulation in the form of lake and land breezes. Taking advantage of three strategic meteorological stations, two installed at the shores and another on a floating platform located near the center of the reservoir, a detailed analysis of lake and land breeze occurrences during two years is presented in this study. The thermal gradient between the reservoir and the surroundings is the main driver for the breeze development and the meteorological stations placed in opposite sides of the reservoir allow to establish the criteria in order to detect lake and land breezes. The results showed more land breeze than lake breeze occurrences, in line with the more negative thermal gradient between shores and reservoir in the annual cycle. Lake breezes are more frequent in summer months during daytime and land breezes in turn are more frequent in winter months during night-time.
Three-Phase Three-Level Isolated DC-DC Soft Switching Converter For Solar Applications

Abstract: Three-level isolated DC-DC converter is an attractive topology in high input voltage applications, which can provide the voltage stress of the power devices to only a half of the dc voltage and also reduce the size of dc filter requirement. But major limitations in the existing three level ZVS converter topologies are brought out with an increased inductance in the primary side and it required to provide complete ZVS of all primary devices down to light loads. By employing an external inductance in the primary of the transformer, total leakage inductance of the transformer increases which is required for realization of soft switching of the converter switches but there are some disadvantages of connecting external inductance in the primary of the transformer. To overcome all these drawbacks, the three-phase threelevel isolated DC-DC soft switching converter has been proposed in order to reduce voltage and current stresses. This converter topology requires less number of control switches and operates with an asymmetrical duty cycle control. The proposed three level DC-DC converters provide twolevel voltage waveform before dc output filter, which significantly reduce the size of dc output filter. The proposed work has been implemented using MATLAB/SIMULINK and the performance of the proposed converter is verified through simulation results.
Scale‐free topology security mechanism of wireless sensor network against cascade failure

As the basic architecture of the Internet of things, wireless sensor networks are the most important technical means to detect data on the Internet of things, and their security is essential to the development and implementation of the Internet of things. The wireless sensor network based on the scale‐free theory has strong fault tolerance when random nodes fail and can better adapt to the unsupervised and complex environment of wireless sensor networks. However, in a wireless sensor network with scale‐free function, the unevenness of its degree distribution causes some nodes to be very critical in the network. Once attacked, it will cause major damage to the network. Selective promotion attacks are relatively common. At the network level, the attacker destroys the normal collection of network data by selectively losing information or not forwarding sensitive information, which is extremely harmful to the network using this function. In order to overcome the influence of excessive dependence on a single path on the balance performance of the network, starting from the entire network, a secure multi‐path routing algorithm for wireless sensor networks based on scale‐free topology is proposed. Through the analysis of the network topology, the highest degree network node can be found. Optimize the load factor, use digital watermarking technology to locate the network path packet loss rate, and perform Gaussian modeling on the packet loss rate. Then the routing loading function and the routing packet loss rate are used as the confidence model factors to create the routing confidence model. We must first establish a model, select the transmission path according to the received function, and then obtain the global optimal security sensor routing algorithm. Through the algorithm in this thesis, the security of the wireless sensor network is improved by 17%.
Suppression of EMI Using Cost-Effective FPGA-Based Digital Communication Modulation Techniques in Power Converters

ABSTRACT Direct-sequence spread-spectrum (DSSS) and frequency-hopping spread-spectrum (FHSS) modulation techniques have been proposed for the operation of three-phase voltage-source rectifiers (VSR) for the mitigation of EMI in AC Grid. For the first time, in the DSSS modulation technique, binary phase shift keying and quadrature phase shift keying (QPSK) techniques have been adopted for the mitigation of electro-magnetic interference (EMI) in three-phase VSR. A cost-effective field programmable gate array (FPGA) has been employed for carrying out these proposed modulation techniques. A VHDL coding for each modulation technique is written in ISE Xilinx, verified by Model-Sim tool and then implemented using FPGA to produce gate pulses for the rectifier. Rather than building a modulator physically, the control logic is implemented using low-cost FPGA, resulting in the cost and size reduction of the control circuit. The modulation techniques recommended in this paper are compared with the traditional sinusoidal pulse width modulation (SPWM). It is shown that the FHSS and QPSK techniques proposed in this paper result in improved power quality and the conducted EMI levels are reduced by 22.1 and 12.4 dBµV, respectively, when compared with SPWM.
The state of discipline-based research cultures at two leading research-oriented universities in Vietnam

ABSTRACT Vietnam aspires to have a tier of research-intensive universities, including some that will soon attain “world-class” status. This goal is ambitious and will require, amongst other things, a significantly increased level of commitment to the development of discipline-based research cultures at the universities concerned. This paper reports on the state of discipline-based research cultures at two leading research-oriented universities in Vietnam. Discipline-based research cultures are found to be present at these universities, but they are stronger in the sciences and technologies. Measures required to nurture discipline-based research across all knowledge areas are discussed.
Identification of TENORM in Zirconium Oxychloride with Gamma Spectrometry

Gamma spectrometer used to determine the type and activity of gamma emitting radionuclides, such as the measurement of TENORM (Th-232, U-238, Ra-26 dan K-40) in the zirconium oxychloride or environmental radioactivity. This research was carried out to know each the TENORM on the zirconium oxychloride (ZrOCl2.8H2O) which accommodation of environment data the radioactivity in draft job safety about the workers. Zirconium oxychloride is a result of chloride acid leaching process from sodium zirconate, containing uranium and thorium, so that it has the potential for contamination and increase the radiation exposure. The instrument used for counting by HPGe detector and the spectrum were analyzed further using software Genie 2000. Mean measured activity concentrations (radioactivity) of U-238, Th232, Ra-226 and K-40 respectively were 13.43±0.876 Bq/kg, 12.040±1.483 Bq/kg, 11.400±0.582 Bq/kg dan 32.940±3.270 Bq/kg.
High-efficiency detection photoacoustic imaging for rapid physiological response by breaking the sampling law

In recent years, photoacoustic imaging, as a new type of biomedical imaging method, combines the advantages of high selectivity in pure optical tissue imaging and deep penetration in pure ultrasound tissue imaging to obtain high-resolution and high-contrast tissue images. The use of photoacoustic imaging technology to deal with complex medical tissue problems is still a new research direction. How to compress large amounts of data and quickly transmit and store important value information has become a problem waiting for optimization. This paper uses the StagewiseOMP and tracking algorithm to combine it with the photoacoustic imaging of the k-wave simulation toolbox to rebuild a virtual simulation platform for blood vessel imaging. On the one hand, compressed sensing can reduce the sampling rate and speed up imaging. On the other hand, it can modify the demand for hardware equipment to facilitate data transmission and storage. A simulation model of photoacoustic field propagation, photoacoustic signal recording and image reconstruction was established using the k-wave simulation toolbox. We have used the excellent performance of the simulation platform through imaging technology to complete the imaging restoration of part of the blood area tube tissue.
Research on the Mechanical Characteristics of Cyclic Loading and Unloading of Rock Based on Infrared Thermal Image Analysis

In the operations of underground rock engineering, such as mining, the formation of goafs is often accompanied by unloading and energy effects. In this study, a cyclic loading and unloading stress test is carried out to analyze the strength characteristics of the loaded samples under different loading and unloading ranges as well as different numbers of cycles. The rock force is accompanied by substantial energy changes. To better fit the energy analysis under cyclic loading and unloading conditions, thermal infrared radiation characteristic analysis is performed during rock loading and unloading. An infrared radiation camera is adopted to detect the infrared characteristics of the rock force process after cyclic loading and unloading. Multiangle detection is implemented on the temperature, temperature field, and frequency histogram. The analysis shows that cyclic loading and unloading first strengthen and then weaken the rock. Moreover, the failure caused by the local stress concentration leads to a sharp increase in the temperature. There are significant temperature fluctuations before and after failure, and the temperature field after failure can be divided into three zones, namely, the normal temperature zone, heating zone, and mutational temperature zone, to comprehensively reflect that rock compression failure which is accompanied by the process of energy accumulation and release. On the basis of infrared energy analysis, the index of the energy release rate is introduced, and the loading and unloading analysis model is constructed. The research results reveal that rock failure is accompanied by the process of energy accumulation and release, which provides evidence for the analysis of the spatial stability of the rock mass under cyclic loading and unloading conditions and engineering excavation.
COVID-19 and Extremeness Aversion: The Role of Safety Seeking in Travel Decision Making

Combining conceptual perspectives from emerging research on COVID-19, safety-seeking motivations, and extremeness aversion in choice (i.e., compromise effects), we examine how and why the perceived threat of COVID-19 affects consumers’ choice and decision making in the hotel and restaurant domains. Across seven studies (two studies from secondary data sets and five experimental studies), we provide novel evidence that the perceived threat or threat salience of COVID-19 amplifies the general tendency to select compromise options, avoiding extreme ones, within a choice set. We highlight the role of safety-seeking motivations as the underlying mechanism in the relationship between perceived threat and extremeness aversion in choice. We further document a boundary condition that the extremeness aversion effect is stronger for leisure travelers than for business travelers.
Versatile supercontinuum generation by using χ(2) and χ(3) nonlinearities in PPLN crystal for direct multiplex CARS measurement

In this study, we report on experiments of spatio-temporal nonlinear frequency conversion in a periodically poled Lithium Niobate (PPLN) crystal designed for second-harmonic generation (SHG). We demonstrated a novel supercontinuum source based on the mixing of second and third-order nonlinearities. We could adjust the (X(2), X(3)) nonlinearities by controlling the input laser polarization orientation, the pulse duration and the PPLN crystal temperature. We obtained an ultra-broadband spectrum, ranging from visible to infrared domains, by pumping a 20-mm-long PPLN crystal with a 3 ps pulse at 1030 nm. This broadband pulse was used to achieve direct multiplex Coherent Anti-Stokes Raman Scattering (M-CARS) imaging, without the need for any optical delay line to temporally synchronize the pump and the Stokes waves. Simultaneous vibrational signatures ranging from -3200 cm-1 to -500 cm-1 were obtained. Several filters were placed on the broadband supercontinuum path, to shape the output spectrum between 1030 nm and 1650 nm, before sending it into the microscope. The output spectral analysis allows for the demonstration of multimodal imaging, by using SHG, M-CARS and multiphoton fluorescence processes.
Improving Platinum Catalyst Durability with a Doped Graphene Support

Improving the durability of a platinum catalyst is an important step in increasing its utility when incorporated as the anode or cathode of a proton-exchange membrane fuel cell. Using density functional theory, the binding energy between a platinum atom and five graphene surfaces, one pure, and four others singly doped with beryllium, boron, nitrogen, and oxygen, was calculated. The oxygen-doped surface showed the highest binding energy and was calculated to be 7 times higher than the undoped surface. Each dopant modified the surface bonding arrangement within the graphene lattice, which then affected how the surface bonded to the platinum atom. Using molecular orbitals, natural bond orbitals, and the gradient of the electron density, these interactions were explored to explain the strength of the Pt–surface bond, which, in ascending order by dopant, was found to be undoped, nitrogen, boron, beryllium, and oxygen.
Effect of light intensity on growth, yield and indigo content of Indigofera tinctoria L.

Synthetic dyes can increase the amount of pollutants that become a serious problem in the environment. The use of synthetic dyes can be replaced with dyes from natural ingredients, namely Indigofera tinctoria. These plants are a source of blue natural dyes because it contains indigo. The content of indigo is very responsive to light. The impact of climate change is a serious threat to the supply of natural dyes. So, judge the suitability of the environment and indigo content under climate change are essential for the sustainable production of natural dyes Indigofera tinctoria. The research aimed to examine the role of light on the growth, yield, and indigo content in Indigofera tinctoria. The study was conducted using a randomized complete design with one factor, namely light intensity with 3 levels namely light intensity 100%, 50%, and 25%, with 9 replications. Light intensity affected the number of leaves, nodes, fresh weight, and indigo content. The highest number of leaves, nodes, and fresh weight were at 100% light intensity, while the highest indigo content was at 25% light intensity. The fresh weight with indigo paste is positively correlated. The higher the fresh weight of the plant, the more paste will be produced. However, the content of indigo was negatively correlated with indigo paste.
Single‐phase front‐end modified interleaved Luo power factor correction converter for on‐board electric vehicle charger

This paper proposes a modification in the interleaved negative output elementary Luo converter to act as front‐end power factor correction converter for on‐board electric vehicle (EV) charger. The proposed converter is simple in design and offers non‐inverted DC link output voltage. The proposed converter has the advantages—high efficiency, near unity power factor, low AC source current distortion resulting in power quality enhancement, better DC load voltage regulation, and reduced component count. Due to interleaved configuration, rating of circuit components gets greatly reduced. Also, minimum numbers of circuit components pave the way for simple system design of on‐board EV charger. The steady‐state performance of the designed 100‐W, 48‐V converter with closed‐loop controller is analyzed under universal input voltage variation and wide range of load power variation. The converter is designed to provide stable operation when subjected to sudden disturbance in load power/supply voltage. The simulation analysis is done using MATLAB/Simulink platform. A prototype of 48‐V, 100‐W converter is built and tested. Results obtained reveal the superior performance of proposed converter under steady‐state and transient conditions.