Miracle-dz/UniFAR-FTUs huggingface dataset:
Personal Hygiene Assessment Among Different University Students of Dhaka, Bangladesh: A Step Towards the Prevention of COVID-19 Pandemic

Personal hygiene is deemed a necessary precautionary measure against different communicable diseases. Its importance is further reiterated during the current COVID-19 global pandemic. Maintaining personal hygiene, such as washing hands and sneezing etiquette are being considered as effective means of precaution. In the present study, the knowledge and practice level of hand hygiene and sneezing etiquette among different university students in the city of Dhaka in Bangladesh were investigated as these students represent a substantial fraction of the total population in Bangladesh. It was also observed if they have adopted any change in their hygiene practices due to the COVID-19 pandemic. A crosssectional study was conducted among 240 students from different universities. An online-based questionnaire was provided to them. In this study, 96.7% of students were found to be aware of personal hygiene. 45% of students washed their hands 10 times a day, while 60% of them were unaware and maintained random durations of handwashing. The majority of them were aware of the sneezing rules and 48.3% of them used their elbows during sneezing. 79.2% of the tissue user students usually dispose of the tissue in a designated covered bin. Their hygiene practice had also been changed due to the COVID-19 pandemic. However, our result is insufficient to reflect the overall condition of Bangladeshi university students as it was done with limited resources via an online survey during the countrywide COVID-19 lockdown. Thus, future research is required to draw a conclusive picture. World Scientific News 147 (2020) 197-208 -198
Stator Optimization of Wind Power Generators With High-Temperature Superconducting Armature Windings and Permanent Magnet Rotor

Electrical machines with high-temperature superconducting (HTS) armature windings can benefit from high power density and efficiency. Furthermore, by using permanent magnets (PM) on the rotor, the cryogenic system can be significantly simplified compared with the fully superconducting (SC) machines or the machines with SC field windings. Compared with the conventional electrical machines, the performance of machines with HTS armature windings can be more sensitive to the design parameters due to the interaction between the operating current and the flux density. In this article, the influence of stator geometry on the machine with HTS armature windings and PM rotor is investigated. By considering the interaction between the operating current and the flux density, an iteration procedure for calculating the operating current of the HTS armature windings is proposed. A 10-MW surface-mounted PM wind power generator with HTS armature windings is studied by the finite element analysis. It is found that machines with different coil angle have different behaviors when changing the tooth width and the dimensions of tooth tips, which is different from conventional electrical machines. A new design and optimization method is then developed. Finally, the optimal design is identified with global optimization.
The Quantitative Determination of Butylated Hydroxytoluene in Chewing Gum Using GC--MS.

An undergraduate experiment for the quantitative determination of the synthetic antioxidant butylated hydroxytoluene (BHT) in chewing gum is described. A simple extraction procedure was used that did not require sample derivatization for analysis. Gum samples were ground in a coffee grinder into a free-flowing powder. The internal standard 3,5-di-tert-butylphenol, was added and the ground samples were extracted in acetonitrile. The BHT-containing extract was concentrated using rotary evaporation and resuspended in ethyl acetate. Butylated hydroxyanisole (BHA) was added as a recovery surrogate, and gas chromatography-mass spectrometry with selected-ion monitoring (SIM) was used to identify and quantify BHT. Butylated hydroxytoluene recoveries from the chewing gum matrix were typically > 80%, and student results (42-172 mg BHT per g gum) agreed closely with BHT concentrations determined in other studies (50-200 mg BHT per g gum).
A Facile Synthesis of AuAg Alloy Nanoparticles Using a Chemical Reaction Induced by Sputter Deposition of Metal onto Ionic Liquids

Sputter deposition of silver (Ag) onto an ionic liquid (IL) produced Ag nanoparticles whose size was varied greatly dependent on the sputtering conditions. Change in discharge current from 10 to 40 mA increased Ag particle size from 5.7 to 11 nm, though prolongation of sputtering time simply caused a higher concentration of Ag nanoparticles in IL without change in their size. Sputter deposition of Ag onto IL solutions containing HAuCl4 resulted in the appearance of a single surface plasmon resonance peak in the absorption spectra of the resulting solution, and their peak position was red-shifted with an increase in the concentration of HAuCl4. The obtained results clearly indicated that Ag metal species sputter-deposited in IL can reduce HAuCl4 to give AuAg alloy nanoparticles and that their chemical composition varies depending on the initial concentration of HAuCl4.
Structure of the layer compound ZrSiTe

Zirconium silicon telluride, ZrSiTe, crystallizes is a layer-type structure which is related to the PbFCl type. The Zr atom is coordinated by four Si and four Te atoms. The Si and Te atoms are arranged in square planes. These planes are situated at opposite sides of the Zr atom; the coordination polyhedron may be described as a distorted quadratic antiprism. The distances between the Si atoms [2.614 (1) A] are longer than that of a Si-Si single bond (2.35 A), but comparable with the Si-Si separations in transition metal disilicides. The Te-Te separations within the Te 4 plane give no indication of significant interactions
Adaptive and Robust Routing With Lyapunov-Based Deep RL in MEC Networks Enabled by Blockchains

The most recent development of the Internet of Things brings massive timely sensitive and bursty data flows. Also, joint optimization on storage, computation, and communication is in need for multiaccess edge computing frameworks. The adaptive network control has been explored using deep reinforcement learning (RL), but it is not sufficient for bursty network traffic flows, especially when the network traffic pattern may change over time. We formulate the routing control in an environment with time-variant link delays as a Lyapunov optimization problem. We identify that there is a tradeoff between optimization performance and modeling accuracy when the propagation delays are included. We propose a novel deep RL (DRL)-based adaptive network routing method to tackle the issues mentioned above. A Lyapunov optimization technique is used to reduce the upper bound of the Lyapunov drift, improving queuing stability in networked systems. By modeling the network traffic pattern using the Markovian arrival process, we show that network routing problems can be modeled as Markov decision processes and value-iteration-based RL methods can be used to solve them. We design a blockchain-based protocol using proof of elapsed time consensus mechanism to ensure a trustworthy network statistics information exchange for the routing framework. Experiment results show that the proposed method can learn a routing policy and adapt to the changing environment. The proposed method outperforms the baseline backpressure method in multiple settings and converges faster than existing methods. Moreover, the DRL module can effectively learn a better estimation of the long-term Lyapunov drift and penalty functions, providing superior results in terms of the backlog size, end-to-end latency, age of information, and throughput. Furthermore, the blockchain-based network statistics exchange can provide the routing framework against malicious nodes. In addition, the proposed model performs well under various topologies, and thus can be used in general cases.
Learning ecologies in the digital era: challenges for higher education

The immersion of society in the digital age has decisively influenced people’s ways of behaving, in the field of work, economy, entertainment and teaching. Higher education is undergoing a great transformation due to the technological development in which we are immersed, and these continuous changes have shown the need to keep us updated permanently, thus adopting the idea of ​​life-long learning. Each person and each professional has a wide and diverse range of possibilities to be trained and to learn, which requires individuals to take more and more control over their own learning process. The concept of learning ecologies provides a framework of analysis to know how we learn, and what contexts and/or elements we use to train ourselves, in order to provide us with new learning opportunities. Being aware of the elements and / or contexts that make up our learning ecologies can be a very useful strategy to help us update ourselves in a self-directed and effective way. This has led us to carry out a bibliographic study aimed at identifying some of the aspects that characterize the new ways in which we learn, which will allow us to understand the role that the university should play in today’s society.
Two-Dimensional Computational Fluid Dynamics Simulation of Biomass Gasification in a Downdraft Fixed-Bed Gasifier with Highly Preheated Air and Steam

Biomass gasification is regarded as one of the most promising energy recovery technologies for the widespread use of biomass. Mathematical models have been developed to understand this process in downdraft fixed beds using zero- and one-dimensional models, but only a limited number of two-dimensional (2D) models for downdraft fixed-bed reactors can be found in the literature. In this study, a 2D computational fluid dynamics (CFD) model was developed to study the gasification process in a downdraft configuration, considering drying, pyrolysis, combustion, and gasification reactions. The gas and solid phases were resolved using an Euler–Euler multiphase approach, with exchange terms for the momentum, mass, and energy. The standard k–e turbulence model was used in the gas phase. The model results were compared to existing data from a demonstration-scale fixed-bed downdraft gasifier. The simulation results exhibit a reasonable agreement with the experimental data. Parameter studies were performed on the basis.
Growth of Dysprosium-, Scandium-, and Hafnium-based Third Generation High-κ Dielectrics by Atomic Vapor Deposition†

Thin dysprosium-, scandium-, and hafnium-based oxide dielectric films are deposited by atomic vapor deposition (AVD) using tris(6-ethyl-2,2-dimethyl-3,5-decanedionato) dysprosium [Dy(EDMDD)3], tris(6-ethyl-2,2-dimethyl-3,5-decanedionato) scandium [Sc(EDMDD)3], and bis(tert-butoxide) bis(methoxymethyl propanoxide) hafnium [Hf(OtBu)2(mmp)2] as precursors. Spectroscopic ellipsometry (SE), Rutherford backscattering (RBS) spectrometry, and X-ray photoemission spectroscopy (XPS) demonstrate good control of the thickness and composition of the films. In particular, ternary and quaternary oxide alloys of any desired composition are grown. X-ray diffraction (XRD) shows that the (Dy0.5Sc0.5)2O3 films are amorphous as grown, whereas the (Dy0.5Hf0.5)4O7 and (Sc0.5Hf0.5)4O7 films are crystalline. The crystal structures of DyxHf1–xOy and ScxHf1–xOy change from monoclinic to cubic around x∼0.1.
Infrared Uplink Implementation for Software Defined Visible Light Communication Systems

A R T I C L E I N F O A B S T R A C T Article history: Received: 30 July, 2020 Accepted: 01 October, 2020 Online: 08 November, 2020 The main advantage of software-defined visible light communication (VLC) systems is that they allow us to reuse modulation, coding, synchronization and medium access techniques used in conventional radio systems. This article focuses on the implementation of an uplink alternative using an infrared (IR) light communication system. For this goal, analog frontends are designed and implemented. Therefore, they convert a radio frequency signal into an optical signal. In addition, a Universal Software Radio Peripheral (USRP) is used as a software-defined radio platform. The obtained bit error rate is 5.33 × 10 using QPSK modulation with a bit rate of 4 Mbps at a distance of 160 cm between transmitter and receiver.
“Living” Free-Radical Polymerizations in the Absence of Initiators: Controlled Autopolymerization

The autopolymerization of styrene, styrenic derivatives, and styrene/(meth)acrylate comonomer mixtures in the presence of stable nitroxide free radicals has been shown to be a “living” process. Molecular weight can be controlled by varying the ratio of vinyl monomer to TEMPO and low-polydispersity materials are obtained. Significantly, a definite incubation period is observed during these polymerizations, and the length of this incubation period increases with increasing amounts of TEMPO. The structures of the in situ generated unimolecular initiators which are formed during this incubation period correspond to those expected from a Mayo mechanism for the autopolymerization of styrene. The isolated and purified adducts, 4 and 5, were shown to be effective unimolecular initiators leading to low-polydispersity, controlled molecular weight polymers.
Fluorine‐enhanced oxidation of polycrystalline silicon and application to thin‐film transistor fabrication

The kinetics of the fluorinated oxidation of polycrystalline silicon thin films has been investigated and compared to the (100) single‐crystal silicon case. The growth of silicon dioxide was performed at oxidation temperatures down to 650 °C in dry ambients, which was made possible by fluorine‐induced oxidation enhancement; growth rates in the presence of fluorine additions approach those of wet oxidation. Silicon dioxide films grown on polycrystalline silicon were found to be thicker by about 10%–20% compared to films grown on (100) single‐crystal silicon oxidized under the same conditions. The application of fluorinated gate oxides in the fabrication of n‐channel polycrystalline silicon thin‐film transistors was found to improve the effective electron mobility.
Fundamental studies of microscopic wetting on organic surfaces. 2. Interaction of secondary adsorbates with chemically textured organic monolayers

Self-assembled monolayers of a series of terminally substituted alkyl thiols and disulfides chemisorbed on an Au(111) single-crystal surface were used as substrates for subsequent temperature-programmed desorption (TPD) studies. The monolayers studied were derived from adsorbates of the general structure HS(CH 2 ) 15 X or (S(CH 2 ) 15 X 1 ) (where X=CH 3 , CO 2 CH 3 , CH 2 OH, CO 2 H, and CONH 2 ). The adsorption of n-hexane, methanol, and water on these materials as well as on the clean Au(111) surface was examined. The data reveal complex behavior for the adsorption of secondary overlayers on these dense molecular solids especially in those substrate-adsorbate pairings capable of forming interlayer hydrogen bonds. It is also found that certain correlations can be made between the TPD data, a microscopic measurement, and the macroscopic wetting properties as defined by contact angle data
Luminescent carbon nanoparticles: effects of chemical functionalization, and evaluation of Ag+ sensing properties

Luminescent carbon-based nanoparticles, addressed as carbon dots (CDs), were synthesized at relatively low temperature from lactose following an easy and inexpensive procedure. Modification of their surface was done by functionalization with mercaptosuccinic acid (MSA) (CDs–MSA). Transmission electron microscopy images showed regular spherical nanoparticles of 5 nm diameter. Raw and functionalized (CDs–MSA) CDs were highly fluorescent at 448 and 472 nm, with relative high quantum yield (Φ = 0.21 and 0.46 respectively). At the maximum fluorescence of CDs–MSA the intensity was quenched by addition of Ag+ ions by a static mechanism with a Stern–Volmer constant of 3.7 × 103 M−1. The analysis of the emission spectra showed that the CD–MSA complex was stable after this process. The quenching profiles showed that only 44% of the CD–MSA fluorophores are accessible to Ag+. The main figures of merit were detection and quantification limits of 385.8 nM and 1.2 μM respectively, and the precision as relative standard deviation was 1.76%. No interference was observed when other metal ions were present indicating a high selectivity for Ag+ detection. The results showed that CDs–MSA can be used for efficient quantification of Ag+ in silver nanoparticle dissolution.
THE APPLICATION AND LIMITATIONS OF THE EDGE-DIFFRACTION TEST FOR ASTIGMATISM IN THE ELECTRON MICROSCOPE

The ultimate resolving power of the electron microscope lies between 2 and 3 A. In practice, astigmatism usually sets a higher limit. It is not difficult to correct astigmatism provided a sufficiently sensitive test is available. The paper analyses the edge-diffraction test quantitatively and shows that it can be used to give correction adequate for a resolving power at least as good as 10 A without resort to photography, and below this with the help of a series of micrographs. The conditions for the successive application of the test method are specified and practical aspects of its use discussed. It is shown that the edge-diffraction fringe can also be used as a test for the adequacy of mechanical and electrical stability, etc.
Effect of Heavy Metals on the Andrographolide Content, Phytochemicals and Antioxidant Activity of Andrographis paniculata

Andrographis paniculata is a medicinal plant that has several medicinal properties and has been traditionally used in different medicinal preparations. The present study deals with the influence of heavy metals (lead, mercury and silver) on andrographolide, phytochemicals and antioxidant activity in Andrographis paniculata. Two months old saplings were subjected to heavy metal stress of two different concentrations (0.2 mM and 0.4 mM) for three different times at 3 day time interval. The results showed that the saplings treated with heavy metals showed increased concentration of andrographolide content. The saplings treated with 0.4 mM silver showed the highest increase in the andrographolide content (24.58 ± 2.85 mg/g of DW) compared with control (9.41 ± 1.26 mg/g of DW) and other treatments. Variations in the biochemical parameters like total phenolic content, total flavonoid content, etc. were also prominent with all the treated samples when compared to that of control.
Secure Localization and Velocity Estimation in Mobile IoT Networks With Malicious Attacks

Secure localization and velocity estimation are of great importance in Internet-of-Things (IoT) applications and are particularly challenging in the presence of malicious attacks. The problem becomes even more challenging in practical scenarios in which attack information is unknown and anchor node location uncertainties occur due to node mobility and falsification of malicious nodes. This challenging problem is investigated in this article. With reasonable assumptions on the attack model and uncertainties, the secure localization and velocity estimation problem is formulated as an intractable maximum a posterior (MAP) problem. A variational-message-passing (VMP)-based algorithm is proposed to approximate the true posterior distribution iteratively and find the closed-form estimates of the location and velocity securely. The identification of malicious nodes is also achieved in the meantime. The convergence of the proposed VMP-based algorithm is also discussed. Numerical simulations are finally conducted and the results show the VMP-based joint localization and velocity estimation algorithm can approach the Bayesian Cramer Rao bound and is superior to other secure algorithms.
Sexting among University Students: Links to Internet Addiction and Psychological Variables

levels of Internet addiction are rising in this population. This has caused students to present certain risk behaviors that are linked to the development of psychological variables that affect health such as low self-control, depression, anxiety and stress. In this paper it was proposed as objective of the study to analyze the links that are established between the practice of sexting, Internet addiction, selfcontrol, depression, anxiety and stress. For this purpose, an online survey was applied to a sample of 1013 university students from a Spanish university, which collected four standardized instruments to measure the constructs of the study. The results showed that students who practiced sexting were associated with low self-control and higher levels of depression, anxiety and stress, as well as problematic Internet use. Furthermore, gender, living with parents, and daily Internet use were predictors of sexting. Finally, the main implications derived from the study in relation to the links of sexting and Internet addiction were collected
Heat Contents above 298.15°K. of Oxides of Cobalt and Nickel

High temperature heat content measurements of cobaltous oxide, cobalt spinel and nckelous oxide were conducted from 298 deg K to 1805, 999, and 1810 deg K, respectively. The heat content-temperature curve of nickelous oxide shows abrupt changes in slope at 525 and 565 deg K, indicating secondorder transformations. A table of heat content and entropy increments ahove 298.15 deg K and heat content equations are included for use in thermodynamic calculations. (auth)
Multihelical Lamb Wave Imaging for Pipe-Like Structures Based on a Probabilistic Reconstruction Approach

The special form of pipe-like structure provides the helical route for ultrasonic guided wave. Considering the pipe as a flattened plate but with periodical replications, the helical wave becomes intuitional and a corresponding imaging algorithm can be constructed. This work proposes the multihelical Lamb wave imaging method by utilizing the multiple arrival wavepackets which are denoted as different orders. The helical wave signal model is presented and the constant group velocity point is illustrated. The probabilistic reconstruction algorithm is combined with the separation and fusion of different helical routes. To verify the proposed scheme, finite element simulations and corresponding experiments are conducted. The cases of single-defect simulation and two-defect simulation indicate the successful and robust implementation of the imaging algorithm. The test on actual pipe damage is also investigated to show its capability in imaging an irregular defect. The comparison with imaging results from only first arrival demonstrates the advantage of multihelical wave imaging, including the better imaging resolution and higher localization accuracy.