Miracle-dz/UniFAR-FTUs huggingface dataset:
Novel cost-effective approach to produce nano-sized contact openings in an aluminum oxide passivation layer up to 30 nm thick for CIGS solar cells

This work presents a novel method of local contact openings formation in an aluminum oxide (Al2O3) rear surface passivation layer by the selenization of the lithium fluoride (LiF) salt on top of the Al2O3 for ultra-thin copper indium gallium (di)selenide (CIGS) solar cells (SCs). This study introduces the potentially cost-effective, fast, industrially viable, and environmentally friendly way to create the nano-sized contact openings with the homogeneous distribution in the thick, i.e. up to 30 nm, Al2O3 passivation layer. The passivation layer is deposited by atomic layer deposition, while the LiF layer is spin-coated. Selenization is done in the H2Se atmosphere and the optimal process parameters are deduced to obtain nano-sized and uniformly allocated openings as confirmed by scanning electron microscopy images. The contact openings were produced in the different thicknesses of the alumina layer from 6 nm to 30 nm. Furthermore, the Al2O3 rear surface passivation layer with the contact openings was implemented into ultra-thin CIGS SC design, and one trial set was produced. We demonstrated that the created openings facilitate the effective current collection through the dielectric Al2O3 layer up to 30 nm thick. However, the upper limit of Al2O3 thickness in which the contact openings can be created by the described method is not established yet. The produced passivated CIGS SCs show increased external quantum efficiency response due to the optical enhancement of the passivated cells. However, the production of SCs on the Al2O3 passivation layer with the openings created by selenization of LiF is not optimized yet.
Fabrication and characterization of PCL/gelatin/curcumin nanofibers and their antibacterial properties

Phytochemicals have been used over the centuries in order to cure various diseases and still do to this day. Phytochemicals are herbal extracts that are also named herbal remedies. Curcumin (CUR), which is a natural polyphenolic compound derived from the roots of the plant Curcuma Longa, has many therapeutic properties. CUR has poor water solubility and instability that has confined its further applications, thus there is need for a carrier to deliver the drug consistently. In this research, the feasibility of using polycaprolactone/gelatin nanofibers as carriers for CUR is examined. Nanofibers are obtained by electrospinning method. The morphology of nanofibers was observed by scanning electron microscopy. Fourier Transform Infrared Spectroscopy and differential scanning calorimetry is used to study the thermal behavior of the nanofibers. Antibacterial tests were conducted against methicillin-resistant staphylococcus aureus (MRSA) and extended spectrum β lactamase (ESBL). These pathogens are very dangerous and versatile pathogens emerging rapidly causing nosocomial infections in hospitals. The nanofibers were 99.9% antibacterial against MRSA and 82.56% against ESBL. The results showed that these nanofibers have potent antibacterial activity against both Gram positive and Gram negative bacteria. As a result, these nanofibers are very promising materials for antibacterial applications.
Distributed adaptive robust
 H
 ∞
 control of intelligent‐connected electric vehicles platooning subject to communication delay

With an aim to improve the performances of intelligent-connected electric vehicle platoon with communication delay, we present a distributed adaptive robust H ∞ control scheme in this paper. First, the longitudinal non-linear dynamic model of vehicle i is established, and in order to reduce the difﬁculty of analysing such a non-linear system, a simpliﬁed uncertain dynamic model of vehicle i is obtained via a feedback linearisation method. Second, a novel distributed state-feedback robust platoon controller is designed by using the relative information between neighbouring electric vehicles. Third, we derive the sufﬁcient condition that the presented distributed robust platoon controller exists under the inﬂuence of communication delay. This condition is given in the form of a linear matrix inequality, which is low dimensional and whose dimension is independent of the length of the intelligent electric vehicle platoon. Furthermore, the closed-loop platoon system controlled by the presented controller is proved stable subject to communication delay by using the Lyapunov stability theory. In addition, an adaptive control term is added to the robust platoon controller. We present the sufﬁcient condition that such a modiﬁed controller exists and prove the platoon string stability. Finally, the effectiveness of the presented adaptive robust platoon control scheme is veriﬁed by conducting numerical simulation tests.
Cellular Communication-Based Autonomous UAV Navigation with Obstacle Avoidance for Unknown Indoor Environments

: The technology of Unmanned Aerial Vehicles (UAV) has been the subject of pioneering research in recent years. Also, the subject has been used in various situations for both outdoor and indoor. In this paper, a cellular communication-based autonomous UAV Navigation is proposed that enables UAVs to maneuver independently in previously unknown and GPS-denied indoor environments with LiDAR sensors. The main idea of the proposed scheme is to implement LTE connection to UAV Navigation and compared it to a Wi-Fi connection. We have proposed that autonomous UAV navigation system for unknown environment like indoor. This system relies on the combination of ROS-based Hector SLAM systems, 2D-LiDAR sensor and LTE connection. The performance of proposed scheme is evaluated as the error distance and exploration time for unknown area like indoor environment. The mapping efficiency of LTE connection is 57.5% greater than the Wi-Fi connection. Computation time for flight is approximately 200 seconds.
Spatial variability of Regosol chemical atributes in guava management with neem under semi-arid conditions

Considering the relevant importance of guava (Psidium guajava) in Northeastern Brazil along with the benefits of neem cake amendments on soil characteristics, this work evaluated the effects of neem cake on chemical attributes of a Regosol under irrigated guava orchard in an alluvial valley of Pernambuco semi-arid region. Evaluations were carried out in two areas (area 1 - with neem cake; area 2 - without neem cake) at three periods: before the first application of neem cake, 90 days after the first application and 90 days after the second application. A regular 8 × 6-point grid was designed in each area and the soil was sampled for total organic carbon, pH, soluble salts (Na+, K+, Ca2+ and Mg2+) and total nitrogen contents, as well as soil C-CO2 evolution rate in soil. Geostatistical analysis pointed out the spherical model as the best fit to the studied variables, followed by the Gaussian model, with ranges from 12 to 60.5 m. Neem cake incorporation increased spatial variability and the contents of the evaluated soil chemical attributes.
Miniaturize four‐port UWB‐MIMO antenna with tri‐notched band characteristics

In this article, a compact and high performance 4‐port ultra‐wideband multiple‐input multiple‐output antenna is presented. The proposed antenna is designed by using a novel technology which includes integration of four orthogonal octad‐shaped radiators, four D‐shaped ground planes, multi‐stub techniques and slot techniques. The overall size of the design is effectively miniaturized and the ultra‐wideband characteristics are achieved through feed line tapering and by inserting slot in the D‐shape ground structure. Moreover, tri‐band notch characteristics are achieved in the proposed design by embedding L‐shaped stubs in the octad radiating elements. This results in impedance bandwidth of 2.6‐12.2GHz with notched characteristics at bands ranging from 3‐3.7GHz, 5‐6GHz and 7.9‐8.3GHz. In addition, the antenna shows high isolation and good diversity performance in terms of Envelop Correlation coefficient, Diversity gain and Total active reflection coefficient. A good trade‐off of performance has achieved from the proposed design makes it best candidate for wireless communication applications.
Stochastic Response of Hysteresis System Under Combined Periodic and Stochastic Excitation Via the Statistical Linearization Method

A statistical linearization approach is proposed for determining the response of the single-degree-of-freedom of the classical Bouc–Wen hysteretic system subjected to excitation both with harmonic and stochastic components. The method is based on representing the system response as a combination of a harmonic and of a zero-mean stochastic component. Specifically, first, the equation of motion is decomposed into a set of two coupled non-linear differential equations in terms of the unknown deterministic and stochastic response components. Next, the harmonic balance method and the statistical linearization method are used for the determination of the Fourier coefficients of the deterministic component, and the variance of the stochastic component, respectively. This yields a set of coupled algebraic equations which can be solved by any of the standard apropos algorithms. Pertinent numerical examples demonstrate the applicability, and reliability of the proposed method.
A molecular dynamics study on the local mobility of cis-polyisoprene within the mixed glassy/rubbery states induced by graphene planes

The glass transition behavior of a simulated model consisting of cis-1,4-polyisoprene nanofilm confined within parallel graphene planes was visualized through chain mobility statistics. Firstly, simulated annealing molecular dynamics (MD) simulations were performed for a system of bulk polyisoprene and the polyisoprene nanofilm within parallel graphene planes at two different gap sizes. The glass transition temperature (T g) and the critical density of bulk polyisoprene were then calculated. The critical density was used to compare with the local density of the confined polyisoprene segments. The mixed glassy/rubbery states were found at temperatures higher than the bulk T g. It was also shown that bulk modulus was increased when graphene planes are present and was further increased when the gap between graphene planes became narrow, and a ‘glassy bridge’ was formed by the highly confined nanofilm with highly-ordered polymer chains. Then, local mobility of each polyisoprene chain segment was quantified through the square displacement (SD) after a 1 ns motion. Local glass transition within any region was determined by whether local SD was lower than the critical mean square displacement (MSD0) of bulk polyisoprene, which was in the ‘glassy regime. ’ The analysis results showed that decreasing the temperature and reducing the gap between graphene planes increased the proportion of chain segments in the glassy regime and were in concurrence with the increased bulk modulus.
Factor Structure and Invariance Analysis of the Center for Epidemiologic Studies Depression Scale – Revised (CESD-R) in a Brazilian Population

Introduction: The Center for Epidemiologic Studies Depression Scale – Revised (CESD-R) was developed to provide an efficient screening scale for depression syndrome, mimicking the original CESD, one of the most widely used screening tools to measure depressive symptoms globally. This investigation examined the factor structure of the CESD-R with a non-clinical Brazilian population. Method: We performed exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) of two adult samples, and also conducted invariance analysis by sex and place of residence of the participants. The full sample consisted of 1,427 adults, divided into two groups. The first sample (n = 400) was used for the EFA and the second sample (n = 1027) for the CFA. Results: The EFA indicated an internal structure composed of a single factor, which explained 53.2% of the variance. The CFA attested to the unidimensionality of the measure. Fit indices and reliability indicators showed values higher than expected, without modifications in the initial structure. The model was invariant in relation to the variables investigated at four different levels (configural, metric, scalar, and strict). Conclusions: Our findings support the utility of the CESD-R and suggest its validity for application to the Brazilian population in general. © 2021 Fundación Universitaria Konrad Lorenz. This is an open access article under the CC BY-NCND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Estrutura Fatorial e Análise de Invariância da Center for Epidemiologic Studies Depression Scale – Revised (CESD-R) em uma População Brasileira Resumo Introdução: A Center for Epidemiologic Studies Depression Scale – Revised (CESD-R) foi elaborada para fornecer um eficiente diagnóstico de sintomas de depressão, seguindo a proposta original da CESD, que é uma das escalas para rastreamento da depressão mais utilizadas mundialmente. Esta pesquisa avaliou a estrutura fatorial da CESD-R em uma população não-clínica no Brasil. Método: Realizaram-se análises fatoriais exploratória (AFE) e confirmatória (AFC) com duas amostras compostas por adultos. Também foi verificada a invariância do modelo por sexo e local de residência do participante. A amostra total foi composta por Factor Structure and Invariance Analysis of the Center for Epidemiologic Studies Depression Scale – Revised (CESD-R) in a Brazilian Population Andre Faro *, Daiane Nunes dos Santos a, William W. Eaton b a Department of Psychology, Federal University of Sergipe, Brazil b Department of Mental Health, Bloomberg School of Public Health, Johns Hopkins University (JHU), Baltimore, MD, USA Received 7 September 2019; accepted 4 September 2020
Effect of Fluid Flow Direction on Charging of Multitube Thermal Energy Storage for Flat Plate Solar Collectors

Flat plate solar collector plays a significant role in domestic water heating due to the ease of operation and maintenance. The rmal energy storage with phase change materials is used to store heat energy. The thermal performance of paraffin wax-based multitube latent heat storage with a flat plate solar collector is investigated experimentally. The present work focuses on the fluid flow direction for charging and discharging in a vertical multitube-based thermal storage unit. The charging process took about four hours, with a fluid flow rate of 0.02 kg/s at about 70°C . The flat plate solar collector's thermal efficiency is 56.42% for the fluid flow rate of 0.02 kg/s at the average solar radiation of about 600 W/m 2 . During the discharge process, there was an increase in water temperature by 40°C at a fluid flow rate of 0.01 kg/s in 30 minutes. The 25-liters of water is circulated to discharge the stored heat. The heat storage effectiveness is varied between about 0.4 and 0.75. During the discharge, the flow of water from the center to the periphery showed about a 1.7% higher temperature than that of the water from the periphery to the center. For charging the heat storage, the preferred fluid flow mode is from the periphery to the center. The employment of latent heat storage with a solar collector is beneficial for our thermal needs after sunshine hours.
Dehazing of Satellite Images using Adaptive Black Widow Optimization-based framework

ABSTRACT Haze is a common atmospheric disturbance that adversely affects the quality of optical data, thus often restricting their usability. Since these effects are inherent in the process of spaceborne Earth sensing, it is important to develop effective methods to remove them. This work proposes a novel method for de-hazing satellite imagery and outdoor camera images. It is developed by modifying the transmission map used in Dark Channel Prior (DCP) method. A Weighted Variance Guided Filter (WVGF) is introduced for enhancing the image quality, which included a two-stage image decomposition and fusion process. The method also optimally combines the radiance and transmission components along with an additional stage modelling a fusion-based transparency function. A final guided filter-based image refinement scheme is incorporated to improve the processed image quality. The optimal tuning of the image-dependent parameters at various stages is achieved using the newly proposed Adaptive Black Widow Optimization (ABWO) algorithm, which makes the proposed de-hazing scheme fully automatic. Qualitative and quantitative performance analyses, and the results are compared with other state-of-the-art methods. The experimental results reveal that the proposed method performs better as compared with others, independent of the haze density, without losing the natural look of the scene.
The shape memory properties of multi-layer graphene reinforced poly(L-lactide-co-ϵ-caprolactone) by an atomistic investigation

In this paper, an atomistic investigation was performed to reveal the dependence of the graphene content on the shape memory effect of the multilayer graphene reinforced poly (L-lactide-co-ε-caprolactone). Uniaxial compression deformation was carried out to show the shape memory effect of the graphene composites. The temperature response of the composites was obtained during shape recovery. It is observed that the composites with higher graphene content exhibit larger recovery ratio and are more sensitive to temperature during a gradual warming recovery. The graphene composites show good reusable properties and the shape of composites is able to fully recover by constant temperature recovery tests. Especially, the graphene of the composite was subjected to a separate heating test to check the role of the graphene in shape recovery of the composite, where electro-induced indirect heating was qualitatively simulated. It is shown that the recovery first appeared in composites with the most content of graphene. The polymer will have a temperature hysteresis compared with graphene in composites. The shape recovery trajectory of graphene and the evolution of the interaction between graphene and polymers during the process of shape memory were clearly presented to reveal the mechanism how graphene promotes the performance of shape memory. This research can provide a guidance for obtaining composite materials with ideal shape memory effect.
The Choice between Renewables and Non-renewables: Evidence from Electricity Generation in 29 Countries

We examine how per capita income and relative fossil fuel prices influence the use of non-renewables (oil, coal and natural gas), nuclear, hydroelectric, and other renewables in electricity generation. Panel regressions are estimated using the fully modified ordinary least squares method and data across 29 countries (1985-2017). We include both developed and developing economies whose classification status is allowed to vary during the sample period depending on per capita income.Results suggest that oil prices play a dominant role in boosting the use of renewables, while gas serves as a transition fuel. For developing nations, income is a significant constraint in the use of renewables, while coal and gas prices do not significantly influence the use of hydro and nuclear. This finding supports a shift away from the exclusive use of pricing mechanisms towards set targets linked to per capita income to encourage the use of renewables in developing economies.
Wave characteristics in elliptical orthorhombic media

An elliptical anisotropic medium is defined as a simplified representation of anisotropy in which the anelliptic parameters are set to zero in all symmetry planes. Despite the fact that this model is rather seldom observed for real rocks, it is often used as a reference model. The P-wave equations for an elliptical anisotropic medium are well known. However, the shear wave (S-wave) equations have not been derived. Thus, we have defined all wave modes in elliptical orthorhombic models focusing mostly on the S-wave properties. We determine that all wave modes in elliptical orthorhombic model are generally coupled and analyze the effect of the additive coupling term. As a result, there is an S-wave fundamental singularity point located in one of the symmetry planes depending on the relative magnitude of S-wave stiffness coefficients.
Modelling of minor hysteresis loop of shape memory alloy wire actuator and its application in self-sensing

Shape memory alloy (SMA) wire actuators offer large force and displacement capabilities out of the stress and temperature-dependent martensitic phase transformation. Among the various modelling approaches in the literature, the one proposed by Boyd and Lagoudas (1996), is mostly used in analysing SMA based components. In practice, partial actuation is often required and is enacted by aborting and subsequently resuming the phase transformation; exhibiting minor hysteresis response. The existing models are found to be inaccurate in simulating such partial transformation cases. In this study, a novel yield parameter, which depends on the martensite volume fraction, has been proposed; enabling the model of Boyd and Lagoudas to simulate minor hysteresis loop accurately. The corresponding model parameters are derived, satisfying certain practical aspects of the SMA response. Using the modified model, pseudoelastic responses are simulated for different partial loading cases and are compared against the same obtained from the existing models, illustrating its efficacy. Following the proposed model, the discrete form of the system dynamics of a SMA wire actuator is formulated. Using this, an extended Kalman filter (EKF) has been developed, to estimate the output of the system from the change in electrical resistance of the SMA wire during actuation. This approach eliminates the requirement of external sensors for feedback control. Using the developed EKF, the response of an SMA wire actuated system is estimated from the experimentally measured electrical resistance data of the SMA wire and are compared with the corresponding measured responses. The results reveal that a significant level of accuracy can be achieved with the proposed approach.
An illumination invariant algorithm for subpixel accuracy image stabilization and its e ! ect on MPEG-2 video compression h ig y dem Erog y lu Erdem * ,

This paper o! ers a fast and simple near-closed-form solution for the least mean-squared-error (LMSE) estimation of the frame-to-frame global subpixel motion in an unsteady image sequence. The o! ered near-closed-form solution achieves unlimited subpixel accuracy by always employing a small and "xed number of computations, independent of the desired subpixel accuracy. The algorithm is designed so that it is insensitive to frame-to-frame intensity variations, which is a distinctive feature of the method. Experimental results demonstrate the superiority of the proposed method to the spatio-temporal di! erentiation and surface "tting algorithms under di! erent illumination conditions. This paper furthermore discusses the e! ect of the proposed image stabilization algorithm on the performance of MPEG-2 video compression. We report that removal of global motion down to subpixel accuracy from an unsteady video improves MPEG-2 compression performance signi"cantly (by at least 1 dB for all frame types), in spite of the fact that motion vectors are di! erentially encoded in MPEG-2. This result is supported via experimental results using the proposed subpixel registration algorithm and an analysis of the macroblock coding preferences accepted in MPEG-2. 2001 Elsevier Science B.V. All rights reserved.