Miracle-dz/UniFAR-FTUs huggingface dataset:
Grid Code-Dependent Frequency Control Optimization in Multi-Terminal DC Networks

The increasing deployment of wind power is reducing inertia in power systems. High-voltage direct current (HVDC) technology can help to improve the stability of AC areas in which a frequency response is required. Moreover, multi-terminal DC (MTDC) networks can be optimized to distribute active power to several AC areas by droop control setting schemes that adjust converter control parameters. To this end, in this paper, particle swarm optimization (PSO) is used to improve the primary frequency response in AC areas considering several grid limitations and constraints. The frequency control uses an optimization process that minimizes the frequency nadir and the settling time in the primary frequency response. Secondly, another layer is proposed for the redistribution of active power among several AC areas, if required, without reserving wind power capacity. This method takes advantage of the MTDC topology and considers the grid code limitations at the same time. Two scenarios are defined to provide grid code-compliant frequency control.
The influence of pyrolysing Al2O3 precursor on the high temperature properties of the YSZ-Al2O3 composite coating

In this research, YSZ-Alumina top coat was deposited on the Hastelloy substrate with a NiCrAlY bond coat by Atmospheric plasma spraying process. YSZ-10 wt-% Al2O3 composite coatings with pyrolysed and un-pyrolysed Al2O3 powder were deposited. High temperature oxidation and thermal shock resistance of both coatings were investigated. Thermal shock test results showed that the lifetime of the YSZ-10 wt-% Al2O3 coating was increased by the pyrolysation of the un-pyrolysed Al2O3. The network of micro-segmented cracks produced by the pyrolysation of the un-pyrolysed Al2O3 improved the strain accommodation, introducing it as the main enhancement mechanism for TBC life extension. Using of pyrolysed alumina, resulted increased in the flattening degree of the splats, and so reduction of porosity and intra-splat cracks. This, in turn, reduced the permeability of the top coat and decreased the rate of oxide growth on the bond coat.
Comparison of Parametric and Non-Parametric Techniques to Accurate Classification of Forest Attributes on Satellite Image Data

Satellite images classification techniques obtain large information in forest areas. Among various techniques, k Nearest Neighbors (kNN) as a non-parametric and MLC (Maximum Likelihood Classification) as a parametric technique have popularity in predict forest attributes by integrating the inventory field data and satellite images. In this study, comparisons between k Nearest Neighbor (kNN) non-parametric method and Maximum Likelihood Classification (MLC) parametric method was performed in forest attributes consists of volume, basal area, density, and tree cover type estimation in the north forest of Iran. Results showed that kNN non-parametric method produces an accurate classification map in comparison to the MLC parametric method and the accuracy of kNN has the most amount in all attributes. Kappa coefficient estimation showed that the kNN method had the most amount of this coefficient in all attributes. Accordingly, the kNN non-parametric technique was identified as a feasible classification technique to produce forest attributes thematic maps.
Hang in There: Stock Market Reactions to Withdrawals of COVID-19 Stimulus Measures

The COVID-19 pandemic prompted unprecedented economic stimulus worldwide. We empirically examine the impact of a withdrawal of fiscal stimulus policies on the stock markets. After constructing a database of withdrawal events, we use event study analysis and cross-country regressions to assess the difference between the pre- and post-event stock price returns. We find that markets react negatively to premature withdrawals—defined as withdrawals at a time when the daily COVID cases are high relative to their historical average—likely reflecting concerns about the withdrawal impact on the prospects for economic recovery. The design of a successful exit strategy from COVID-19 policy responses should account for these concerns.
Understanding nanoscale structural distortions in Pb(Zr0.2Ti0.8)O3 by utilizing X-ray nanodiffraction and clustering algorithm analysis.

Hard X-ray nanodiffraction provides a unique nondestructive technique to quantify local strain and structural inhomogeneities at nanometer length scales. However, sample mosaicity and phase separation can result in a complex diffraction pattern that can make it challenging to quantify nanoscale structural distortions. In this work, a k-means clustering algorithm was utilized to identify local maxima of intensity by partitioning diffraction data in a three-dimensional feature space of detector coordinates and intensity. This technique has been applied to X-ray nanodiffraction measurements of a patterned ferroelectric PbZr0.2Ti0. 8O3 sample. The analysis reveals the presence of two phases in the sample with different lattice parameters. A highly heterogeneous distribution of lattice parameters with a variation of 0.02 Å was also observed within one ferroelectric domain. This approach provides a nanoscale survey of subtle structural distortions as well as phase separation in ferroelectric domains in a patterned sample.
Sistema de preensão robótica utilizando Redes Neurais Convolucionais e Primitivas Geométricas

This work presents a grasping method based on RGB+D visual information, utilizing a convolutional neural network and point cloud. The neural network, using the SSD architecture, will detect the object in RGB image and its bounding box will be used as reference to isolate the object to be grasped in the point cloud from environment objects. After detecting the object, a grasping algorithm based on object primitive geometry will be used to estimate the object pose, allowing the grasping task. To validate the system, tests in a real world environment grasping objects from a 3D printer using a UR5 robotic arm, where it was proven that the proposed algorithm allow to detect objects in the point cloud, validating the performance of the proposed system. Resumo: Neste trabalho será apresentado um método de preensão robótica baseado em informação visual RGB+D, utilizando uma rede neural convolucional e nuvem de pontos. A rede neural, com arquitetura SSD512, detectará o objeto em imagem RGB e a área detectada na imagem será utilizada como referência na nuvem de pontos para isolar o objeto desejado do ambiente. Após o isolamento, um algoritmo de preensão robótica baseado em primitivas geométricas será aplicado para estimar a pose do objeto, permitindo a tarefa de preensão. Para validar o sistema, testes com peças feitas em uma impressora 3D e o braço robótico UR5 foram utilizados, onde foi demonstrado que a combinação dos algoritmos permite detectar objetos na nuvem de pontos, validando o desempenho do sistema proposto.
Fund Network Centrality, Hard-to-Value Portfolio, and Investment Performance

Based on the quarterly data of mutual funds in China from the fourth quarter of 2004 to the fourth quarter of 2019, this paper constructs a series of complex bipartite networks based on the overlapped portfolios of mutual funds and then explores the influences of fund network position on mutual fund’s investment behavior and performance. This paper finds that a mutual fund with shorter information transmission path to other entities in the fund network (i.e., having higher closeness centrality) or with stronger ties with those entities in important information positions (i.e., having higher eigenvector centrality) will achieve better investment performance. However, a stronger mediating role over the potential information flow of the fund network (i.e., having higher betweenness centrality) cannot help a mutual fund increase performance. The empirical results also indicate that a mutual fund holding stock portfolios with high valuation difficulties caused by the market or fundamental information uncertainty will achieve better investment performance, while holding hard-to-value portfolios caused by limited public information will reduce the performance of the fund. Furthermore, high closeness centrality or eigenvector centrality can help mutual funds deal with the disclose problems of public information, thus reducing the likelihood of a mutual fund holding hard-to-value portfolios caused by limited public information to achieve worse performance. Eigenvector centrality brings information advantages about company fundamentals, so it is easier for a mutual fund with high eigenvector centrality to profit from holding hard-to-value portfolios caused by the fundamental information uncertainty. The conclusions of this paper can enhance our understanding of the fund network and its information mechanism and shed new light on mutual fund’s information advantages and related asset allocation strategies.
An assessment of cogswell's method for measurement of extensional viscosity

Cogswell's method for measurement of extensional viscosity by determining the entry pressure loss in capillary viscometry is critically examined. Comparisons are made between extensional viscosity values introduced in finite element calculations as input data and predictions based on the calculated entry pressure losses for polymer melts. The calculated pressure losses are in good agreement with experimental data by Laun and Schuch. An equation proposed by Cogswell and another by Binding are used in the extensional viscosity comparisons. The slope of the extensional viscosity versus stretch rate is predicted rather well, but the calculations can shift the results above or below the true values.
A quartz crystal sensor oscillator appropriate for highly viscous liquid measurements

This study describes a sensor oscillator appropriate for quartz crystal microbalance (QCM) based measurements in highly viscous liquids. The oscillator is stabilized by a recently developed impedance transformation QCM filter network which greatly reduces electrical load by the sustaining amplifier. In addition, it provides zero phase and a well-behaved symmetric resonance at the QCM series resonant frequency fs over three orders of magnitude variation range of the motional resistance Rm. The sustaining amplifier has constant pure resistive input and output impedances to eliminate phase shifts due to QCM impedance changes with liquid load. Also, it allows precise gain and phase control for accurate adjustment of the oscillator frequency at fs and extraction of Rm information at the measured liquid load. The oscillator was tested with different water-based glycerol solutions in the 40–100 wt% range. The worst-case frequency error was 4.7% in this viscosity range.
The effect of total quality management on the financial performance by moderating organizational culture

This study aims to learn the effect of the Total Quality Management dimensions, Top Management Support, Customer Focus, Process Management, Employees Participation, Employees' Empowerment, and Continuous Improvement, on financial performance by moderating organizational culture. The study population includes nine transport companies listed on the Amman Stock Exchange until the end of 2019. Alia Company and Royal Jordanian Airlines were excluded since its financial data formed extreme values when compared with the values of the rest of the companies. The study uses Multiple Linear Regression to test the hypotheses. The study found a statistically significant effect at the level of significance (α < 0.05) for both top management support, customer focus, employees’ participation and empowerment, by moderating the organizational culture on financial performance measured by return on asset for the Jordanian transport companies listed on the Amman Stock Exchange. In light of the statistical results, the study presented several recommendations, the most important of which was to increase the top management interest in cultivating a profound organizational culture towards learning, development, mastering performance and improving the quality of its services to attract customers, and distinguish the organization from other organizations, in a way that reflects positively on developing its financial performance.
How language challenges affect the behaviour of immigrant learners in the Foundation Phase at three schools in Gauteng, South Africa

Background: The education of immigrant children is influenced by many factors that emanate from global socio-economic and political issues. In the South African education system, teachers do not have guidelines on how to include immigrant children from diverse linguistic and cultural backgrounds. The question that arose was ‘what effect does poor language proficiency have on immigrant learners’ psychosocial development? ’ Aim: This study focused on how language challenges experienced by immigrant children influence their relationships with themselves and others in the learning environment. The second objective was to find out how teachers are coping with immigrant learners. Setting: Learners were purposively selected from former Model C Foundation Phase classrooms in three selected schools in Gauteng province, South Africa. Former Model C schools are schools that accepted only white children prior to the early 1990s. Methods: This study uses an interpretive research paradigm with thematic analysis of data from focus group interviews and individual interviews. Participants were 48 Foundation Phase learners, 24 female educators and three school principals. Results: The results suggest that language barriers create a vicious cycle of negative emotions and unhealthy interactive patterns between immigrant and local children. Immigrant learners experience cognitive and social inhibition, isolation and bullying by the local learners. Conclusion: There are implications for the integration of psychosocial content in teaching a language. This could empower Foundation Phase teachers with guidelines for teaching English to all second language learners in a way that fosters positive adjustment of immigrant children and prosocial behaviour in the learning environment.
Attainable Region Approach in Analyzing the Breakage Behavior of a Bed of Olivine Sand Particles: Optimizing Impact Energy and Particle Size

In this study, we investigated the breakage behavior of a bed of olivine sand particles using a drop-weight impact test, with drop weights of various shapes (oval, cube, and sphere). An Attainable Region (AR) technique, which is a model-free and equipment-independent technique, was then applied to optimize the impact energy during the breakage process and also to get particles in defined particle size classes. The findings revealed that the different drop weights produce products within the three different particle size classes (feed, intermediate, and fine). A higher mass fraction of materials in the fine-sized class (−75 μm) was obtained when the spherical drop weight was used relative to the cubic and oval drop weights. The drop height was found to have a significant influence on the breakage process. The AR technique proved to be a practical approach for optimizing impact energy and particle size during the breakage of a bed of olivine particles, with potential application in sustainable soil stabilization projects.
Nickel telluride vertically aligned thin film by radio-frequency magnetron sputtering for hydrogen evolution reaction

The demand for renewable energy resources has led to the development of water electrolysis technology. Various transitional metal chalcogenides are investigated to adopt water electrolysis. Nickel telluride, from the family of transition metal chalcogenides, is attractive as a new cathode material for the hydrogen evolution reaction due to its metallic property. However, conventional approaches mainly focus on the solvothermal method and these have difficulty in controlling the alignment of nickel telluride. Therefore, another route to synthesize this material is necessary. In this study, for the first time, a radio-frequency (RF) magnetron sputtering method is used to synthesize a nickel telluride thin film and this method has the benefit of controlling the alignment of the nickel telluride thin film. By RF magnetron sputtering, a nickel telluride thin film is deposited on the substrate along the direction normal to the plane of the substrate, forming a columnar structure with vertical alignment. Its microstructure enables fast flow of electrons, having the advantage of hydrogen evolution reaction as a cathode material. The sample in optimized conditions shows a good performance with an overpotential of 416 mV and a Tafel slope of 63.79 mV dec−1. Therefore, the RF magnetron sputtering method can be adopted as a new approach to synthesize a vertically aligned electrocatalyst.
Engineering Nanoparticle Cluster Arrays for Bacterial Biosensing: The Role of the Building Block in Multiscale SERS Substrates

Noble metal nanoparticle cluster arrays (NCAs) are a novel class of engineered substrates for surface enhanced Raman spectroscopy (SERS), in which the noble metal nanoparticles interact on multiple length scales to create a multiscale E‐field cascade enhancement. In this work the role of the building block for the NCA performance is quantified. Periodic NCAs with constant cluster diameter (D = 200 nm) but variable nanoparticle diameter (d) and intercluster separation (Λ) were assembled on glass and their optical response and SERS enhancement were systematically characterized as a function of D, Λ, and d. An increase of d from 40 to 80 nm and simultaneous decrease of Λ from 200 to 50 nm led to an improvement of the ensemble averaged SERS enhancement factor by a factor of up to ∼8. The coefficient of variation (cv) of the enhancement factors (G) is significantly lower for the d = 80 nm NCAs than for the d = 40 nm and d = 60 nm NCAs. Optimized (D = 200 nm, Λ = 50 nm, d = 80 nm) NCAs show the overall highest signal reproducibility of all investigated NCAs and random nanoparticle substrates and achieve effective single cell detection sensitivity.
Does HIV impact susceptibility to COVID-19 (SARS-CoV-2) infection and pathology? A review of the current literature

Giving appropriate guidance to people living with HIV (PLWH) during the COVID-19 pandemic depends on having adequate data to inform recommendations. Several studies have now been published which inform such advice. The objective of this study was to collate this information and review the implications of emerging data.We performed a systematic literature search of studies relating COVID-19 to HIV infection from the beginning of the pandemic to end of November 2020. We included both published and pre-published manuscripts and analysed papers according to whether they primarily informed risk of infection or risk of adverse outcome.68 papers (including 11 pre-prints) were identified. In terms of risk of infection, it appears that PLWH are no more or less likely to become infected with COVID-19. In terms of outcomes and mortality, most early small studies did not demonstrate an increase in mortality compared to background populations. However, several larger, more recent studies from South Africa, New York and two from the UK demonstrate higher mortality among PLWH when results are adjusted for other risk factors, giving relative risks of 2.1, 1.2, 1.7 and 2.3 respectively. Apparently conflicting results may arise from differences between studies in their power to account for cofactors and confounding variables. HIV-positive non-survivors tend to be younger and have fewer comorbidities than their HIV-negative counterparts; mortality may be higher in PLWH with low CD4 counts.Although the literature appears conflicting, large studies which account for covariates strongly suggest that HIV infection increases COVID-19 mortality.
A streamlined CRISPR/Cas9 approach for fast genome editing in Toxoplasma gondii and Besnoitia besnoiti

Toxoplasma gondii (T. gondii) and Besnoitia besnoiti (B. besnoiti) are closely related coccidian parasites belonging to the phylum Apicomplexa, which comprises many other important pathogens of humans and livestock. T. gondii is considered a model organism for studying the cell biology of Apicomplexa mainly due to the ease of propagation in diverse host cells and the availability of a wide range of genetic tools. Conversely, B. besnoiti in vitro culture systems currently exist only for the acute phase of infection, and genetic manipulation has proven much more challenging. In recent years, the targeted editing of chromosomal DNA by the programmable CRISPR-associated (Cas)9 enzyme has greatly improved the scope and accuracy of genetic manipulation in T. gondii and related parasites but is still lagging in B. besnoiti. The CRISPR/Cas9 technology enables the introduction of single point and insertion/deletion mutations, precise integration of in-frame epitope tags, and deletions of genes at reduced time and cost compared to previous methods. Current protocols for CRISPR-mediated genome editing in T. gondii rely on either constitutive or transient expression of Cas9 as well as target specific sgRNAs encoded separately or together on transfected plasmid vectors. Constitutively expressed Cas9 carries the risk of toxicity, whilst the transient approach is laborious and error-prone. Here we present a protocol for plasmid vector-independent genome-editing using chemically synthesized and modified sgRNAs. This protocol allows for rapid and cost-effective generation of mutant cell lines of T. gondii and B. besnoiti.
Exchange Rate Volatility with Third-Country Risk Impact: A Bilateral Analysis of Pakistan with Major Trading Partners

1. Ph. D. Scholar, School of Economics, Quaid-i-Azam University Islamabad, Pakistan 2. Associate Professor, School of economics, Quaid-i-Azam University, Islamabad, Pakistan PAPER INFO ABSTRACT Received: October 13, 2020 Accepted: December 05, 2020 Online: December 31, 2020 A large body of literature has examined the impact of real exchange rate fluctuation on trade flows. Most of the studies report both positive and negative impact of exchange rate fluctuations on trade flows. In recent years, many studies point to the fact that third-country exchange rate risk also plays a vital role in affecting trade flows. Thus, this study aims to investigate the impact of bilateral exchange rate movements as well as third-country exchange rate risk on trade flows of Pakistan visà-vis her major trading partners. Hence all the previous studies provide country specific results, thus this research contributes by capturing real exchange rate and third country volatility effects by including major trading partners. The study employs the Autoregressive Distributed Lag Bounds testing Approach to co integration. This piece of research work finds significant evidence of the real exchange rate volatility and the thirdcountry risk impacts. The results point to the fact that when evaluating the implications of bilateral exchange rate uncertainty on bilateral trade flows, the third country exchange rate risk also needs to be taken into consideration.
Comparison of theories for the translational and rotational diffusion coefficients of rod‐like macromolecules. Application to short DNA fragments

Two theories relating the translational and rotational diffusion coefficients Dt and Dr of a rod‐like macromolecule to its length and diameter, proposed by Broersma [J. Chem. Phys. 74, 6989 (1981)], and Tirado and Garcia de la Torre [J. Chem. Phys. 71, 2581 (1979); 73, 1986 (1980)] are shown to predict different values of the coefficients for a particle of given dimensions. Next, we use the two theories to analyze existing experimental data of sedimentation coefficients s and translational and rotational diffusion coefficients of short DNA fragments, and obtain values of the hydrated diameter of DNA d which is treated as an adjustable parameter. The results are compared with the expected value, d≂26A. This comparison favors clearly the Tirado–Garcia de la Torre theory in the case of Dt and s. For Dr, and using a rise per base pair r=3.4 A, this theory gives best agreement for all the data examined, while when r=3.3 A, the agreement depends on the source of data.