Miracle-dz/UniFAR-FTUs huggingface dataset:
High Homogeneous Freezing Onsets of Sulfuric Acid Aerosol at Cirrus Temperatures

Abstract. Homogeneous freezing of aqueous solution aerosol particles is an important process for cloud ice formation in theupper troposphere. There the air temperature is low, the ice supersaturation can be high, and the concentration of ice-nucleating particles is too low to initiate and dominate cirrus cloud formation by heterogeneous ice nucleation processes. The most common description to quantify homogeneous freezing processes is based on the water activity criterion (WAC) as proposed by Koop et al. (2000). The WAC describes the homogeneous nucleation rate coefficients only as a function of the water activity, temperature and size of the aqueous aerosol particles, which makes this approach well applicable in numerical models. In this study, we investigate the homogeneous freezing behaviour of aqueous sulfuric acid aerosol particles by means of a comprehensive collection of laboratory homogeneous freezing experiments conducted at the AIDA (Aerosol Interaction and Dynamicsin the Atmosphere) cloud simulation chamber, which were conducted as part of 17 measurement campaigns since 2007. The most recent experiments were conducted during October 2020 with special emphasis on temperatures below 200 K. Aqueous sulfuric acid aerosol particles were generated at high purity by particle nucleation in a gas flow composed of clean synthetic air and sulfuric acid vapor, which was added to the AIDA chamber. The resulting chamber aerosol had number concentrations from 30 cm−3 up to several 1000 cm−3 with particle diameters ranging from about 30 nm to 1.1 μm. Homogeneous freezing of the aerosol particles was measured at simulated cirrus formation conditions in a wide range of temperatures between 185 K and 230 K with a steady increase of relative humidity during each experiment. At temperatures between about 205 K and about 230 K, the AIDA results agree well with the WAC-based predictions of homogeneous freezing onsets. At lower temperatures, however, the AIDA results show an increasing deviation from the WAC-based predictions towards higher freezing onsets. For temperatures between 185 K and 205 K, the WAC-based ice saturation ratios for homogeneous freezing onsets increase from about 1.6 to 1.7, whereas the AIDA measurements show an increase from about 1.7 to 2.0 in the same temperature range. Based on our experimental results, we suggest a new fit line as a parameterization for the onset conditions of homogeneous freezing of sulfuric acid aerosol particles. As a next step, we propose the new parameterization to be implemented in atmospheric models as an improved version of the WAC-based parameterization from Koop et al. (2000). The new homogeneous freezing thresholds may have significant impacts on the prediction of cirrus cloud occurrence and related cloud radiative effects.
Modeling population dynamics for information dissemination through Facebook

Online social networks such as Facebook and Twitter have become part of our daily lives. Their influence on business, politics, and society is considerable. Sensitive or unreliable information can adversely affect individuals, organizations, and governments. Due to the effects of the Covid‐19 epidemic, online news is more plentiful and accessible, which raises concerns about its reliability, quality, and authenticity. This article proposes the use of population dynamics model to study information dissemination on Facebook and a Susceptible‐Infected‐Recovered (SIR) model to examine information propagation as an outbreak of disease. We investigated 27 datasets with more than 270,000 messages, and the experiments showed that the population dynamics model is suitable for modeling the spread of information. The results revealed that information propagation could occur rapidly; after only 1–2 days. Additionally, we discovered that it is very crucial to find immediate solutions for preventing fake information as soon as it appears. This work enables us to understand the mechanism of information dissemination on social networks. This can help control and prevent the spread of misleading information, avoiding unintended consequences.
Comparative tanning ability of extracts from four North American species of acacia

The percentages of tannins in four common Acacia species, A. berlanderi, A. farnesiana, A. greggii, and A. rigidula and the efficacy of these tannins for the production of leather have been determined. Tannins were extracted with 70 percent acetone-water. Hide samples were treated in the conventional manner and suspended in tannin solutions. Tannins from A. farnesiana, A. berlanderi and A. rigidula penetrated the hide in 9 days and gave acceptable color. The yields of leather were best for A. rigidula and A. greggii. Water-soluble portions of the aqueous-acetone extracts of A. berlanderi and A. rigidula were similar to commercial extracts of wattle. Tannins from A. greggii occur in too small amounts to be useful and have some undesirable properties. Because of the widespread distribution and abundance of these plants, they may have potential as sources for commercial tannins.
Impacts of Lightning-Induced Overvoltage on a Hybrid Solar PV–Battery Energy Storage System

With increased electrical energy demands projected in the future, the development of a hybrid solar photovoltaic (PV)–battery energy storage system is considered a good option. However, since such systems are normally installed outdoors and in open areas, they are vulnerable to lightning strikes and may suffer from malfunctions or significant damage to sensitive components, which may result in a major breakdown and loss of revenue due to equipment replacement costs and inefficient operation. Thus, the objective of this paper is to investigate the effect of lightning-induced overvoltage on a hybrid solar PV–battery energy storage system, considering indirect lightning strikes nearby the system. The presented hybrid solar PV–battery energy storage system and lightning-induced overvoltage are modeled in Electro-Magnetic Transient Program-Restructured Version (EMTP-RV) software. The lightning-induced overvoltage is simulated based on a lightning waveshape of 10/350 µs using the Heidler expression, whilst the Rusck model is used to simulate the lightning-induced overvoltage. Different lightning current amplitudes (3, 19, and 169 kA), lightning strike locations (20, 50, and 100 m), and cable lengths (5, 10, and 20 m) are used to investigate the induced effects on the system and on the impulse withstand voltage of 6kV, as stated in MS IEC 60664-1 for solar PV–battery systems and inverters at the DC side. The results indicate that as the lightning strike distance increases from 20 to 100 m, the percentage of strikes exceeding the impulse withstand voltage reduces from 67% to 54% at 19 kA. At 169 kA, the impulse withstand voltage is exceeded by more than 100%, regardless of the strike distance (from 20 to 100 m). Furthermore, differences in cable length do not have much impact on the lightning-induced overvoltage due to the small voltage drop across the short cable length. This study provides useful information for PV systems owners and will be useful in assigning appropriate lightning protection schemes for PV farms.
Effective Selection of Variable Point Neighbourhood for Feature Point Extraction from Aerial Building Point Cloud Data

Existing approaches that extract buildings from point cloud data do not select the appropriate neighbourhood for estimation of normals on individual points. However, the success of these approaches depends on correct estimation of the normal vector. In most cases, a fixed neighbourhood is selected without considering the geometric structure of the object and the distribution of the input point cloud. Thus, considering the object structure and the heterogeneous distribution of the point cloud, this paper proposes a new effective approach for selecting a minimal neighbourhood, which can vary for each input point. For each point, a minimal number of neighbouring points are iteratively selected. At each iteration, based on the calculated standard deviation from a fitted 3D line to the selected points, a decision is made adaptively about the neighbourhood. The selected minimal neighbouring points make the calculation of the normal vector accurate. The direction of the normal vector is then used to calculate the inside fold feature points. In addition, the Euclidean distance from a point to the calculated mean of its neighbouring points is used to make a decision about the boundary point. In the context of the accuracy evaluation, the experimental results confirm the competitive performance of the proposed approach of neighbourhood selection over the state-of-the-art methods. Based on our generated ground truth data, the proposed fold and boundary point extraction techniques show more than 90% F1-scores.
Sustainable utilization of energy from waste: A review of potentials and challenges of Waste-to-energy in South Africa

ABSTRACT In South Africa, the burden placed on energy due to the rise in its demand coupled with the huge amount of untreated waste that ends up in landfills has called for the quest for sustainable energy utilization from waste resources. The literature has revealed a huge amount of theoretical energy potential recoverable from waste generated in Africa. However, many African countries are not yet exploiting the full potential energy inherent in waste to solve their energy and waste management crisis. To achieve success in WTE Industry, it is important to assess the peculiar local factors which impede its growth. The study evaluated the energy potential from waste in Africa with emphasis on South Africa’s case and the existing and proposed waste-to-energy (WTE) projects in South Africa. It was revealed that South Africa has the highest theoretical potential of energy from waste in Africa based on the quantity of generated and collected waste. About 104463 TJ/year and 22710 TJ/year can be recovered from incineration and landfill gas, respectively, in South Africa. Some of the barriers to full-operative WTE processing in South Africa were identified and discussed. Major resource-related barriers which are peculiar to South Africa’s waste management and energy system are the cheap and affordable coal resources and the low landfill tax. Recommendations for the future directions of WTE and sustainable energy recovery from waste in South Africa were made
Online peer feedback on video presentations: type of feedback and improvement of presentation skills

Abstract Peer feedback can be a tool to help higher education students develop presentation skills. This process can be supported by using online tools that enable peers to provide feedback annotated to specific moments in the presentation. The current paper investigated whether providing and receiving peer feedback using an online tool was related to improvement in students’ presentation skills, whether students provided different peer feedback in comments and annotations, and whether student characteristics played a role in students’ presentation skill improvement. Results from 56 second-year undergraduate Education and Child Studies students indicate that providing and receiving feedback did not relate to students’ improvement in presentation skill, and that high ability students showed less improvement in presentation skills than medium and low ability students did.
Photopolymerized additive manufacturing materials: Modeling of the printing process, mechanical behavior, and sensitivity analysis

The physical – chemical processes involved in light-induced polymerization (photopolymerization) are widely exploited in additive manufacturing (AM) technologies such as Stereolithography and Digital Light Processing. The influence of the AM process parameters on the physical properties of manufactured components has been often investigated through empirical methods based on the trial and error approach, that is, by collecting and interpreting a large amount of experimental data. However, when desired physical properties are required, accurate modeling of the liquid – solid conversion is necessary. In this work, in order to determine the properties of the resulting material according to the adopted process setup, we present a multi-physics approach to model the physical – chemical transformation taking place in photopolymerization. The role played on the final mechanical properties by the laser light intensity and by its moving speed is considered. Further, the influence of the uncertainty of the process parameters is investigated through a sensitivity analysis. The proposed approach is suitable for investigating the reliability of additively manufactured components as well as for their design according to an optimum printing strategy. From the perspective of making innovative functional materials, the proposed multi-physics model allows tuning the printing process in order to get the desired distribution of mechanical properties.
An overview of the Brazilian inselberg genus Ameroglossum (Linderniaceae, Lamiales), with the description of seven new species

Field studies of the inselberg fl ora of north-eastern Brazil have resulted in the discovery of much greater morphological diversity of the genus Ameroglossum, than previously envisaged. These enigmatic plants are endemic to isolated rock outcrops, which have long been surrounded by unsuitable habitat. The morphological forms are geographically isolated and stable in cultivation when grown under similar conditions. We here provide detailed descriptions of the two previously known species and propose an additional seven new species in the genus. A taxonomic revision of the genus, including an identifi cation key is provided. We hypothesize that the evolution of this genus is driven by the diversity of their hummingbird pollinators. Due to the threatened nature of inselberg habitats and the small populations found for most taxa, the species described here are likely to be under threat and in need for formal redlisting. European Journal of Taxonomy 746: 1–25 (2021) 2
Academic Language Tasks in Discipline-Specific Courses: Insights from three English-Medium Instruction Universities

Article History: Purpose: This study sought to investigate how undergraduate learners enrolled in EMI programs perceive the frequency and difficulty level of the academic language tasks in English in disciplinespecific courses and whether there is a correlation between the perceived difficulty and frequency levels of these tasks. Research Methods: The research population consisted of undergraduate learners from three English-medium instruction (EMI) universities in Turkey. Data were collected in the 2018-2019 academic year from 513 participants through a 28Received: 08 Aug. 2020 Received in revised form: 18 Sept. 2020 Accepted: 27 Feb. 2021 DOI: 10.14689/ejer.2021. 94.5
A CO-to-H2 Ratio of ≈10−5 toward the Herbig Ae Star HK Ori

Measurements of gas mass in protoplanetary gas disks form the basis for estimating the conditions of planet formation. Among the most important constraints derived from disk diagnostics are the abundances of gas-phase species critical for understanding disk chemistry. Toward this end, we present direct line-of-sight measurements of H2 and CO, employing UV absorption spectroscopy from Hubble Space Telescope Cosmic Origins Spectrograph to characterize disk composition, molecular excitation temperatures, and spatial distribution in the circumstellar material around the Herbig Ae stars HK Ori and T Ori. We observe strong CO (N(CO) = 1015.5 cm−2; T rot(CO) = 19 K) and H2 (N(H2) = 1020.34 cm−2; T rot(H2) = 141 K) absorption toward HK Ori with a CO/H2 ratio of (≡N(CO)/N(H2)) = × 10−5. These measurements place direct empirical constraints on the CO-to-H2 conversion factor in the disk around a Herbig Ae star for the first time, although there is uncertainty concerning the exact viewing geometry of the disk. The spectra of T Ori show CO (N(CO) = 1014.9 cm−2; T rot(CO) = 124 K) absorption. Interestingly, we do not detect any H2 absorption toward this star (N(H2) < 1015.9 cm−2). We discuss a potential scenario for the detection of CO without H2, which deserves further investigation. The low abundance ratio measured around HK Ori suggests significant depletion of CO in the circumstellar gas, which conforms with the handful of other recent CO abundance measurements in protoplanetary disks.
Reactive Current Control Strategy of CHB-DSTATCOM Based on Unit Vector

For a single-phase distribution network static synchronous compensator (DSTATCOM) based on cascaded H-bridge (CHB) converter, the design of dq control-based system is difficult due to the coupling effect and current fiction. To address this issue, first, the mathematical model of dq control is derived, then the unit vector (UV) control based on αβ frame is proposed. In this paper, the compensation current reference is obtained through the instantaneous power theory and unit vector method. Proposed control structure eliminates the effects of the decoupling control and the complex current fiction. In addition, the DC-voltage balance is achieved. Finally, the effectiveness of the proposed control strategy is verified by the simulation and experiments.
Substrate-supported dielectric arrays for refractometric sensing purposes

High index dielectric (HID) metasurfaces are gaining interest in nanophotonics due to their highly tunable optical response which stems from supporting both magnetic and electric resonances, and typically low material losses. These characteristics make them viable candidates for a variety of applications, which if based of silicon, could be in principle compatible with CMOS technology. Being geometrical in nature, the sensitivity of resonances of an isolated dielectric nanoresonator to the refractive index of a homogeneous environment is low. Hence, effort is needed to utilize them as sensors of their surrounding. Herein we discuss various physical aspects that govern the spectral response and sensitivity of HID particles and their metasurfaces to changes in their environment. The specific effects under study are the aspect ratio of a single HID antenna, interaction with a substrate, and the effect of interparticle coupling in amorphous metasurfaces. To provide optimal solutions for HID sensors, it is crucial to understand the interplay of the above effects and strive to attain a regime in which they work in tandem to maximize the sensitivity. We utilize the T-matrix method to carry out calculations with explicit HID nanoantennas as well as describe a computationally efficient and accurate T-matrix-based effective model of amorphous metasurfaces to describe their optical response, accounting for multiple scattering effects and the presence of the substrate. Using this approach, we elucidate how the investigated effects shape the sensitivity of a HID sensor and how to combine the various geometrical aspects to design a sensitive device.
Three-Dimensional Reconstruction of Tunnel Face Based on Multiple Images

The current geological sketch in tunnel engineering is mainly based on sketches of workers. However, geological sketch drawn by workers always offers fundamental data purely due to its drawing mode. A novel drawing method for geological sketch has been introduced using multiview photos in this process. The images of tunnel faces are taken from multiple angles, and every two pictures have overlaps. By measuring the distance between the camera and the tunnel face using a laser range finder, the photographic scale of each photo can be confirmed. SpeededUp Robust Features (SURF) is a good practice for detecting feature points, and the sparse point cloud is reconstructed from multiview photos by structure from motion (SFM). However, the sparse point cloud is not suitable for analysis for structural planes due to its sparsity. Therefore, patch-based multiview stereo (PMVS) is used to reconstruct dense point cloud from the sparse point cloud. After 3D reconstruction, the details of the tunnel face are recorded. The proposed technique was applied to multiview photos acquired in the Xiaosanxia railway tunnel and Fengjie tunnel in Chongqing, China. In order to record the geological conditions of the tunnel face quickly and accurately, Chengdu Tianyou Tunnelkey has developed a set of software and hardware integration system called CameraPad. Besides, CameraPad was used to collect the multiview photos of the tunnel face in the No. 1 Xinan railway tunnel in Jilin, China. By comparing with traditional and existing methods, the proposed method offers a more reductive model for geological conditions of the tunnel face.
Multiple ellipsoidal/elliptical inhomogeneities embedded in infinite matrix by equivalent inhomogeneous inclusion method

Traditional equivalent inclusion method provides unreliable predictions of the stress concentrations of two spherical inhomogeneities with small separation distance. This paper determines the stress and strain fields of multiple ellipsoidal/elliptical inhomogeneities by equivalent inhomogeneous inclusion method. Equivalent inhomogeneous inclusion method is an inverse of equivalent inclusion method and substitutes the subdomains of matrix with known strains by equivalent inhomogeneous inclusions. The stress and strain fields of multiple inhomogeneities are decomposed into the superposition of matrix under applied load and each solitary inhomogeneous inclusion with polynomial eigenstrains by the iteration of equivalent inhomogeneous inclusion method. Multiple circular and spherical inhomogeneities are respectively used as examples and examined by the finite element method. The stress concentrations of multiple inhomogeneities with small separation distances are well predicted by equivalent inhomogeneous inclusion method and the accuracies improve with the increase of eigenstrain orders. Equivalent inhomogeneous inclusion method gives more accurate stress predictions than equivalent inclusion method in the problem of two spherical inhomogeneities.
Synthesizing Cybersecurity Issues And Challenges For The Elderly

There are millions of users using the Internet daily including senior citizens or the elderly. This group is defined for users who are in the age range of 50-60 years old. In cybersecurity, the elderly is one of the most vulnerable groups of Internet users that is prone to cyberattacks. They are always the target and victimized by attackers, especially in cybercrime cases. However, not many pieces of research have been done on this specific group of users. Therefore, this paper will review and discuss cybersecurity issues and challenges involving the elderly. The main objective of this paper is to investigate the critical factors that contribute to the involvement of the elderly in cybercrime. It also includes the patterns of Internet usage, level of IT knowledge, and their awareness of the danger in the digital world. One of the reasons for the surge of the cyberattack vectors is due to lack of awareness on cybersecurity defence among Internet users. From the literature synthesized, the outcome of this paper proposes a framework of cybersecurity awareness for the elderly which can be used as a guide to educate and prevent them from being exploited in cybercrime.
The Microstructure of Cointegrated Assets

We define the micro price of multiple cointegrated assets. This yields a notion of fair prices, as a function of the observable state of multiple order books. We compute the microprices of two highly cointegrated assets, using Level-1 data collected on Interactive Brokers. We design an execution algorithm based on this two dimentional microprice and show that it can save half of the bid-ask spread cost. <br><br>The code for this paper is available here: https://github.com/xhshenxin/Micro_Price