bluuebunny/crossref_metadata_2025 huggingface dataset:
Measuring the Impact of Language Models in Sentiment Analysis for Mexico’s COVID-19 Pandemic
Authors: León-Sandoval Edgar , Zareei Mahdi , Barbosa-Santillán Liliana Ibeth , Falcón Morales Luis Eduardo
Published: August 2022

The world has been facing the COVID-19 pandemic, which has come with an unprecedented impact on general physical health and financial and social repercussions. The adopted mitigation measures also present significant challenges to the population’s mental health and health-related programs. It is complex for public organizations to measure the population’s mental health to incorporate its feedback into their decision-making process. A significant portion of the population has turned to social media to express the details of their daily life, making these public data a rich field for understanding emotional and mental well-being. To this end, by using open sentiment analysis tools, we analyzed 760,064,879 public domain tweets collected from a public access repository to examine the collective shifts in the general mood about the pandemic evolution, news cycles, and governmental policies. Several modern language models were evaluated and compared using intrinsic and extrinsic tasks, that is, the sentiment analysis evaluation of public domain tweets related to the COVID-19 pandemic in Mexico. This study provides a fair evaluation of state-of-the-art language models, such as BERT and VADER, showcasing their metrics and comparing their performance against a real-world task. Results show the importance of selecting the correct language model for large projects such as this one, for there is a need to balance costs with the model’s performance.
Antenna Designs for 5G/IoT and Space Applications
Authors: Tubbal Faisel , Matekovits Ladislau , Raad Raad
Published: August 2022

Antenna design has received renewed attention in the last few years [...]
Crime Scene Shoeprint Image Retrieval: A Review
Authors: Wu Yanjun , Dong Xianling , Shi Guochao , Zhang Xiaolei , Chen Congzhe
Published: August 2022

Shoeprints performs a vital role in forensic investigations. It has been an advanced research issue in forensic science. The main purpose of shoeprint image retrieval is to acquire a ranking list of shoeprint images in a database, according to their feature similarities to the query image. In this way, a shoeprint can not only be used as an exhibit for bringing criminal charges but also to provide a clue to a case. The goal of this work is to present an overview of the existing works conducted in shoeprint image retrieval. We detail the different phases of the shoeprint retrieval task and present a summary of the state-of-the-art methods. We analyzed the difficulties and problems in this field and discussed future work directions. This review may help neophytes become involved in research easily and quickly.
Fundamental Investigation of Wave Propagation inside IC-Striplines upon Excitation with Hertzian Dipole Moments
Authors: Kreindl Dominik , Bauernfeind Thomas , Weiss Bernhard , Stockreiter Christian , Yenumula Suresh Kumar , Narayanan Bhuvnesh , Kaltenbacher Manfred
Published: August 2022

To characterize the electromagnetic compatibility (EMC) of integrated circuits (ICs), especially the radiated emissions in the near field, transversal electromagnetic cell (TEM cell) or IC-stripline measurements (IEC 61967) are utilized. Due to the ongoing miniaturization and the increasing operating frequencies, accurate EMC characterization of ICs is becoming more important to achieve first-time-right designs. In order to avoid expensive redesigns, the prediction of these measurements in terms of a simulation workflow would be of high interest. Because of the high computational burden needed to conduct 3D full-wave finite element (FEM) simulations of both the device under test (DUT) and the measurement system, an equivalent representation of the DUT by means of analytical incident fields, such as Hertzian dipole moments, can be considered. In order to develop an order-reduced model of this kind, it is essential to have a solid understanding of the coupling and wave propagation effects inside the measurement systems. In the present paper, a fundamental investigation of the coupling paths between an IC-stripline and electric or magnetic dipole moments is presented and the results are compared to the existing analytical models. The results show that these analytical models, originally developed for TEM cells, are only partially valid for IC-striplines. It has also been shown that even for simple test structures, such as loop and monopole antennas, the representation in terms of one single dipole moment is insufficient.
Towards Data-Driven Fault Diagnostics Framework for SMPS-AEC Using Supervised Learning Algorithms
Authors: Kareem Akeem Bayo , Hur Jang-Wook
Published: August 2022

The service life of aluminium electrolytic capacitors is becoming a critical design factor in power supplies. Despite rising power density demands, electrolytic capacitors and switching devices are the two most common parts of the power supply that age (deteriorate) under normal and diverse working conditions. This study presents a fault diagnostics framework integrated with long-term frequency for a switched-mode power supply aluminium electrolytic capacitor (SMPS-AEC). Long-term frequency condition monitoring (CM) was achieved using the advanced HIOKI LCR meter at 8 MHz. The data acquired during the experimental study can help to achieve the needed paradigm from various measured characteristics of the SMPS/power converter component to detect anomalies between the capacitors selected for analysis. The CM procedure in this study was bound by the electrical parameters—capacitance (Cs), equivalent series resistance (ESR), dissipation factor (DF), and impedance (Z)—-acting as degradation techniques during physical and chemical changes of the capacitors. Furthermore, the proposed methodology was carried out using statistical feature extraction and filter-based correlation for feature selection, followed by training, testing and validation using the selected supervised learning algorithms. The resulting assessment revealed that with increased data capacity, an improved performance was achieved across the chosen algorithms out of which the k-nearest neighbors (KNN) had the best average accuracy (98.40%) and lowest computational cost (0.31 s) across all the electrical parameters. Further assessment was carried out using the fault visualization aided by principal component analysis (PCA) to validate and decide on the best electrical parameters for the CM technique.
Analysis and Visualization of the Instantaneous Spatial Energy Density and Poynting Vector of the Wireless Power Transfer System
Authors: Kang Jianwei , Lu Jie , Zeng Deyu , Shi Xiangyang
Published: August 2022

This study analyzes the instantaneous spatial energy density and Poynting vector in the WPT system and presents time-varying distributions and animations of this energy density and Poynting vector. First, the energy density is decoupled by two self-energy densities of each coil and the mutual energy density of the two coils. Result reveals how the energy is stored in the WPT system. Second, the Poynting vector is analyzed, and it is found that the power is transferred only in the last half period of the Poynting vector, not at every moment of the whole period. This instantaneous Poynting vector also possesses a characteristic that shows no power flow on the condition that the current phase difference equals zero. This finding is different from the energy density and indicates that the instantaneous Poynting vector can perfectly interpret how power is transferred in the WPT system. Finally, a simulation and an experiment were conducted to verify the correctness of the analysis. This study contributes to a deeper and better understanding of the intrinsic characteristics of energy storage and power flow in the WPT system, and can be referred to for WPT system design and optimization when one considers the EMC or human electromagnetic field exposure problem.
Measurement of Instantaneous Mass Flow Rate of Polypropylene Gasification Products in Airflow
Authors: Vnuchkov Dmitry , Zvegintsev Valery , Nalivaichenko Denis , Frolov Sergey
Published: August 2022

A simple semi-empirical gas-dynamic approach for measuring the instantaneous mass flow rate of gasification products of low-melting solid material (polypropylene) in a flow-through gas generator with ambient-temperature air as gasifying agent is proposed. The approach is validated experimentally in the direct-connect facility allowing for the short-term (~0.5 s) heating of incoming air up to ~1700 K by hydrogen injection and ignition or by pyrotechnic charge activation. The application of the proposed method for processing experimental data for 9 (of over 100) selected typical test fires showed that the time-averaged total yield of polypropylene gasification products varied from 43 to 120 g/s, while the air-to-gasification product mass ratio was 2.3–2.9. The results of all conducted experiments confirm the applicability of the proposed approach for determining the mass flow rate of gasification products. The universality of the proposed approach is confirmed by applying two different schemes of gas generator: one with hydrogen ignition and another with pyro-charge ignition.
Quantitative Evaluation of Imbibition Damage Characteristics of Foaming Agent Solutions in Shale Reservoir
Authors: Dou Liangbin , Chen Jingyang , Li Nan , Bai Jing , Fang Yong , Wang Rui , Zhao Kai
Published: August 2022

Shale reservoirs are characterized by extremely low porosity and permeability, poor connectivity, and high content of clay minerals. This leads to the reservoir being vulnerable to imbibition damage caused by foaming agent solutions during foam drainage gas recovery. It results in the decrease of reservoir permeability and the reduction of gas well production and ultimate recovery. Therefore, as the most commonly used foam drainage gas production, it is particularly important. This study is structured as follows. First, we analyze and evaluate the characteristics of shale reservoirs within the target area, and that of mineral composition and microscopic pore throat structures. Second, we study foaming agent types and two types are selected to be applied in subsequent sensitivity tests. Simultaneously, the nuclear magnetic resonance (NMR) method was used to study the microscopic characteristics of reservoir damage and imbibition damage of shale, caused by the impact of foaming agent solutions during the foam drainage and gas recovery processes. Finally, it is concluded that the degree of damage to the core permeability is minimized when the concentration of foaming agents is 0.4–0.6%. A trend has been established for increased damage to the cores with increasing exposure time. Additionally, this study provides technical guidance for damage evaluation and reservoir protection in shale reservoir exploitation.
Life Cycle Assessment of Dispersed Phase Change Material Heat Accumulators for Cooperation with Buildings in the District Heating System
Authors: Turski Michał , Jachura Agnieszka
Published: August 2022

The wide use of energy-efficient district heating systems allows for decreased atmospheric pollution resulting from lower emissions. One of the ways to increase the efficiency of existing district heating systems, and a key element of new systems using renewable energy sources, is modern heat storage technology—the utilization of dispersed PCM heat accumulators. However, the use of different solutions and the inconsistency of selection methods make it difficult to compare the obtained results. Therefore, in this paper, using TRNSYS software, a standardization of the selection of dispersed PCM heat accumulators for cooperation with buildings in the DHS was proposed along with a Life Cycle Assessment. Life Cycle Assessment could be a good, versatile indicator for new developments in district heating systems. A new contribution to the research topic was the Life Cycle Assessment itself as well as the range of heat output of the substations up to 2000 kW and the development of nomograms and unitary values for the selection of individual parameters based on the relative amount of heat uncollected by buildings. The technical potential of heat storage value, %ΔQi,st, was from 49.4% to 59.6% of the theoretical potential of heat storage. The increases in the active volume of the PCM heat accumulator, dVPCM, and the mass of the required amount of PCM, dmst, were, respectively, 0.8 × 10−2–4.0 m3/kW and 1.3–6.7 × 10−2 kg/kW. Due to dispersed heat storage, an increase in system efficiency of 41% was achieved. LCA analysis showed that a positive impact on the environment was achieved, expressed as negative values of the Eco-indicator from −0.504 × 10−2 to −6.44 × 10−2 kPt/kW.
Design Optimization of a Switched Reluctance Machine with an Improved Segmental Rotor for Electric Vehicle Applications
Authors: Lan Yuanfeng , Frikha Mohamed Amine , Croonen Julien , Benômar Yassine , El Baghdadi Mohamed , Hegazy Omar
Published: August 2022

In this article, a switched reluctance machine (SRM) with six phases and a misaligned segmental rotor is proposed. The segmental rotor has an internal 15-degree misalignment, allowing the SRM structure to be a one-layer 2D structure with a short flux path structure. The proposed SRM produces a relatively low torque ripple by exciting two phases simultaneously. Additionally, an optimization method is applied, allowing for the maximum torque position of one phase to be aligned with the zero-torque position of the adjacent phase. The finite element method (FEM) is used to analyze and design the proposed SRM and to simulate the proposed liquid cooling system. The static torque waveforms are analyzed, and the dynamic torque waveforms are simulated with a drive using SiC MOSFETs. Finally, a prototype is manufactured, and the experiment is performed to validate the design and simulation results.
Do Charging Stations Benefit from Cryptojacking? A Novel Framework for Its Financial Impact Analysis on Electric Vehicles
Authors: Malik Asad Waqar , Anwar Zahid
Published: August 2022

Electric vehicles (EVs) are becoming popular due to their efficiency, eco-friendliness, and the increasing cost of fossil fuel. EVs support a variety of apps because they house powerful processors and allow for increased connectivity. This makes them an attractive target of stealthy cryptomining malware. Recent incidents demonstrate that both the EV and its communication model are vulnerable to cryptojacking attacks. The goal of this research is to explore the extent to which cryptojacking impacts EVs in terms of recharging and cost. We assert that while cryptojacking provides a financial advantage to attackers, it can severely degrade efficiency and cause battery loss. In this paper we present a simulation model for connected EVs, the cryptomining software, and the road infrastructure. A novel framework is proposed that incorporates these models and allows an objective quantification of the extent of this economic damage and the advantage to the attacker. Our results indicate that batteries of infected cars drain more quickly than those of normal cars, forcing them to return more frequently to the charging station for a recharge. When just 10% of EVs are infected we observed 70.6% more refueling requests. Moreover, if the hacker infects a charging station then he can make a USD 436.4 profit per day from just 32 infected EVs. Overall, our results demonstrate that cryptojackers injected into EVs indirectly provide a financial advantage to the charging stations at the cost of an increased energy strain on society.
Well Construction Action Planning and Automation through Finite-Horizon Sequential Decision-Making
Authors: Saini Gurtej Singh , Erge Oney , Ashok Pradeepkumar , van Oort Eric
Published: August 2022

Well construction operations require continuous complex decision-making and multi-step action planning. Action selection at every step demands a careful evaluation of the vast action space, while guided by long-term objectives and desired outcomes. Current human-centric decision-making introduces a degree of bias, which can result in reactive rather than proactive decisions. This can lead from minor operational inefficiencies all the way to catastrophic health and safety issues. This paper details the steps in structuring unbiased purpose-built sequential decision-making systems. Setting up such systems entails representing the operation as a Markov decision process (MDP). This requires explicitly defining states and action values, defining goal states, building a digital twin to model the process, and appropriately shaping reward functions to measure feedback. The digital twin, in conjunction with the reward function, is utilized for simulating and quantifying the different action sequences. A finite-horizon sequential decision-making system, with discrete state and action space, was set up to advise on hole cleaning during well construction. The state was quantified by the cuttings bed height and the equivalent circulation density values, and the action set was defined using a combination of controllable drilling parameters (including mud density and rheology, drillstring rotation speed, etc.). A non-sparse normalized reward structure was formulated as a function of the state and action values. Hydraulics, cuttings transport, and rig state detection models were integrated to build the hole cleaning digital twin. This system was then used for performance tracking and scenario simulations (with each scenario defined as a finite-horizon action sequence) on real-world oil wells. The different scenarios were compared by monitoring state–action transitions and the evolution of the reward with actions. This paper presents a novel method for setting up well construction operations as long-term finite-horizon sequential decision-making systems, and defines a way to quantify and compare different scenarios. The proper construction of such systems is a crucial step towards automating intelligent decision-making.
Effect of Potassium Salts on Biochar Pyrolysis
Authors: Wongmat Yuthapong , Wagner David R.
Published: August 2022

Alkali pretreatment is one of the chemical pretreatment technologies that has been examined on various types of lignocellulosic biomass. To gain a better insight into the effects of a potassium-based catalyst on pyrolysis behavior with different materials, potassium bicarbonate (KHCO3) and potassium nitrate (KNO3) were used as additives in this study. The experimental parameters which included particle size, heating rate, and additive loading were investigated. The results showed that adding potassium for both KHCO3 and KNO3 to feedstocks led to increase in biochar. A model-free method, Flynn–Wall–Ozawa (FWO), was implemented in this study to determine the activation energy values for untreated and potassium-treated feedstocks. A reduction in apparent activation energy values of treated biomass was observed. This indicates that adding potassium salt to biomass influenced the structures of the main components and promoted the catalytic effect of pyrolysis. Activation energies of treated pine range from 250 to 308 kJ/mol, and energies of wheat straw range from 277 to 402 kJ/mol.
Heat Transfer during Nitrogen Boiling on Surfaces Modified by Microarc Oxidation
Authors: Kuznetsov Denis , Pavlenko Aleksandr
Published: August 2022

Despite the many different methods for creating modified heat transfer surfaces to increase critical heat fluxes and heat transfer coefficients at pool boiling of various liquids at given reduced pressures, active research is currently underway to find optimal surface morphology and geometric parameters of structures for practical application. In this work, we used the method of microarc oxidation (MAO) to obtain coatings with different microstructures on the surface of duralumin heaters. In the present work, we studied the effect of MAO coatings on heat transfer, critical heat flux, and evaporation dynamics during liquid nitrogen boiling under conditions of steady-state heat release at pressures of 0.1, 0.05, and 0.017 MPa. It was shown that the modification of heaters led to a 50–60% increase in heat transfer coefficients as compared to the smooth one under the atmospheric pressure. Based on the data of high-speed video filming of boiling, it was shown that the main mechanism of intensification is the increase in quantity of active nucleation sites. A significant decrease in pressure led to the absence of a significant difference in both heat transfer intensity and evaporation dynamics for the smooth and modified heaters.
The Implementation Environment for a Digital Technology Platform of Renewable Energy Sources
Authors: Bartczak Krzysztof , Łobejko Stanisław
Published: August 2022

The study addressed broad aspects related to digital technology platforms and renewable energy sources, including the integration of these systems and concepts. The main objective was to identify the implementation environment for a digital technology platform of renewable energy sources (RES) based on business and consumer feedback. This gives an insight into whether there is a favourable environment for implementing a RES digital technology platform. The study was based on research carried out using computer-assisted telephone interview (CATI) and computer-assisted web interview (CAWI) methods. Additionally, an alternative model of attitudes towards digital technology platforms (DTPs) built using CATREG (categorical regression) analysis was also referred to. The study found that currently, there is a positive attitude among companies, including those which install RES systems, as well as among consumers towards the implementation of DTP-based RES projects. This attitude is driven by the many benefits that can be achieved by using these platforms. However, there are some obstacles to the implementation of a digital RES platform. These relate to cyber security concerns, including computer or internet failures. However, the obstacles are not crucial for the practical implementation of the discussed platform.
Techno-Economic Analysis of Low Carbon Hydrogen Production from Offshore Wind Using Battolyser Technology
Authors: Jenkins Brian , Squires David , Barton John , Strickland Dani , Wijayantha K. G. U. , Carroll James , Wilson Jonathan , Brenton Matthew , Thomson Murray
Published: August 2022

A battolyser is a combined battery electrolyser in one unit. It is based on flow battery technology and can be adapted to produce hydrogen at a lower efficiency than an electrolyser but without the need for rare and expensive materials. This paper presents a method of determining if a battolyser connected to a wind farm makes economic sense based on stochastic modelling. A range of cost data and operational scenarios are used to establish the impact on the NPV and LCOE of adding a battolyser to a wind farm. The results are compared to adding a battery or an electrolyser to a wind farm. Indications are that it makes economic sense to add a battolyser or battery to a wind farm to use any curtailed wind with calculated LCOE at £56/MWh to £58/MWh and positive NPV over a range of cost scenarios. However, electrolysers, are still too expensive to make economic sense.
Relationship between Renewable Biogas Energy Sources and Financial Health of Food Business Operators
Authors: Cierpiał-Wolan Marek , Stec-Rusiecka Jolanta , Twaróg Dariusz , Bilińska Katarzyna , Dewalska-Opitek Anna , Wierzbiński Bogdan
Published: August 2022

Biogas production within cooperatives and energy clusters that include both food businesses and biogas plants seems to be a good way to both improve financial health and increase energy self-sufficiency. The paper assesses the financial health of more than 2100 food businesses operating during the period of 2014–2020; the analysis was based on data from public statistics. The financial analysis carried out using the ROS (Return on Sale) indicator and the SI for the study (saving indicator) showed that the average SI/ROS increased by more than 2.78-fold over the study period. Moreover, for 185 powiats, the observed growth remained above average over a period of one to five years. The application of the Data Envelopment Analysis (DEA) method allowed the relative efficiency of biogas utilization to be calculated at the powiat level (former LAU level 1). It was found that the utilization of biogas potential within cooperatives and energy clusters grouping food businesses is most effective mainly for urban powiats.
Mutual Support—Modern Energy Planning Inclusive of Cooking—A Review of Research into Action in Africa and Asia since 2018
Authors: Batchelor Simon , Brown Ed , Scott Nigel , Leach Matthew , Clements Anna , Leary Jon
Published: August 2022

This paper is a review of research undertaken, and subsequent policy change enacted, in the years 2018 to 2022 regarding the integration of cooking loads and needs into modern energy planning. Building on an earlier paper which described how the dominant global approaches to tackling the enduring problem of biomass-fuelled cooking was failing, and how a new UK Aid programme (Oct 2018) would be seeking to intentionally change international energy policy towards cooking and enable a significant transition in energy use, in this paper we review whether this strategy is being adopted by researchers, governments, and the private sector across the world and whether it is likely to make a significant contribution to the fulfilment of Sustainable Development Goal 7. In particular, the call is for integrated planning of modern energy inclusive of cooking loads—the potential ‘Mutual Support’ that both can lend to each other. The review considers the international commitments made by donors and governments to this end, the research that positions the use of modern energy as a cost-effective proposition, the urbanisation and societal changes reinforcing such planning, and positions the review in the light of climate change and the need to reach net zero carbon by 2050.
Thermal and Mechanical Improvement of Filling Mixture for Shallow Geothermal Systems by Recycling of Carbon Fiber Waste
Authors: Floridia Giovanni , Urso Salvatore , Belfiore Giuseppe Maria , Viccaro Marco
Published: August 2022

The reuse of waste materials such as carbon fiber (CF) as filling additive for closed-loop vertical geothermal probes in shallow geothermal systems has been evaluated as a new grout mixture for the improvement of geothermal energy systems efficiency and a sustainable supply of raw materials from special waste. The study evaluates the improvement in both thermal exchange characteristics and mechanical properties of the filling grout for geothermal purposes through the addition of 5% of CF to standard (ST) materials currently on the market. Uniaxial and flexural tests investigating the material response after 14 and 28 days from sample preparation on samples of both standard and mixed grout material as well as non-stationary hot wire method were used to define the thermal conductivity for both the standard and innovative mixtures. The experimental analysis provides evidence for increasing the thermal conductivity by about 3.5% with respect to standard materials. Even the mechanical properties are better in the innovative mixture, being the compressive strength 187% higher and flexural strength 81% higher than standard materials. The obtained results become useful for the optimization of low enthalpy geothermal systems and mostly for the design of the vertical heat exchange system in terms of depth/number of installed probes. Principally, thermal conductivity improvements result in a reduction of about 24% of the geothermal exchanger’s length, affecting the economic advantages in the implementation of the entire system. A simple analysis of the reuse of CF waste shows the reduction of industrial waste and the simultaneous elimination of disposal costs, defining new perspectives for industrial waste management. This research provides essential elements for the development of a circular economy and is well integrated with the European challenges about the End of Waste process and reduction of environmental impact, suggesting new perspectives for economic development and sectorial work.
Simulation, Verification and Optimization Design of Electromagnetic Vibration and Noise of Permanent Magnet Synchronous Motor for Vehicle
Authors: Xu Jie , Zhang Lijun , Meng Deijian , Su Hui
Published: August 2022

Aiming at the electromagnetic vibration and noise problem of an 8-pole 48-slot permanent magnet synchronous motor for a vehicle, the multi-physics coupling simulation model of the motor is introduced to optimize the rotor structure of the motor to reduce the vibration and noise of the permanent magnet synchronous motor. The effectiveness of the research method is verified by the bench test in the anechoic chamber. Finite element software was used to establish the stator core and system model considering the anisotropy of materials, and the simulation model was verified by modal experiment. For the 2in1 electric drive system, the electromagnetic-structure-acoustic multi-physics coupling noise prediction model is established. Based on the three-dimensional distributed electromagnetic force excitation, the electromagnetic radiation noise of the motor under full load acceleration is calculated, and the characteristics of electromagnetic noise are analyzed. The accuracy of the electromagnetic-structure-acoustic multi-physics coupling model of permanent magnet synchronous motor is verified by the bench test results of the anechoic chamber. By changing the angle and shape of the motor rotor, the cogging torque ripple between the stator and the rotor is reduced, and the 48th order harmonic amplitude is reduced. Finally, the optimized sample is tested on the vehicle, and the 48th order electromagnetic noise can be reduced by 5–15 dB(A). The accuracy of the electromagnetic-structure-acoustic multi-physics coupling model of permanent magnet synchronous motor is verified by the bench test results of the anechoic chamber. Therefore, the research results can be further used for the design and development of a vehicle permanent magnet synchronous motor and the research on the mechanism of electromagnetic vibration and noise.
3D Fracture Propagation Simulation and Pressure Decline Analysis Research for I-Shaped Fracture of Coalbed
Authors: Wang Chengwang , Guo Zixi , Zhang Lifeng , Kang Yunwei , You Zhenjiang , Li Shuguang , Wang Yubin , Zhen Huaibin
Published: August 2022

After hydraulic fracturing, some treatments intended for production enhancement fail to yield predetermined effects. The main reason is the insufficient research about the fracture propagation mechanism. There is compelling evidence that I-shaped fracture, two horizontal fractures at the junction of coalbed and cover/bottom layer, and one vertical fracture in the coalbed have formed in part of the coalbed after hydraulic fracturing. Therefore, this paper aims at I-shaped fracture propagation simulation. A novel propagation model is derived on the basis of a three-dimensional (3D) model, and the coupling conditions of vertical fracture and horizontal fractures are established based on the flow rate distribution and the bottom-hole pressure equality, respectively. Moreover, an associated PDA (pressure decline analysis of post-fracturing) model is established. Both models complement with each other and work together to guide fracturing treatment. Finally, a field case is studied to show that the proposed models can effectively investigate and simulate fracture initiation/propagation and pressure decline.
Site Class Effects on Stump and Coarse Root Biomass Models of Larix olgensis in Northeastern China
Authors: Men Xiuli , Yue Yang , Sun Zhihu , Han Shaojie , Pan Li , Chen Xiangwei , Wang Xiuwei
Published: August 2022

The stump and coarse root biomass remaining after tree harvesting are often overlooked by researchers, which may lead to underestimation of their role in carbon cycling, so we constructed two sets of additive models for larch (Larix olgensis Henry) plantations in Northeast China. Due to the absence of tree diameter at breast height data after harvesting, only the sole predictor variable stump disc diameter could be used to predict stump and coarse root biomass, and the results showed that stump disc diameter predicted stump biomass with higher accuracy than coarse root biomass predictions. In addition, to investigate the effect of the site class of complex stands on the predictive capability of the model, the generic model in this study was employed with all site class data and a specific model was developed and employed with all the site class data. We found that the generic model had different degrees of error compared to the predicted results for each site class, overestimating the total biomass by 15% and underestimating it by 10%, especially for site class IV. In conclusion, to obtain a biomass prediction model with reliable results, the impact of more complex site class effects should be considered.
Increasing the Efficiency of Taxifolin Encapsulation in Saccharomyces cerevisiae Yeast Cells Based on Ultrasonic Microstructuring
Authors: Kalinina Irina , Fatkullin Rinat , Naumenko Natalya , Ruskina Alena , Popova Natalia , Naumenko Ekaterina
Published: August 2022

The aim of the present study was to investigate the possibility of encapsulating the plant antioxidant taxifolin in the living cells of the yeast Saccharomyces cerevisiae. Taxifolin is an unstable substance prone to oxidative degradation and actively enters into chemical reactions with a decrease or loss of bioactive properties. To minimize these problems, the use of encapsulation technology has been proposed. The cells of the yeast Saccharomyces cerevisiae have been chosen as a protective material for taxifolin. The encapsulation process was carried out using simple diffusion methods in living Saccharomyces cerevisiae cells in a thermostatically controlled shaker for 24 h. The aim of the study was to evaluate the effect of preliminary microstructuring of taxifolin on the efficiency of its encapsulation in yeast cells. The microstructuring process was carried out using low-frequency ultrasonic cavitation exposure for 7 min with a frequency of 22 ± 1.6 kHz and a power of 600 W/100 mL. The studies confirmed the feasibility of the proposed approach. It was found that microstructuring changes the dispersed composition of taxifolin particles and their morphology in solution and also increases the value of the antioxidant activity. Preliminary microstructuring of taxifolin increases the efficiency of its encapsulation in Saccharomyces cerevisiae yeast cells by 1.42 times compared to the initial form. A positive dependence of the growth of the encapsulation efficiency on the duration of the process was also established. Thus, the conducted studies confirmed the advantage of encapsulation of taxifolin in living cells of the yeast Saccharomyces cerevisiae in microstructured form.
Evaluation of Physically and/or Chemically Modified Chitosan Hydrogels for Proficient Release of Insoluble Nystatin in Simulated Fluids
Authors: Enache Andra-Cristina , Cojocaru Corneliu , Samoila Petrisor , Bele Adrian , Bostanaru Andra-Cristina , Mares Mihai , Harabagiu Valeria
Published: August 2022

To avoid fungal spreading in the bloodstream and internal organs, many research efforts concentrate on finding appropriate candidiasis treatment from the initial stage. This paper proposes chitosan-based physically or chemically cross-linked hydrogels aimed to provide sustained release of micronized nystatin (NYSm) antifungal drug, known for its large activity spectrum. Nystatin was demonstrated itself to provide hydrodynamic/mechanic stability to the chitosan hydrogel through hydrophobic interactions and H-bonds. For chemical cross-linking of the succinylated chitosan, a non-toxic diepoxy-functionalized siloxane compound was used. The chemical structure and composition of the hydrogels, also their morphology, were evidenced by infrared spectroscopy (FTIR), by energy dispersive X-ray (EDX) analysis and by scanning electron microscopy (SEM), respectively. The hydrogels presented mechanical properties which mimic those of the soft tissues (elastic moduli < 1 MPa), necessary to ensure matrix accommodation and bioadhesion. Maximum swelling capacities were reached by the hydrogels with higher succinic anhydride content at both pH 7.4 (429%) and pH 4.2 (471%), while higher amounts of nystatin released in the simulative immersion media (57% in acidic pH and 51% in pH 7.4) occurred from the physical cross-linked hydrogel. The release mechanism by non-swellable matrix diffusion and the susceptibility of three Candida strains make all the hydrogel formulations effective for NYSm local delivery and for combating fungal infections.
Influence of Unequal Amplification of Methylated and Non-Methylated Template on Performance of Pyrosequencing
Authors: Taryma-Lesniak Olga , Kjeldsen Tina E. , Hansen Lise Lotte , Wojdacz Tomasz K.
Published: August 2022

Pyrosequencing is one of the technologies widely used for quantitative methylation assessment. The protocol of pyrosequencing experiment consists of PCR amplification of a locus of interest and subsequent sequencing via synthesis of the amplified PCR product. As the PCR in this protocol utilizes one primer set for the amplification of a template originating from both methylated and non-methylated versions of the analysed locus, the unequal amplification of one of the templates may affect the methylation level assessment by pyrosequencing. We have investigated whether the unequal amplification of one of the templates challenges the quantitative properties of the pyrosequencing technology. Our results show that the sensitivity and dynamic range of pyrosequencing can be significantly affected by unequal amplification of the methylated and non-methylated version of the locus of interest in an assay specific manner. Thus, the assessment of the effect of unequal template amplification on the performances of the specific pyrosequencing assay is necessary before using the assay either in research or especially in diagnostic settings.
An Optimized Protocol for Indirect Organogenesis from Root Explants of Agapanthus praecox subsp. orientalis ‘Big Blue’
Authors: Tang Qianwen , Guo Xiangxin , Zhang Yuanshan , Li Qingyun , Chen Guanqun , Sun Huale , Wang Weiming , Shen Xiaohui
Published: August 2022

Agapanthus praecox has become a burgeoning variety in the flower market due to its high ornamental value with unique large blue-purple inflorescence. For rapid entering into the market, tissue culture technology or organogenesis has an attractive application over the conventional reproduction approach. In this study, a highly efficient protocol based on indirect organogenesis has been successfully established for A. praecox subsp. orientalis ‘Big Blue’. Two types of explants, root tips versus root segments, were compared for callus induction frequency in response to the induction culture media. The induction media contain Murashige and Skoog’s (MS) Basal Salt supplemented with various concentrations of picloram (PIC), 2,4-Dichlorophenoxyacetic acid (2,4-D), thidiazuron (TDZ), kinetin (KT) and naphthalene acetic acid (NAA). Of the two types of explants, root tips were found to be more effective for callus induction than root segments. Among the induction media tested, the highest callus induction rate (100.00%) was achieved when cultured on MS supplemented with 2.0 mg/L PIC, 1.5 mg/L KT and 0.1 mg/L NAA, which was probably accredited to higher endogenous phytohormone contents, especially of 3-indoleacetic (IAA). The optimal medium for callus proliferation was MS + 1.0 mg/L PIC + 1.0 mg/L 6-BA + 0.4 mg/L NAA, and the fresh weight increased by 72.74%. After being transferred onto the adventitious bud induction medium for 25 days, shoots were dedifferentiated from the surface of the flourishing callus, which then developed to the plantlet with roots in 90 days. The plantlets were transplanted in a greenhouse with a survival rate of 92.86%. This study innovatively established an indirect organogenesis tissue culture system of A. praecox with roots as explants, which provided a practical reference in its application.
Anatomical and Physiological Performance of Jojoba Treated with Proline under Salinity Stress Condition
Authors: Aboryia M. S. , El-Dengawy El-Refaey F. A. , El-Banna Mostafa F. , El-Gobba Mervat H. , Kasem Mahmoud M. , Hegazy Ahmed A. , Hassan Heba Metwally , El-Yazied Ahmed Abou , El-Gawad Hany G. Abd , Al-Qahtani Salem Mesfir , Al-Harbi Nadi Awad , Dessoky Eldessoky S. , Ismail Ismail A. , El-Mogy Mohamed M. , EL-Boraie El-Sayed A.
Published: August 2022

A field trial study was conducted for two consecutive seasons 2020 and 2021 in approximately 8-month-old jojoba plants to evaluate the physiological responses following salt treatment and the role of proline as a foliar application to enhance jojoba tolerance to salinity stress. Jojoba plants were irrigated once a week for four months with diluted seawater in concentrations of 5000, 10,000, and 15,000 ppm and tap water (control). Anti-stress proline was applied four times throughout the experiment, the first at the beginning of the experiment and another three times at 30-day intervals, at concentrations of 0, 300, and 450 ppm. The effect of proline treatments on jojoba plant behavior includes growth vegetative characteristics, namely plant height increase percentage (PHIP), shoot number increase percentage (NSIP), stem diameter increase percentage (SDIP), number of leaves, leaf thickness, leaf area, and fresh and dry weights of leaves, and chemical characteristics, namely chlorophyll a and b, total chlorophyll, carotenoids, leaf mineral contents (N, P, K, Na, and Cl), total phenolic content (TPC), and proline concentration. Moreover, the impacts of proline on hydrogen peroxide (H2O2), superoxide anion (O2•−), malondialdehyde (MDA), and ion leakage (IL) under salinity stress were investigated. Briefly, proline at 450 ppm enhanced all studied growth and physiological characteristics and promoted the antioxidant system of jojoba plants compared with the control and other treatments. The anatomical structure of leaves was also examined, and favorable variations in the anatomical structure were detected in the stressed and proline-treated plants. Exogenous application of proline enhanced most of this anatomical characteristic of jojoba leaf under saline stress. In conclusion, proline as a foliar application at 450 ppm under salinity stress of 10,000 ppm enhances jojoba tolerance to salinity stress by modifying the physicochemical and morphological characteristics of jojoba plants.
Comparison of Waterlogging Tolerance of Three Peach Rootstock Seedlings Based on Physiological, Anatomical and Ultra-Structural Changes
Authors: Xu Fangjie , Cai Huaqing , Zhang Xianan , Su Mingshen , Zhou Huijuan , Li Xiongwei , Zhang Minghao , Hu Yang , Gu Chao , Du Jihong , Ye Zhengwen
Published: August 2022

Peach (Prunus persica (L.) Batsch) is a typical shallow-rooted fruit plant with a high respiratory intensity and oxygen demand, which makes it highly susceptible to oxygen-deficient soil conditions resulting from waterlogging. Rootstock waterlogging resistance is essential to the performance of cultivated peaches under waterlogging stress. In comparison to Prunus persica var. persica (‘Maotao’, M) and Prunus davidiana (Carr.) C. de Vos (‘Shantao’, S), Prunus persica f. Hossu (‘Hossu’, H) exhibited superior leaf photosynthetic electron transfer efficiency, a higher rate of mycorrhizal fungi infection in both fine roots and mesophyll palisade cells, as well as earlier air cavity formation in both leaf midvein and fine roots under waterlogging stress. Furthermore, under non-waterlogging conditions, Hossu had greater leaf superoxide dismutase (SOD) activity, higher proline content, and a greater content of starch granules in the pith and xylem ray cells of stems and roots than rootstocks M and S. As a result, Hossu’s tolerance to waterlogging may be due to its higher photosynthetic efficiency, improved tissue oxygen permeability, higher energy metabolism, and increased intracellular mycorrhizal fungus infection rates in both root parenchyma cells and mesophyll palisade cells.
Students’ Attitudes toward COVID-19 Vaccination: An Inter-University Study from Bulgaria
Authors: Moskova Martina , Zasheva Anelia , Kunchev Metodi , Popivanov Ivan , Dimov Dimo , Vaseva Virsavia , Kundurzhiev Todor , Tsachev Ilia , Baymakova Magdalena
Published: August 2022

In Bulgaria, vaccination coverage against the SARS-CoV-2 virus is low. The reasons for this fact are many and varied. The aim of the present study was to establish what the attitudes towards the COVID-19 vaccination process are among students from various specialties from several Bulgarian universities. In this research, 600 students participated, divided into two groups: Doctor of Medicine (MD) students (n = 300) and non-MD students, i.e., students of specialties, such as mathematics, engineering, finance and economics, law, human sciences, etc. (n = 300). Each respondent completed a questionnaire which was divided into three parts with closed questions. The mean age of all students was 21.19 ± 1.87 years (95% CI: 20.48–21.90). The female sex dominated among the analyzed participants (sex ratio: female/male = 1/0.85). Nearly 62% (371/600) of individuals declared that they have been COVID-19 vaccinated with at least one dose (p < 0.001). Overall, 33% of the participants sought information on vaccines from video sharing platforms and 36.0% (216/600) from social media platforms. From the conducted multivariable logistic regression the odds of vaccination against COVID-19 were 6.225 times higher in individuals with a positive attitude towards these vaccines than in people with a negative attitude towards them (p < 0.001). We have found that those students who trust the international health organizations had an OR of 2.365 (p = 0.004) to be SARS-CoV-2 vaccinated. We estimated that the odds of vaccination against SARS-CoV-2 among children were 4.794 times higher in parents (students) who had been vaccinated than in non-vaccinated parents (students) (p < 0.001). Our results could support the national public health organizations, the national educational/scientific systems, and the management of Bulgarian universities in making future decisions about the field of COVID-19 control and prevention.