bluuebunny/crossref_metadata_2025 huggingface dataset:
Paracetamol Is Associated with a Lower Risk of COVID-19 Infection and Decreased ACE2 Protein Expression: A Retrospective Analysis
Authors: Leal Nuno Santos , Yu Yizhou , Chen Yuwen , Fedele Giorgio , Martins Luís Miguel
Published: August 2021

Ibuprofen is a common over-the-counter drug taken for pain relief. However, recent studies have raised concerns about its potential toxic effect with coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has been proposed that ibuprofen may increase levels of angiotensin-converting enzyme 2 (ACE2), the human receptor for SARS-CoV-2 infection. Therefore, paracetamol is suggested as an alternative to ibuprofen for treating COVID-19 symptoms. Nevertheless, the relationship between intake of paracetamol or ibuprofen and either susceptibility to infection by SARS-CoV-2 or modulation of cellular ACE2 levels remains unclear. In this study, we combined data from human medical records and cells in culture to explore the role of the intake of these drugs in COVID-19. Although ibuprofen did not influence COVID-19 infectivity or ACE2 levels, paracetamol intake was associated with a lower occurrence of COVID-19 in our cohort. We also found that paracetamol led to decreased ACE2 protein levels in cultured cells. Our work identifies a putative protective effect of paracetamol against SARS-CoV-2 infection. Future work should explore the molecular mechanisms underlying the relationship between paracetamol and COVID-19.
Morphology of Barite Synthesized by In-Situ Mixing of Na2SO4 and BaCl2 Solutions at 200 °C
Authors: Wang Chunyao , Zhou Li , Zhang Shuai , Wang Li , Wei Chunwan , Song Wenlei , Xu Liping , Zhou Wenge
Published: August 2021

Barite is an abundant sulfate mineral in nature. Especially, the variety of morphologies of barite is often driven by the mixing of Ba-bearing hydrothermal fluid and sulfate-bearing seawater around hydrothermal chimneys. In order to better understand the factors affecting the morphology and precipitation mechanism(s) of barite in seafloor hydrothermal systems, we synthesized barite by a new method of in-situ mixing of BaCl2 and Na2SO4 solutions at 200 °C while varying Ba concentrations and ratios of Ba2+/SO42−, and at room temperature for comparison. The results show that barite synthesized by in-situ mixing of BaCl2 and Na2SO4 solutions at 200 °C forms a variety of morphologies, including rod-shaped, granular, plate-shaped, dendritic, X-shaped, and T-shaped morphologies, while room temperature barites display relatively simple, granular, or leaf-like morphologies. Thus, temperature affects barite morphology. Moreover, dendritic barite crystals only occurred at conditions where Ba2+ is in excess of SO42− at the experimental concentrations. The dendritic morphology of barite may be an important typomorphic feature of barite formed in high-temperature fluids directly mixing with excess Ba2+ relative to SO42−.
The Role of Acidity in the Synthesis of Novel Uranyl Selenate and Selenite Compounds and Their Structures
Authors: Murphy Gabriel L. , Kegler Philip , Langer Eike M. , Alekseev Evgeny V.
Published: August 2021

Herein, the novel uranyl selenate and selenite compounds Rb2[(UO2)2(SeO4)3], Rb2[(UO2)3(SeO3)2O2], Rb2[UO2(SeO4)2(H2O)]·2H2O, and (UO2)2(HSeO3)2(H2SeO3)2Se2O5 have been synthesized using either slow evaporation or hydrothermal methods under acidic conditions and their structures were refined using single crystal X-ray diffraction. Rb2[(UO2)2(SeO4)3] synthesized hydrothermally adopts a layered 2D tetragonal structure in space group P42/ncm with a = 9.8312(4) Å, c = 15.4924(9) Å, and V = 1497.38(15) Å, where it consists of UO7 polyhedra coordinated via SeO4 units to create units UO2(SeO4)58− moieties which interlink to create layers in which Rb+ cations reside in the interspace. Rb2[(UO2)3(SeO3)2O2] synthesized hydrothermally adopts a layered 2D triclinic structure in space group P1¯ with a = 7.0116(6) Å, b = 7.0646(6) Å, c = 8.1793(7) Å, α = 103.318(7)°, β = 105.968(7)°, γ = 100.642(7)° and V = 365.48(6) Å3, where it consists of edge sharing UO7, UO8 and SeO3 polyhedra that form [(UO2)3(SeO3)2O2] layers in which Rb+ cations are found in the interlayer space. Rb2[UO2(SeO4)2(H2O)]·2H2O synthesized hydrothermally adopts a chain 1D orthorhombic structure in space group Pmn21 with a = 13.041(3) Å, b = 8.579(2) Å, c = 11.583(2) Å, and V = 1295.9(5) Å3, consisting of UO7 polyhedra that corner share with one H2O and four SeO42− ligands, creating infinite chains. (UO2)2(HSeO3)2(H2SeO3)2Se2O5 synthesized under slow evaporation conditions adopts a 0D orthorhombic structure in space group Cmc21 with a = 28.4752(12) Å, b = 6.3410(3) Å, c = 10.8575(6) Å, and V = 1960.45(16) Å3, consisting of discrete rings of [(UO2)2(HSeO3)2(H2SeO3)2Se2O5]2. (UO2)2(HSeO3)2(H2SeO3)2Se2O5 is apparently only the second example of a uranyl diselenite compound to be reported. A combination of single crystal X-ray diffraction and bond valance sums calculations are used to characterise all samples obtained in this investigation. The structures uncovered in this investigation are discussed together with the broader family of uranyl selenates and selenites, particularly in the context of the role acidity plays during synthesis in coercing specific structure, functional group, and topology formations.
Applying Population Viability Analysis to Inform Genetic Rescue That Preserves Locally Unique Genetic Variation in a Critically Endangered Mammal
Authors: Zilko Joseph P. , Harley Dan , Pavlova Alexandra , Sunnucks Paul
Published: August 2021

Genetic rescue can reduce the extinction risk of inbred populations, but it has the poorly understood risk of ‘genetic swamping’—the replacement of the distinctive variation of the target population. We applied population viability analysis (PVA) to identify translocation rates into the inbred lowland population of Leadbeater’s possum from an outbred highland population that would alleviate inbreeding depression and rapidly reach a target population size (N) while maximising the retention of locally unique neutral genetic variation. Using genomic kinship coefficients to model inbreeding in Vortex, we simulated genetic rescue scenarios that included gene pool mixing with genetically diverse highland possums and increased the N from 35 to 110 within ten years. The PVA predicted that the last remaining population of lowland Leadbeater’s possum will be extinct within 23 years without genetic rescue, and that the carrying capacity at its current range is insufficient to enable recovery, even with genetic rescue. Supplementation rates that rapidly increased population size resulted in higher retention (as opposed to complete loss) of local alleles through alleviation of genetic drift but reduced the frequency of locally unique alleles. Ongoing gene flow and a higher N will facilitate natural selection. Accordingly, we recommend founding a new population of lowland possums in a high-quality habitat, where population growth and natural gene exchange with highland populations are possible. We also recommend ensuring gene flow into the population through natural dispersal and/or frequent translocations of highland individuals. Genetic rescue should be implemented within an adaptive management framework, with post-translocation monitoring data incorporated into the models to make updated predictions.
Why Is the Alpine Flora Comparatively Robust against Climatic Warming?
Authors: Körner Christian , Hiltbrunner Erika
Published: August 2021

The alpine belt hosts the treeless vegetation above the high elevation climatic treeline. The way alpine plants manage to thrive in a climate that prevents tree growth is through small stature, apt seasonal development, and ‘managing’ the microclimate near the ground surface. Nested in a mosaic of micro-environmental conditions, these plants are in a unique position by a close-by neighborhood of strongly diverging microhabitats. The range of adjacent thermal niches that the alpine environment provides is exceeding the worst climate warming scenarios. The provided mountains are high and large enough, these are conditions that cause alpine plant species diversity to be robust against climatic change. However, the areal extent of certain habitat types will shrink as isotherms move upslope, with the potential areal loss by the advance of the treeline by far outranging the gain in new land by glacier retreat globally.
Estimation of Nitrogen Use Efficiency for Ryegrass-Fed Dairy Cows: Model Development Using Diet- and Animal-Based Proxy Measures
Authors: Aizimu Wumaierjiang , Al-Marashdeh Omar , Hodge Simon , Dewhurst Richard J. , Chen Ao , Zhao Guangyong , Talukder Saranika , Edwards Grant R. , Cheng Long
Published: August 2021

This study aimed to identify suitable predictors of nitrogen (N) use efficiency (NUE; milk N/N intake) for cows that differed in breeds and were fed with ryegrass pasture, using existing data from the scientific literature. Data from 16 studies were used to develop models based on the relationships between NUE and dietary and animal-based factors. Data from a further 10 studies were used for model validation. Milk urea N (MUN) and dietary water-soluble carbohydrate-to-crudeprotein ratio (WSC/CP) were the best and most practical animal- and diet-based proxies to predict NUE. The results indicate that it might be necessary to adopt separate models for different breeds when using WSC/CP to predict NUE but not when using MUN.
Biomedical Courses Should Also Be Designed for Dental Students: The Perceptions of Dental Students
Authors: Mussalo Fanny , Karaharju-Suvanto Terhi , Mäntylä Päivi , Pyörälä Eeva
Published: August 2021

Introduction: It can be challenging integrating biomedical sciences into dentistry programs. The aim was to examine students’ perceptions of how joint biomedical courses with medical students and courses tailored for dental students supported their clinical studies. Materials and methods: The target group was clinical phase dental students. Cross-sectional survey data were collected using a questionnaire, which consisted of questions covering biomedical and clinical study content and learning methods. Results: A total of 110 (82%) students completed the survey. Students had difficulty recognising the relevance of joint biomedical courses for clinical work, but when the link was clear, their interest in the content increased. The closer the respondents were to graduation, the less relevance they expressed the biomedical sciences had. Almost all students (95%) wanted more dental content for the early study years. Discussion: The student perspective provides valuable information for the development of biomedical courses. Students should be offered customised courses that include dental content and perspectives on clinical work, whenever suitable to the didactic content of the basic science course. Our study shows that the dental perspective needs greater integration with the biomedical content. This also supports interprofessional learning and appreciation for the other field’s contribution to human health.
Numerical Study of Air Flow Induced by Shock Impact on an Array of Perforated Plates
Authors: Zhang Lite , Feng Zilong , Sun Mengyu , Jin Haozhe , Shi Honghui
Published: August 2021

This study is focused on the propagation behavior and attenuation characteristics of a planar incident shock wave when propagating through an array of perforated plates. Based on a density-based coupled explicit algorithm, combined with a third-order MUSCL scheme and the Roe averaged flux difference splitting method, the Navier–Stokes equations and the realizable k-ε turbulence model equations describing the air flow are numerically solved. The evolution of the dynamic wave and ring vortex systems is effectively captured and analyzed. The influence of incident shock Mach number, perforated-plate porosity, and plate number on the propagation and attenuation of the shock wave was studied by using pressure- and entropy-based attenuation rates. The results indicate that the reflection, diffraction, transmission, and interference behaviors of the leading shock wave and the superimposed effects due to the trailing secondary shock wave are the main reasons that cause the intensity of the leading shock wave to experience a complex process consisting of attenuation, local enhancement, attenuation, enhancement, and attenuation. The reflected shock interactions with transmitted shock induced ring vortices and jets lead to the deformation and local intensification of the shock wave. The formation of nearly steady jets following the array of perforated plates is attributed to the generation of an oscillation chamber for the inside dynamic wave system between two perforated plates. The vorticity diffusion, merging and splitting of vortex cores dissipate the wave energy. Furthermore, the leading transmitted shock wave attenuates more significantly whereas the reflected shock wave from the first plate of the array attenuates less significantly as the shock Mach number increases. The increase in the porosity weakens the suppression effects on the leading shock wave while increases the attenuation rate of the reflected shock wave. The first perforated plate in the array plays a major role in the attenuation of the shock wave.
A New Universal Domain Adaptive Method for Diagnosing Unknown Bearing Faults
Authors: Yan Zhenhao , Liu Guifang , Wang Jinrui , Bao Huaiqian , Zhang Zongzhen , Zhang Xiao , Han Baokun
Published: August 2021

The domain adaptation problem in transfer learning has received extensive attention in recent years. The existing transfer model for solving domain alignment always assumes that the label space is completely shared between domains. However, this assumption is untrue in the actual industry and limits the application scope of the transfer model. Therefore, a universal domain method is proposed, which not only effectively reduces the problem of network failure caused by unknown fault types in the target domain but also breaks the premise of sharing the label space. The proposed framework takes into account the discrepancy of the fault features shown by different fault types and forms the feature center for fault diagnosis by extracting the features of samples of each fault type. Three optimization functions are added to solve the negative transfer problem when the model solves samples of unknown fault types. This study verifies the performance advantages of the framework for variable speed through experiments of multiple datasets. It can be seen from the experimental results that the proposed method has better fault diagnosis performance than related transfer methods for solving unknown mechanical faults.
Partitioning Entropy with Action Mechanics: Predicting Chemical Reaction Rates and Gaseous Equilibria of Reactions of Hydrogen from Molecular Properties
Authors: Kennedy Ivan R. , Hodzic Migdat
Published: August 2021

Our intention is to provide easy methods for estimating entropy and chemical potentials for gas phase reactions. Clausius’ virial theorem set a basis for relating kinetic energy in a body of independent material particles to its potential energy, pointing to their complementary role with respect to the second law of maximum entropy. Based on this partitioning of thermal energy as sensible heat and also as a latent heat or field potential energy, in action mechanics we express the entropy of ideal gases as a capacity factor for enthalpy plus the configurational work to sustain the relative translational, rotational, and vibrational action. This yields algorithms for estimating chemical reaction rates and positions of equilibrium. All properties of state including entropy, work potential as Helmholtz and Gibbs energies, and activated transition state reaction rates can be estimated, using easily accessible molecular properties, such as atomic weights, bond lengths, moments of inertia, and vibrational frequencies. We conclude that the large molecular size of many enzymes may catalyze reaction rates because of their large radial inertia as colloidal particles, maximising action states by impulsive collisions. Understanding how Clausius’ virial theorem justifies partitioning between thermal and statistical properties of entropy, yielding a more complete view of the second law’s evolutionary nature and the principle of maximum entropy. The ease of performing these operations is illustrated with three important chemical gas phase reactions: the reversible dissociation of hydrogen molecules, lysis of water to hydrogen and oxygen, and the reversible formation of ammonia from nitrogen and hydrogen. Employing the ergal also introduced by Clausius to define the reversible internal work overcoming molecular interactions plus the configurational work of change in Gibbs energy, often neglected; this may provide a practical guide for managing industrial processes and risk in climate change at the global scale. The concepts developed should also have value as novel methods for the instruction of senior students.
Bridging Offline Functional Model Carrying Aging-Specific Growth Rate Information and Recombinant Protein Expression: Entropic Extension of Akaike Information Criterion
Authors: Urniezius Renaldas , Kemesis Benas , Simutis Rimvydas
Published: August 2021

This study presents a mathematical model of recombinant protein expression, including its development, selection, and fitting results based on seventy fed-batch cultivation experiments from two independent biopharmaceutical sites. To resolve the overfitting feature of the Akaike information criterion, we proposed an entropic extension, which behaves asymptotically like the classical criteria. Estimation of recombinant protein concentration was performed with pseudo-global optimization processes while processing offline recombinant protein concentration samples. We show that functional models including the average age of the cells and the specific growth at induction or the start of product biosynthesis are the best descriptors for datasets. We also proposed introducing a tuning coefficient that would force the modified Akaike information criterion to avoid overfitting when the designer requires fewer model parameters. We expect that a lower number of coefficients would allow the efficient maximization of target microbial products in the upstream section of contract development and manufacturing organization services in the future. Experimental model fitting was accomplished simultaneously for 46 experiments at the first site and 24 fed-batch experiments at the second site. Both locations contained 196 and 131 protein samples, thus giving a total of 327 target product concentration samples derived from the bioreactor medium.
Improved Adaptive Augmentation Control for a Flexible Launch Vehicle with Elastic Vibration
Authors: Pang Aiping , Zhou Hongbo , Cai Wenjie , Zhang Jing
Published: August 2021

The continuous development of spacecraft with large flexible structures has resulted in an increase in the mass and aspect ratio of launch vehicles, while the wide application of lightweight materials in the aerospace field has increased the flexible modes of launch vehicles. In order to solve the problem of deviation from the nominal control or even destabilization of the system caused by uncertainties such as unknown or unmodelled dynamics, frequency perturbation of the flexible mode, changes in its own parameters, and external environmental disturbances during the flight of such large-scale flexible launch vehicles with simultaneous structural deformation, rigid-elastic coupling and multimodal vibrations, an improved adaptive augmentation control method based on model reference adaption, and spectral damping is proposed in this paper, including a basic PD controller, a reference model, and an adaptive gain adjustment based on spectral damping. The baseline PD controller was used for flight attitude control in the nominal state. In the non-nominal state, the spectral dampers in the adaptive gain adjustment law extracted and processed the high-frequency signal from the tracking error and control-command error between the reference model and the actual system to generate the adaptive gain. The adjustment gain was multiplied by the baseline controller gain to increase/decrease the overall gain of the system to improve the system’s performance and robust stability, so that the system had the ability to return to the nominal state when it was affected by various uncertainties and deviated from the nominal state, or even destabilized.
PFC: A Novel Perceptual Features-Based Framework for Time Series Classification
Authors: Wu Shaocong , Wang Xiaolong , Liang Mengxia , Wu Dingming
Published: August 2021

Time series classification (TSC) is a significant problem in data mining with several applications in different domains. Mining different distinguishing features is the primary method. One promising method is algorithms based on the morphological structure of time series, which are interpretable and accurate. However, existing structural feature-based algorithms, such as time series forest (TSF) and shapelet traverse, all features through many random combinations, which means that a lot of training time and computing resources are required to filter meaningless features, important distinguishing information will be ignored. To overcome this problem, in this paper, we propose a perceptual features-based framework for TSC. We are inspired by how humans observe time series and realize that there are usually only a few essential points that need to be remembered for a time series. Although the complex time series has a lot of details, a small number of data points is enough to describe the shape of the entire sample. First, we use the improved perceptually important points (PIPs) to extract key points and use them as the basis for time series segmentation to obtain a combination of interval-level and point-level features. Secondly, we propose a framework to explore the effects of perceptual structural features combined with decision trees (DT), random forests (RF), and gradient boosting decision trees (GBDT) on TSC. The experimental results on the UCR datasets show that our work has achieved leading accuracy, which is instructive for follow-up research.
Analyzing the Effects of Topological Defect (TD) on the Energy Spectra and Thermal Properties of LiH, TiC and I2 Diatomic Molecules
Authors: Nwabuzor Peter , Edet Collins , Ndem Ikot Akpan , Okorie Uduakobong , Ramantswana Morris , Horchani Ridha , Abdel-Aty Abdel-Haleem , Rampho Gaotsiwe
Published: August 2021

In this study, the impacts of TD on the energy spectra and thermal properties of LiH, TiC and I2 diatomic molecules is considered. The Schrodinger equation in cosmic string spacetime is solved with the generalized Morse potential using the well-known (NU) method. The energy spectra and eigenfunction are obtained respectively. The energy spectra is used to obtain the partition function which is then used to evaluate the thermal properties of the system is evaluated accordingly. We find that the energy spectra in the presence of the TD differ from their flat Minkowski spacetime analogue. The effects of the deformation parameter and TD on the thermal properties of the system is also analysed in detail. We observe that the specific heat capacity of the system tends to exhibit quasi-saturation as the deformation parameter and topological defect approaches unity. The results of our study can be applied in the astrophysical situation where these modifications exist in the understanding of spectroscopical data and it may be used as a probe of the presence of a cosmic string or a global monopole in the Universe.
Development and Application of Water and Land Resources Degradation Index (WLDI)
Authors: Tsesmelis Demetrios E. , Karavitis Christos A. , Kalogeropoulos Kleomenis , Tsatsaris Andreas , Zervas Efthimios , Vasilakou Constantina G. , Stathopoulos Nikolaos , Skondras Nikolaos A. , Alexandris Stavros G. , Chalkias Christos , Kosmas Constantinos
Published: August 2021

Natural resources are gradually coming under continuous and increasing pressure due to anthropogenic interventions and climate variabilities. The result of these pressures is reflected in the sustainability of natural resources. Significant scientific efforts during the recent years focus on mitigating the effects of these pressures and on increasing the sustainability of natural resources. Hence, there is a need to develop specific indices and indicators that will reveal the areas having the highest risks. The Water and Land Resources Degradation Index (WLDI) was developed for this purpose. WLDI consists of eleven indicators and its outcome results from the spatiotemporal performance of these indicators. The WLDI is based on the Standardized Drought Vulnerability Index (SDVI) and the Environmentally Sensitive Areas Index (ESAI). The WLDI is applied for the period from October 1983 to September 1996, considering Greece as a study area. The results of the application of this index reveal the areas with the highest risks, especially in the agricultural sector, with less than the needed water quantities due to extensive periods of droughts. This index could be used by scientists, but also by policy makers, to better and more sustainably manage environmental pressures.
A New Method for Measuring Total Factor Productivity Growth Based on the Full Industry Equilibrium Approach: The Case of the Greek Economy
Authors: Tsounis Nicholas , Steedman Ian
Published: August 2021

A new method of identifying the sources of output growth and measuring total factor productivity (TFP) is proposed, with an application to data from the Greek economy. The price accounting approach, based on the full industry equilibrium (FIE) framework introduced by Opocher and Steedman, where technical progress not only increases outputs relative to inputs but also reduces output prices relative to input rewards, is used. The contributions of this paper are that, first, it amends the FIE TFP measurement approach to account for heterogeneous labor inputs, imported inputs, and indirect taxes, and applies the method to real-world data from the Greek economy; second, it provides a comparison of the results with those found by the use of the neoclassical approach to TFP measurement arguing that the FIE approach measures better sectoral TFP change, and third, it provides an estimate of the effects of sectoral research and development (R&D) expenditures and R&D diffusion from other sectors on TFP change for the Greek economy.
The COVID-19 Pandemic and the Acceptance of E-Learning among University Students: The Role of Precipitating Events
Authors: Weerathunga Prageeth Roshan , Samarathunga W. H. M. S. , Rathnayake H. N. , Agampodi S. B. , Nurunnabi Mohammad , Madhunimasha M. M. S. C.
Published: August 2021

This study examined the effect of the COVID- 19 pandemic and related events on the use of e-learning, as well as other key determinants of it. The data were collected from 1039 university students in Sri Lanka. To examine the influence of the COVID-19 pandemic, which was viewed through the lens of precipitating events, on the intention–behaviour relationship, we employed the Technology Acceptance Model (TAM) with the inclusion of a moderating variable. While the findings indicated that the COVID-19 pandemic had clearly increased the usage of e-learning, we found no evidence to establish a moderating impact on the intention–behaviour relationship. The empirical model, however, was well fitted to the data, and the key components of the TAM were likewise adequately described by the relevant predictors. Furthermore, attitudes toward e-learning and perceived ease of use emerged as the most important factors in explaining behavioural intention, whereas relevance and experience were shown to be more significant in relation to perceived usefulness and perceived ease of use. Our work is significant because it adds to the existing empirical evidence on e-learning and supports the relevance of TAM in understanding the usage of e-learning even in extreme situations such as the COVID-19 pandemic. Our research has significant implications for educators and other higher education authorities.
Impact of Low-Pressure UV Lamp on Swimming Pool Water Quality and Operating Costs
Authors: Włodyka-Bergier Agnieszka , Bergier Tomasz
Published: August 2021

UV lamps are being increasingly used in the treatment of swimming pool water, mainly due to their abilities to disinfect and effectively remove chloramines (combined chlorine). However, the application of UV lamps in a closed loop system, such as that in which swimming pool water is treated, creates conditions under which chlorinated water is then also irradiated with UV. Thus, the advanced oxidation process occurs, which affects the transformation of organic matter and its increased reactivity, and hence the higher usage of chlorine disinfectant. In addition, UV lamps require electrical power and the periodic replacement of filaments. In order to assess whether the application of a low-pressure UV lamp is justified, water quality tests and an analysis of the operating costs (including the energy consumption) of the water treatment system were carried out for two operation variants—those of the low-pressure UV lamp being turned on and off. The experiments were carried out on the real object of the AGH University of Science and Technology sports swimming pool for one year. The consumption of electricity and water treatment reagents was also measured. The following values of the selected parameters of the swimming pool water quality were observed (for without and with UV lamp, respectively): 0.68 and 0.52 mg/L combined chlorine; 3.12 and 3.02 mg/L dissolved organic carbon; 15.70 and 15.26 µg/L trihalomethanes; 7 and 6 cfu/mL mesophilic bacteria; and 6 and 20 cfu/mL psychrophilic bacteria. Generally, the statistically important differences in water quality parameters were not observed, thus the application of the low-pressure UV lamp in the swimming pool water treatment technology did not bring the expected improvement in water quality. However, the higher consumption of electric energy (by 29%) and chlorine disinfectant (by 15%), and the need to periodically replace the lamp filaments significantly increased the operating costs of the water treatment system (by 21%) and its ecological impact, thus this technology cannot be considered as profitable or ecological.
Parameter Matching of Energy Regeneration System for Parallel Hydraulic Hybrid Loader
Authors: Yang Jixiang , Bian Yongming , Yang Meng , Shao Jie , Liang Ao
Published: August 2021

Oil shortages and environmental pollution are attracting worldwide attention incrementally. Hybrid falls within one of the effective techniques for those two problems. Taking the loader with high energy consumption and high emission as the target, combined with the hydraulic hybrid technology with high power density and strong energy storage capacity, the parallel hydraulic hybrid loader (PHHL) based on brake energy regeneration is proposed. Firstly, the dynamic models of the key components of the PHHL are established, and the parameters of the part which coincides with the ordinary loader are corrected based on the V-type duty cycle. Then, consid-ering the energy recovery efficiency as well as the characteristics of the loader from the V-type duty cycle, the parameters for several major parts of the energy regeneration system (ERS) were calculated and matched. Then, based on the initial matching, the improved adaptive genetic al-gorithm (AGA) is employed to optimize the control variable of the control strategy and the design parameters of ERS to enhance the economic benefit and performance of the ERS. Furthermore, a simulation validation was conducted. Simulation results show that the ERS with optimized pa-rameters could improve the fuel-saving effect by 25% compared to the ERS with initial parameters, which indicated the rationality of the optimized parameters. Finally, the fuel consumption test of the PHHL prototype under the V-type duty cycle is performed. The results show that the PHHL with the optimization scheme can achieve 9.12% fuel saving, which is on the brink of the potential of brake energy recovery and verifies the feasibility of applying hydraulic hybrid technology on the loader.
Beyond the Diffusion of Residential Solar Photovoltaic Systems at Scale: Allegorising the Battery Energy Storage Adoption Behaviour
Authors: Alipour Mohammad , Stewart Rodney A. , Sahin Oz
Published: August 2021

Understanding the residential adoption decision of battery energy storage systems (BESSs) is central to the implementation of successful intervention policies. However, when the residential solar photovoltaics (PV) becomes a widely accepted technology across a society, accurately modelling the behaviour shows a higher degree of complexity. In this vein, the uptake pathway of BESS and PV coupled with BESS (PV–BESS) would predictably exhibit similar attitudinal traits to that of PV consumption. This notion implies that the antecedent PV decision can be regarded as the past behaviour of the BESS adopter by creating attitudinal implications. The PV use status also yields a higher degree of heterogeneity through the emergence of four new household groups and the inherent imbalances in the involvement of the interwoven financial, technical, sociodemographic, and psychological predictors. This perspective employs the Reasoned Action Approach (RAA) to allegorise a decision-making model of BESS and PV–BESS adoption behaviour in a mature PV market (Australia). It argues that the particularised background factors will likely shape the individual’s attitudes and perceived norms for intention, and showcases affordability and the use of PV as the two control components that dictate the final decision.
Heat and Mass Transfer Analysis in Chemically Reacting Flow of Non-Newtonian Liquid with Local Thermal Non-Equilibrium Conditions: A Comparative Study
Authors: Alhadhrami A. , Prasanna B. M. , K. C. Rajendra Prasad , Sarada K. , Alzahrani Hassan A. H.
Published: August 2021

In the current paper, we endeavour to execute a numerical analysis in connection with the boundary layer flow induced in a non-Newtonian liquid by a stretching sheet with heat and mass transfer. The effects of chemical reactions and local thermal non-equilibrium (LTNE) conditions are considered in the modelling. The LTNE model is based on energy equations, and provides unique heat transfer for both liquid phases. As a result, different temperature profiles for both the fluid and solid phases are used in this work. The model equation system is reduced by means of appropriate similarity transformations, which are then numerically solved by employing the classical Runge–Kutta (RK) scheme along with the shooting method. The resultant findings are graphed to show the effects of various physical factors on the involved distributions. Outcomes reveal that Jeffrey fluid shows improved velocity for lower values of porosity when compared to Oldroyd-B fluid. However, for higher values of porosity, the velocity of the Jeffery fluid declines faster than that of the Oldroyd-B fluid. Jeffery liquid shows improved fluid phase mass transfer, and decays more slowly than Oldroyd-B liquid for higher values of chemical reaction rate parameter.
Ab-Initio Molecular Dynamics Simulation of the Electrolysis of Nucleobases
Authors: Frank Irmgard , Nadimi Ebrahim
Published: August 2021

Electrolysis is potentially a valuable tool for cleansing waste water. One might even hope that it is possible to synthesize valuable products in this way. The question is how the reaction conditions can be chosen to obtain desired compounds. In the present study we use Car–Parrinello molecular dynamics to simulate the reaction of nucleobases under electrolytic conditions. We use our own scheme (F. Hofbauer, I. Frank, Chem. Eur. J., 18, 277, 2012) for simulating the conditions after the electron transfer in a self-consistent field calculation. This scheme was employed previously to the electrolysis of pure water and of polluted solutions. On the picosecond timescale, we find a strongly different reaction behavior for each of the four nucleobases contained in DNA.
Parameter Identification of Proton Exchange Membrane Fuel Cell Based on Hunger Games Search Algorithm
Authors: Fahim Samuel Raafat , Hasanien Hany M. , Turky Rania A. , Alkuhayli Abdulaziz , Al-Shamma’a Abdullrahman A. , Noman Abdullah M. , Tostado-Véliz Marcos , Jurado Francisco
Published: August 2021

This paper presents a novel minimum seeking algorithm referred to as the Hunger Games Search (HGS) algorithm. The HGS is used to obtain optimal values in the model describing proton exchange membrane fuel cells (PEMFCs). The PEMFC model has many parameters that are linked in a nonlinear manner, as well as a set of constraints. The HGS was used with the aforementioned model to test its performance against nonlinear models. The main aim of the optimization problem was to obtain accurate values of PEMFC parameters. The proposed heuristic algorithm was used with two commercial PEMFCs: the Ballard Mark V and the BCS 500 W. The simulation results obtained using the HGS-based model were compared to the experimental results. The effectiveness of the proposed model was verified under various temperature and partial pressure conditions. The numerical output results of the HGS-based fuel cell model were compared with other optimization algorithm-based models with respect to their efficiency. Moreover, the parametric t-test and other statistical analysis methods were employed to check the robustness of the proposed algorithm under various independent runs. Using the proposed HGS-based PEMFC model, a model with very high precision could be obtained, affecting the operation and control of the fuel cells in the simulation analyses.
Differential Evolution-Based Overcurrent Protection for DC Microgrids
Authors: Li Miao , Zhang Daming , Lu Shibo , Tang Xiuhui , Phung Toan
Published: August 2021

DC microgrids have advantages over AC microgrids in terms of system efficiency, cost, and system size. However, a well-designed overcurrent protection approach for DC microgrids remains a challenge. Recognizing this, this paper presents a novel differential evolution (DE) based protection framework for DC microgrids. First, a simplified DC microgrid model is adopted to provide the analytical basis of the DE algorithm. The simplified model does not sacrifice performance criterion in steady-state simulation, which is verified through extensive simulation studies. A DE-based novel overcurrent protection scheme is then proposed to protect the DC microgrid. This DE method provides an innovative way to calculate the maximum line current, which can be used for the overcurrent protection threshold setting and the relay coordination time setting. The detailed load condition and solar irradiance for each bus can be obtained by proposed DE-based method. Finally, extensive case studies involving faults at different locations are performed to validate the proposed strategy’s effectiveness. The expandability of the proposed DE-based overcurrent protection framework has been confirmed by further case studies in seven bus mesh systems.
Analysis of Scenarios for the Insertion of Electric Vehicles in Conjunction with a Solar Carport in the City of Curitiba, Paraná—Brazil
Authors: Kulik Ana Carolina , Tonolo Édwin Augusto , Scortegagna Alberto Kisner , da Silva Jardel Eugênio , Urbanetz Junior Jair
Published: August 2021

The growing environmental impact and rising emission of greenhouse gases have accelerated the research toward renewable energy sources and electric vehicles since one of the main sources of pollution is the CO2 emissions produced by conventional combustion vehicles. This article presents the analysis of the energy balance between a photovoltaic carport with 4.89 kWp installed capacity and an EV, model Renault Fluence ZE DYN, driven in real conditions. The driving tests were performed during the winter season in the city of Curitiba, the capital of the state of Paraná, Brazil, with approximately 1.7 million inhabitants and 1.1 million vehicles. During the test period, we attempt to reproduce the citizen’s daily routes through the city, presenting an average consumption of 15.75 kWh/100 km. The carport PV module’s energy generation and in-plane incident irradiation were acquired to calculate the performance ratio, making a comparison after cleaning maintenance possible. The solar carport system has 4.89 kWp and has generated an average of 465.37 kWh during its 24 months of operation. The analysis scenarios consist of replacing part of the city’s combustion vehicle fleet with the EVs (the same as used in the study) and thus determining how many replicas of the presented photovoltaic systems might be needed, as well as the area required for the installations. In a simulation with 15% of the fleet’s replacement, it would be necessary to generate 17,151.8 MWh, which requires the construction of 36,856 carports, covering an area of approximately 1,105,685 m². Finally, an economic comparison between an internal combustion vehicle and the EV determined that the expenditures involving electric energy to charge the batteries are 3.3 times lower than buying gasoline, assuming the same driving routines.
The Socio-Economic Heterogeneity of Rural Areas: Towards a Rural Typology of Poland
Authors: Stanny Monika , Komorowski Łukasz , Rosner Andrzej
Published: August 2021

The paper aims to identify the significant heterogeneity of socio-economic rural development in Poland by identifying different types of rural areas and clarifying the existing diversity. This objective requires the following: (1) defining the rural development in Polish conditions, (2) abandoning the urban–rural continuum concept, and (3) conducting an analysis involving data aggregated from the local administrative units (2173 gminas/communes). The approach is exploratory and is limited to two questions elaborating the main problem related to the scale and character of rural variety: What socio-economic types of rural area are found in Poland? How are they distributed spatially? The statistical procedure is based on Diday’s dynamic clouds typological analysis. This yielded seven types of rural areas that exhaust their diversity. The main indicator of the character of the different types is related to the level of deagrarianisation of the local economy. The authors argue that the a priori urban–rural continuum model should be abandoned in favour of a more open approach. Typologies based on local administrative unit data, which avoid a priori assumptions concerning rurality, provide an excellent insight into the heterogeneity of rural areas.
An Investigation into CO2–Brine–Cement–Reservoir Rock Interactions for Wellbore Integrity in CO2 Geological Storage
Authors: Jahanbakhsh Amir , Liu Qi , Hadi Mosleh Mojgan , Agrawal Harshit , Farooqui Nazia Mubeen , Buckman Jim , Recasens Montserrat , Maroto-Valer Mercedes , Korre Anna , Durucan Sevket
Published: August 2021

Geological storage of CO2 in saline aquifers and depleted oil and gas reservoirs can help mitigate CO2 emissions. However, CO2 leakage over a long storage period represents a potential concern. Therefore, it is critical to establish a good understanding of the interactions between CO2–brine and cement–caprock/reservoir rock to ascertain the potential for CO2 leakage. Accordingly, in this work, we prepared a unique set of composite samples to resemble the cement–reservoir rock interface. A series of experiments simulating deep wellbore environments were performed to investigate changes in chemical, physical, mechanical, and petrophysical properties of the composite samples. Here, we present the characterisation of composite core samples, including porosity, permeability, and mechanical properties, determined before and after long-term exposure to CO2-rich brine. Some of the composite samples were further analysed by X-ray microcomputed tomography (X-ray µ-CT), X-ray diffraction (XRD), and scanning electron microscopy–energy-dispersive X-ray (SEM–EDX). Moreover, the variation of ions concentration in brine at different timescales was studied by performing inductively coupled plasma (ICP) analysis. Although no significant changes were observed in the porosity, permeability of the treated composite samples increased by an order of magnitude, due mainly to an increase in the permeability of the sandstone component of the composite samples, rather than the cement or the cement/sandstone interface. Mechanical properties, including Young’s modulus and Poisson’s ratio, were also reduced.
Solid Fraction of Digestate from Biogas Plant as a Material for Pellets Production
Authors: Czekała Wojciech
Published: August 2021

One of the anaerobic digestion process products in an agricultural biogas plant is digestate (digested pulp). Large quantities of digestate generated in the process of biogas production all over the world require proper management. Fertilization is the main management of this substrate, so it is essential to look for new alternatives. The work aims to determine and discuss the possibilities of using digestate solid fraction (DSF) for pellets as biofuel production. Pellets from DSF alone and pellets with sawdust, grain straw additives were analyzed. The lower heating value (LHV) based on the dry matter for all analyzed pellets ranged from 19,164 kJ∙kg−1 to 19,879 kJ∙kg−1. The ash content was similar for all four samples and ranged from 3.62% to 5.23%. This value is relatively high, which is related to the degree of fermentation in the anaerobic digestion process. The results showed that the DSF substrate after the anaerobic digestion process still has energy potential. Analyzing those results, it seems that DSF can be a highly valuable substrate for solid biofuels production.
Oak Competition Dominates Interspecific Interactions in Growth and Water-Use Efficiency in a Mixed Pine–Oak Mediterranean Forest
Authors: Ferrio Juan Pedro , Shestakova Tatiana A. , del Castillo Jorge , Voltas Jordi
Published: August 2021

In the Mediterranean, mixed forests of Aleppo pine and holm oak are widespread. Generally considered a transition stage in the succession towards climax oak communities, niche segregation may also contribute to the prevalence of these communities. So far, there is increasing evidence of hydrological niche segregation, with the two species showing complementary water use and seasonal growth patterns. However, it remains unknown whether interspecific interactions affect the response to climate and the mid-term (decadal) growth and water-use efficiency of pines and oaks in mixed stands. Here, we combined tree-ring chronologies, built on different competition classes within a mixed stand, with a spatially explicit assessment of individual growth and wood carbon isotope discrimination (∆13C), as a proxy of intrinsic water-use efficiency, and compared these results with previously reported water uptake patterns. We found that competition with pines modulated the climate response of oaks, whereas pine climate response was insensitive to competition. On the other hand, pine density affected only pine growth, whereas oak competition affected both species. We conclude that the presence of pines had negligible or even positive effects on the oaks, but competition with neighbor oaks limited their ability to recover after drought. Conversely, pines experienced greater drought stress under competition, with both oaks and pines.