bluuebunny/crossref_metadata_2025 huggingface dataset:
Vascular Epiphyte Assemblages on Isolated Trees along an Elevational Gradient in Southwest Panama
Authors: Rodríguez Quiel Calixto , Zotz Gerhard
Published: January 2021

Ongoing destruction of tropical forests makes isolated pasture trees potentially important for the persistence of original forest dwellers such as many vascular epiphytes. We studied epiphyte assemblages on 100 isolated trees at ten pasture sites in southwest Panama along an elevational gradient ranging from 140 to 1240 m a.s.l. We analysed epiphyte species composition (richness, similarity) and registered climate and host trait variables of potential influence on their occurrence. We found a total of 5876 epiphyte individuals belonging to 148 species. Epiphyte abundance, species richness and diversity all varied about 4-fold among the 10 sites, with a high similarity of epiphyte assemblages among sites. Two sites at 870 and 1050 m a.s.l. did not fit into the overall elevational trend of increased abundance, species richness and diversity. However, all three measures were significantly correlated with humidity as the independent variable. This highlights that a gradient in humidity, and not elevation as such, is responsible for the typical elevational changes in epiphyte assemblages, so that special local conditions may lead to deviations from expected patterns. Our documentation of current elevational diversity patterns also provides a baseline for the study of long-term changes in epiphyte assemblages in anthropogenically modified landscapes.
Bird Occupancy of a Neotropical Forest Fragment Is Mostly Stable over 17 Years but Influenced by Forest Age
Authors: Campos-Cerqueira Marconi , Robinson W. Douglas , Augusto Leite Gabriel , Mitchell Aide T.
Published: January 2021

The effects of forest degradation, fragmentation, and climate change occur over long time periods, yet relatively few data are available to evaluate the long-term effects of these disturbances on tropical species occurrence. Here, we quantified changes in occupancy of 50 bird species over 17 years on Barro Colorado Island (BCI), Panama, a model system for the long-term effects of habitat fragmentation. The historical data set (2002–2005) was based on point counts, whereas the contemporary data set (2018) was based on acoustic monitoring. For most species, there was no significant change in occupancy; however, the occupancy of four species (Tinamus major, Polioptila plumbea, Myiarchus tuberculifer, and Ceratopipra mentalis) increased significantly, and the occupancy of three species (Saltator grossus, Melanerpes pucherani, and Cyanoloxia cyanoides) decreased significantly. Forest age explained the majority of occupancy variation and affected the occupancy of more bird species than survey period or elevation. Approximately 50% of the species seem to favor old-growth forest, and 15 species (30%) had a significantly higher occupancy in old-growth forest sites. Elevation had no significant impact on the occupancy of the majority of bird species. Although BCI has been a protected reserve for approximately 100 years, land-use legacies (i.e., forest age) continue to influence bird distribution.
Estimating the Potential of Radiomics Features and Radiomics Signature from Pretherapeutic PSMA-PET-CT Scans and Clinical Data for Prediction of Overall Survival When Treated with 177Lu-PSMA
Authors: Moazemi Sobhan , Erle Annette , Lütje Susanne , Gaertner Florian C. , Essler Markus , Bundschuh Ralph A.
Published: January 2021

Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PSMA-PET/CT) scans can facilitate diagnosis and treatment of prostate disease. Radiomics signature (RS) is widely used for the analysis of overall survival (OS) in cancer diseases. This study aims at investigating the role of radiomics features (RFs) and RS from pretherapeutic gallium-68 (68Ga)-PSMA-PET/CT findings and patient-specific clinical parameters to analyze overall survival of prostate cancer (PC) patients when treated with lutethium-177 (177Lu)-PSMA. A cohort of 83 patients with advanced PC was retrospectively analyzed. Average values of 73 RFs of 2070 malignant hotspots as well as 22 clinical parameters were analyzed for each patient. From the Cox proportional hazard model, the least absolute shrinkage and selection operator (LASSO) regularization method is used to select most relevant features (standardized uptake value (SUV)Min and kurtosis with the coefficients of 0.984 and −0.118, respectively) and to calculate the RS from the RFs. Kaplan–Meier (KM) estimator was used to analyze the potential of RFs and conventional clinical parameters, such as metabolic tumor volume (MTV) and standardized uptake value (SUV) for the prediction of survival. As a result, SUVMin, kurtosis, the calculated RS, SUVMean, as well as Hemoglobin (Hb)1, C-reactive protein (CRP)1, and ECOG1 (clinical parameters) achieved p-values less than 0.05, which suggest the potential of findings from 68Ga-PSMA-PET/CT scans as well as patient-specific clinical parameters for the prediction of OS for patients with advanced PC treated with 177Lu-PSMA therapy.
Selective Surface Electrostimulation of the Denervated Zygomaticus Muscle
Authors: Arnold Dirk , Thielker Jovanna , Klingner Carsten M. , Puls Wiebke Caren , Misikire Wengelawit , Guntinas-Lichius Orlando , Volk Gerd Fabian
Published: January 2021

This article describes a first attempt to generate a standardized and safe selective surface electrostimulation (SES) protocol, including detailed instructions on electrode placement and stimulation parameter choice to obtain a selective stimulation of the denervated zygomaticus muscle (ZYG), without unwanted simultaneous activation of other ipsilateral or contralateral facial muscles. Methods: Single pulse stimulation with biphasic triangular and rectangular waveforms and pulse widths (PW) of 1000, 500, 250, 100, 50, 25, 15, 10, 5, 2, 1 ms, at increasing amplitudes between 0.1 and 20 mA was performed. Stimulations delivered in trains were assessed at a PW of 50 ms only. The stimulation was considered successful exclusively if it drew the ipsilateral corner of the mouth upwards and outwards, without the simultaneous activation of other ipsilateral or contralateral facial muscles. I/t curves, accommodation quotient, rheobase, and chronaxie were regularly assessed over 1-year follow-up. Results: 5 facial paralysis patients were assessed. Selective ZYG response in absence of discomfort and unselective contraction of other facial muscle was reproducibly obtained for all the assessed patients. The most effective results with single pulses were observed with PW ≥ 50 ms. The required amplitude was remarkably lower (≤5 mA vs. up to 15 mA) in freshly diagnosed (≤3 months) than in long-term facial paralysis patients (>5 years). Triangular was more effective than rectangular waveform, mostly because of the lower discomfort threshold of the latter. Delivery of trains of stimulation showed similar results to the single pulse setting, though lower amplitudes were necessary to achieve the selective ZYG response. Initial reinnervation signs could be detected effectively by needle-electromyography (n-EMG). Conclusion: It is possible to define stimulation parameters able to elicit an effective selective stimulation of a specific facial muscle, in our case, of the ZYG, without causing discomfort to the patient and without causing unwanted unspecific reactions of other ipsilateral and/or contralateral facial muscles. We observed that the SES success is strongly conditioned by the correct electrode placement, which ideally should exclusively interest the area of the target muscles and its immediate proximity.
Teaching during COVID-19: The Decisions Made in Teaching
Authors: Lepp Liina , Aaviku Triinu , Leijen Äli , Pedaste Margus , Saks Katrin
Published: January 2021

The emergency caused by COVID-19 and the transition to distance learning has made teachers face novel decision-making situations. As the teachers’ pedagogical decisions have an impact on the students’ learning experience, the aim of this study was to describe and explain what influenced the teachers’ teaching-related decisions and how these decisions were reflected in the teaching process during distance learning. The study was based on semi-structured interviews with 16 Estonian basic school science teachers. The data were analyzed using qualitative thematic analysis. The results show that teachers’ teaching-related decisions were influenced by factors that were related to the existence of digital tools as well as to the ability to use them purposefully in the home settings of teachers and students. Teachers’ teaching decisions were mostly motivated by short-term goals, such as maintaining students’ social interaction and supporting student motivation. The desire of teachers to keep students’ and teachers’ own workload affordable was also considered as a factor influencing teachers’ teaching-related decisions. According to the interviews, the switch of focus to workload and well-being and valuing socialization and student motivation over subject matter competences seems to be unique for this new situation.
Magnetic Elastomer Sensor for Dynamic Torque and Speed Measurements
Authors: Mateev Valentin , Marinova Iliana
Published: January 2021

In this paper is proposed a dynamic torque, rotational speed, and shaft position sensor. It is built of magnetic elastomer coating directly applied over a rotating shaft. The sensor is used for precise measurements of changes in torque and speed, and it is usable at high rotational speeds, directly on the device shaft. The sensor is based on magnetic elastomer material deformation and the corresponding change in magnetic field amplitude and direction. The proposed sensor design is simple and can acquire reliable readings for a wide range of rotational speeds. Sensor design consists of the following: magnetic elastomer coating with nanoparticles, in which, elastomer is used for a sensing convertor; magneto-resistive linear field sensor; and microprocessor unit for calibration and control. Numerical and experimental test results are demonstrated and analyzed. Sensor implementation aims to meet magnetic mechatronic systems’ specific requirements.
Toward a Substation Automation System Based on IEC 61850
Authors: Kumar Shantanu , Abu-Siada Ahmed , Das Narottam , Islam Syed
Published: January 2021

With the global trend to digitalize substation automation systems, International Electro technical Commission 61850, a communication protocol defined by the International Electrotechnical Commission, has been given much attention to ensure consistent communication and integration of substation high-voltage primary plant assets such as instrument transformers, circuit breakers and power transformers with various intelligent electronic devices into a hierarchical level. Along with this transition, equipment of primary plants in the switchyard, such as non-conventional instrument transformers, and a secondary system including merging units are expected to play critical roles due to their fast-transient response over a wide bandwidth. While a non-conventional instrument transformer has advantages when compared with the conventional one, extensive and detailed performance investigation and feasibility studies are still required for its full implementation at a large scale within utilities, industries, smart grids and digital substations. This paper is taking one step forward with respect to this aim by employing an optimized network engineering tool to evaluate the performance of an Ethernet-based network and to validate the overall process bus design requirement of a high-voltage non-conventional instrument transformer. Furthermore, the impact of communication delay on the substation automation system during peak traffic is investigated through a detailed simulation analysis.
A Longitudinal Analysis of the Creation of Environmental Identity and Attitudes towards Energy Sustainability Using the Framework of Identity Theory and Big Data Analysis
Authors: Domalewska Dorota
Published: January 2021

Embracing sustainability in the 21st century entails developing environmental identity, so that attitudes towards energy sustainability result from the core values of one’s individual and social identity. This study aims to explore the shift in the formation of environmental identity and attitudes towards energy sustainability throughout the course of the two-year study period (2018–2020). A dataset of 8,677,961 tweets, Facebook posts and comments and 325,228 news articles was collected to carry out quantitative analysis of the distribution of the posts, likes, and comments. A correlation with media coverage of energy and green topics was sought to establish the impact of the media on public debate. A qualitative analysis of posts and tweets was carried out to establish dominant themes. The findings of the study reveal that both positive attitudes towards energy sustainability and environmental identity have been consolidated throughout the two-year study period. Social media users are not only increasingly interested in green issues but also produce more reactions towards posts related to sustainability topics. The results also suggest that sustainable values and green behavior are independent from the media coverage of current events and the perceived threat to one’s health from COVID-19. Social networking sites provide a context in which users not only reinforce their beliefs and values, but also mimic the behavior of other users, which leads to the formation of a social media identity bubble that reinforces shared identity—in this case, environmental identity. This study offers a multidisciplinary perspective on sustainable development that will be able to drive equitable energy security and environmental security.
Modeling and Mitigation Control of the Submodule-Capacitor Voltage Ripple of a Modular Multilevel Converter under Unbalanced Grid Conditions
Authors: Wang Songda , Bao Danyang , Gontijo Gustavo , Chaudhary Sanjay , Teodorescu Remus
Published: January 2021

A modular multilevel converter’s (MMC’s) submodule (SM)-capacitor voltage will increase under unbalanced grid conditions. Depending on the imbalance level, the voltage ripple can be considerably high, and it can exceed the pre-defined safe limits. If this occurs, the converter will trip, which can lead to serious stability problems for the grid. This paper first proposes an analytical solution for deriving the three-phase imbalanced SM ripple of an MMC under an unbalanced grid. With this analytical tool, the imbalance mechanism of the SM voltage ripple can be easily understood. What is more, the symmetrical component method is first applied to analyze the three-phase SM capacitor ripple, and the positive-/negative-/zero-sequence components of the three-phase SM voltage ripple are easily identified by the proposed analytical method. Then, based on this powerful analytical tool, the proper circulating-current profile to be injected can be obtained, allowing for the right compensation of the voltage ripple. Based on this approach, two new voltage ripple compensation methods are proposed in this paper. Simulations were carried out to validate the analytical description of the submodule-capacitor voltage ripple proposed in this paper. Moreover, simulation and experimental results are provided to validate the new compensation techniques introduced in this paper.
Well Killing Technology before Workover Operation in Complicated Conditions
Authors: Mardashov Dmitry V. , Rogachev Mikhail K. , Zeigman Yury V. , Mukhametshin Vyacheslav V.
Published: January 2021

Well killing is an important technological stage before conducting workover operation, one of the tasks of which is to preserve and restore the natural filtration characteristics of the bottomhole formation zone (BFZ). Special attention should be paid to the choice of well killing technologies and development of wells in complicated conditions, which include abnormally low reservoir pressure, high oil-gas ratio and carbonate reservoir type. To preserve the filtration characteristics of the productive formation and prevent fluid losses in producing wells during well killing operation, blocking compositions are used. At the same time, an informed choice of the most effective well killing technologies is required. Consequently, there is a need to conduct laboratory physicochemical and coreflood experiments simulating geological, physical, and technological conditions of field development, as similar as possible to actual reservoir conditions. The article presents the results of experimental studies on the development well killing technologies of producing wells during workover operation in various geological, physical, and technological conditions of oil field development. Physicochemical and coreflood laboratory experiments were carried out with the simulation of the processes of well killing and development of wells in reservoir conditions with the use of modern high-technology equipment in the Enhanced Oil Recovery Laboratory of the Department of Development and Operation of Oil and Gas Fields at St. Petersburg Mining University. As a result of the experimental studies, new compositions of well killing and stimulation fluids were developed, which ensure to prevent fluid loss, gas breakthrough, as well as the preservation, restoration and improvement of the filtration characteristics of the BFZ in the conditions of terrigenous and carbonate reservoirs at different stages of oil field development. It is determined that the developed process fluids, which include surfactants (YALAN-E2 and NG-1), have a hydrophobic effect on the porous medium of reservoir rocks, which ultimately contributes to the preservation, restoration and improvement of the filtration characteristics of the BFZ. The value of the presented research results is relevant for practice and confirmed by the fact that, as a result of field tests of the technology for blocking the BFZ with the composition of inverse water–oil emulsion during well killing before workover operation, an improvement in the efficiency of wells operation was obtained in the form of an increase in their oil production rate by an average of 5–10 m3/day, reducing the time required for the well to start operating up to 1–3 days and reducing the water cut of formation fluid by 20–30%.
Investigation on the Operating Conditions of Proton Exchange Membrane Fuel Cell Based on Constant Voltage Cold Start Mode
Authors: Yang Yanbo , Ma Tiancai , Du Boyu , Lin Weikang , Yao Naiyuan
Published: January 2021

The cold start property is one of the main factors restricting the fuel cell application in the automotive field. The constant voltage cold start method of the fuel cell works under low start voltage and produces high heat, which can shorten the start-up time of the fuel cell at low temperature and has the opportunity to be applied to fuel cell vehicles. Meanwhile, in the constant voltage cold start mode, the fuel cell needs to operate under a large current, and more water is generated during the start-up process. Thus, the optimization of operating conditions for the constant voltage cold start is particularly important. However, there are relatively few studies on the optimization of operating conditions for the constant voltage cold start with a single-cell voltage less than 0.3 V. In this work, the cold start experiment of the fuel cell with constant voltage is carried out. According to the cold start experiment, the different cold start voltage, back-pressure, and the inlet flow rate are examined. Based on the experiment data, the operating conditions have a great influence on the cold start property of the fuel cell and the optimized operating conditions of the constant voltage cold start are obtained.
Emission Characteristics for Swirl Methane–Air Premixed Flames with Ammonia Addition
Authors: Jójka Joanna , Ślefarski Rafał
Published: January 2021

This paper details the experimental and numerical analysis of a combustion process for atmospheric swirl burners using methane with added ammonia as fuel. The research was carried out for lean methane–air mixtures, which were doped with ammonia up to 5% and preheated up to 473 K. A flow with internal recirculation was induced by burners with different outflow angles from swirling blades, 30° and 50°, where tested equivalence ratio was 0.71. The NO and CO distribution profiles on specified axial positions of the combustor and the overall emission levels at the combustor outlet were measured and compared to a modelled outcome. The highest values of the NO emissions were collected for 5% NH3 and 50° (1950 ppmv), while a reduction to 1585 ppmv was observed at 30°. The doubling of the firing rates from 15 kW up to 30 kW did not have any great influence on the overall emissions. The emission trend lines were not proportional to the raising share of the ammonia in the fuel. 3D numerical tests and a kinetic study with a reactor network showed that the NO outlet concentration for swirl flame depended on the recirculation ratio, residence time, wall temperature, and the mechanism used. Those parameters need to be carefully defined in order to get highly accurate NO predictions—both for 3D simulations and simplified reactor-based models.
Conceptual Study of Vernier Generator and Rectifier Association for Low Power Wind Energy Systems
Authors: Enrici Philippe , Meny Ivan , Matt Daniel
Published: January 2021

In this paper, we study a wind energy conversion system designed for domestic use in urban or agricultural areas. We first present the turbine, which was specifically designed to be installed on the buildings that it supplies. Based on turbine characteristics, we perform analytical sizing of a Permanent Magnet Vernier Machine (PMVM), which will be used as a generator in our energy conversion system. We show the influence of this generator on system operation by studying its association with a PWM rectifier and with a diode bridge rectifier. We then seek to improve generator design so that the turbine operates closely to maximum power points, while using a simple and robust energy conversion system. We use simulation to show the improvements achieved by taking into account the entire energy conversion system during machine design.
The Beneficial Effect of the Addition of Fly Ash on Reduction of the Size of Microcracks in the ITZ of Concrete Composites under Dynamic Loading
Authors: Golewski Grzegorz
Published: January 2021

The paper presents results of tests on the effect of the addition of fly ash (FA) in the amounts of 0%, 20%, and 30% by weight of cement on the interfacial microcracks in concrete composites subjected to dynamic loads. The analyses were carried out based on the results of the microstructural tests using a scanning electron microscope (SEM). The average width of the microcracks (Wc) in the interfacial transition zone (ITZ) of coarse aggregate with cement matrix was evaluated. During the studies beneficial effect of the addition of FA on reduction of the size of Wc in the ITZ of concrete composites under dynamic loading were observed. Based on obtained test results, it was found that using the 20% FA additive causes favorable changes in the microstructure of mature concrete. In this composite, the average value of Wc was lower by more than 40% compared to the result obtained for the reference concrete. In contrast, concrete containing 30% FA additive had greater microcracks in the ITZ area by over 60% compared to the material without additive. In all analyzed composites, an increase in the Wc value by almost 70% to over 110% in the case of occurrence of dynamic loads was also observed. This was the most evident in the case of concrete with a higher content of FA.
Spectacular Enhancement of the Thermal and Photochemical Stability of MAPbI3 Perovskite Films Using Functionalized Tetraazaadamantane as a Molecular Modifier
Authors: Ozerova Victoria V. , Zhidkov Ivan S. , Boldyreva Aleksandra , Dremova Nadezhda N. , Emelianov Nikita A. , Shilov Gennady V. , Frolova Lyubov A. , Kurmaev Ernst Z. , Sukhorukov Alexey Y. , Aldoshin Sergey M. , Troshin Pavel A.
Published: January 2021

Perovskite solar cells represent a highly promising third-generation photovoltaic technology. However, their practical implementation is hindered by low device operational stability, mostly related to facile degradation of the absorber materials under exposure to light and elevated temperatures. Improving the intrinsic stability of complex lead halides is a big scientific challenge, which might be addressed using various “molecular modifiers”. These modifiers are usually represented by some additives undergoing strong interactions with the perovskite absorber material, resulting in enhanced solar cell efficiency and/or operational stability. Herein, we present a derivative of 1,4,6,10-tetraazaadamantane, NAdCl, as a promising molecular modifier for lead halide perovskites. NAdCl spectacularly improved both the thermal and photochemical stability of methylammonium lead iodide (MAPbI3) films and, most importantly, prevented the formation of metallic lead Pb0 as a photolysis product. NAdCl improves the electronic quality of perovskite films by healing the traps for charge carriers. Furthermore, it strongly interacts with the perovskite framework and most likely stabilizes undercoordinated Pb2+ ions, which are responsible for Pb0 formation under light exposure. The obtained results feature 1,4,6,10-tetraazaadamantane derivatives as highly promising molecular modifiers that might help to improve the operational lifetime of perovskite solar cells and facilitate the practical implementation of this photovoltaic technology.
Research on Model Predictive Control for Automobile Active Tilt Based on Active Suspension
Authors: Yao Jialing , Wang Meng , Li Zhihong , Jia Yunyi
Published: January 2021

To improve the handling stability of automobiles and reduce the odds of rollover, active or semi-active suspension systems are usually used to control the roll of a vehicle. However, these kinds of control systems often take a zero-roll-angle as the control target and have a limited effect on improving the performance of the vehicle when turning. Tilt control, which actively controls the vehicle to tilt inward during a curve, greatly benefits the comprehensive performance of a vehicle when it is cornering. After analyzing the advantages and disadvantages of the tilt control strategies for narrow commuter vehicles by combining the structure and dynamic characteristics of automobiles, a direct tilt control (DTC) strategy was determined to be more suitable for automobiles. A model predictive controller for the DTC strategy was designed based on an active suspension. This allowed the reverse tilt to cause the moment generated by gravity to offset that generated by the centrifugal force, thereby significantly improving the handling stability, ride comfort, vehicle speed, and rollover prevention. The model predictive controller simultaneously tracked the desired tilt angle and yaw rate, achieving path tracking while improving the anti-rollover capability of the vehicle. Simulations of step-steering input and double-lane change maneuvers were performed. The results showed that, compared with traditional zero-roll-angle control, the proposed tilt control greatly reduced the occupant’s perceived lateral acceleration and the lateral load transfer ratio when the vehicle turned and exhibited a good path-tracking performance.
Radial Turbine Design for Solar Chimney Power Plants
Authors: Caicedo Paul , Wood David , Johansen Craig
Published: January 2021

Solar chimney power plants (SCPPs) collect air heated over a large area on the ground and exhaust it through a turbine or turbines located near the base of a tall chimney to produce renewable electricity. SCPP design in practice is likely to be specific to the site and of variable size, both of which require a purpose-built turbine. If SCPP turbines cannot be mass produced, unlike wind turbines, for example, they should be as cheap as possible to manufacture as their design changes. It is argued that a radial inflow turbine with blades made from metal sheets, or similar material, is likely to achieve this objective. This turbine type has not previously been considered for SCPPs. This article presents the design of a radial turbine to be placed hypothetically at the bottom of the Manzanares SCPP, the only large prototype to be built. Three-dimensional computational fluid dynamics (CFD) simulations were used to assess the turbine’s performance when installed in the SCPP. Multiple reference frames with the renormalization group k-ε turbulence model, and a discrete ordinates non-gray radiation model were used in the CFD simulations. Three radial turbines were designed and simulated. The largest power output was 77.7 kW at a shaft speed of 15 rpm for a solar radiation of 850 W/m2 which exceeds by more than 40 kW the original axial turbine used in Manzanares. Further, the efficiency of this turbine matches the highest efficiency of competing turbine designs in the literature.
The Conceptual Research over Low-Switching Modulation Strategy for Matrix Converters with the Coupled Reactors
Authors: Szczepankowski Pawel , Luszcz Jaroslaw , Usoltsev Alexander , Strzelecka Natalia , Romero-Cadaval Enrique
Published: January 2021

In this paper, different Pulse Width Modulation (PWM) strategies for operating with a low-switching frequency, a topology that combines Conventional Matrix Converters (CMCs), and Coupled Reactors (CRs) are presented and discussed. The principles of the proposed strategies are first discussed by a conceptual analysis and later validated by simulation. The paper shows how the combination of CMCs and CRs could be of special interest for sharing the current among these converters’ modules, being possible to scale this solution to be a modular system. Therefore, the use of coupled reactors allows one to implement phase shifters that give the solution the ability to generate a stair-case load voltage with the desired power quality even the matrix converters are operated with a low-switching frequency close to the grid frequency. The papers also address how the volume and weight of the coupled reactors decrease with the growth of the fundamental output frequency, making this solution especially appropriate for high power applications that are supplied at high AC frequencies (for example, in airport terminals, where a supply of 400 Hz is required).
Individual vs. Community: Economic Assessment of Energy Management Systems under Different Regulatory Frameworks
Authors: Alonso Àlex , de la Hoz Jordi , Martín Helena , Coronas Sergio , Matas José
Published: January 2021

In the context of the increasing popularity of self-sufficient communities around the globe, this study aims to compare the economic performance of energy management in two distinct situations: whether it is conducted individually or collectively within a community. After setting the context and completing a literature review, a research gap concerning the influence of regulatory frameworks in the economic results is identified. Therefore, this work presents this comparison under several frameworks employed to promote renewable energy, in order to provide a more realistic point of view and deliver insights in policy making. To this end, a mixed integer linear program (MILP) is developed, and the formulation of three key regulatory schemes is embedded into it: feed-in tariff, net metering, and self-consumption schemes. A what-if analysis is performed in order to take into account different combinations of rewarding parameters for each regulatory framework, as well as different profiles of consumption for the individual case. Results show that energy management within a community improves the overall average benefit of the customers up to 0.44 €/day·dwelling, for all of the studied frameworks except feed-in-tariff and some instances of type-B self-consumption, which can reduce it up to −0.87 €/day·dwelling. The conclusions determine fundamental differences between regulatory schemes and their suitability to promote collective or individual facilities, and emphasize the need to design a set of policies that take into account the habits of consumption of the individuals to foster effectively energy communities.
Effects of MgO Nanoparticles on Thermo-Physical Properties of LiNO3-NaNO3-KNO3 for Thermal Energy Storage
Authors: Lu Jianfeng , Zhang Zhan , Wang Weilong , Ding Jing
Published: January 2021

Molten salt LiNO3-NaNO3-KNO3 has been investigated as heat transfer and thermal storage media for its low melting point and good thermal performance. In this paper, nanofluids were synthesized by dispersing MgO nanoparticles into LiNO3-NaNO3-KNO3, and the effects of nanoparticles on thermal properties were studied with different sizes (20–100 nm) and mass percent concentrations (0.5–2.0 wt.%). The addition of nanoparticles had little effect on melting temperature, and led to a slight increase in enthalpy of fusion by 2.0–5.5%. Compared with base salt, the density of nanofluid increased a little by 0.22–1.15%. The scanning electron microscope (SEM) test implied that nubby and punctate microstructures were responsible for larger surface area and interfacial energy, which could lead to the improvement of specific heat capacity reaching 2.6–10.6%. The heat transfer characteristics remarkably increased with the addition of nanoparticles, and the enhancement of average thermal diffusivity and conductivity of salt with 1 wt.% nano-MgO could be 5.3–11.7% and 11.3–21.2%, respectively. Besides, the viscosities of nanofluids slightly increased for 3.3–8.1%. As a conclusion, nano-MgO was positively influential on the thermal properties of LiNO3-NaNO3-KNO3 base salt.
Kinetic Parameters of Nut Shells Pyrolysis
Authors: Noszczyk Tomasz , Dyjakon Arkadiusz , Koziel Jacek A.
Published: January 2021

The European Union created a European Green Deal Program (EGDP). This program aims at a sustainable economy through the transformation of the challenges related to climate and the environment. The main goal of EGDP is climate neutrality by 2050. The increase of alternative biomass residues utilization from various food processing industries and cooperation in the energy and waste management sector is required to meet these expectations. Nut shells are one of the lesser-known, yet promising, materials that can be used as an alternative fuel or a pre-treated product to further applications. However, from a thermal conversion point of view, it is important to know the energy properties and kinetic parameters of the considered biowaste. In this study, the energy and kinetic parameters of walnut, hazelnut, peanut, and pistachio shells were investigated. The results showed that raw nut shells are characterized by useful properties such as higher heating value (HHV) at 17.8–19.7 MJ∙kg−1 and moisture content of 4.32–9.56%. After the thermal treatment of nut shells (torrefaction, pyrolysis), the HHV significantly increased up to ca. 30 MJ∙kg−1. The thermogravimetric analysis (TGA) applying three different heating rates (β; 5, 10, and 20 °C∙min−1) was performed. The kinetic parameters were determined using the isothermal model-fitting method developed by Coats–Redfern. The activation energy (Ea) estimated for β = 5 °C∙min−1, was, e.g., 60.3 kJ∙mol−1∙K−1 for walnut, 59.3 kJ∙mol−1∙K−1 for hazelnut, 53.4 kJ∙mol−1∙K−1 for peanut, and 103.8 kJ∙mol−1∙K−1 for pistachio, respectively. Moreover, the increase in the Ea of nut shells was observed with increasing the β. In addition, significant differences in the kinetic parameters of the biomass residues from the same waste group were observed. Thus, characterization of specific nut shell residues is recommended for improved modeling of thermal processes and designing of bioreactors for thermal waste treatment.
Effects of the Application of Biochar to Plant Growth and Net Primary Production in an Oak Forest
Authors: Ohtsuka Toshiyuki , Tomotsune Mitsutoshi , Ando Masaki , Tsukimori Yuki , Koizumi Hiroshi , Yoshitake Shinpei
Published: January 2021

Few studies have evaluated the application of biochar to forest ecosystems and their responses under field conditions. We manually spread grounded biochar on the forest floor, at rates of 0 (control), 5, and 10 Mg ha−1 (C0, C5 and C10, respectively), of an oak forest in central Japan to test the effects of biochar on tree growth and productivity. The relative growth rate of the diameter at breast height (dbh) of canopy oak trees (dbh > 20 cm) significantly increased in C10 compared with that of the control (C0), but not in C5, in the second to third years after application. Despite the increasing growth rate of canopy trees, foliage production (NPPF) and woody production (NPPW) did not respond to biochar application. Conversely, the production of reproductive organs (NPPR, mainly oak acorns) increased in line with the biochar application rate gradients (1.04 ± 0.09 Mg ha−1 yr−1 in C0, 1.30 ± 0.08 Mg ha−1 yr−1 in C5, and 1.47 ± 0.13 Mg ha−1 yr−1 in C10). Since the contribution of NPPR to total NPP was fairly small, there were no significant differences in total NPP (=NPPW + NPPF + NPPR) for C5 (14.57 ± 0.20 Mg ha−1 yr−1) or C10 (16.11 ± 0.73 Mg ha−1 yr−1) compared with the control (15.07 ± 0.48 Mg ha−1 yr−1).
Post-Fire Demography, Growth, and Control of Eucalyptus globulus Wildlings
Authors: Silva Joaquim S. , Nereu Mauro , Pinho Simão , Queirós Luís , Jesús Cláudio , Deus Ernesto
Published: January 2021

Several eucalypt species are known for their capacity to massively regenerate through seeds in recently burned areas, becoming an ecological problem in regions where the species is not native. Here we study the demography and the development of highly dense Eucalyptus globulus wildling populations established one year after a fire and test two methods to control these populations. We monitored five mixed E. globulus stands across one year, in Central Portugal. We established a set of plots in each stand, with three treatments: mechanical cutting, herbicide spraying and no disturbance (control plots). Herbicide was applied in four concentrations. We tagged randomly selected plants in the control plots to monitor their growth. The initial mean wildling density was 322,000 plants ha−1, the highest ever recorded in the introduced range. Wildling density was significantly dependent on the density of surrounding adult E. globulus trees. Wildling density in control plots decreased 30% in one year, although showing positive variations over time because of new recruitment. Despite seasonal growth differences, wildlings showed a high growth rate throughout the year, reaching 15.6 cm month−1 in the summer. The growth rate of tagged wildings was positively affected by solar radiation and negatively affected by evapotranspiration and maximum temperature. Mechanical cutting reduced wildling density by 97% while herbicide treatment reduced density between 80% (for the lowest concentration) and 99% (for the highest concentration). Herbicide-treated plants were more likely to resprout than cut plants. Regardless of the control method adopted (cutting or herbicide), management strategies should include the follow-up of the treated areas, to detect the establishment of new recruits and resprouting.
Crossover of Rate-Limiting Process in Plasma Gel Growth by Contact with Source of Gelator
Authors: Kawabata Akitsugu , Yamamoto Takao , Shinoda Hiroki , Yoshiba Kazuto , Toyama Yoshiharu , Tanaka Susumu , Dobashi Toshiaki
Published: January 2021

Plasma is regarded as a solution of precursor polymers specifically transformed to gel-forming polymers by a reaction with initiators. We developed a theory for the gel growth dynamics of plasma induced by contact with a source of gelators that are yielded by the initiation. In developing the theory, we combined the Ginzburg–Landau type dynamics with the gelator diffusion dynamics expressed by the moving boundary picture. The theory predicts the crossover of the rate-limiting process in the time course of the thickness of the gel layer X from the energy-limited process expressed by X∼t to the diffusion-limited process expressed by X∼t, where t is the time elapsed from when the plasma comes into contact with the source of gelators. A demonstration experiment was performed by placing a tissue factor coating plate as the initiator in plasma. Log–log plot of X vs. t showed a crossover as predicted by the theory, and the parameters characterizing plasma were determined.
EpiMOGA: An Epistasis Detection Method Based on a Multi-Objective Genetic Algorithm
Authors: Chen Yuanyuan , Xu Fengjiao , Pian Cong , Xu Mingmin , Kong Lingpeng , Fang Jingya , Li Zutan , Zhang Liangyun
Published: January 2021

In genome-wide association studies, detecting high-order epistasis is important for analyzing the occurrence of complex human diseases and explaining missing heritability. However, there are various challenges in the actual high-order epistasis detection process due to the large amount of data, “small sample size problem”, diversity of disease models, etc. This paper proposes a multi-objective genetic algorithm (EpiMOGA) for single nucleotide polymorphism (SNP) epistasis detection. The K2 score based on the Bayesian network criterion and the Gini index of the diversity of the binary classification problem were used to guide the search process of the genetic algorithm. Experiments were performed on 26 simulated datasets of different models and a real Alzheimer’s disease dataset. The results indicated that EpiMOGA was obviously superior to other related and competitive methods in both detection efficiency and accuracy, especially for small-sample-size datasets, and the performance of EpiMOGA remained stable across datasets of different disease models. At the same time, a number of SNP loci and 2-order epistasis associated with Alzheimer’s disease were identified by the EpiMOGA method, indicating that this method is capable of identifying high-order epistasis from genome-wide data and can be applied in the study of complex diseases.
Innovation Pathways for Age-Friendly Homes in Europe
Authors: Sengers Frans , Peine Alexander
Published: January 2021

A variety of innovative pilot projects are being implemented to improve the life-course resilience of existing and newly built home environments. We refer to these projects as “socio-technical experiments” that embody different kinds of promising futures and provide direction to current developments in the emerging domain of age-friendly homes. To take stock of this diversity within Europe; this paper provides an overview of 53 ongoing socio-technical experiments that are being conducted in the Netherlands, France, Ireland and Poland. We find that, besides the variation between European countries, there is a more important type variation in terms of the character of the experiments themselves and the differences in development direction that they propose. Our findings suggest that most of the innovations tested in these experiments are not primarily material or technical but primarily social or conceptual in character (i.e., new organizational modes or everyday practices that re-arrange social relations or new housing concepts that bridge the divide between ageing in place individually and a nursing home). This variety of innovations tested in the experiments can be categorized into seven distinct innovation pathways: (1) Showcasing Technology, (2) Innovation Ecosystem, (3) Sheltered Elite, (4) Specific Community, (5) Conscious Retrofitting, (6) Home Sharing and (7) Retrovation Challenge.
Inconvenience of Living Place Affects Individual HbA1c Level in a Rural Area in Japan: Shimane CoHRE Study
Authors: Fukuoka Rie , Takeda Miwako , Abe Takafumi , Yamasaki Masayuki , Kimura Shinji , Okuyama Kenta , Isomura Minoru , Nabika Toru
Published: January 2021

Background: It has been shown that the socio-geographical environment of residential areas, such as altitude, affects the health status and health-maintenance behavior of residents. Here, we examined a hypothesis that altitude of residence would influence glycemic control in a general elderly population living in a rural area. Methods: A thousand and sixteen participants living in a mountainous region in Japan were recruited at health examinations. Hemoglobin A1c (HbA1c) was measured in serum as a parameter of glycemic control. The altitude of residence, distance to grocery stores and to medical facilities were estimated using a geographic information system. Results: Linear regression analysis confirmed a significant effect of the altitude on log HbA1c even after adjustment of other demographic and biochemical factors. When the distance to grocery stores or medical facilities were used instead of the altitude in a linear regression analysis, distance to secondary medical facilities alone showed a significant effect on HbA1c. Conclusions: We found a positive correlation between HbA1c level and residential altitude in a rural area of Japan. The altitude seemed to be a parameter substituting the inconvenicence of residential areas. Socio-geographical factors of living place, such as inconvenience, may influence glycemic control of the residents.
Prevalence of Diabetes and Hypertension among Hajj Pilgrims: A Systematic Review
Authors: Yezli Saber , Mushi Abdulaziz , Almuzaini Yasir , Balkhi Bander , Yassin Yara , Khan Anas
Published: January 2021

The Hajj mass gathering is attended by over two million Muslims each year, many of whom are elderly and have underlying health conditions. Data on the number of pilgrims with health conditions would assist public health planning and improve health services delivery at the event. We carried out a systematic review of literature based on structured search in the MEDLINE/PubMed, SCOPUS and CINAHL databases, and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, to estimate the prevalence of diabetes and hypertension among Hajj pilgrims. Twenty-six studies conducted between 1993 and 2018 with a total of 285,467 participants were included in the review. The weighted pooled prevalence rates of hypertension and diabetes among Hajj pilgrims in all included studies were 12.2% (95% CI: 12.0–12.3) and 5.0% (95% CI: 4.9–5.1), respectively. The reported prevalence of other underlying health conditions such as chronic respiratory, kidney or liver disease, cardiovascular disease, cancer and immune deficiency were generally low. Potentially a large number of pilgrims each Hajj have diabetes and/or hypertension and other underlying health conditions. Hajj could be a great opportunity to reduce the burden of these diseases within the over 180 countries participating in the event by identifying undiagnosed cases and optimizing patients’ knowledge and management of their conditions. Prospero registration number: CRD42020171082.
The Moderating Role of Perceived Risks in the Relationship between Financial Knowledge and the Intention to Invest in the Saudi Arabian Stock Market
Authors: Shehata Saleh M. , Abdeljawad Alaa M. , Mazouz Loqman A. , Aldossary Lamia Yousif Khalaf , Alsaeed Maryam Y. , Noureldin Sayed Mohamed
Published: January 2021

This research study aims to investigate the moderating role of perceived risks in the relationship between financial knowledge (represented by objective knowledge and subjective knowledge) and the intention to invest in the Saudi Arabian Stock Market. The researcher collected data from four hundred Saudi Arabian participants who were interested in investing in the Saudi Arabian Stock Market. The researcher used structural equation modeling (SEM) through the Smart PLS 3.3.2 software to analyze the data. This study’s findings indicate that, in the formation of financial knowledge, the total effect of Subjective knowledge is greater than the total effect of objective knowledge. The findings also indicate that there is a positive relationship between financial knowledge and perceived risks and between financial knowledge and the intention to invest. Finally, the findings indicate that perceived risks have a negative effect on the relationship between financial knowledge and the intention to invest in the Saudi Arabian Stock Market.