bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomass Yield and Nutritive Value of Rye (Secale cereale L.) and Wheat (Triticum aestivum L.) Forages While Grazed by Cattle
Authors: Phillips Hannah N. , Heins Bradley J. , Delate Kathleen , Turnbull Robert
Published: July 2021

Management strategies that integrate crops and livestock may lengthen the productivity of seasonal pasture systems in agroecological zones with short growing seasons. The biomass yield and nutritive value of fall-planted rye (Secale cereale L.) and wheat (Triticum aestivum L.) forages were determined in an integrated crop–livestock system under rotational cattle (Bos taurus L.) grazing and organic conditions for seven weeks during the spring and summer in Minnesota, USA. Rye yielded greater forage biomass at the beginning of the grazing interval, while wheat yielded greater forage biomass in the latter part of the grazing interval. In general, wheat had greater crude protein and less neutral detergent fiber, compared to rye, throughout the grazing interval. The predicted total tract neutral detergent fiber digestibility of forages was ≥50 g 100 g−1 of neutral detergent fiber for at least the first four weeks of the grazing interval, indicating high forage digestibility in immature forages. Results from this study suggest that rye may provide more forage biomass for grazing earlier in the spring at the expense of lower nutritive quality, compared to wheat. Thus, the biomass yield and nutritional value of rye and wheat forages vary during the grazing interval, which informs producers of grazing schedule modifications in order to meet the nutritional demands of cattle.
Structural Evolution in the RE(OAc)3 · 2AcOH Structure Type. A Non-Linear, One-Dimensional Coordination Polymer with Unequal Interatomic Rare Earth Distances
Authors: Haase Markus , Rissiek Philipp , Gather-Steckhan Marianne , Henkel Felix , Reuter Hans
Published: July 2021

The existing range of the centrosymmetric, triclinic RE(OAc)3 · 2AcOH structure type has been extended for RE = Eu and Gd while the structure data of the Nd- and Sm-compounds have been revised and corrected, respectively, using low temperature (T = 100 K), well resolved (2θmax = 56°), highly redundant SCXRD data in order to evaluate the structural evolution within this class of acetic acid solvates by statistical methods. Within the nine-fold mono-capped square-antiprismatic coordination spheres of the RE3+ ions, RE-O distances decrease as a result of lanthanide contraction; some with different rates depending on the coordination modes (2.11/2.21) of the acetate ions. The experimental data show that the internal structural parameters of the acetate ions also correlate with their coordination modes. Both acetic acid molecules act as hydrogen bond donors but only one as monodentate ligand. The geometries of the hydrogen bonds reveal that they are strongly influenced by the size of the rare earth atom. The non-linear, one-dimensional coordination polymer propagates with unequal RE···RE distances along the a-axis. Rods of the coordination polymer are arranged in layers congruently stacked above each other with the hydrogen bonded acetic acid molecules as filler in between. In most cases, data fitting is best described in terms of a quadratic rather than a linear regression analysis.
Microstructure and Mechanical Properties of Vacuum Diffusion Bonded Ti2AlNb/Ti/TC4 Joint
Authors: Wang Yifeng , Hu Bingxu , Wei Yan , Feng Guangjie , Deng Dean
Published: July 2021

In this paper, the Ti2AlNb alloy was bonded to TC4 alloy using the vacuum diffusion bonding method with a Ti interlayer. The interfacial microstructure of the Ti2AlNb/Ti/TC4 joint was characterized. The relationship between the bonding parameters and the microstructure and mechanical property of the joints was explored. Results indicated that the interdiffusion of Nb and Al elements between the interlayer and substrates promoted the formation of the lamellar α + β dual-phase structure in the joint. The bonding parameters determined the diffusion distance of Nb and Al elements, thus controlling the characteristics of the lamellar α + β dual-phase structure. When the Ti2AlNb alloy and TC4 alloy were bonded at 950 °C for 30 min under a pressure of 10 MPa, the elemental diffusion in the bonding couple was sufficient and the joint possessed the maximum shear strength of 549 MPa.
A Feasibility Study to Increase Chronic Hepatitis C Virus RNA Testing and Linkage to Care among Clients Attending Homeless Services in Amsterdam, The Netherlands
Authors: Generaal Ellen , Logtenberg van der Grient Hilje , Schatz Eberhard , van Santen Daniela K. , Boyd Anders , Woods Sara K. , Baak Bert L. C. , Prins Maria
Published: July 2021

People who inject drugs (PWID) are disproportionately affected by hepatitis C virus (HCV) infections and are frequently homeless. To improve HCV case finding in these individuals, we examined the feasibility of rapid HCV RNA testing in homeless services in Amsterdam. In 2020, we provided a comprehensive service to homeless facilities, which included workshops on HCV for personnel, a “hepatitis ambassador” at each facility, a rapid, onsite HCV RNA fingerstick test service, and assistance with linkage to care. Risk factors for HCV RNA-positive status were examined using Bayesian logistic regression. Of the 152 participants enrolled, 150 (87% men; median age: 47 years) accepted rapid HCV testing. Seven tested HCV RNA positive (4.7%, 95%CrI = 1.31–8.09; 7/150). Of these, five (71%) were linked to care, of whom four (57%, 4/7) initiated treatment and one (14%, 1/7) delayed treatment due to a drug–drug interaction. Of these four people, two completed treatment (50%), of whom one (25%) achieved sustained virologic response after 12 weeks. HCV RNA-positive individuals were more likely to originate from Eastern Europe (posterior-odds ratio (OR) = 3.59 (95% credible interval (CrI) = 1.27–10.04)) and to inject drugs (ever: posterior-OR = 3.89 (95% CrI = 1.37–11.09); recent: posterior-OR = 3.94 (95% CrI = 1.29–11.71)). We identified HCV RNA-positive individuals and linkage to care was relatively high. Screening in homeless services with rapid testing is feasible and could improve HCV case finding for PWID who do not regularly attend primary care or other harm reduction services for people who use drugs.
18F-FDG PET/CT versus Diagnostic Contrast-Enhanced CT for Follow-Up of Stage IV Melanoma Patients Treated by Immune Checkpoint Inhibitors: Frequency and Management of Discordances over a 3-Year Period in a University Hospital
Authors: Le Goubey Jean-Baptiste , Lasnon Charline , Nakouri Ines , Césaire Laure , de Pontville Michel , Nganoa Catherine , Kottler Diane , Aide Nicolas
Published: July 2021

Aim: To perform a comprehensive analysis of discordances between contrast-enhanced CT (ceCT) and 18F-FDG PET/CT in the evaluation of the extra-cerebral treatment monitoring in patients with stage IV melanoma. Materials and methods: We conducted a retrospective monocentric observational study over a 3-year period in patients referred for 18F-FDG PET/CT and ceCT in the framework of therapy monitoring of immune checkpoint (ICIs) as of January 2017. Imaging reports were analyzed by two physicians in consensus. The anatomical site responsible for discordances, as well as induced changes in treatment were noted. Results: Eighty patients were included and 195 pairs of scans analyzed. Overall, discordances occurred in 65 cases (33%). Eighty percent of the discordances (52/65) were due to 18F-FDG PET/CT scans upstaging the patient. Amongst these discordances, 17/52 (33%) led to change in patient’s management, the most frequent being radiotherapy of a progressing site. ceCT represented 13/65 (20%) of discordances and induced changes in patients’ management in 2/13 cases (15%). The most frequent anatomical site involved was subcutaneous for 18F-FDG PET/CT findings and lung or liver for ceCT. Conclusions: Treatment monitoring with 18F-FDG PET/CT is more efficient than ceCT and has a greater impact in patient’s management.
A Qualitative Analysis of Burn Injury Patient and Caregiver Experiences in Kwazulu-Natal, South Africa: Enduring the Transition to a Post-Burn Life
Authors: Rencken Camerin A. , Harrison Abigail D. , Aluisio Adam R. , Allorto Nikki
Published: July 2021

Over 95% of fire-related burns occur in low- and middle-income countries (LMICs), an important and frequently overlooked global health disparity, yet research is limited from LMICs on how survivors and their caregivers recover and successfully return to their pre-burn lives. This study examines the lived experiences of burn patients and caregivers, the most challenging aspects of their recoveries, and factors that have assisted in recovery. This qualitative study was conducted in KwaZulu-Natal, South Africa at a 900-bed district hospital. Participants (n = 35) included burn patients (n = 13) and caregivers (n = 22) after discharge. In-depth interviews addressed the recovery process after a burn injury. Data were coded using NVivo 12. Analysis revealed three major thematic categories. Coded data were triangulated to analyze caregiver and patient perspectives jointly. The participants’ lived experiences fell into three main categories: (1) psychological impacts of the burn, (2) enduring the transition into daily life, and (3) reflections on difficulties survivors face in returning for aftercare. The most notable discussions regarded stigma, difficulty accepting self-image, loss of relationships, returning to work, and barriers in receiving long-term aftercare at the hospital outpatient clinic. Patients and caregivers face significant adversities integrating into society. This study highlights areas in which burn survivors may benefit from assistance to inform future interventions and international health policy.
Technological Skills in Higher Education—Different Needs and Different Uses
Authors: Rodrigues Ana Luísa , Cerdeira Luísa , Machado-Taylor Maria de Lourdes , Alves Helena
Published: July 2021

Technological skills development is a central issue for a country’s educational and social policies. Throughout their school career, from primary to secondary education and later in higher education, students have the opportunity to build and develop various skills, including technological. Considering the different needs and different uses that these skills encompass, these will certainly be necessary and useful in students’ academic and professional life. This study reports on an investigation of technological skills development in higher education. It aims to analyze the relevance of technologies integration, which technological skills are built and developed by higher education students, and what their perception about the importance of technological skills is. Based on a literature review, an online questionnaire was designed and applied to 217 students from three public higher education institutions located in the North, Center, and South of Portugal. This intended to verify which areas of technological skills (from the European Digital Competence Framework for Citizens) are most developed and to understand respective repercussions. It is concluded that the balanced development of students’ technological skills in higher education is crucial for their personal, social, and professional future and consequently, for their quality of life, with the integration of digital technologies being relevant in the change of the academic work organization, in the relations between learners, teachers, and institutions, and in the new ways of teaching and learning.
Making Good of a Pandemic: A Long-Distance Remedial Summer Course in Calculus
Authors: Rizzo Ottavio G.
Published: July 2021

What do you do when a change in enrollment policies leaves you with more than 600 students in a first-term university calculus class, three-quarters of those students had a failing mark in mathematics in the pre-enrollment test, you planned a series of remedial activities for the second term, and the COVID-19 pandemic shuts the university down with a two-day notice? The pandemic hit instruction with might, forcing schools and universities that were timidly experimenting with digital tools to reinvent themselves in days. The pandemic also offered incentives for creative solutions that, in normal times, would have been considered fit for submission to the committee for recursive committee submissions at best. This paper narrates a teaching experience of how we proposed and managed an at-distance remedial course in August that not only catered to more than twice the number of students expected by our best forecasts, but was a very good success once its effectiveness was compared to the outcomes predicted by the pre-enrollment test scores. We expose the design of the course and link its measured effectiveness with both its design and student engagement; in particular, we show that a different approach to the examination of cognitive load and to fostering student–teacher and student–student communication thanks to digital mediation could be effective in countermanding the math-induced drop-out phenomenon in STEM.
A Revised Pedagogy Model for Simulator-Based Training with Biomedical Laboratory Science Students
Authors: Björn Marko Henrik , Ravyse Werner , Botha-Ravyse Chrisna , Laurila Jonne M. , Keinonen Tuula
Published: July 2021

Methods based on simulation pedagogy are widely used to practice hands-on skills in safety environment. The usability of an EEG simulator on clinical neurophysiology course was evaluated. Second-year biomedical laboratory science students (N = 35) on this course were included in the study. They were divided into three groups. Two groups used the EEG simulator with different feedback modes and one group did not use the simulator. Results were expected to reveal a correlation between user experience and learning outcomes. This study made used of a mixed method study design. During the study, students were asked to keep a learning diary throughout the course on their experience. Diaries were analyzed qualitatively based on content analyses. Quantitative analyses based on an UX questionnaire that measures classical usability aspects (efficiency, perspicuity, dependability) and user experience aspects (novelty, stimulation) and the students’ feelings to use simulator. The quantitative data was analyzed using SPSSTM software. The quantitative and qualitative analyses showed that the use of the EEG simulator, which was evaluating teaching–learning process, has an extra benefit in clinical neurophysiology education and students felt that the simulator was useful in learning. The simulation debriefing session should be followed by a full theoretical and practical session. Students compared their learning from the simulator with that of the actual placement which fosters the reflective practice of learning, again deepening the understanding of the EEG electrode placement and different wave patterns.
Calculation of Band Offsets of Mg(OH)2-Based Heterostructures
Authors: Ichimura Masaya
Published: July 2021

The band alignment of Mg(OH)2-based heterostructures is investigated based on first-principles calculation. (111)-MgO/(0001)-Mg(OH)2 and (0001)-wurtzite ZnO/(0001)-Mg(OH)2 heterostructures are considered. The O 2s level energy is obtained for each O atom in the heterostructure supercell, and the band edge energies are evaluated following the procedure of the core-level spectroscopy. The calculation is based on the generalized gradient approximation with the on-site Coulomb interaction parameter U considered for Zn. For MgO/Mg(OH)2, the band alignment is of type II, and the valence band edge of MgO is higher by 1.6 eV than that of Mg(OH)2. For ZnO/Mg(OH)2, the band alignment is of type I, and the valence band edge of ZnO is higher by 0.5 eV than that of Mg(OH)2. Assuming the transitivity rule, it is expected that Mg(OH)2 can be used for certain types of heterostructure solar cells and dye-sensitized solar cells to improve the performance.
Application of Nonlinear Adaptive Control in Temperature of Chinese Solar Greenhouses
Authors: Wang Yonggang , Lu Yujin , Xiao Ruimin
Published: July 2021

The system of a greenhouse is required to ensure a suitable environment for crops growth. In China, the Chinese solar greenhouse plays a crucial role in maintaining a proper microclimate environment. However, the greenhouse system is described with complex dynamic characteristics, such as multi-disturbance, parameter uncertainty, and strong nonlinearity. It is difficult for the conventional control method to deal with the above problems. To address these problems, a dynamic model of Chinese solar greenhouses was developed based on energy conservation laws, and a nonlinear adaptive control strategy combined with a Radial Basis Function neural network was presented to deal with temperature control. In this approach, nonlinear adaptive controller parameters were determined through the generalized minimum variance laws, while unmodeled dynamics were estimated by a Radial Basis Function neural network. The control strategy consisted of a linear adaptive controller, a neural network nonlinear adaptive controller, and a switching mechanism. The research results show that the mean errors were 0.8460 and 0.2967, corresponding to a conventional PID method and the presented nonlinear adaptive scheme, respectively. The standard errors of the conventional PID method and the nonlinear adaptive control strategy were 1.8480 and 1.3342, respectively. The experimental results fully prove that the presented control scheme achieves better control performance, which meets the actual requirements.
Low-Process–Voltage–Temperature-Sensitivity Multi-Stage Timing Monitor for System-on-Chip Applications
Authors: Sheng Duo , Lin Hsueh-Ru , Tai Li
Published: July 2021

High performance and complex system-on-chip (SoC) design require a throughput and stable timing monitor to reduce the impacts of uncertain timing and implement the dynamic voltage and frequency scaling (DVFS) scheme for overall power reduction. This paper presents a multi-stage timing monitor, combining three timing-monitoring stages to achieve a high timing-monitoring resolution and a wide timing-monitoring range simultaneously. Additionally, because the proposed timing monitor has high immunity to the process–voltage–temperature (PVT) variation, it provides a more stable time-monitoring results. The time-monitoring resolution and range of the proposed timing monitor are 47 ps and 2.2 µs, respectively, and the maximum measurement error is 0.06%. Therefore, the proposed multi-stage timing monitor provides not only the timing information of the specified signals to maintain the functionality and performance of the SoC, but also makes the operation of the DVFS scheme more efficient and accurate in SoC design.
Estimation of Lithium-Ion Batteries State-Condition in Electric Vehicle Applications: Issues and State of the Art
Authors: Laadjal Khaled , Cardoso Antonio J. Marques
Published: July 2021

Lithium-ion batteries are the most used these days for charging electric vehicles (EV). It is important to study the aging of batteries because the deterioration of their characteristics largely determines the cost, efficiency, and environmental impact of electric vehicles, especially full-electric ones. The estimation of batteries’ state-condition is also very important for improving energy efficiency, lengthening the life cycle, minimizing costs and ensuring safe implementation of batteries in electric vehicles. However, batteries with large temporal variables and non-linear characteristics are often affected by random factors affecting the equivalent internal resistance (EIR), battery state of charge (SoC), and state of health (SoH) in EV applications. The estimation of batteries’ parameters is a complex process, due to its dependence on various factors such as batteries age and ambient temperature, among others. A good estimate of SoC and internal resistance leads to long battery life and disaster prevention in the event of a battery failure. The classification of estimation methodologies for internal parameters and the charging status of batteries will be very helpful in choosing the appropriate method for the development of a reliable and secure battery management system (BMS) and an energy management strategy for electric vehicles.
Modeling, Verification, and Signal Integrity Analysis of High-Speed Signaling Channel with Tabbed Routing in High Performance Computing Server Board
Authors: Song Kyunghwan , Kim Jongwook , Kim Hyunwoong , Lee Seonghi , Ahn Jangyong , Brito Andres , Kim Hyunsik , Park Minho , Ahn Seungyoung
Published: July 2021

It is necessary to reduce the crosstalk noise in high-speed signaling channels. In the channel routing area, the tabbed routing pattern is used to mitigate far-end crosstalk (FEXT), and the electrical length is controlled with a time domain reflectometer (TDR) and time domain transmission (TDT). However, unlike traditional channels having uniform width and space, the width and space of tabbed routing changes by segment, and the capacitance and inductance values of tabbed routing also change. In this paper, we propose a tabbed routing equivalent circuit modeling method using the segmentation approach. The proposed model was verified using 3D EM simulation and measurement results in the frequency domain. Based on the calculated inductance and capacitance parameters, we analyzed the insertion loss, FEXT, and self-impedance in the frequency domain, and TDT and FEXT in the time domain, by comparing the values of these metrics with and without tabbed routing. Using the proposed tabbed routing model, we analyzed tabbed routing with variations of design parameters based on self- and mutual-capacitance and inductance.
Optimal Distribution Coefficients of Energy Resources in Frequency Stability of Hybrid Microgrids Connected to the Power System
Authors: Arzani Mohsen , Abazari Ahmadreza , Oshnoei Arman , Ghafouri Mohsen , Muyeen S. M.
Published: July 2021

The continuous stability of hybrid microgrids (MGs) has been recently proposed as a critical topic, due to the ever-increasing growth of renewable energy sources (RESs) in low-inertia power systems. However, the stochastic and intermittent nature of RESs poses serious challenges for the stability and frequency regulation of MGs. In this regard, frequency control ancillary services (FCAS) can be introduced to alleviate the transient effects during substantial variations in the operating point and the separation from main power grids. In this paper, an efficient scheme is introduced to create a coordination among distributed energy resources (DERs), including combined heat and power, diesel engine generator, wind turbine generators, and photovoltaic panels. In this scheme, the frequency regulation signal is assigned to DERs based on several distribution coefficients, which are calculated through conducting a multi-objective optimization problem in the MATLAB environment. A meta-heuristic approach, known as the artificial bee colony algorithm, is deployed to determine optimal solutions. To prove the efficiency of the proposed scheme, the design is implemented on a hybrid MG. Various operational conditions which render the system prone to experience frequency fluctuation, including switching operation, load disturbance, and reduction in the total inertia of hybrid microgrids, are studied in PSCAD software. Simulation results demonstrate that this optimal control scheme can yield a more satisfactory performance in the presence of grid-following and grid-forming resources during different operational conditions.
Wavy Walls, a Passive Way to Control the Transition to Turbulence. Detailed Simulation and Physical Explanation
Authors: Mateo-Gabín Andrés , Chávez Miguel , Garicano-Mena Jesús , Valero Eusebio
Published: July 2021

Inducing spanwise motions in the vicinity of solid boundaries alters the energy, mass and/or momentum transfer. Under some conditions, these motions are such that drag is reduced and/or transition to turbulence is delayed. There are several possibilities to induce those spanwise motions, be it through active imposition a predefined velocity distribution at the walls or by careful design of the wall shape, which corresponds to passive control.In this contribution, we investigate the effect that wavy walls might have on delaying transition to turbulence. Direct Numerical Simulation of both planar and wavy-walled channel flows at laminar and turbulent regimes are conducted. A pseudo laminar regime that remains stable until a Reynolds number 20% higher that the critical is found for the wavy-walled simulations. Dynamic Mode Decomposition applied to the simulation data reveals that in these configurations, modes with wavelength and frequency compatible with the surface undulation pattern appear. We explain and visualize the appearance of these modes. At higher Reynolds numbers we show that these modes remain present but are not dominant anymore. This work is an initial demonstration that flow control strategies that trigger underlying stable modes can keep or conduct the flow to new configurations more stable than the original one.
Energy Transitions in Western European Countries: Regulation Comparative Analysis
Authors: Cucchiella Federica , Condemi Alessia , Rotilio Marianna , Annibaldi Valeria
Published: July 2021

Shifting from fossil to renewable energy sources is a major global challenge, and in this context, the European Union has promoted sustainable and environmentally friendly growth as early as the Maastricht Treaty of 1992. To date, European institutions have promulgated a series of environmental regulations and directives aimed at promoting and imposing adoption by member states of internal regulations. This paper is focused on Western Europe, and it explores, for each state under analysis, energy policies adopted, the results achieved and recommendations for the future growth of renewable energy. The results show that in countries where energy policy is not fragmented, the yield in renewable energies has been higher, and also in the states where more and various forms of subsidies are foreseen, growth seems to be greater. Finally, the paper provides useful recommendations and future policy implications for states that have not met the 2020 targets.
Effect of Roof Cooling and Air Curtain Gates on Thermal and Wind Conditions in Stadiums for Hot Climates
Authors: Zhong Fangliang , Chaudhry Hassam Nasarullah , Calautit John Kaiser
Published: July 2021

To host the 2022 FIFA World Cup, Qatar is facing the greatest challenge in balancing the energy consumptions for cooling the stadiums and the thermal comfort for both players and spectators. Previous studies have not considered using a combined configuration of air curtain and roof cooling supply slot in stadiums to prevent the infiltration of outside hot air and reduce the cooling system’s energy consumption. This paper presents a Computational Fluid Dynamics (CFD) study of thermal and wind modeling around a baseline stadium and simulates the cooling scenarios of air curtains and roof cooling along with the energy consumption estimations for the World Cup matches using Building Energy Simulation (BES). Sensitivity analysis of different supply speeds and supply temperatures of air curtain gates and roof cooling was carried out, and the results showed that scenario six, which provides supply air of 25 m/s and 20 m/s at the roof and air curtain gates with a supply temperature of 10 °C, demonstrates optimal thermal performances on both the spectator tiers and the pitch. Compared with the baseline stadium performance, the average reductions in temperature on the pitch and spectator tiers under scenario six could reach 15 °C and 14.6 °C. The reductions in the Predicted Percentage of Dissatisfied values for the upper and lower tiers as well as the pitch were 63%, 74%, and 78%. In terms of the estimated energy consumptions, scenario six would consume electric energy per match at a rate of 25.5 MWh compared with 22.8 MWh for one of the stadiums in the 2010 South Africa World Cup and 42.0 MWh for the 2006 Germany World Cup. Future research is recommended to explore the influence of supply angle on air curtain gates and roof cooling supply slots’ performances.
Energy Consumption and Its Structures in Food Production Systems of the Visegrad Group Countries Compared with EU-15 Countries
Authors: Bajan Bartłomiej , Łukasiewicz Joanna , Mrówczyńska-Kamińska Aldona
Published: July 2021

While joining the European Union (EU) in 2004, the countries of the Visegrad Group (V4) had to face a major challenge in the context of adapting to the EU standards in the field of energy use and energy efficiency. One of the sectors that heavily depends on the use of energy (mainly from fossil fuels) is the food production system, whose energy transformation is essential for future food security. The study aimed to measure the use of energy and its structures in the food production systems of the V4 countries and the EU-15 countries in relation to the implementation of the EU energy targets. The targets assumed, among other things, a reduction in overall energy use and an increase in the share of renewables in the energy mix. The proprietary method based on the assumptions of lifecycle assessment was applied to measure energy consumption in the food production systems with the use of input–output tables and energy accounts, which are part of the World Input–Output Database. The research shows a decreasing share of the food production systems in energy use of the V4 countries, while in the EU-15 countries, it remains on average at a stable, low level (around 4.4%). The discussed share for Poland averaged 8.8% in the period considered, for Hungary 7.6%, for the Czech Republic 3.8%, and for Slovakia 3.3%. The share of renewables in energy use of the food production systems is growing. However, in some countries of the EU-15, it increases at a slower pace than the assumed strategic goals, mainly in the countries that are the largest food producers in the EU. For Germany, the Netherlands, Spain, and Italy, the average deviation of the share of renewables use in the food production system from the 2020 target for the entire economy is around 12 percentage points. In the case of V4 countries, the share of renewable energy use in food production systems is close to the assumed strategic targets.
Heat of Decomposition and Fire Retardant Behavior of Polyimide-Graphene Nanocomposites
Authors: Akinyi Caroline J. , Iroh Jude O.
Published: July 2021

Polyimide is a high-performance engineering polymer with outstanding thermomechanical properties. Because of its inherent fire-retardant properties, polyimide nanocomposite is an excellent material for packaging electronic devices, and it is an attractive electrode material for batteries and supercapacitors. The fire-retardant behavior of polyimide can be remarkably improved when polyimide is reinforced with multilayered graphene sheets. Differential scanning calorimetry and thermogravimetric analysis were used to study the heat of decomposition and gravimetric decomposition rate, respectively, of polyimide-graphene nanocomposites. Polyimide/graphene nanocomposites containing 10, 20, 30, 40, and 50 wt.% of multilayered graphene sheets were heated at a rate of 10 and 30 °C/min in air and in nitrogen atmosphere, respectively. The rate of mass loss was found to remarkably decrease by up to 198% for nanocomposites containing 50 wt.% of graphene. The enthalpy change resulting from the decomposition of the imide ring was found to decrease by 1166% in nitrogen atmosphere, indicating the outstanding heat-shielding properties of multilayered graphene sheets due to their high thermal conductivity. Graphene sheets are believed to form a continuous carbonaceous char layer that protects the imide ring against decomposition, hence decreasing initial mass loss. The enthalpy changes due to combustion, obtained from differential scanning calorimetry, were used to calculate the theoretical heat release rates, a major parameter in the determination of flammability of polymers. The heat release rate decreased by 62% for composites containing 10 wt.% of graphene compared to the neat polyimide matrix. Polyimide has a relatively lower heat of combustion as compared with graphene. However, graphene significantly decreases the mass loss rates of polyimide. The combined interaction of graphene and polyimide led to an overall decrease in the heat release rate. It is noted that both mass loss rate and heat of combustion are important factors that contribute to the rate of heat released.
An Overview of Biodiesel Production via Calcium Oxide Based Catalysts: Current State and Perspective
Authors: Mazaheri Hoora , Ong Hwai Chyuan , Amini Zeynab , Masjuki Haji Hassan , Mofijur M. , Su Chia Hung , Anjum Badruddin Irfan , Khan T.M. Yunus
Published: July 2021

Biodiesel is a clean, renewable, liquid fuel that can be used in existing diesel engines without modification as pure or blend. Transesterification (the primary process for biodiesel generation) via heterogeneous catalysis using low-cost waste feedstocks for catalyst synthesis improves the economics of biodiesel production. Heterogeneous catalysts are preferred for the industrial generation of biodiesel due to their robustness and low costs due to the easy separation and relatively higher reusability. Calcium oxides found in abundance in nature, e.g., in seashells and eggshells, are promising candidates for the synthesis of heterogeneous catalysts. However, process improvements are required to design productive calcium oxide-based catalysts at an industrial scale. The current work presents an overview of the biodiesel production advancements using calcium oxide-based catalysts (e.g., pure, supported, and mixed with metal oxides). The review discusses different factors involved in the synthesis of calcium oxide-based catalysts, and the effect of reaction parameters on the biodiesel yield of calcium oxide-based catalysis are studied. Further, the common reactor designs used for the heterogeneous catalysis using calcium oxide-based catalysts are explained. Moreover, the catalytic activity mechanism, challenges and prospects of the application of calcium oxide-based catalysts in biodiesel generation are discussed. The study of calcium oxide-based catalyst should continue to be evaluated for the potential of their application in the commercial sector as they remain the pivotal goal of these studies.
Experimental Study and Conjugate Heat Transfer Simulation of Pulsating Flow in Straight and 90° Curved Square Pipes
Authors: Guo Guanming , Kamigaki Masaya , Inoue Yuuya , Nishida Keiya , Hongou Hitoshi , Koutoku Masanobu , Yamamoto Ryo , Yokohata Hideaki , Sumi Shinji , Ogata Yoichi
Published: July 2021

The turbulent pulsating flow and heat transfer in straight and 90° curved square pipes are investigated in this study. Both experimental temperature field measurements at the cross-sections of the pipes and conjugate heat transfer (CHT) simulation were performed. The steady turbulent flow was investigated and compared to the pulsating flow under the same time-averaged Reynolds number. The time-averaged Reynolds number of the pulsating flow, as well as the steady flow, was approximately 60,000. The Womersley number of the pulsating flow was 43.1, corresponding to a 30 Hz pulsating frequency. Meanwhile, the Dean number in the curved pipe was approximately 31,000. The results showed that the local heat flux of the pulsating flow was greater than that of the steady flow when the location was closer to the upstream pulsation generator. However, the total heat flux of the pulsating flow was less than that of the steady flow. Moreover, the instantaneous velocity and temperature fields of the simulation were used to demonstrate the heat transfer mechanism of the pulsating flow. The behaviors, such as the obvious separation between the air and pipe wall, the low-temperature core impingement, and the reverse flow, suppress the heat transfer.
The Use of Hierarchical Agglomeration Methods in Assessing the Polish Energy Market
Authors: Bluszcz Anna , Manowska Anna
Published: July 2021

Energy markets play an important role in achieving sustainable development goals. The sector of energy has a huge impact on the environment, hence changes in it are the highest priority in the European Union. The process of shaping and developing the internal energy market plays an important role in improving the security of supply of energy resources for the entire union. It requires a number of political negotiations, strategic decisions regarding energy liberalization, in particular, the electricity and gas sectors, as well as the adoption of sectoral legislation. The aim of the conducted research is to estimate the level of development of energy markets in the EU countries and to indicate the position of Poland in comparison to other countries. The research was performed in several stages. The first phase consisted of selecting appropriate diagnostic variables that comprehensively describe energy markets in countries belonging to the European Union. The next stage was collecting data, subjecting them to standardization, and then, based on the agglomeration algorithm, the process of dividing into groups of similar countries was carried out. The research results can be used as guidelines for legal regulations being prepared in the energy sectors of all member states, which can be used for selected clusters comprising similar countries in terms of the development of energy markets.
Achieving Efficient and Stable Deammonification at Low Temperatures—Experimental and Modeling Studies
Authors: Al-Hazmi Hussein , Lu Xi , Grubba Dominika , Majtacz Joanna , Kowal Przemysław , Mąkinia Jacek
Published: July 2021

The short-term effects of temperature on deammonification sludge were evaluated in a laboratory-scale sequencing batch reactor (SBR). Mathematical modeling was used for further evaluations of different intermittent aeration strategies for achieving high and stable deammonification performance at decreasing temperatures. As for the biomass cultivated at high temperatures (e.g., 30 °C), a higher temperature dependency (the adjusted Arrhenius coefficient θ for 11–17 °C = 1.71 vs. θ for 17–30 °C = 1.12) on the specific anammox growth rates was found at lower temperatures (11–17 °C) in comparison with higher temperatures (17–30 °C). Further evaluations of recovering the nitrogen removal efficiency at decreasing temperatures with the mathematical model by modifying the intermittent aeration strategies (aeration frequency (F) and the ratio (R) between non-aerated (non-aer) phase and aerated (aer) phase durations) indicated that intermittent aeration with a prolonged non-aerated phase (e.g., R ≥ 4 regardless of F value) would help to maintain high and stable deammonification performance (~80%) at decreasing temperatures (14–22 °C). Extending the non-aerated phases (increasing R) and reducing the frequency (F) of off/on phase changes have a positive effect on increasing energy savings, leading to increasing interest in this method.
Acquiring the Foremost Window Allocation Strategy to Achieve the Best Trade-Off among Energy, Environmental, and Comfort Criteria in a Building
Authors: Mousavi Motlagh Seyedeh Farzaneh , Sohani Ali , Djavad Saghafi Mohammad , Sayyaadi Hoseyn , Nastasi Benedetto
Published: July 2021

The purpose of this investigation is to propose a way for acquiring the foremost window allocation scheme to have the best trade-off among energy, environmental, and comfort criteria in a building. An advanced decision-making tool, named the technique for order preference by similarity to ideal solution (TOPSIS), is utilized to find the best building amongst different alternatives for having windows on the building façades. Three conditions, namely two parallel, two perpendicular, and three façades, considered as A, B, and C types, respectively, are investigated. For each type, four possible orientations are studied. Heating, cooling, and lighting energy demands in addition to carbon dioxide equivalent emission and thermal and visual comfort are taken into account as the investigated criteria, and they are all evaluated in a simulation environment. The results show that for the modular residential buildings chosen as the case study and located in Tehran, Iran, having windows on the north and east façades is the best scheme. This alternative, which belongs to the B type, has about 40% and 37% lower heating and cooling energy demands than the C type’s foremost alternative. It is also able to provide about 10% better CO2 equivalent emission and 28% higher thermal comfort.
Defect Properties and Lithium Incorporation in Li2ZrO3
Authors: Rex Kobiny Antony , Iyngaran Poobalasuntharam , Kuganathan Navaratnarajah , Chroneos Alexander
Published: July 2021

Lithium zirconate is a candidate material in the design of electrochemical devices and tritium breeding blankets. Here we employ an atomistic simulation based on the classical pair-wise potentials to examine the defect energetics, diffusion of Li-ions, and solution of dopants. The Li-Frenkel is the lowest defect energy process. The Li-Zr anti-site defect cluster energy is slightly higher than the Li-Frenkel. The Li-ion diffuses along the c axis with an activation energy of 0.55 eV agreeing with experimental values. The most favorable isovalent dopants on the Li and Zr sites were Na and Ti respectively. The formation of additional Li in this material can be processed by doping of Ga on the Zr site. Incorporation of Li was studied using density functional theory simulation. Li incorporation is exoergic with respect to isolated gas phase Li. Furthermore, the semiconducting nature of LZO turns metallic upon Li incorporation.
Air Quality during Covid-19 Lockdown
Authors: Donzelli Gabriele , Cioni Lorenzo , Cancellieri Mariagrazia , Llopis-Morales Agustin , Morales-Suárez-Varela María
Published: July 2021

Air pollution exposure is one of the greatest risks to health worldwide. It is estimated to be responsible for about 4.2 million deaths around the world every year owing to many serious diseases such as heart disease, stroke, acute and chronic respiratory diseases, and lung cancer. The WHO guideline limits are exceeded in several areas around the world, and it is estimated that about 90% of the world’s population is exposed to high air pollution levels, especially in low- and middle-income countries. The COVID-19 pandemic has forced governments to implement severe mobility restriction measures to limit the spread of the virus. This represented a unique opportunity to study the impact of mobility on urban air quality. Several studies which have investigated the relations between the quality of the air and such containment measures have shown the significant reduction of the main pollutants in the urban environment so to encourage the adoption of new approaches for the improvement of the quality of air in the cities. The aims of this entry are both a brief analysis and a discussion of the results presented in several papers to understand the relationships between COVID-19 containment measures and air quality in urban areas.
Monitoring Consumer Purchasing Behavior for Wood Furniture before and during the COVID-19 Pandemic
Authors: Pirc Barčić Andreja , Kitek Kuzman Manja , Vergot Tihana , Grošelj Petra
Published: July 2021

Monitoring consumer buying behaviors in terms of their preferences and attitudes has been known as an important driver for the success and development of various industries, including a wood furniture manufacturing. The aim of this study was to identify and compare the purchasing behaviors of furniture consumers in the period before and during the COVID-19 pandemic. Two surveys were conducted in Croatia, the first in April and May 2020 with the assumption that consumer purchasing behaviors will change during the COVID-19 pandemic in the following year and the second one during March 2021. Differences regarding consumer purchasing behaviors and preferences for wood furniture between respondents regarding demographic and economic factors before and during the pandemic were found. The coronavirus pandemic is teaching us all hard lessons about resilience and adaptability, and new opportunities and solutions are essential. Nowadays, it is becoming increasingly important to produce information. Research offers insights into future design and building communication to better meet the information needs of different types of consumers and to more broadly increase the acceptance and appeal of wood furniture in society in the spirit of sustainable and bio-based circular economy.
Flexural Performance of a New Hybrid Basalt-Polypropylene Fiber-Reinforced Concrete Oriented to Concrete Pipelines
Authors: Deng Zhiyun , Liu Xinrong , Liang Ninghui , de la Fuente Albert , Peng Haoyang
Published: July 2021

The bending performance of a basalt-polypropylene fiber-reinforced concrete (HBPFRC) was characterized by testing 24,400 × 100 × 100 mm3 prismatic specimens in a four-point bending test JSCE-SF4 configuration. The type and content of both fibers were varied in order to guarantee different target levels of post-cracking flexural performance. The results evidenced that mono-micro basalt fiber reinforced concrete (BFRC) allows the increase of the flexural strength (pre-cracking stage), while macro polypropylene fiber reinforced concrete (PPFRC) can effectively improve both bearing capacity and ductility of the composite for a wide crack width range. Compared with the plain concrete specimens, flexural toughness and equivalent flexural strength of macro PPFRC and the hybrid fiber-reinforced concrete (HFRC) increased by 3.7–7.1 times and 10–42.5%, respectively. From both technical and economic points of view, the optimal mass ratio of basalt fiber (BF) to polypropylene fiber (PPF) resulted in being 1:2, with a total content of 6 kg/m3. This HFRC is seen as a suitable material to be used in sewerage pipes where cracking control (crack formation and crack width control) is of paramount importance to guarantee the durability and functionality of the pipeline as well as the ductility of the system in case of local failures.
Turbulence Characteristics of the Flexible Circular Cylinder Agitator
Authors: Dol Sharul Sham , Yong Tshun Howe , Chan Hiang Bin , Wee Siaw Khur , Sulaiman Shaharin Anwar
Published: July 2021

A flexible protruding surface was employed as the flow disturbance to promote turbulence at the area of interest. An ultrasonic velocity profiler, UVP technique, was used to study the mean and fluctuating flow properties in the near wake of the rigid and flexible protruding surface in a water tunnel. The polymer based, ethylene-vinyl acetate (EVA) with an aspect ratio of AR = 10, 12, 14, 16 was used as the flexible circular cylinder, and submerged in a flow at Re = 4000, 6000 and 8000. The motion of the cylinder altered the fluid flow significantly. As a means to quantify turbulence, the wakes regions and production terms were analyzed. In general, the flexible cylinders show better capability in augmenting the turbulence than the rigid cylinder. The results show that the turbulence production term generated by the flexible cylinder is higher than that of rigid cylinder. The localized maximum shear production values have increased significantly from 131%, 203% and 94% against their rigid counterparts of AR = 16 at the Re = 4000, 6000 and 8000, respectively. The performance of turbulence enhancement depends heavily on the motion of the cylinder. The findings suggest that the turbulence enhancement was due to the oscillation of the flexible cylinder. The results have concluded that the flexible cylinder is a better turbulence generator than the rigid cylinder, thus improving the mixing of fluid through augmented turbulent flow.