bluuebunny/crossref_metadata_2025 huggingface dataset:
Discovery and Engineering of an Aldehyde Tolerant 2-deoxy-D-ribose 5-phosphate Aldolase (DERA) from Pectobacterium atrosepticum
Authors: Haridas Meera , Bisterfeld Carolin , Chen Le Min , Marsden Stefan R. , Tonin Fabio , Médici Rosario , Iribarren Adolfo , Lewkowicz Elizabeth , Hagedoorn Peter-Leon , Hanefeld Ulf , Abdelraheem Eman
Published: August 2020

DERA (2-Deoxy-D-ribose 5-phosphate aldolase) is the only known aldolase that accepts two aldehyde substrates, which makes it an attractive catalyst for the synthesis of a chiral polyol motif that is present in several pharmaceuticals, such as atorvastatin and pravastatin. However, inactivation of the enzyme in the presence of aldehydes hinders its practical application. Whole cells of Pectobacterium atrosepticum were reported to exhibit good tolerance toward acetaldehyde and to afford 2-deoxyribose 5-phosphate with good yields. The DERA gene (PaDERA) was identified, and both the wild-type and a C49M mutant were heterologously expressed in Escherichia coli. The purification protocol was optimized and an initial biochemical characterization was conducted. Unlike other DERAs, which show a maximal activity between pH 4.0 and 7.5, PaDERA presented an optimum pH in the alkaline range between 8.0 and 9.0. This could warrant its use for specific syntheses in the future. PaDERA also displayed fourfold higher specific activity than DERA from E. coli (EcDERA) and displayed a promising acetaldehyde resistance outside the whole-cell environment. The C49M mutation, which was previously identified to increase acetaldehyde tolerance in EcDERA, also led to significant improvements in the acetaldehyde tolerance of PaDERA.
A “Numerical Evo-Devo” Synthesis for the Identification of Pattern-Forming Factors
Authors: Bailleul Richard , Manceau Marie , Touboul Jonathan
Published: August 2020

Animals display extensive diversity in motifs adorning their coat, yet these patterns have reproducible orientation and periodicity within species or groups. Morphological variation has been traditionally used to dissect the genetic basis of evolutionary change, while pattern conservation and stability in both mathematical and organismal models has served to identify core developmental events. Two patterning theories, namely instruction and self-organisation, emerged from this work. Combined, they provide an appealing explanation for how natural patterns form and evolve, but in vivo factors underlying these mechanisms remain elusive. By bridging developmental biology and mathematics, novel frameworks recently allowed breakthroughs in our understanding of pattern establishment, unveiling how patterning strategies combine in space and time, or the importance of tissue morphogenesis in generating positional information. Adding results from surveys of natural variation to these empirical-modelling dialogues improves model inference, analysis, and in vivo testing. In this evo-devo-numerical synthesis, mathematical models have to reproduce not only given stable patterns but also the dynamics of their emergence, and the extent of inter-species variation in these dynamics through minimal parameter change. This integrative approach can help in disentangling molecular, cellular and mechanical interaction during pattern establishment.
Distribution of Pediatric Vital Signs in the Emergency Department: A Nationwide Study
Authors: Bae Woori , Kim Kyunghoon , Lee Bongjin
Published: August 2020

To effectively use vital signs as indicators in children, the magnitude of deviation from expected vital sign distribution should be determined. The purpose of this study is to derive age-specific centile charts for the heart rate and respiratory rate of the children who visited the emergency department. This study used the Korea’s National Emergency Department Information System dataset. Patients aged <16 years visiting the emergency department between 1 January 2016 and 31 December 2017 were included. Heart rate and respiratory rate centile charts were derived from the population with normal body temperature (36 to <38 °C). Of 1,901,816 data points retrieved from the database, 1,454,372 sets of heart rates and 1,458,791 sets of respiratory rates were used to derive centile charts. Age-specific centile charts and curves of heart rates and respiratory rates showed a decline in heart rate and respiratory rate from birth to early adolescence. There were substantial discrepancies in the reference ranges of Advanced Paediatric Life Support and Pediatric Advanced Life Support guidelines. Age-based heart rate and respiratory rate centile charts at normal body temperature, derived from children visiting emergency departments, serve as new evidence-based data and can be used in follow-up studies to improve clinical care for children.
Security Analysis of Lightweight IoT Cipher: Chaskey
Authors: Dwivedi Ashutosh Dhar
Published: August 2020

This paper presents the differential cryptanalysis of ARX based cipher Chaskey using tree search based heuristic approach. ARX algorithms are suitable for resource-constrained devices such as IoT and very resistant to standard cryptanalysis such as linear or differential. To make a differential attack, it is important to make differential characteristics of the cipher. Finding differential characteristics in ARX is the most challenging task nowadays. Due to the bigger block size, it is infeasible to calculate lookup tables for non-linear components. Transition through the non-linear layer of cipher faces a huge state space problem. The problem of huge state space is a serious research topic in artificial intelligence (AI). The proposed heuristic tool use such methods inspired by Nested Tree-based sampling to find differential paths in ARX cipher and successfully applied to get a state of art results for differential cryptanalysis with a very fast and simpler framework. The algorithm can also be applied in different research areas in cryptanalysis where such huge state space is a problem.
New Mononuclear Complex of Europium(III) and Benzoic Acid: From Synthesis and Crystal Structure Solution to Luminescence Emission
Authors: Hernández-Fuentes Carlos , Ruiz-Guerrero Rosario , Morales-Ramírez Angel , Molina-Maldonado Paulina , Medina-Velazquez Dulce
Published: August 2020

This study presents a general method which can be used for the synthesis of mononuclear complexes with europium(III) and organic ligands with carboxylic groups. It describes the procedure for preparing a new mononuclear coordination complex with europium(III) and carboxylate ligands sourced from benzoic acid. The construction of mononuclear complexes with a coordination sphere saturated in carboxylic ligands must go through the preparation and purification of a europium(III) intermediate complex that presents a coordination sphere with anions that will be later exchanged for carboxylic groups and finally precipitated as a solvent-free or anion-free complex within the coordination sphere. The detailed synthesis procedure for powders of a new complex, as well as studies of its structural composition at each phase and luminescent properties, are detailed in this study. Analytical and spectroscopic data reveal the formation of a new mononuclear complex of the general formula [Eu(OOCC6H5)3·(HOOCC6H5)2]. The crystal structure of the Eu(III) complex was solved using X-ray powder diffraction data and EXPO2014 software, and the crystal structure result was deposited in the CCDC service with number 19771999.
Historical and Contemporary Diversity of Galaxiids in South America: Biogeographic and Phylogenetic Perspectives
Authors: Vera-Escalona Iván , Delgado M. Lisette , Habit Evelyn , Ruzzante Daniel E.
Published: August 2020

Galaxiid fishes from South America are represented by three genera (Aplochiton, Brachygalaxias and Galaxias) and eight species. Their genetic patterns have been studied over the last two decades to disentangle how historical and contemporary processes influenced their biogeographic distribution and phylogeographic patterns. Here we review and synthesize this body of work. Phylogeographic approaches reveal the important role played by orogeny and the expansion/melting of glacial ice during the Quaternary. Populations retreated to glacial refugia during glacial times and some systems experienced drainage reversals from the Atlantic to the Pacific following deglaciation. Although most species expanded their populations and increased their genetic diversity during the Holocene, the introduction of salmonids and the construction of dams are likely to lead to a decline in genetic diversity for at least some species. An improvement in our understanding of the processes that influenced historical and contemporary diversity patterns among galaxiid and other native fishes in South America is necessary for addressing the cumulative and synergistic impacts of human activity on this unique freshwater fauna.
Automated Test Case Generation for Digital System Designs: A Mapping Study on VHDL, Verilog, and SystemVerilog Description Languages
Authors: Vivekananda Ashish Alape , Enoiu Eduard
Published: August 2020

Researchers have proposed different methods for testing digital systems and circuits in the last couple of decades. The need for testing digital logic circuits has become more important than ever due to the growing complexity of such systems. During the design phase, testing is focusing on design defects, as well as manufacturing and wear out type of defects. Failures in digital systems could be caused, for example, by design errors, the use of inherently probabilistic devices, and manufacturing variability. As a way to test digital systems in a more efficient way, automated test generation has been proposed to automatically create tests that can quickly and accurately identify faulty components. Examples of such techniques are the sequential test generation, the scan path testing, and the random test generation techniques. With the research domain becoming more mature and growing, it is essential to systematically identify, analyze, and classify these contributions. We performed a systematic mapping study of automated test generation for digital circuits aimed at providing an overview of the application of these techniques. We focused on three of the most widely-used and well-supported hardware description languages (HDLs) for digital systems: Verilog, SystemVerilog, and VHDL. Our results suggest that the majority of the test generation methods for digital circuits are focused on the behavioral and register-transfer design levels. Fault-independent and fault-oriented test generation are the most frequently reported types of test generation methods, while HDL model simulation is the most common test generation technology used to search for test cases in these academic studies. While the results are suggesting a growing interest in this area, the majority of articles are published as conferences papers. Our results show that only 31% of the methods are implemented as software tools and only 63% of all contributions are actually generating executable test cases. This study makes three important contributions, (i) a state-of-the-art of test generation for digital system designs research is provided, (ii) the reported characteristics are identified in both the primary papers and experimental reports, (iii) gaps and opportunities for future test generation for digital system designs research are identified.
Ultrasound Assessment of Hepatic Steatosis by Using the Double Nakagami Distribution: A Feasibility Study
Authors: Fang Feng , Fang Jui , Li Qiang , Tai Dar-In , Wan Yung-Liang , Tamura Kazuki , Yamaguchi Tadashi , Tsui Po-Hsiang
Published: August 2020

Ultrasound imaging is a first-line assessment tool for hepatic steatosis. Properties of tissue microstructures correlate with the statistical distribution of ultrasound backscattered signals, which can be described by the Nakagami distribution (a widely adopted approximation of backscattered statistics). The double Nakagami distribution (DND) model, which combines two Nakagami distributions, was recently proposed for using high-frequency ultrasound to analyze backscattered statistics corresponding to lipid droplets in the fat-infiltrated liver. This study evaluated the clinical feasibility of the DND model in ultrasound parametric imaging of hepatic steatosis by conducting clinical experiments using low-frequency ultrasound dedicated to general abdominal examinations. A total of 204 patients were recruited, and ultrasound image raw data were acquired using a 3.5 MHz array transducer for DND parametric imaging using the sliding window technique. The DND parameters were compared with hepatic steatosis grades identified histologically. A receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic performance. The results indicated that DND parametric imaging constructed using a sliding window with the side length of five times the pulse length of the transducer provided stable and reliable DND parameter estimations and visualized changes in the backscattered statistics caused by hepatic steatosis. The DND parameter increased with the hepatic steatosis grade. The areas under the ROC curve for identifying hepatic steatosis were 0.76 (≥mild), 0.81 (≥moderate), and 0.82 (≥severe). When using low-frequency ultrasound, DND imaging allows the clinical detection of hepatic steatosis and reflects information associated with lipid droplets in the fat-infiltrated liver.
Two Reliable Methodical Approaches for Non-Invasive RHD Genotyping of a Fetus from Maternal Plasma
Authors: Bohmova Jana , Lubusky Marek , Holuskova Iva , Studnickova Martina , Kratochvilova Romana , Krejcirikova Eva , Durdova Veronika , Kratochvilova Tereza , Dusek Ladislav , Prochazka Martin , Vodicka Radek
Published: August 2020

Noninvasive fetal RHD genotyping is an important tool for predicting RhD incompatibility between a pregnant woman and a fetus. This study aimed to assess a methodological approach other than the commonly used one for noninvasive fetal RHD genotyping on a representative set of RhD-negative pregnant women. The methodology must be accurate, reliable, and broadly available for implementation into routine clinical practice. A total of 337 RhD-negative pregnant women from the Czech Republic region were tested in this study. The fetal RHD genotype was assessed using two methods: real-time PCR and endpoint quantitative fluorescent (QF) PCR. We used exon-7-specific primers from the RHD gene, along with internal controls. Plasma samples were analyzed and measured in four/two parallel reactions to determine the accuracy of the RHD genotyping. The RHD genotype was verified using DNA analysis from a newborn buccal swab. Both methods showed an excellent ability to predict the RHD genotype. Real-time PCR achieved its greatest accuracy of 98.6% (97.1% sensitivity and 100% specificity (95% CI)) if all four PCRs were positive/negative. The QF PCR method also achieved its greatest accuracy of 99.4% (100% sensitivity and 98.6% specificity (95% CI)) if all the measurements were positive/negative. Both real-time PCR and QF PCR were reliable methods for precisely assessing the fetal RHD allele from the plasma of RhD-negative pregnant women.
Use of Twitter as an Educational Resource. Analysis of Concepts of Active and Trainee Teachers
Authors: Higueras-Rodríguez Lina , Medina-García Marta , Pegalajar-Palomino Mª del Carmen
Published: August 2020

The use of innovative tools is a key element in the improvement of the educational process, and consequently, the use of social networks as a means of training to improve not only the learning of students, but also to improve the expectations of the teacher. Therefore, in this research we tried to investigate the incidence of social networks as facilitators of resources and didactic/playful experiences. Starting from a qualitative methodology, a descriptive–interpretative study of the information from 31 interviews with both primary education teachers and future teachers who were in training and in their last year of initial training was approached. The results indicate that the interviewees confirmed the great usefulness of social networks as educational resources and for teacher communication. The possibilities of social networks within the educational field are overly broad. They become a way of interaction between teacher and student, encourage dialogue, share didactic resources, favor collaborative learning, and develop communication skills in all aspects. In short, these are results that have a special incidence and impact on the field and social development, since we are referring fundamentally to the improvements that are produced in interpersonal relations.
Study on the Capacity of an Active Phase Controller for Autonomous Grid Connection
Authors: Jeong Da-Woom , Kim Soo-Yeon , Park Sung-Jun , Kim Dong-Hee
Published: August 2020

For the efficient power allocation of the distribution line, several studies on intelligent distribution management systems that enable connection or separation between distribution networks are being conducted. However, in case the systems are linked together and if the voltage and phase of each distribution network are different, uncontrolled circulating current and inrush current flow into the line. To resolve this, we introduced the active phase controller (APC) as a solution and performed an analysis using the capacity calculation method for the APC connected to each distribution network. When connecting lines between distribution networks, the phase of each contact was ensured to be the same. Specifically, the phase value compensated by each APC is different because the amounts of active power and reactive power to be controlled are also different. In this study, we analyzed the APC capacity according to the impedance state of the distribution line and calculated the APC output voltage for the phase matching of each distribution network at the connection point. As a result, the minimum design capacity of APC was derived; moreover, simulation results were used to validate the analysis.
Profitable Decarbonization through E-Mobility
Authors: Kumbaroğlu Gürkan , Canaz Cansu , Deason Jonathan , Shittu Ekundayo
Published: August 2020

This paper focuses on the interdependent relationship of power generation, transportation and CO2 emissions to evaluate the impact of electric vehicle deployment on power generation and CO2 emissions. The value of this evaluation is in the employment of a large-scale, bottom-up, national energy modeling system that encompasses the complex relationships of producing, transforming, transmitting and supplying energy to meet the useful demand characteristics with great technological detail. One of such models employed in this analysis is the BUEMS model. The BUEMS model provides evidence of win-win policy options that lead to profitable decarbonization using Turkey’s data in BUEMS. Specifically, the result shows that a ban on diesel fueled vehicles reduces lifetime emissions as well as lifetime costs. Furthermore, model results highlight the cost-effective emission reduction potential of e-buses in urban transportation. More insights from the results indicate that the marginal cost of emission reduction through e-bus transportation is much lower than that through other policy measures such as carbon taxation in transport. This paper highlights the crucial role the electricity sector plays in the sustainability of e-mobility and the value of related policy prescriptions.
Network and Market-Aware Bidding to Maximize Local RES Usage and Minimize Cost in Energy Islands with Weak Grid Connections
Authors: Smpoukis Konstantinos , Steriotis Konstantinos , Efthymiopoulos Nikolaos , Tsaousoglou Georgios , Makris Prodromos , Varvarigos Emmanouel (Manos)
Published: August 2020

The increasing renewable energy sources RES penetration in today’s energy islands and rural energy communities with weak grid connections is expected to incur severe distribution network stability problems (i.e., congestion, voltage issues). Tackling these problems is even more challenging since RES spillage minimization and energy cost minimization for the local energy community are set as major pre-requisites. In this paper, we consider a Microgrid Operator (MGO) that: (i) gradually decides the optimal mix of its RES and flexibility assets’ (FlexAsset) sizing, siting and operation, (ii) respects the physical distribution network constraints in high RES penetration contexts, and (iii) is able to bid strategically in the existing day-ahead energy market. We model this problem as a Stackelberg game, expressed as a Mathematical Problem with Equilibrium Constraints (MPEC), which is finally transformed into a tractable Mixed Integer Linear Program (MILP). The performance evaluation results show that the MGO can lower its costs when bidding strategically, while the coordinated planning and scheduling of its FlexAssets result in higher RES utilization, as well as distribution network aware and cost-effective RES and FlexAsset operation.
Rebound Effect from Income Savings Due to an Energy Efficiency Improvement by Households: An Input–Output Approach
Authors: Wei Taoyuan , Wang Xue
Published: August 2020

In previous studies on the indirect rebound effect due to income saved from energy efficiency improvement by households in an input–output model, household income is typically assumed constant before and after an efficiency improvement of their energy use. The assumption is implausible if we observe that households may not re-spend the saved income, which potentially reduces their consumption and national income including households, at least in the short term, in a country like China, where they have high saving propensity. In addition, income of other economic agents than households may also be affected. In this article, we provide an improved input–output model to clarify the issue and then use the 2017 input–output data of China to illustrate the potential indirect rebound effect due to household income saved from an energy efficiency improvement. Our results show that if the income impact in the short term is properly considered, then the indirect rebound effect due to the income savings could be trivial at the national level while still considerable at the household level. Hence, the indirect rebound effect at the household level alone is likely misleading for national policy makers by providing an overestimated value of the short-term indirect rebound effect.
A Numerical and Experimental Study of a Novel Heat Sink Design for Natural Convection Cooling of LED Grow Lights
Authors: Adhikari Ram , Beyragh Dawood , Pahlevani Majid , Wood David
Published: August 2020

Light-emitting diode (LED) grow lights are increasingly used in large-scale indoor farming to provide controlled light intensity and spectrum to maximize photosynthesis at various growth stages of plants. As well as converting electricity into light, the LED chips generate heat, so the boards must be properly cooled to maintain the high efficiency and reliability of the LED chips. Currently, LED grow lights are cooled by forced convection air cooling, the fans of which are often the points of failure and also consumers of a significant amount of power. Natural convection cooling is promising as it does not require any moving parts, but one major design challenge is to improve its relatively low heat transfer rate. This paper presents a novel heat sink design for natural convection cooling of LED grow lights. The new design consists of a large rectangular fin array with openings in the base transverse to the fins to increase air flow, and hence the heat transfer. Numerical simulations and experimental testing of a prototype LED grow light with the new heat sink showed that openings achieved their intended purpose. It was found that the new heat sink can transfer the necessary heat flux within the safe operating temperature range of LED chips, which is adequate for cooling LED grow lights.
A Modular Simulation Testbed for Energy Management in AC/DC Microgrids
Authors: Solano Javier , Jimenez Diego , Ilinca Adrian
Published: August 2020

This paper introduces a modular testbed to simulate AC/DC microgrids. The testbed is implemented in Matlab Simulink and is based on the energetic macroscopic representation (EMR) formalism. It is designed to be a tool to evaluate energy management strategies in AC/DC microgrids. The microgrid simulation model includes a photovoltaic generator, a fuel cell system, ultracapacitors, and batteries on the DC side. It includes voltage source converters (VSC) to couple the DC side with the AC side of the microgrid, which includes a variable AC load and a synchronous generator. Two case studies illustrate the use of the testbed. The model is implemented in Matlab Simulink and made openly available for the scientific community. Using this model, researchers can develop and evaluate energy management strategies in AC/DC microgrids.
Dynamic Modeling of Multiple Microgrid Clusters Using Regional Demand Response Programs
Authors: Rostami Ziba , Ravadanegh Sajad Najafi , Kalantari Navid Taghizadegan , Guerrero Josep M. , Vasquez Juan C.
Published: August 2020

Preserving the frequency stability of multiple microgrid clusters is a serious challenge. This work presents a dynamic model of multiple microgrid clusters with different types of distributed energy resources (DERs) and energy storage systems (ESSs) that was used to examine the load frequency control (LFC) of microgrids. The classical proportional integral derivative (PID) controllers were designed to tune the frequency of microgrids. Furthermore, an imperialist competitive algorithm (ICA) was proposed to investigate the frequency deviations of microgrids by considering renewable energy resources (RERs) and their load uncertainties. The simulation results confirmed the performance of the optimized PID controllers under different disturbances. Furthermore, the frequency control of the microgrids was evaluated by applying regional demand response programs (RDRPs). The simulation results showed that applying the RDRPs caused the damping of frequency fluctuations.
Mixed Detailed and Compact Multi-Domain Modeling to Describe CoB LEDs
Authors: Pohl László , Hantos Gusztáv , Hegedüs János , Németh Márton , Kohári Zsolt , Poppe András
Published: August 2020

Large area multi-chip LED devices, such as chip-on-board (CoB) LEDs, require the combined use of chip-level multi-domain compact LED models (Spice-like compact models) and the proper description of distributed nature of the thermal environment (the CoB substrate and phosphor) of the LED chips. In this paper, we describe such a new numerical solver that was specifically developed for this purpose. For chip-level, the multi-domain compact modeling approach of the Delphi4LED project is used. This chip-level model is coupled to a finite difference scheme based numerical solver that is used to simulate the thermal phenomena in the substrate and in the phosphor (heat transfer and heat generation). Besides solving the 3D heat-conduction problem, this new numerical simulator also tracks the propagation and absorption of the blue light emitted by the LED chips, as well as the propagation and absorption of the longer wavelength light that is converted by the phosphor from blue. Heat generation in the phosphor, due to conversion loss (Stokes shift), is also modeled. To validate our proposed multi-domain model of the phosphor, dedicated phosphor and LED package samples with known resin—phosphor powder ratios and known geometry were created. These samples were partly used to identify the nature of the temperature dependence of phosphor-conversion efficiency and were also used as simple test cases to “calibrate” and test the new numerical solver. With the models developed, combined simulation of the LED chip and the CoB substrate + phosphor for a known CoB LED device is shown, and the simulation results are compared to measurement results.
The Role of Low-Load Diesel in Improved Renewable Hosting Capacity within Isolated Power Systems
Authors: Hamilton James , Negnevitsky Michael , Wang Xiaolin , Semshchikov Evgenii
Published: August 2020

Isolated communities are progressively integrating renewable generation to reduce the societal, economic and ecological cost of diesel generation. Unfortunately, as renewable penetration and load variability increase, systems require greater diesel generation reserves, constraining renewable utilisation. Improved diesel generator flexibility can reduce the requirement for diesel reserves, allowing increased renewable hosting. Regrettably, it is uncommon for utilities to modify diesel generator control during the integration of renewable source generation. Identifying diesel generator flexibility and co-ordination as an essential component to optimising system hosting capacity, this paper investigates improved diesel generator flexibility and coordination via low-load diesel application. Case study comparisons for both high- and low-penetration hybrid diesel power systems are presented in King Island, Australia, and Moloka`i, Hawai`i, respectively. For King Island, the approach details a 50% reduction in storage requirement, while for Moloka`i the application supports a 27% increase in renewable hosting capacity.
Transient CFD Simulation on Dynamic Characteristics of Annular Seal under Large Eccentricities and Disturbances
Authors: Zhang Kai , Jiang Xinkuo , Li Shiyang , Huang Bin , Yang Shuai , Wu Peng , Wu Dazhuan
Published: August 2020

Annular seals of turbomachinery usually suffer from various degrees of eccentricities and disturbances due to the rotor–stator misalignment and radial loads, while the discussion of annular seal under both large static eccentricities and dynamic disturbances is relatively limited. In this paper, the applicability of linear assumption and reliability of nonlinear dynamic model for eccentric annular seals under large eccentricities and disturbances is discussed based on the investigation of seals with various rotor motions through computational fluid dynamics (CFD). After the validation of transient CFD methods by comparison with experimental and bulk theory results, the dynamic behaviors of annular seal are analyzed by adopting both direct transient simulations and the nonlinear Muszynska model. The results show that the nonlinear dynamic model based on rotor circular whirls around seal center can predict the fluid excitations of different types of rotor motions well under small static eccentricities, while it is limited severely with large static eccentricities, which indicates that the dynamic characteristics of annular seal under large eccentricities are related with the rotor’s motion ways. The paper provides a reference for studies of rotor–seal system with complex rotor motions considering radial loads or running across the resonance region.
An Enhanced Vertical Ground Heat Exchanger Model for Whole-Building Energy Simulation
Authors: Mitchell Matt S. , Spitler Jeffrey D.
Published: August 2020

This paper presents an enhanced vertical ground heat exchanger (GHE) model for whole-building energy simulation (WBES). WBES programs generally have computational constraints that affect the development and implementation of component simulation sub-models. WBES programs require models that execute quickly and efficiently due to how the programs are utilized by design engineers. WBES programs also require models to be formulated so their performance can be determined from boundary conditions set by upstream components and environmental conditions. The GHE model developed during this work utilizes an existing response factor model and extends its capabilities to accurately and robustly simulate at timesteps that are shorter than the GHE transit time. This was accomplished by developing a simplified dynamic borehole model and then exercising that model to generate exiting fluid temperature response factors. This approach blends numerical and analytical modeling methods. The existing response factor models are then extended to incorporate the exiting fluid temperature response factor to provide a better estimate of the GHE exiting fluid temperature at short simulation timesteps.
Numerical Study of the Turbulent Flow from a Steam Dumping Pressurizer Relief Tank
Authors: Zhang Sen , Guo Xiao-Wei , Li Chao , Liu Yi , Zhao Ran , Yang Canqun
Published: August 2020

Due to the complex geometry and turbulent flow characteristics, it is hard to simulate the process of steam dumping of the pressurizer relief tank (PRT). In this study, we develop a compressible fluid solver PRTFOAM to numerically study the turbulent flow dynamics from a PRT. The PRTFOAM is implemented based on the OpenFOAM and designed to be capable of integrating various turbulence models. Two representative Reynolds-averaged Navier–Stokes (RANS) models and a Smagorinsky–Lilly SGS model based on Large Eddy Simulation (LES) are coupled and tested with PRTFOAM. The case of a flow past a circular cylinder (Re = 3900) is tested and analyzed comprehensively as a benchmark case. Then, the turbulent steam dumping process in the full geometry of a PRT is analyzed and compared with ANSYS CFX and literature reports. In addition, we tested the WALE model based on the PRT steam dumping process. The results show that SST k-ω model and Smagorinsky–Lilly SGS model-based LES approach are more appropriate than the LRR model for PRT simulations. Moreover, it shows that the simulation results of Smagorinsky–Lilly SGS model and WALE model are basically consistent under the condition of PRT steam dumping process. Under this condition, the drawbacks of Smagorinsky–Lilly SGS model are not obvious. Furthermore, the comparison with CFX showed that our open source solver could be used to obtain better results in complex engineering cases. The design and testing results would provide guidance for further analysis of thermal-hydraulics in reactors based on open source codes.
En-Route Battery Management and a Mixed Network Equilibrium Problem Based on Electric Vehicle Drivers’ En-Route Recharging Behaviors
Authors: Liu Kai , Luo Sijia , Zhou Jing
Published: August 2020

With the rapidly increasing number of electric vehicle users, in many urbans transport networks, there are mixed traffic flows (i.e., electric vehicles and gasoline vehicles). However, limited by driving ranges and long battery recharging, the battery electric vehicle (BEV) drivers’ route choice behaviors are inevitably affected. This paper assumes that in a transportation network, when BEV drivers are traveling between their original location and destinations, they tend to select the path with the minimal driving times and recharging time, and ensure that the remaining charge is not less than their battery safety margin. In contrast, gasoline vehicle drivers tend to select the path with the minimal driving time. Thus, by considering BEV drivers’ battery management strategies, e.g., battery safety margins and en-route recharging behaviors, this paper developed a mixed user equilibrium model to describe the resulting network equilibrium flow distributions. Finally, a numerical example is presented to demonstrate the mixed user equilibrium model. The results show that BEV drivers’ en-route recharging choice behaviors are significantly influenced by their battery safety margins, and under the equilibrium, the travel routes selected by some BEV drivers may not be optimal, but the total travel time may be more optimal.
Emerging Tools for Energy System Design Increasing Economic and Environmental Sustainability
Authors: Fan Yee Van , Pintarič Zorka Novak , Klemeš Jiří Jaromír
Published: August 2020

Energy is a fundamental element supporting societal development, particularly with the increasing dependency on the Internet of Things. It is also the main contributor to environmental impacts and subsequently, a potential sector for mitigation. Sustainable energy system design considers energy savings and energy efficiency, waste and consumption reduction, process efficiency enhancement, waste heat recovery, and integration of renewable energy. Emerging tools range from advanced Process Integration, modelling, simulation, and optimisation, to system analysis and assessment. This review covers selected emerging studies promoting sustainable system design, including the recent developments reported in the Special Issue (SI) of the 22nd Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES’19). The primary emphasis was to enhance the economic and environmental performance. However, social factors were also highlighted as essential for future sustainable development. The discussion and analysis in this review focus on the most recent developments of (a) heat integration and heat transfer; (b) integrated and newly developed heat exchangers, (c) integration of renewables, and (d) roles in economic and environmental sustainability. The key results are highlighted, and future research ideas are suggested according to their links to a broader context.
Assessment of Non-Anthropogenic Addition of Uric Acid to a Water Treatment Wetlands
Authors: Welch Joseph , Simmons Vanessa , Meléndez Eduardo , Sees Mark , Gold Yolanda , Heider Emily C.
Published: August 2020

Artificial water-treatment wetlands can reduce nitrogen and phosphorous nutrient concentrations in wastewater effluent to improve water quality and decrease eutrophication in natural waters. The Orlando Easterly Wetlands (OEW) is an engineered wetland that polishes 57 million liters of wastewater per day, lowering the total nitrogen and phosphorous concentrations through biological, physical, and chemical processes. In addition to purifying the water, the wetlands provide habitat for avian, mammalian, reptilian and macroinvertebrate species. Previous research has shown that avian species affect the eutrophication of agricultural reservoirs near their roost. The research herein quantifies uric acid in avian and reptilian excretory product and tracks its concentration profile throughout the OEW over a seven-month period. This measure of the non-anthropogenic contribution to nitrogen within the park includes winter months when large numbers of migratory birds occupy the wetland. The enzymatic decomposition of uric acid and the subsequent fluorimetric analysis were used to quantify uric acid throughout the flow train of the OEW. High concentrations of 2–4 mg/L uric acid were found in the influent, but drastically declined to concentrations below 0.2 mg/L in the effluent.
The Pattern of Genetic Variation, Survival and Growth in the Abies alba Mill. Population within the Introgression Zone of Two Refugial Lineages in the Carpathians
Authors: Kempf Marta , Zarek Marcin , Paluch Jarosław
Published: August 2020

Background and Objectives: The contact zones of different refugial lineages, where mixing of genetic backgrounds leads to new gene combinations or pre-adaptations, represent hotspots of genetic diversity. The aim of the study was to compare patterns in the genetic structure of the Abies alba Mill. population in the Eastern and Western Carpathians (Eastern Europe) within the introgression zone of two refugial lineages and the growth response of provenances located in a gradient of pollen-mediated gene fluxes. Materials and Methods: The mitochondrial nad5-4 marker and five polymorphic microsatellite nuclear markers (nSSR) were analyzed in 56 subpopulations from Romania, Ukraine, Slovakia and Poland. The survival rate and height growth up to an age of 15 years were compared for 33 subpopulations, forming a distance gradient between 170 and 470 km from the meeting zone of the refugial lineages. Results: The results of the analysis of molecular variance indicated that 8.2% of the total genetic variation is attributable to the between-subpopulation level and 1.7% to the between-lineage level. The pollen-mediated influence of the eastern lineage was detectable at a distance of at least 300 km in the western direction. Eastern provenances with origin sites closer to the meeting zone of the refugial lineages were characterized by lower survival rate and lower heights (about 8% lower than the average tree height) compared to subpopulations from the central and western part of the studied region. Conclusions: Pollen-mediated gene flow between lineages appears to have been sufficient to cause a significant change in phenotypic traits related to tree growth. Subpopulations from the central and western parts of the studied region are better adapted to current climatic conditions. Nonetheless, given the increasing aridity of the regional climate, a safe guideline is to increase genetic mixing.
Nitrogen Sources Added to Must: Effect on the Fermentations and on the Tempranillo Red Wine Quality
Authors: Santamaría Pilar , González-Arenzana Lucía , Garijo Patrocinio , Gutiérrez Ana Rosa , López Rosa
Published: August 2020

Nitrogen supplementation in musts or during the alcoholic fermentation is a common practice to promote fermentations. In this study, the impact of the supplementation of two different sources of nitrogen during Tempranillo red wine elaboration was studied. Mineral and organic nitrogen was added after the exponential yeast growth phase and during winemaking, examining its impact on the alcoholic and malolactic fermentation development, on the aromatic wine composition and on the nitrogenous wine composition. The nitrogen supplementation did not provide neither significant advantages in kinetics and fermentations time, nor differences in the chemical wine composition. The aromatic composition of the wines improved with the addition of inorganic nitrogen, although its organoleptic evaluation was not favored. Moreover, the concentration of amino acids in wines increased slightly after the malolactic fermentation and significantly during the stabilization time, especially with organic nitrogen addition. However, the synthesis of biogenic amines did not increase in wines neither after the malolactic fermentation, nor after the storage period.
Partially Averaged Navier-Stokes: A (k-ω)/(k-ε) Bridging Model
Authors: Frendi Abdelkader , Harrison Christopher
Published: August 2020

A new Partially Averaged Navier-Stokes (PANS) bridging model is derived from existing (k−ω) and (k−ε) PANS formulations. The model behaves like the PANS (k−ω) model near rigid walls and like the PANS (k−ε) model away from walls. The new model is tested using well-known benchmark problems; a backward-facing step representing wall-bounded flows, and a circular cylinder representing free shear flows. Our results are compared to existing experimental data and previous simulation results using PANS (k−ω) and PANS (k−ε). The comparisons show our model to be superior at predicting velocity profiles in both flows. In addition, Reynolds stress predictions are also shown to improve.
Effectiveness of Oat-Hull-Based Ingredient as Fat Replacer to Produce Low Fat Burger with High Beta-Glucans Content
Authors: Summo Carmine , De Angelis Davide , Difonzo Graziana , Caponio Francesco , Pasqualone Antonella
Published: August 2020

Low-fat beef burgers with high beta-glucan content was obtained using a gel made from an oat-hull-based ingredient as fat replacer. Two levels of fat substitution were considered: 50% (T1) and 100% (T2). The nutritional composition, cooking yield, textural properties, color characteristics and consumer preference were evaluated, in comparison with a burger without fat replacer (CTRL). After cooking, T2 burger showed a significant increase in the cooking yield and a very low lipid content (3.48 g 100 g−1) as well as a level of beta-glucans per single portion (2.96 g 100 g−1) near the recommended daily intake. In T1 burger, the decrease of lipid content was mitigated during the cooking process, because the beta-glucans added had a fat-retaining effect. Compared to CTRL, replacing fat led to a softer texture of cooked burgers evaluated by Texture Profile Analysis. The differences in color, significant in raw burgers, were smoothed with cooking. The consumer evaluation, carried out according to the duo-trio test, highlighted significant differences between CTRL and T2 burgers in terms of odor, taste, color and texture. The consumers expressed a higher preference for the T2 burger, probably due to its softer texture and greater juiciness.
Nutritional and Physicochemical Characterization of Strychnos madagascariensis Poir (Black Monkey Orange) Seeds as a Potential Food Source
Authors: van Rayne Kiana Kirsty , Adebo Oluwafemi Ayodeji , Ngobese Nomali Ziphorah
Published: August 2020

Strychnos madagascariensis Poir is an underutilized fruit that is considered a valuable food during droughts and famine. The aim of this research was to characterize the nutritional composition and the flour functional properties, for the use as a potential food source. Seed flour was analysed using a standard enzymatic assay for sugars, acid/neutral detergent analysis for fibre, ether extraction for fat and HPLC for strychnine. Results showed that the seeds contained 41% reducing sugars and 53% fibre. The mineral composition, determined using microwave-assisted acid digestion and inductively coupled plasma optical emission spectrometry (ICP–OES), showed that the seeds contained high quantities of iron (15.78 mg/100 g) and manganese (9.86 mg/100 g). The flour water absorption index (1.37 g/g) was substantially higher than that of wheat, brown rice and tapioca flours and the oil absorption index showed similarities to the reference flours (1.09 g/g). The flour peak (37,788 RVU) and final viscosities (62,928 RVU) were significantly (p < 0.001) higher than the reference flours. This study was the first to quantify the strychnine content (0.08%) in the seeds. Results suggest that the seeds have good potential for food product development; however, further processing is essential to ensure safety for consumption.
Metabolite Profile and Immunomodulatory Properties of Bellflower Root Vinegar Produced Using Acetobacter pasteurianus A11-2
Authors: Gil Na-Young , Gwon Hee-Min , Yeo Soo-Hwan , Kim So-Young
Published: August 2020

Fermented vinegar is prepared from grains and medicinal plants. Here, we produced vinegar from peeled and unpeeled roots of bellflowers (Platycodon grandiflorum) using Acetobacter pasteurianus A11-2 and analyzed bellflower vinegar (BV) samples using gas chromatography–mass spectrometry and quadrupole time-of-flight mass spectrometry over 15 days of fermentation to assess the quality. We also evaluated their antibacterial and immunoenhancing effects using RAW 264.7 macrophage cells. The major metabolites in BV are organic acids, with the main volatile compounds being ethyl acetate, isoamyl acetate, 1-pentanol, hydroxypropanoic acid, and malonic acid. When we fermented BV from unpeeled roots for 10 days with a starter culture, we observed significant antibacterial and immunoenhancing effects in macrophages. Therefore, we could determine the metabolite and functional differences in vinegar obtained from bellflower roots and proposed that bellflower roots with peel are an effective substrate for developing vinegar and healthy food products.