bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of High-Temperature Pavement Paving on Fatigue Durability of Bearing-Supported Steel Decks
Authors: Wang Qiudong , Ji Bohai , Fu Zhongqiu , Wang Hao
Published: October 2020

Orthotropic steel deck (OSD) is a better choice for urban bridges and the replacement of damaged concrete slabs. Gussasphalt concrete (GAC) is usually adopted as the asphalt surfacing; however, the paving temperature of GAC is high, which will affect the fatigue durability of fatigable welds in OSD. In this study, such influence of high-temperature pavement paving was comprehensively investigated based on in-situ monitoring and numerical analysis. The temperature of OSD and displacement of bearings were investigated based on the monitored data and numerical results. After that, the deformation and residual temperature stress of OSD during the paving process were analyzed. On this basis, the effect of residual temperature stress on fatigue damage accumulation of OSD was investigated and discussed. Results show that the uplift and expanded deformation of OSD arise during the paving process, leading to the displacement of bearings. Residual displacement of bearings, as well as the residual temperature stress at fatigable details of OSD, is observed. The residual temperature stress has considerable effect on fatigue damage accumulation at rib-deck weld. A fatigue damage amplification factor of 1.1 is recommended for taking into consideration of the adverse effect of high-temperature pavement paving.
On a New Type of Combined Solar–Thermal/Cold Gas Propulsion System Used for LEO Satellite’s Attitude Control
Authors: Sandu Constantin , Silivestru Valentin , Cican Grigore , Șerbescu Horațiu , Tipa Traian , Totu Andrei , Radu Andrei
Published: October 2020

This paper presents the development, construction and testing of a new type of solar–thermal propulsion system which can be used for low earth orbit (LEO) satellites. Currently, the vast majority of LEO satellites are fitted with a cold gas propulsion system. Although such a propulsion system is preferred, the service duration of an LEO satellite is limited by the amount of cold gas they carry onboard. In the case of the new type of solar–thermal propulsion system proposed in this paper, the cold gas is first transferred from the main tank in a cylindrical service tank/buffer tank which is placed in the focal line of a concave mirror. After the gas is heated by the solar light focused on the service tank by the concave mirror, it expands by opening the appropriate solenoid valve for the satellite’s attitude control. In this way the service duration of LEO satellite on orbit can increase by 2.5 times compared with a classic cold gas propulsion system. This is due to the propellant’s internal energy increase by the focused solar light. This paper also presents the results achieved by carrying out tests for the hot gas propulsion system in a controlled environment.
Synthesis of Alkynyl Ketones by Sonogashira Cross-Coupling of Acyl Chlorides with Terminal Alkynes Mediated by Palladium Catalysts Deposited over Donor-Functionalized Silica Gel
Authors: Semler Miloslav , Horký Filip , Štěpnička Petr
Published: October 2020

Palladium catalysts deposited over silica gel bearing simple amine (≡Si(CH2)3NH2) and composite functional amide pendants equipped with various donor groups in the terminal position (≡Si(CH2)3NHC(O)CH2Y, Y = SMe, NMe2 and PPh2) were prepared and evaluated in Sonogashira-type cross-coupling of acyl chlorides with terminal alkynes to give 1,3-disubstituted prop-2-yn-1-ones. Generally, the catalysts showed good catalytic activity in the reactions of aroyl chlorides with aryl alkynes under relatively mild reaction conditions even without adding a copper co-catalyst. However, their repeated use was compromised by a significant loss of activity after the first catalytic run.
Production of Biodiesel from Brown Grease
Authors: Kolet Mirit , Zerbib Daniel , Nakonechny Faina , Nisnevitch Marina
Published: October 2020

Among the renewable energy sources is biodiesel. This fuel is usually produced by catalytic transesterification of vegetable oils and animal fats under heating and pressure. Brown grease is a mixture of oils, fats, solids and detergents from food industry wastes that is captured in grease traps. Brown grease is classified as waste and must be treated and disposed of appropriately. It contains oils and fats that can be converted into biodiesel. However, the high concentration of free fatty acids in brown grease does not enable the use of conventional biodiesel production schemes. This study proposes a new scheme for biodiesel production from brown grease. In addition, conditions for the effective separation of a fat phase from brown grease were tested, and the composition of a fatty phase was determined for several grease traps. Esterification and transesterification of brown grease lipids were carried out with methanol, where the Lewis acids BF3 and AlCl3 were used as catalysts and the reaction was activated by ultrasound. The results show that biodiesel can be obtained from brown grease by esterification and transesterification within several minutes under ultrasonic activation at room temperature. These results open prospects for the development of efficient, low-cost and environmentally friendly biodiesel production.
The HD-Domain Metalloprotein Superfamily: An Apparent Common Protein Scaffold with Diverse Chemistries
Authors: Langton Michelle , Sun Sining , Ueda Chie , Markey Max , Chen Jiahua , Paddy Isaac , Jiang Paul , Chin Natalie , Milne Amy , Pandelia Maria-Eirini
Published: October 2020

The histidine–aspartate (HD)-domain protein superfamily contains metalloproteins that share common structural features but catalyze vastly different reactions ranging from oxygenation to hydrolysis. This chemical diversion is afforded by (i) their ability to coordinate most biologically relevant transition metals in mono-, di-, and trinuclear configurations, (ii) sequence insertions or the addition of supernumerary ligands to their active sites, (iii) auxiliary substrate specificity residues vicinal to the catalytic site, (iv) additional protein domains that allosterically regulate their activities or have catalytic and sensory roles, and (v) their ability to work with protein partners. More than 500 structures of HD-domain proteins are available to date that lay out unique structural features which may be indicative of function. In this respect, we describe the three known classes of HD-domain proteins (hydrolases, oxygenases, and lyases) and identify their apparent traits with the aim to portray differences in the molecular details responsible for their functional divergence and reconcile existing notions that will help assign functions to yet-to-be characterized proteins. The present review collects data that exemplify how nature tinkers with the HD-domain scaffold to afford different chemistries and provides insight into the factors that can selectively modulate catalysis.
Sensitive Electrochemical Detection of Tryptophan Using a Hemin/G-Quadruplex Aptasensor
Authors: Hashkavayi Ayemeh Bagheri , Raoof Jahan Bakhsh , Park Ki Soo
Published: October 2020

In this study, we design an electrochemical aptasensor with an enzyme-free amplification method to detect tryptophan (Trp). For the amplified electrochemical signal, the screen-printed electrode was modified with dendritic gold nanostructures (DGNs)/magnetic double-charged diazoniabicyclo [2.2.2] octane dichloride silica hybrid (Fe3O4@SiO2/DABCO) to increase the surface area as well as electrical conductivity, and the hemin/G-quadruplex aptamer was immobilized. The presence of Trp improved the catalytic characteristic of hemin/G-quadruplex structure, which resulted in the efficient catalysis of the H2O2 reduction. As the concentration of Trp increased, the intensity of H2O2 reduction signal increased, and Trp was measured in the range of 0.007–200 nM with a detection limit of 0.002 nM. Compared with previous models, our sensor displayed higher detection sensitivity and specificity for Trp. Furthermore, we demonstrated that the proposed aptasensor successfully determined Trp in human serum samples, thereby proving its practical applicability.
Ferroelectricity, Superconductivity, and SrTiO3—Passions of K.A. Müller
Authors: Scheerer Gernot , Boselli Margherita , Pulmannova Dorota , Rischau Carl Willem , Waelchli Adrien , Gariglio Stefano , Giannini Enrico , van der Marel Dirk , Triscone Jean-Marc
Published: October 2020

SrTiO3 is an insulating material which, using chemical doping, pressure, strain or isotope substitution, can be turned into a ferroelectric material or into a superconductor. The material itself, and the two aforementioned phenomena, have been subjects of intensive research of Karl Alex Müller and have been a source of inspiration, among other things, for his Nobel prize-winning research on high temperature superconductivity. An intriguing outstanding question is whether the occurrence of ferroelectricity and superconductivity in the same material is just a coincidence, or whether a deeper connection exists. In addition there is the empirical question of how these two phenomena interact with each other. Here we show that it is possible to induce superconductivity in a two-dimensional layer at the interface of SrTiO3 and LaAlO3 when we make the SrTiO3 ferroelectric by means of 18O substitution. Our experiments indicate that the ferroelectricity is perfectly compatible with having a superconducting two-dimensional electron system at the interface. This provides a promising avenue for manipulating superconductivity in a non centrosymmetric environment.
Quantum Gases of Dipoles, Quadrupoles and Octupoles in Gross–Pitaevskii Formalism with Form Factor
Authors: Alexandrov Artem A. , Badamshina Alina U. , Ogarkov Stanislav L.
Published: October 2020

Here, classical and quantum field theory of dipolar, axisymmetric quadrupolar and octupolar Bose gases is considered within a general approach. Dipole, axisymmetric quadrupole and octupole interaction potentials in the momentum representation are calculated. These results clearly demonstrate attraction and repulsion areas in corresponding gases. Then the Gross–Pitaevskii (GP) equation, which plays a key role in the present paper, is derived from the corresponding functional. The zoology of the form factors appearing in the GP equation is studied in details. The proper classes for the description of spatially non-uniform condensates form factors are chosen. In the Thomas–Fermi approximation a general solution of the GP equation with a quasilocal form factor is obtained. This solution has an interesting form in terms of a double rapidly converging series that universally includes all the interactions considered. Plots of condensate density functions for the exponential-trigonometric form factor are given. For the sake of completeness, in this paper we consider the GP equation with an optical lattice potential in the limit of small condensate densities. This limit does not distinguish between dipolar, quadrupolar and octupolar gases. An important analysis of the condensate stability, in other words the study of condensate excitations, is also performed in this paper. In the Gaussian approximation (from the Gross–Pitaevskii functional), a functional describing the perturbations of the condensate is derived in detail. This problem is an analog of the Bogolubov transformation used in the study of quantum Bose gases in operator formalism. For a probe wave function in the form of a plane wave, a spectrum of (Bogoliubov) excitations was obtained, from which an equation describing the threshold momentum for the emergence of instability was derived. An important result of this paper is the dependence of the threshold on the momentum of a stationary condensate. For completeness of the presentation, the approximating expression in the form of a rapidly converging series is obtained for the corresponding dependence, and plots of the corresponding series for the exponential-trigonometric form factor are given. Finally, in the conclusion a quantum hydrodynamic theory for dipolar, axisymmetric quadrupolar and octupolar gases is briefly presented, giving a clue to the experimental determination of the form factors.
Investigation of Thermally Induced Deterioration Processes in Cold Worked SAF 2507 Type Duplex Stainless Steel by DTA
Authors: Berecz Tibor , Fazakas Éva , Fábián Enikő Réka , Jenei Péter , Maróti János Endre
Published: October 2020

Thermally induced deterioration processes were studied in cold worked (up to 60% deformation) SAF 2507 type super-duplex stainless steel (SDSS) by differential thermal analysis (DTA). DTA results revealed two transformations. Parent and inherited phases of these transformations were examined by other methods too, such as micro-hardness tests, optical metallography and X-ray diffraction (XRD). Finally, these transformations were identified as the formation of α’- and σ-phases. Formation of strain-induced martensite (SIM) and recrystallization were not experienced until 1000 °C, despite high degree of cold working. Activation energies of the σ-phase precipitation and α’-phase formation were determined from the Kissinger plot, through DTA measurements—they are 275 and 220 kJ/mol, respectively—in good agreement with the values found in the literature.
An Eddy Covariance Mesonet For Measuring Greenhouse Gas Fluxes in Coastal South Carolina
Authors: Forsythe Jeremy D. , O’Halloran Thomas L. , Kline Michael A.
Published: October 2020

Coastal ecosystems are vulnerable to climate change and have been identified as sources of uncertainty in the global carbon budget. Here we introduce a recently established mesonet of eddy covariance towers in South Carolina and describe the sensor arrays and data workflow used to produce three site-years of flux observations in coastal ecosystems. The tower sites represent tidal salt marsh (US-HB1), mature longleaf pine forest (US-HB2), and longleaf pine restoration (replanted clearcut; US-HB3). Coastal ecosystems remain less represented in climate studies despite their potential to sequester large amounts of carbon. Our goal in publishing this open access dataset is to contribute observations in understudied coastal ecosystems to facilitate synthesis and modeling analyses that advance carbon cycle science.
Impact of Blood Type O on Mortality of Sepsis Patients: A Multicenter Retrospective Observational Study
Authors: Hasegawa Daisuke , Nishida Kazuki , Kawaji Takahiro , Hara Yoshitaka , Shimomura Yasuyo , Moriyama Kazuhiro , Niimi Daisuke , Kuriyama Naohide , Shintani Ayumi , Komura Hidefumi , Nishida Osamu
Published: October 2020

ABO blood groups have been implicated as potential risk factors for various diseases. However, no study has investigated the association between sepsis mortality and ABO blood types. We aimed to evaluate the impact of these blood types on mortality in patients with sepsis and septic shock. This retrospective observational study was conducted at two general hospitals in Japan. Patients diagnosed with sepsis or septic shock were included and divided into four groups based on blood type (O, A, B, and AB). The association between type O vs. other types and 28- and 90-day mortalities was evaluated using multivariate logistic regression analysis adjusted for age, sex, and Sequential (Sepsis-related) Organ Failure Assessment score. This study included 415 patients, of whom 131 (31.6%), 171 (41.2%), 81 (19.5%), and 32 (7.7%) had type O, A, B, and AB, respectively. Blood type O was not associated with 28-day (odds ratio: 1.7 p = 0.08) or 90-day mortality (odds ratio: 1.53, p = 0.091). However, type O was significantly associated with higher 90-day mortality (odds ratio: 3.26, p = 0.009) in patients with septic shock. The role of ABO blood type in risk stratification for septic shock and the mechanisms that potentially affect the prognosis of sepsis patients need further investigation.
Diagnostic Value of C-Reactive Protein in Discrimination between Uncomplicated and Complicated Parapneumonic Effusion
Authors: Kogan Yana , Sabo Edmond , Odeh Majed
Published: October 2020

Objectives: The role of serum C-reactive protein (CRPs) and pleural fluid CRP (CRPpf) in discriminating uncomplicated parapneumonic effusion (UCPPE) from complicated parapneumonic effusion (CPPE) is yet to be validated since most of the previous studies were on small cohorts and with variable results. The role of CRPs and CRPpf gradient (CRPg) and of their ratio (CRPr) in this discrimination has not been previously reported. The study aims to assess the diagnostic efficacy of CRPs, CRPpf, CRPr, and CRPg in discriminating UCPPE from CPPE in a relatively large cohort. Methods: The study population included 146 patients with PPE, 86 with UCPPE and 60 with CPPE. Levels of CRPs and CRPpf were measured, and the CRPg and CRPr were calculated. The values are presented as mean ± SD. Results: Mean levels of CRPs, CRPpf, CRPg, and CRPr of the UCPPE group were 145.3 ± 67.6 mg/L, 58.5 ± 38.5 mg/L, 86.8 ± 37.3 mg/L, and 0.39 ± 0.11, respectively, and for the CPPE group were 302.2 ± 75.6 mg/L, 112 ± 65 mg/L, 188.3 ± 62.3 mg/L, and 0.36 ± 0.19, respectively. Levels of CRPs, CRPpf, and CRPg were significantly higher in the CPPE than in the UCPPE group (p < 0.0001). No significant difference was found between the two groups for levels of CRPr (p = 0.26). The best cut-off value calculated by the receiver operating characteristic (ROC) analysis for discriminating UCPPE from CPPE was for CRPs, 211.5 mg/L with area under the curve (AUC) = 94% and p < 0.0001, for CRPpf, 90.5 mg/L with AUC = 76.3% and p < 0.0001, and for CRPg, 142 mg/L with AUC = 91% and p < 0.0001. Conclusions: CRPs, CRPpf, and CRPg are strong markers for discrimination between UCPPE and CPPE, while CRPr has no role in this discrimination.
Hepatitis C Virus Infection Increases Fatigue in Health Care Workers
Authors: Catania Vito Emanuele , Malaguarnera Giulia , Fiorenza Giorgia , Chisari Eleonora Margherita , Lipari Anna Rita , Gallina Valentino , Pennisi Manuela , Lanza Giuseppe , Malaguarnera Michele
Published: October 2020

Fatigue is a common state associated with a weakening or depletion of one’s physical and mental resources, that leads to the inability to continue the individual functioning at a normal level of activity. Frequently, fatigue represents a response to infections, inflammation and autoimmune diseases. The scope of this study was to evaluate the fatigue in healthcare workers with and without hepatitis C virus (HCV) infection. Mental, physical and severity fatigue were evaluated through Krupp, Wessely and Powell fatigue scale. Anti-HCV antibodies, HCV RNA and HCV genotypes were also measured. Physical, mental and severity fatigue were higher in healthcare workers with HCV infection than the healthcare workers without infection (p < 0.01). Our data showed a direct link between fatigue and HCV infection in healthcare workers. Further studies are needed to evaluate HCV antiviral treatments on fatigue severity and on quality of life in healthcare workers
Smart Sensing: An Info-Structural Model of Cognition for Non-Interacting Agents
Authors: Iovane Gerardo , Fominska Iana , Landi Riccardo Emanuele , Terrone Francesco
Published: October 2020

This study explores an info-structural model of cognition for non-interacting agents affected by human sensation, perception, emotion, and affection. We do not analyze the neuroscientific or psychological debate concerning the human mind working, but we underline the importance of modeling the above cognitive levels when designing artificial intelligence agents. Our aim was to start a reflection on the computational reproduction of intelligence, providing a methodological approach through which the aforementioned human factors in autonomous systems are enhanced. The presented model must be intended as part of a larger one, which also includes concepts of attention, awareness, and consciousness. Experiments have been performed by providing visual stimuli to the proposed model, coupling the emotion cognitive level with a supervised learner to produce artificial emotional activity. For this purpose, performances with Random Forest and XGBoost have been compared and, with the latter algorithm, 85% accuracy and 92% coherency over predefined emotional episodes have been achieved. The model has also been tested on emotional episodes that are different from those related to the training phase, and a decrease in accuracy and coherency has been observed. Furthermore, by decreasing the weight related to the emotion cognitive instances, the model reaches the same performances recorded during the evaluation phase. In general, the framework achieves a first emotional generalization responsiveness of 94% and presents an approximately constant relative frequency related to the agent’s displayed emotions.
The Long-Run Effects of Trade Openness on Carbon Emissions in Sub-Saharan African Countries
Authors: Sun Huaping , Enna Love , Monney Augustine , Tran Dang Khoa , Rasoulinezhad Ehsan , Taghizadeh-Hesary Farhad
Published: October 2020

Using a panel cointegration model developed based on the data extracted from the World Bank indicators, this study quantified the relationship between carbon emissions, energy consumption, economic growth, and trade openness in sub-Saharan African countries. It discovered from our analysis that there exists a long-run causality association amongst CO2 emissions, energy consumption, economic growth, and trade openness. The study noted the existence of the Environmental Kuznets Curve (EKC) in the panel using the square term for trade openness; it was found to have a negative impact, thus trade in the long run will somewhat decrease the environmental pollution in this region. The study results imply that there should be stringent policies and rigorous enforcement in sub-Saharan African to ensure sustainable growth without associative environmental issues.
Adaptive Takagi–Sugeno Fuzzy Model Predictive Control for Permanent Magnet Synchronous Generator-Based Hydrokinetic Turbine Systems
Authors: Lin Yu-Chen , Balas Valentina Emilia , Yang Ji-Fan , Chang Yu-Heng
Published: October 2020

This paper presents a sensorless model predictive torque control strategy based on an adaptive Takagi–Sugeno (T–S) fuzzy model for the design of a six–phase permanent magnet synchronous generator (PMSG)–based hydrokinetic turbine systems (PMSG-HTs), which not only provides clean electric energy and stable energy-conversion efficiency, but also improves the reliability and robustness of the electricity supply. An adaptive T–S fuzzy model is first formed to characterize the nonlinear system of the PMSG before a model predictive torque controller based on the T–S fuzzy model for the PMSG system is employed to indirectly control the stator current and the stator flux magnitude, which improves the performance in terms of anti–disturbance, and achieves maximum hydropower tracking. Finally, we consider two types of tidal current, namely the mixed semidiurnal tidal current and the northwest European shelf tidal current. The simulation results demonstrate that the proposed control strategy can significantly improve the voltage–support capacity, while ensuring the stable operation of the PMSG in hydrokinetic turbine systems, especially under uneven tidal current speed conditions.
Use of Tanδ and Partial Discharge for Evaluating the Cable Termination Assembly
Authors: Uydur Cihat Cagdas , Arikan Oktay
Published: October 2020

It is known that the failure of cable terminations causes power outages and impairs system quality and continuity. Besides, serious economic losses on both the distribution and consumer sides occur. In this study, the dielectric behavior of the cable and the faults caused by the defects in the cable termination under overvoltage has been examined. As test samples, 12 kV XLPE insulated cable is used and they were aged at three (3*U0) and five (5*U0) times the rated voltage. After each aging cycle, dielectric parameters of the cable were measured by an OMIRCRON CPC100/CPTD1 device, and the partial discharge (PD) was measured by an OMICRON MPD600 device. In the measurements, it was observed that the cable was broken down at different aging cycle numbers as a result of defects in the cable termination due to weak workmanship. As a result of the measurements, it is concluded that defects in the cable termination give information about the increase in the probability of failure and the decrease of the cable lifetime. Consequently, it is concluded that fine workmanship and timely maintenance of cable terminations prevent the system from unwanted power outages and economic losses.
The Paradoxical Malthusian. A Promethean Perspective on Vaclav Smil’s Growth: From Microorganisms to Megacities (MIT Press, 2019) and Energy and Civilization: A History (MIT Press, 2017)
Authors: Desrochers Pierre
Published: October 2020

Prolific energy writer Vaclav Smil’s “Growth: From Microorganisms to Megacities” (MIT Press, Cambridge, MA, USA, 2019) is marketed as the most comprehensive study of the modalities of growth in Earth’s life systems in their many natural, social, and technological forms. While the book reflects Smil’s strength as a polymath, it also brings into focus his Malthusian outlook. Smil’s Malthusianism is puzzling in light of much empirical evidence to the contrary and of his own detailed histories of human technological achievements, including his recent massive synthesis “Energy and Civilization: A History” (MIT Press, Cambridge, MA, USA, 2017). In keeping with Smil’s historical emphasis, in this review essay, the Malthusian assumptions, assertions, and conclusions of these books are challenged through the Promethean insights of numerous writers whose output long predates the modern environmental movement and can thus avoid charges of “greenwashing”. I make a case that, in the context of market economies (i.e., competition, price system, and private property rights), humans’ unique propensity to trade physical goods and to (re)combine things in new ways have long delivered both improved standards of living and environmental remediation. I further suggest that it is not the volume of materials handled, but rather how they are handled that determines the impact of economic growth on the biosphere. While Professor Smil is fond of saying that “numbers don’t lie”, his work illustrates that they are sometimes made to tell an unduly pessimistic story through the intellectual filters created by an author’s assumptions and value judgements.
Maximization of Distribution Network Hosting Capacity through Optimal Grid Reconfiguration and Distributed Generation Capacity Allocation/Control
Authors: Čađenović Rade , Jakus Damir
Published: October 2020

High penetration of small-scale distributed energy sources into the distribution network increase negative impacts related to power quality causing adverse conditions. This paper presents a mathematical model that maximizes distribution network hosting capacity through optimal distributed generation capacity allocation and control and grid reconfiguration. In addition to this, the model includes on-load tap changer control for stabilization of grid voltage conditions primarily in grid operating conditions related to voltage rise problems, which can limit grid hosting capacity. Moreover, the objective function allows the possibility of energy transfer between distribution and transmission grids. The proposed model considers alternative grid connection points for distributed generation and determines optimal connection points as well as install capacity while considering network operating limits. The model is cast as a multiperiod second-order cone linear program and involves aspects of active power management. The model is tested on a modified IEEE 33 bus test network.
Reverse Water–Gas Shift Chemical Looping Using a Core–Shell Structured Perovskite Oxygen Carrier
Authors: Lee Minbeom , Kim Yikyeom , Lim Hyun Suk , Jo Ayeong , Kang Dohyung , Lee Jae W.
Published: October 2020

Reverse water–gas shift chemical looping (RWGS-CL) offers a promising means of converting the greenhouse gas of CO2 to CO because of its relatively low operating temperatures and high CO selectivity without any side product. This paper introduces a core–shell structured oxygen carrier for RWGS-CL. The prepared oxygen carrier consists of a metal oxide core and perovskite shell, which was confirmed by inductively coupled plasma mass spectroscopy (ICP-MS), XPS, and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) measurements. The perovskite-structured shell of the prepared oxygen carrier facilitates the formation and consumption of oxygen defects in the metal oxide core during H2-CO2 redox looping cycles. As a result, amounts of CO produced per unit weight of the core–shell structured oxygen carriers were higher than that of a simple perovskite oxygen carrier. Of the metal oxide cores tested, CeO2, NiO, Co3O4, and Co3O4-NiO, La0.75Sr0.25FeO3-encapsulated Co3O4-NiO was found to be the most promising oxygen carrier for RWGS-CL, because it was most productive in terms of CO production and exhibited long-term stability.
PV Forecast for the Optimal Operation of the Medium Voltage Distribution Network: A Real-Life Implementation on a Large Scale Pilot
Authors: Dimovski Aleksandar , Moncecchi Matteo , Falabretti Davide , Merlo Marco
Published: October 2020

The goal of the paper is to develop an online forecasting procedure to be adopted within the H2020 InteGRIDy project, where the main objective is to use the photovoltaic (PV) forecast for optimizing the configuration of a distribution network (DN). Real-time measurements are obtained and saved for nine photovoltaic plants in a database, together with numerical weather predictions supplied from a commercial weather forecasting service. Adopting several error metrics as a performance index, as well as a historical data set for one of the plants on the DN, a preliminary analysis is performed investigating multiple statistical methods, with the objective of finding the most suitable one in terms of accuracy and computational effort. Hourly forecasts are performed each 6 h, for a horizon of 72 h. Having found the random forest method as the most suitable one, further hyper-parameter tuning of the algorithm was performed to improve performance. Optimal results with respect to normalized root mean square error (NRMSE) were found when training the algorithm using solar irradiation and a time vector, with a dataset consisting of 21 days. It was concluded that adding more features does not improve the accuracy when adopting relatively small training sets. Furthermore, the error was not significantly affected by the horizon of the forecast, where the 72-h horizon forecast showed an error increment of slightly above 2% when compared to the 6-h forecast. Thanks to the InteGRIDy project, the proposed algorithms were tested in a large scale real-life pilot, allowing the validation of the mathematical approach, but taking also into account both, problems related to faults in the telecommunication grids, as well as errors in the data exchange and storage procedures. Such an approach is capable of providing a proper quantification of the performances in a real-life scenario.
Hybrid Adaptive Control for PEMFC Gas Pressure
Authors: Chen Jing , Zhang Chenghui , Li Ke , Zhan Yuedong , Sun Bo
Published: October 2020

This paper addresses the issues of nonlinearity and coupling between anode pressure and cathode pressure in proton exchange membrane fuel cell (PEMFC) gas supply systems. A fuzzy adaptive PI decoupling control strategy with an improved advanced genetic algorithm (AGA) is proposed. This AGA s utilized to optimize the PI parameters offline, and the fuzzy adaptive algorithm s used to adjust the PI parameters dynamically online to achieve the approximate decoupling control of the PEMFC gas supply system. According to the proposed dynamic model, the PEMFC gas supply system with the fuzzy–AGA–PI decoupling control method was simulated for comparison. The simulation results demonstrate that the proposed control system can reduce the pressure difference more efficiently with the classical control method under different load changes.
System Identification and LQR Controller Design with Incomplete State Observation for Aircraft Trajectory Tracking
Authors: Lichota Piotr , Dul Franciszek , Karbowski Andrzej
Published: October 2020

This paper presents a controller design process for an aircraft tracking problem when not all states are available. In the study, a nonlinear-transport aircraft simulation model was used and identified through Maximum Likelihood Principle and Extended Kalman Filter. The obtained mathematical model was used to design a Linear–Quadratic Regulator (LQR) with optimal weighting matrices when not all states are measured. The nonlinear aircraft simulation model with LQR controller tracking abilities were analyzed for multiple experiments with various noise levels. It was shown that the designed controller is robust and allows for accurate trajectory tracking. It was found that, in ideal atmospheric conditions, the tracking errors are small, even for unmeasured variables. In wind presence, the tracking errors were proportional to the wind velocity and acceptable for small and moderate disturbances. When turbulence was present in the experiment, state variable oscillations occurred that were proportional to the turbulence intensity and acceptable for small and moderate disturbances.
Promoting and Inhibitory Effects of Hydrophilic/Hydrophobic Modified Aluminum Oxide Nanoparticles on Carbon Dioxide Hydrate Formation
Authors: Liu Yu , Liao Xiangrui , Shi Changrui , Ling Zheng , Jiang Lanlan
Published: October 2020

Hydrate-based CO2 capture from large emission sources is considered a promising process for greenhouse gas mitigation. The addition of nanoparticles may promote or inhibit the formation of hydrates. In this work, CO2 hydrate formation experiments were performed in a dual-cell high-pressure reactor. Non-modified, hydrophilic modified and hydrophobic modified aluminum oxide (Al2O3) nanoparticles at different concentrations were added to assess their promoting or inhibitory effects on CO2 hydrate formation. The equilibrium temperature and pressure, induction time, and total gas consumption during CO2 hydrate formation were measured. The results show that the presence of Al2O3 nanoparticles exerts little effect on the phase equilibrium of CO2 hydrates. Under the experimental conditions, the addition of all Al2O3 nanoparticles imposes an inhibitory effect on the final gas consumption except for the 0.01 wt% addition of hydrophilic modified Al2O3 nanoparticles. The induction time required for the nucleation of CO2 hydrates mainly ranges from 70 to 90 min in the presence of Al2O3 nanoparticles. Compared to the absence of nanoparticles, the addition of non-modified and hydrophilic modified Al2O3 nanoparticle reduces the induction time. However, the hydrophobic modified Al2O3 nanoparticles extend the induction time.
Remuneration of Distribution Grids for Enhanced Regenerative Electricity Deployment—An Analysis and Model for the Analysis of Grid Structures in Southern Germany Using Linear Programming
Authors: Rösch Tobias , Treffinger Peter , Koch Barbara
Published: October 2020

Ecological concerns on the climatic effects of the emissions from electricity production stipulate the remuneration of electricity grids to accept growing amounts of intermittent regenerative electricity feed-in from wind and solar power. Germany’s eager political target to double regenerative electricity production by 2030 puts pressure on grid operators to adapt and restructure their transmission and distribution grids. The ability of local distribution grids to operate autonomous of transmission grid supply is essential to stabilize electricity supply at the level of German federal states. Although congestion management and collaboration at the distribution system operator (DSO) level are promising approaches, relatively few studies address this issue. This study presents a methodology to assess the electric energy balance for the low-voltage grids in the German federal state of Baden-Württemberg, assuming the typical load curves and the interchange potential among local distribution grids by means of linear programming of the supply function and for typical seasonal electricity demands. The model can make a statement about the performance and development requirements for grid architecture for scenarios in 2035 and 2050 when regenerative energies will—according to present legislation—account for more than half of Germany’s electricity supply. The study details the amendment to Baden-Württemberg’s electricity grid required to fit the system to the requirements of regenerative electricity production. The suggested model for grid analysis can be used in further German regions and internationally to systematically remunerate electricity grids for the acceptance of larger amounts of regenerative electricity inflows. This empirical study closes the research gap of assessing the interchange potential among DSO and considers usual power loads and simultaneously usual electricity inflows.
Measuring Soil Metal Bioavailability in Roadside Soils of Different Ages
Authors: De Silva Shamali , Huynh Trang , Ball Andrew S. , Indrapala Demidu V. , Reichman Suzie M.
Published: October 2020

Finding a reliable method to predict soil metal bioavailability in aged soil continues to be one of the most important problems in contaminated soil chemistry. To investigate the bioavailability of metals aged in soils, we used roadside soils that had accumulated metals from vehicle emissions over a range of years. We collected topsoil (0–10 cm) samples representing new-, medium- and old-aged roadside soils and control site soil. These soils were studied to compare the ability of the diffusive gradients in thin films technique (DGT), soil water extraction, CaCl2 extraction, total metal concentrations and optimised linear models to predict metal bioavailability in wheat plants. The response time for the release of metals and the effect on metal bioavailability in field aged soils was also studied. The DGT, and extractable metals such as CaCl2 extractable and soil solution metals in soil, were not well correlated with metal concentrations in wheat shoots. In comparison, the strongest relationships with concentrations in wheat shoots were found for Ni and Zn total metal concentrations in soil (e.g., Ni r = 0.750, p = 0.005 and Zn r = 0.833, p = 0.001); the correlations were still low, suggesting that total metal concentrations were also not a robust measure of bioavailability. Optimised linear models incorporating soil physiochemical properties and metal extracts together with road age as measure of exposure time, demonstrated a very strong relationship for Mn R2 = 0.936; Ni R2 = 0.936 and Zn R2 = 0.931. While all the models developed were dependent on total soil metal concentrations, models developed for Mn and Zn clearly demonstrated the effect of road age on metal bioavailability. Therefore, the optimised linear models developed have the potential for robustly predicting bioavailable metal concentrations in field soils where the metals have aged in situ. The intrinsic rate of release of metals increased for Mn (R2 = 0.617, p = 0.002) and decreased for Cd (R2 = 0.456, p = 0.096), Cu (R2 = 0.560, p = 0.083) and Zn (R2 =0.578, p = 0.072). Nickel did not show any relationship between dissociation time (Tc) and road age. Roadside soil pH was likely to be the key parameter controlling metal aging in roadside soil.
Humidity Controlled Mechanical Properties of Electrospun Polyvinylidene Fluoride (PVDF) Fibers
Authors: Szewczyk Piotr , Ura Daniel , Stachewicz Urszula
Published: October 2020

Processing parameters in electrospinning allow us to control the properties of fibers on a molecular level and are able to tailor them for specific applications. In this study, we investigate how relative humidity (RH) affects the mechanical properties of electrospun polyvinylidene fluoride (PVDF). The mechanical properties of single fibers were carried out using a specialized tensile stage. The results from tensile tests were additionally correlated with high-resolution imaging showing the behavior of individual fibers under tensile stress. The mechanical characteristic is strongly dependent on the crystallinity, chain orientation, and fiber diameter of electrospun PVDF fibers. Our results show the importance of controlling RH during electrospinning as the mechanical properties are significantly affected. At low RH = 30% PVDF fibers are 400% stiffer than their counterparts prepared at high RH = 60%. Moreover, the vast differences in the strain at failure were observed, namely 310% compared to 75% for 60% and 30% RH, respectively. Our results prove that humidity is a crucial parameter in electrospinning able to control the mechanical properties of polymer fibers.
Application of Plant Extracts to Control Postharvest Gray Mold and Susceptibility of Apple Fruits to B. cinerea from Different Plant Hosts
Authors: Šernaitė Lina , Rasiukevičiūtė Neringa , Valiuškaitė Alma
Published: October 2020

Sustainable plant protection can be applied on apples against fungal pathogens such as Botrytis cinerea (which is responsible for gray mold)—a significant global postharvest disease. This pathogen can affect a wide range of hosts; and fruits may have variable susceptibilities to B. cinerea from different plant hosts. New possibilities to control gray mold in food production are under demand due to the emergence of resistance against antifungal agents in fungal pathogens. Cinnamon, pimento, and laurel extracts were previously assessed for antifungal activities under in vitro conditions and were found to have the potential to be effective against postharvest gray mold. Therefore, this study aimed to investigate the antifungal activity of cinnamon, pimento, and laurel extracts in vitro and against postharvest gray mold on apples to determine the susceptibility of apple fruits to B. cinerea from different plant hosts, and to analyze the chemical composition of the extracts. Apples (cv. “Connell Red”) were treated with different concentrations of extracts and inoculated with B. cinerea isolates from apple and strawberry followed by evaluation of in vitro antifungal activity. The results reveal that most of the concentrations of the extracts that were investigated were not efficient enough when assessed in the postharvest assay, despite having demonstrated a high in vitro antifungal effect. Apples were less susceptible to B. cinerea isolated from strawberry. To conclude, cinnamon extract was found to be the most effective against apple gray mold; however, higher concentrations of the extracts are required for the efficient inhibition of B. cinerea in fruits during storage.
Effect of Different Cooking Methods on Folate Content in Chicken Liver
Authors: Czarnowska-Kujawska Marta , Draszanowska Anna , Gujska Elżbieta
Published: October 2020

Common liver sources in European countries include cow, chicken, duck, lamb and pig. Despite its decreasing popularity, liver is possibly one of the most nutrient-dense foods, being rich in high-quality protein and low in calories. In animals, the liver is the storage organ for folate. In this study, the effect of different cooking methods on folate vitamers content in chicken liver was investigated. Three folate derivatives, 5-CH3-H4PteGlu, H4PteGlu and 5-HCO-H4PteGlu, were identified in the analyzed samples using high performance liquid chromatography (HPLC). The folate content in liver after sous-vide (60 °C/75 min) and steaming (100 °C/30 min) did not differ significantly (p ≤ 0.05) from raw liver folate content (781 µg/100 g). Even liver cooked in a combi oven or grilled (which resulted in significant folate losses) showed much higher folate content, 455–631 µg/100 g and 612–715 µg/100 g, respectively, than the most folate-abundant plant foods. These findings are important as they demonstrate that processed liver has the potential to improve the supply of folate and meet the recommended daily requirements, particularly when folate deficiency is common worldwide.
Biodegradable Antimicrobial Food Packaging: Trends and Perspectives
Authors: Motelica Ludmila , Ficai Denisa , Ficai Anton , Oprea Ovidiu Cristian , Kaya Durmuş Alpaslan , Andronescu Ecaterina
Published: October 2020

This review presents a perspective on the research trends and solutions from recent years in the domain of antimicrobial packaging materials. The antibacterial, antifungal, and antioxidant activities can be induced by the main polymer used for packaging or by addition of various components from natural agents (bacteriocins, essential oils, natural extracts, etc.) to synthetic agents, both organic and inorganic (Ag, ZnO, TiO2 nanoparticles, synthetic antibiotics etc.). The general trend for the packaging evolution is from the inert and polluting plastic waste to the antimicrobial active, biodegradable or edible, biopolymer film packaging. Like in many domains this transition is an evolution rather than a revolution, and changes are coming in small steps. Changing the public perception and industry focus on the antimicrobial packaging solutions will enhance the shelf life and provide healthier food, thus diminishing the waste of agricultural resources, but will also reduce the plastic pollution generated by humankind as most new polymers used for packaging are from renewable sources and are biodegradable. Polysaccharides (like chitosan, cellulose and derivatives, starch etc.), lipids and proteins (from vegetal or animal origin), and some other specific biopolymers (like polylactic acid or polyvinyl alcohol) have been used as single component or in blends to obtain antimicrobial packaging materials. Where the package’s antimicrobial and antioxidant activities need a larger spectrum or a boost, certain active substances are embedded, encapsulated, coated, grafted into or onto the polymeric film. This review tries to cover the latest updates on the antimicrobial packaging, edible or not, using as support traditional and new polymers, with emphasis on natural compounds.
Insight into the Effects of Sous Vide on Cathepsin B and L Activities, Protein Degradation and the Ultrastructure of Beef
Authors: Yin Yantao , Pereira Jailson , Zhou Lei , Lorenzo Jose M. , Tian Xiaona , Zhang Wangang
Published: October 2020

This study aimed to evaluate the effects of sous vide cooking (SV) on beef tenderness and its underlying potential mechanism. Beef semimembranosus (SM) were subjected to SV treatments at 45 °C, 55 °C and 65 °C for 4 h. Compared with control samples (CK, cooked at 75 °C until a core temperature of 72 °C was attained), SV treatment significantly promoted the release of cathepsin B and cathepsin L from lysosomes and decreased the shear force of beef SM (p < 0.05). In comparison with CK, samples treated with SV had more hydrolysis of myosin heavy chain and obtained higher myofibrillar fragmentation index, collagen solubility as well as longer sarcomere length (p < 0.05). The current study showed that the proteolysis of myofibrillar protein and collagen induced by cathepsin B and cathepsin L, and the limited longitudinal shrinkage together contributed to the improvement of beef tenderness upon SV.