bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Carbon Content on Methanol Oxidation and Photo-Oxidation at Pt-TiO2-C Electrodes
Authors: Papaderakis Athanasios , Spyridou Olga , Karanasios Nikolaos , Touni Aikaterini , Banti Angeliki , Dimitrova Nina , Armyanov Stephan , Valova Eugenia , Georgieva Jenia , Sotiropoulos Sotiris
Published: February 2020

The oxidation of methanol is studied at TiO2-supported Pt electrodes of varied high surface area carbon content (in the 30-5% w/w range) and C÷Ti atom ratio (in the 3.0-0.4 ratio). The Pt-TiO2 catalyst is prepared by a photo-deposition process and C nanoparticles (Vulcan XC72R) are added by simple ultrasonic mixing. The optimum C÷Ti atom ratio of the prepared catalyst for methanol electro-oxidation is found to be 1.5, resulting from the interplay of C properties (increased electronic conductivity and methanol adsorption), those of TiO2 (synergistic effect on Pt and photo-activity), as well as the catalyst film thickness. The intrinsic catalytic activity of the best Pt-TiO2/C catalyst is better than that of a commercial Pt/C catalyst and could be further improved by nearly 25% upon UV illumination, whose periodic application can also limit current deterioration.
Development of (γ-Al2O3-Zeolite Y)/α-Al2O3-HPCM Catalyst based on Highly Porous α-Al2O3-HPCM Support for Decreasing Oil Viscosity
Authors: Kirgizov Alexey , Valieva Gulnaz , Laskin Artem , Il’yasov Il’dar , Lamberov Alexander
Published: February 2020

Highly porous cellular material (α-Al2O3-HPCM) support was synthesized by the template method. Highly porous support was used for the synthesis of the catalyst. A thin secondary layer with 25–30 μ thick γ-Al2O3 and zeolite Y was applied on the α-Al2O3-HPCM surface ((γ-Al2O3 (85%)-zeolite Y (15%))/α-Al2O3-HPCM). The catalyst based on the highly porous support was tested in a process of decreasing oil viscosity. The catalyst in the form of cylindrical granules and a thermal process of decreasing oil viscosity without the catalyst were used as the basis for comparison. α-Al2O3-HPCM in the catalyst provides low-quantity pores (d < 10 nm) and a quantity of general acid centers compared with the granular catalyst. On the other hand, it shows a more significant oil viscosity decrease (from 2500 to 41 cPs) and a low rate of gas generation (137 mL/h) for the catalyst with highly porous support. A high oil fraction was observed in the presence of the (γ-Al2O3-zeolite Y)/α-Al2O3-HPCM compared to the granular catalyst. The presence of large transport cells (pores) 1500–2000 μ for the catalyst based on highly porous support allowed a work period four times longer than that of experiment only with temperature without catalysts.
Enhanced Visible Light Photocatalytic Activity of N and Ag Doped and Co-Doped TiO2 Synthesized by Using an In-Situ Solvothermal Method for Gas Phase Ammonia Removal
Authors: Sirivallop Adilah , Areerob Thanita , Chiarakorn Siriluk
Published: February 2020

Single doping and co-doping of N and Ag on TiO2 were successfully prepared by using an in-situ solvothermal method and their structural properties and chemical compositions were characterized. The results indicated that all photocatalysts displayed in TiO2 anatase crystal phase, and a small mesoporous structure was observed in the doped materials. The main roles of N and Ag on the property and photocatalytic activity of TiO2 were different. The N doping has significantly enhanced homogenous surface morphology and specific surface area of the photocatalyst. While Ag doping was narrowing the band gap energy, extending light absorption toward a visible region by surface plasmon resonance as well as delaying the recombination rate of electron and hole of TiO2. The existence of N in TiO2 lattice was observed in two structural linkages such as substitutional nitrogen (Ti-O-N) and interstitial nitrogen (O-Ti-N). Silver species could be in the form of Ag0 and Ag2O. The photocatalytic performance of the photocatalysts coated on stainless steel mesh was investigated by the degradation of aqueous MB and gas phase NH3 under visible LED light illumination for three recycling runs. The highest photocatalytic activity and recyclability were reached in 5% N/Ag-TiO2 showing the efficiency of 98.82% for methylene blue (MB) dye degradation and 37.5% for NH3 removal in 6 h, which was 2.7 and 4.3 times, respectively. This is greater than that of pure TiO2. This was due to the synergistic effect of N and Ag doping.
SnO2-Containing Clinoptilolite as a Composite Photocatalyst for Dyes Removal from Wastewater under Solar Light
Authors: Šuligoj Andraž , Pavlović Jelena , Arčon Iztok , Rajić Nevenka , Novak Tušar Nataša
Published: February 2020

Due to their adsorbent, ion exchange and catalytic properties zeolites are suitable for a variety of applications. We report on the photocatalytic activity of a readily available and inexpensive natural zeolite clinoptilolite (Z) containing SnO2 (Sn-Z). The Sn-Z samples with 3–15 wt. % of Sn were prepared by using a precipitation–deposition method. Powder X-ray diffraction analysis showed that the zeolite structure was unaffected by the introduction of the Sn-phase. Diffuse reflectance UV/VIS spectra of the Sn-Z samples confirmed the presence of SnO2 and X-Ray absorption spectroscopy analyses suggested that the SnO2 particles mainly resided on the surface of the clinoptilolite, while ATR-FTIR analysis gave some clues that part of the SnO2 phase was incorporated in the pores of the zeolite. The presence of SnO2 in Sn-Z increased both adsorption capacity and photocatalytic performance which could be partially explained by higher surface area and partially with an increased negative potential of the surface. Adsorption and total degradation of methylene blue (MB) for the Sn-Z with the highest amount of Sn (15 wt.%) was about 30% and 45%, respectively, suggesting a synergetic effect between SnO2 and the clinoptilolite lattice. Reusability tests showed that these catalysts present a promising material for water purification.
Characterization of the Novel Ene Reductase Ppo-Er1 from Paenibacillus Polymyxa
Authors: Aregger David , Peters Christin , Buller Rebecca M.
Published: February 2020

Ene reductases enable the asymmetric hydrogenation of activated alkenes allowing the manufacture of valuable chiral products. The enzymes complement existing metal- and organocatalytic approaches for the stereoselective reduction of activated C=C double bonds, and efforts to expand the biocatalytic toolbox with additional ene reductases are of high academic and industrial interest. Here, we present the characterization of a novel ene reductase from Paenibacillus polymyxa, named Ppo-Er1, belonging to the recently identified subgroup III of the old yellow enzyme family. The determination of substrate scope, solvent stability, temperature, and pH range of Ppo-Er1 is one of the first examples of a detailed biophysical characterization of a subgroup III enzyme. Notably, Ppo-Er1 possesses a wide temperature optimum (Topt: 20–45 °C) and retains high conversion rates of at least 70% even at 10 °C reaction temperature making it an interesting biocatalyst for the conversion of temperature-labile substrates. When assaying a set of different organic solvents to determine Ppo-Er1′s solvent tolerance, the ene reductase exhibited good performance in up to 40% cyclohexane as well as 20 vol% DMSO and ethanol. In summary, Ppo-Er1 exhibited activity for thirteen out of the nineteen investigated compounds, for ten of which Michaelis–Menten kinetics could be determined. The enzyme exhibited the highest specificity constant for maleimide with a kcat/KM value of 287 mM−1 s−1. In addition, Ppo-Er1 proved to be highly enantioselective for selected substrates with measured enantiomeric excess values of 92% or higher for 2-methyl-2-cyclohexenone, citral, and carvone.
Impact of Degree of Hydrophilicity of Pyridinium Bromide Derivatives on HCl Pickling of X-60 Mild Steel: Experimental and Theoretical Evaluations
Authors: Odewunmi Nurudeen A. , Jafar Mazumder Mohammad A. , Ali Shaikh A. , Aljeaban Norah A. , Alharbi Bader G. , Al-Saadi Abdulaziz A. , Obot Ime B.
Published: February 2020

Dodecyl pyridinium bromide (DDPB), tetradecyl pyridinium bromide (TDPB) and dodecyl 1,1′-bispyridinium dibromide (DDBPB) were successfully synthesized, characterized and evaluated for HCl pickling of X-60 low carbon steel. Order of corrosion inhibitions efficiencies, as revealed by both electrochemical and gravimetric studies, is TDPB > DDPB > DDBPB. The degree of hydrophilicity of inhibitors as predicted by a partition coefficient (Log P) and supported by a contact angle measurement was found to be responsible for their order of corrosion inhibition efficiencies. Adsorption of DDPB, TDPB, and DDBPB through the pyridinium nitrogen on mild steel surface was confirmed by ATR-FTIR and SEM-EDX analyses. The pyridinium nitrogen was found not to be the only factor responsible for their efficiency, but hydrophobes and the orientation of the hydrophilic ring were responsible, which incline to the deviation of experimental results and the order of Monte Carlo simulation adsorption energies. DDPB, TDPB, and DDBPB obey the Langmuir isotherm model despite major contributions of the film formed on the surface of X-60 mild steel on their overall inhibition corrosion resistance.
MHD Effects on Ciliary-Induced Peristaltic Flow Coatings with Rheological Hybrid Nanofluid
Authors: Awais M. , Shah Zahir , Perveen N. , Ali Aamir , Kumam Poom , Rehman Habib ur , Thounthong Phatiphat
Published: February 2020

Present theoretical investigation is a mathematical illustration of an application to endoscopy by incorporating hybrid nanoparticles and an induced magnetic field with a rheological fluid model for more realistic results. Rheological fluid behavior is characterized by the Ostwald-de-Waele power-law model. A hybrid nanofluid mechanism is considered comprising platelet-shaped nanoparticles since nanoparticles are potential drug transportation tools in biomedical applications. Moreover, ciliary activity is encountered regarding their extensive applications in performing complex functions along with buoyancy effects. An endoscope is inserted inside a ciliated tube and peristalsis occurred due to ciliary activity in the gap between tube and endoscope. A non-Newtonian model is developed by mathematical formulation which is tackled analytically using homotopy analysis. The outcomes are interpreted graphically along with the pressure rise and streamlining configuration for the case of negligible inertial forces and long wavelength. A three-dimensional graphical interpretation of axial velocity is studied as well. Moreover, tables are prepared and displayed for a more physical insight.
Deep Learning for the Inverse Design of Mid-Infrared Graphene Plasmons
Authors: Phan Anh D. , Nguyen Cuong V. , Linh Pham T. , Huynh Tran V. , Lam Vu D. , Le Anh-Tuan , Wakabayashi Katsunori
Published: February 2020

We theoretically investigate the plasmonic properties of mid-infrared graphene-based metamaterials and apply deep learning of a neural network for the inverse design. These artificial structures have square periodic arrays of graphene plasmonic resonators deposited on dielectric thin films. Optical spectra vary significantly with changes in structural parameters. To validate our theoretical approach, we carry out finite difference time domain simulations and compare computational results with theoretical calculations. Quantitatively good agreements among theoretical predictions, simulations, and previous experiments allow us to employ this proposed theoretical model to generate reliable data for training and testing deep neural networks. By merging the pre-trained neural network with the inverse network, we implement calculations for inverse design of the graphene-based metameterials. We also discuss the limitation of the data-driven approach.
A Thermal and Nanomechanical Study of Molecular Crystals as Versatile Mocks for Pentaerythritol Tetranitrate
Authors: Burch Alexandra C. , Wilde Zakary R. , Bahr David F. , Yeager John D.
Published: February 2020

Pentaerythritol tetranitrate (PETN) is a commonly used high explosive (HE) in detonators. Often, surrogate or “mock” materials are used in place of HE for mechanical tests, proofing out equipment, or developing new diagnostics. However, there is no commonly accepted mock for PETN. A good mock should match at least one physical property of the target material, and ideally mimic multiple thermal and mechanical properties. Here, we investigate several molecular crystals to evaluate their efficacy in mocking PETN density, melting point, elastic modulus, hardness, plastic deformation, and fracture behavior. Materials were tested with a combination of calorimetry and nanoindentation. Two materials, 2,4,6-trifluorobenzoic acid (246 TFBA) and mesoerythritol, were downselected for detailed indentation study after the initial round of screening experiments, both were found to mimic PETN mechanical behavior quite well, 246 TFBA closer to PETN in most properties (hardness, modulus, and density) than erythritol, but erythritol having advantages in relative cost and matching the onset of yield. Depending on the desired implementation of the mock, one material may be preferred over the other, but both have potential as generic mocks for PETN. Nanoindentation is demonstrated as a versatile tool to provide rapid screening of these materials’ mechanical properties.
The Role of Climate and Topography in Shaping the Diversity of Plant Communities in Cabo Verde Islands
Authors: Neto Carlos , Costa José Carlos , Figueiredo Albano , Capelo Jorge , Gomes Isildo , Vitória Sónia , Semedo José Maria , Lopes António , Dinis Herculano , Correia Ezequiel , Duarte Maria Cristina , Romeiras Maria M.
Published: February 2020

The flora and vegetation of the archipelago of Cabo Verde is dominated by Macaronesian, Mediterranean, and particularly by African tropical elements, resulting from its southernmost location, when compared to the other islands of the Macaronesia (i.e., Azores, Madeira, Selvagens, and Canary Islands). Very likely, such a geographical position entailed higher susceptibility to extreme climatic fluctuations, namely those associated with the West African Monsoon oscillations. These fluctuations led to a continuous aridification, which is a clear trend shown by most recent studies based on continental shelf cores. Promoting important environmental shifts, such climatic fluctuations are accepted as determinant to explain the current spatial distribution patterns of taxa, as well as the composition of the plant communities. In this paper, we present a comprehensive characterization of the main plant communities in Cabo Verde, and we discuss the role of the climatic and topoclimatic diversity in shaping the vegetation composition and distribution of this archipelago. Our study reveals a strong variation in the diversity of plant communities across elevation gradients and distinct patterns of richness among plant communities. Moreover, we present an overview of the biogeographical relationships of the Cabo Verde flora and vegetation with the other Macaronesian Islands and northwestern Africa. We discuss how the distribution of plant communities and genetic patterns found among most of the endemic lineages can be related to Africa’s ongoing aridification, exploring the impacts of a process that marks northern Africa from the Late Miocene until the present.
Relative Efficiency of Pitfall Trapping vs. Nocturnal Hand Collecting in Assessing Soil-Dwelling Spider Diversity along A Structural Gradient of Neotropical Habitats
Authors: Privet Kaïna , Vedel Vincent , Fortunel Claire , Orivel Jérôme , Martinez Quentin , Cerdan Axel , Baraloto Christopher , Pétillon Julien
Published: February 2020

Assessing spider diversity remains a great challenge, especially in tropical habitats where dozens of species can locally co-occur. Pitfall trapping is one of the most widely used techniques to collect spiders, but it suffers from several biases, and its accuracy likely varies with habitat complexity. In this study, we compared the efficiency of passive pitfall trapping versus active nocturnal hand collecting (NHC) to capture low understory-dwelling spider taxonomical (morpho-species) and functional (hunting guilds) diversity along a structural gradient of habitats in French Guiana. We focused on four habitats describing a structural gradient: garden to the orchard to the forest edge to the undisturbed forest. Overall, estimated morpho-species richness and composition did not vary consistently between habitats, but abundances of ground-hunting spiders decreased significantly with increasing habitat complexity. We found habitat-dependence differences in taxonomic diversity between sampling strategies: NHC revealed higher diversity in the orchard, whereas pitfalls resulted in higher diversity in the forest. Species turnover resulted in high dissimilarity in species composition between habitats using either method. This study shows how pitfall trapping is influenced by habitat structure, rendering this sampling method incomplete for complex, tropical environments. However, pitfall traps remain a valuable component of inventories because they sample distinct assemblage of spiders.
Effects of Invasive Watermilfoil on Primary Production in Littoral Zones of North-Temperate Lakes
Authors: Van Goethem Ryan R. , Huckins Casey J , Marcarelli Amy M.
Published: February 2020

Species invasions are changing aquatic ecosystems worldwide. Submerged aquatic macrophytes control lake ecosystem processes through their direct and indirect interactions with other primary producers, but how these interactions may be altered by macrophyte species invasions in temperate lakes is poorly understood. We addressed whether invasive watermilfoil (IWM) altered standing crops and gross primary production (GPP) of other littoral primary producers (macrophytes, phytoplankton, attached algae, and periphyton) in littoral zones of six Michigan lakes through a paired-plot comparison study of sites with IWM (standardized abundance 7–56%) compared to those with little or no IWM (standardized abundance 0–2%). We found that primary producer standing crops and the GPP of epiphytes, phytoplankton, and benthic periphyton were variable among lakes and not significantly different between paired study plots. Macrophyte standing crops predicted rates of benthic periphyton GPP, and standing crops of all other primary producers across all study plots. Overall, our results suggest that the effects of IWM on other primary producers in littoral zones may be lake-specific, and are likely dependent on the density of IWM, or whether it is functionally similar to other native species that it replaces or co-exists with. Moreover, in lakes where IWM is established but does not dominate macrophyte assemblages, the effects on littoral zone productivity may be minimal. Instead, overall macrophyte biomass is the primary factor controlling the rates of production and biomass of the other littoral zone primary producers, as has long been understood and observed in lake ecosystems.
Pediatric Thyroid Cancer in Europe: An Overdiagnosed Condition? A Literature Review
Authors: Stefan Andreea-Ioana , Piciu Andra , Mester Alexandru , Apostu Dragos , Badan Marius , Badulescu Claudiu-Iulian
Published: February 2020

Thyroid neoplastic pathology is the most common form of cancer associated with radiation exposure. The most common histopathological type of thyroid carcinoma is the differentiated thyroid cancer (these include papillary and follicular type), which represents over 90% of all cases, especially affecting girls rather than boys. Although patients are diagnosed in advanced stages as compared to adults, the prognosis of the disease is very good, with a 30-year survival rate of over 95% but post-therapeutic morbidity remains quite high. The treatment is based in particular on the therapeutic guidelines for adults, but as children have some histopathological and genetic characteristics of thyroid cancer, as well as different initial clinical presentations, we decided to review the literature on this pathology among the pediatric population, focusing on cases in Europe. The major interest is the impact of the Chernobyl accident.
Urinary MicroRNA-21-5p as Potential Biomarker of Interstitial Fibrosis and Tubular Atrophy (IFTA) in Kidney Transplant Recipients
Authors: Gniewkiewicz Michal S. , Paszkowska Izabela , Gozdowska Jolanta , Czerwinska Katarzyna , Sadowska-Jakubowicz Anna , Deborska-Materkowska Dominika , Perkowska-Ptasinska Agnieszka , Kosieradzki Maciej , Durlik Magdalena
Published: February 2020

Chronic renal allograft dysfunction (CAD) is a major limiting factor of long-term graft survival. The hallmarks of progressive CAD are interstitial fibrosis and tubular atrophy (IFTA). MicroRNAs are small, regulatory RNAs involved in many immunological processes. In particular, microRNA-21-5p (miR-21) is considered to be strongly associated with pathogenesis regarding tubulointerstitium. The aim of this study was to assess urinary miR-21 expression levels in the kidney transplant recipients and determine their application in the evaluation of IFTA and kidney allograft function. The expression levels of miR-21 were quantified in the urine of 31 kidney transplant recipients with biopsy-assessed IFTA (IFTA 0 + I: n = 17; IFTA II + III: n = 14) by real-time quantitative PCR. Urine samples were collected at the time of protocolar biopsies performed 1 or 2 years after kidney transplantation. MicroRNA-191-5p was used as reference gene. MiR-21 was significantly up-regulated in IFTA II + III group compared to IFTA 0 + I group (p = 0.003). MiR-21 correlated significantly with serum concentration of creatinine (r = 0.52, p = 0.003) and eGFR (r = −0.45; p = 0.01). ROC analysis determined the diagnostic value of miR-21 with an area under curve (AUC) of 0.80 (p = 0.0002), sensitivity of 0.86 and specificity of 0.71. miR-21 is associated with renal allograft dysfunction and IFTA. Therefore, it could be considered as a potential diagnostic, non-invasive biomarker for monitoring renal graft function.
“My Teacher Doesn’t Like Me”: Perceptions of Teacher Discrimination and School Discipline among African-American and Caribbean Black Adolescent Girls
Authors: Butler-Barnes Sheretta T. , Inniss-Thompson Misha N.
Published: February 2020

This study examined the impact of perceived teacher discrimination on the school discipline of African-American and Caribbean Black adolescent girls. The findings are drawn from a nationally representative sample of (n = 410) African-American and (n = 193) Caribbean Black adolescent girls age 13 to 17 (Mage = 15). Results indicate that perceiving discrimination from teachers was associated with higher school discipline (e.g., suspension, expulsion, and spending time in a jail, detention center) for African-American girls. For Caribbean Black girls, higher household income and school bonding was associated with lower school discipline. Older Caribbean Black girls were also more likely to receive higher school discipline. However, perceiving discrimination from teachers was not associated with school discipline for Caribbean Black girls. The developmental significance and implications for future research are discussed.
BPR-TCAM—Block and Partial Reconfiguration based TCAM on Xilinx FPGAs
Authors: Ullah Anees , Zahir Ali , Khan Noaman A. , Ahmad Waleed , Ramos Alexis , Reviriego Pedro
Published: February 2020

Field Programmable Gate Arrays (FPGAs) based Ternary Content Addressable Memories (TCAMs) are widely used in high-speed networking applications.However, TCAMs are not present on state-of-the-art FPGAs and need to be emulated on SRAM-based memories (i.e., LUTRAMs and Block RAMs) which requires a large amount of FPGA resources. In this paper, we present an efficient methodology to implement FPGA-based TCAMs with significant resource savings compared to existing schemes. The proposed methodology exploits the fracturable nature of Look Up Tables (LUTs) and the built-in slice carry-chains for simultaneous mapping of two rules and its matching logic to a single FPGA slice. Multiple slices can be stacked together to build deeper and wider TCAMs in a modular way. The combination of all these techniques results in significant savings in resource utilization compared to existing approaches.
Non-Cooperative Indirect Energy Trading with Energy Storage Systems for Mitigation of Demand Response Participation Uncertainty
Authors: Ryu Jeseok , Kim Jinho
Published: February 2020

This work focuses on the demand response (DR) participation using the energy storage system (ESS). A probabilistic Gaussian mixture model based on market operating results Monte, Carlo Simulation (MCS), is required to respond to an urgent DR signal. However, there is considerable uncertainty in DR forecasting, which occasionally fails to predict DR events. Because this failure is attributable to the intermittency of the DR signals, a non-cooperative game model that is useful for decision-making on DR participation is proposed. The game is conducted with each player holding a surplus of energy but incomplete information. Consequently, each player can share unused electricity during DR events, engaging in indirect energy trading (IET) under a non-cooperative game framework. The results of the game, the Nash equilibrium (N.E.), are verified using a case study with relevant analytical data from the campus of Gwangju Institute of Science and Technology (GIST) in Korea. The results of the case study show that IET is useful in mitigating the uncertainty of the DR program.
Energy Saving Potential of Industrial Solar Collectors in Southern Regions of Russia: The Case of Krasnodar Region
Authors: Ratner Svetlana , Gomonov Konstantin , Revinova Svetlana , Lazanyuk Inna
Published: February 2020

Industrial low-temperature processes are a promising sector for the introduction of solar collectors, which can partially, and in some cases, completely, replace traditional heat supply technologies. In Krasnodar Region (Russia), it is shown that the energy-saving potential when introducing industrial solar collectors only at food industry enterprises can make up 16%–17% of the total amount of thermal energy produced in the region annually. The global market of industrial solar collectors is currently developing almost without any government incentives, only due to market mechanisms, which indicates the commercial attractiveness of the technology. According to the predicted estimates, levelized cost of energy produced by industrial solar collectors in the southern regions of Russia may amount to 3.8–6.6 rubles per kWh. Even though the forecast estimates are higher than current tariffs, the economic feasibility of using solar collectors in the industry increases significantly if it is not possible to connect to centralized heating networks, as well as in the case of the seasonal load of industrial facilities. As a measure of state incentives for the development of industrial solar collectors in Russia, we offer state co-financing of demonstration projects of Russian manufacturers. This will increase the level of awareness of the population and businesses about the capabilities of this technology. Also, it will increase the technical competencies and innovative potential of companies involved in the production and installation of solar collectors.
Solving the Cold-Start Problem in Short-Term Load Forecasting Using Tree-Based Methods
Authors: Moon Jihoon , Kim Junhong , Kang Pilsung , Hwang Eenjun
Published: February 2020

An energy-management system requires accurate prediction of the electric load for optimal energy management. However, if the amount of electric load data is insufficient, it is challenging to perform an accurate prediction. To address this issue, we propose a novel electric load forecasting scheme using the electric load data of diverse buildings. We first divide the electric energy consumption data into training and test sets. Then, we construct multivariate random forest (MRF)-based forecasting models according to each building except the target building in the training set and a random forest (RF)-based forecasting model using the limited electric load data of the target building in the test set. In the test set, we compare the electric load of the target building with that of other buildings to select the MRF model that is the most similar to the target building. Then, we predict the electric load of the target building using its input variables via the selected MRF model. We combine the MRF and RF models by considering the different electric load patterns on weekdays and holidays. Experimental results demonstrate that combining the two models can achieve satisfactory prediction performance even if the electric data of only one day are available for the target building.
Characterization of Fast Pyrolysis Bio-Oil from Hardwood and Softwood Lignin
Authors: Echresh Zadeh Zahra , Abdulkhani Ali , Saha Basudeb
Published: February 2020

The depletion of fossil fuel reserves and the increase of greenhouse gases (GHG) emission have led to moving towards alternative, renewable, and sustainable energy sources. Lignin is one of the significant, renewable and sustainable energy sources of biomass and pyrolysis is one of the most promising technologies that can convert lignocellulosic biomass to bio-oil. This study focuses on the production and characterization of bio-oil from hardwood and softwood lignin via pyrolysis process using a bench-scale batch reactor. In this study, a mixed solvent extraction method with different polarities was developed to fractionate different components of bio-crude oil into three fractions. The obtained fractions were characterized by using gas chromatography and mass spectrometry (GCMS). The calculated bio-oil yields from Sigma Kraft lignin and Chouka Kraft lignin were about 30.2% and 24.4%, respectively. The organic solvents, e.g., toluene, methanol, and water were evaluated for chemical extraction from bio-oil, and it was found that the efficiency of solvents is as follows: water > methanol > toluene. In both types of the bio-oil samples, phenolic compounds were found to be the most abundant chemical groups which include phenol, 2-methoxy, 2-methoxy-6-methylphenol and phenol, 4-ethyl-2-methoxy that is due to the structure and the originality of lignin, which is composed of phenyl propane units with one or two methoxy groups (O-CH3) on the aromatic ring.
Development of a Reduced Order Model for Fuel Burnup Analysis
Authors: Castagna Christian , Aufiero Manuele , Lorenzi Stefano , Lomonaco Guglielmo , Cammi Antonio
Published: February 2020

Fuel burnup analysis requires a high computational cost for full core calculations, due to the amount of the information processed for the total reaction rates in many burnup regions. Indeed, they reach the order of millions or more by a subdivision into radial and axial regions in a pin-by-pin description. In addition, if multi-physics approaches are adopted to consider the effects of temperature and density fields on fuel consumption, the computational load grows further. In this way, the need to find a compromise between computational cost and solution accuracy is a crucial issue in burnup analysis. To overcome this problem, the present work aims to develop a methodological approach to implement a Reduced Order Model (ROM), based on Proper Orthogonal Decomposition (POD), in fuel burnup analysis. We verify the approach on 4 years of burnup of the TMI-1 unit cell benchmark, by reconstructing fuel materials and burnup matrices over time with different levels of approximation. The results show that the modeling approach is able to reproduce reactivity and nuclide densities over time, where the accuracy increases with the number of basis functions employed.
Combined Control of DFIG-Based Wind Turbine and Battery Energy Storage System for Frequency Response in Microgrids
Authors: Gomez Luis. A. G. , Grilo Ahda P. , Salles M. B. C. , Sguarezi Filho A. J.
Published: February 2020

This paper presents a novel methodology for frequency control of a microgrid through doubly fed induction generator (DFIG) employing battery energy storage system (BESS) and droop control. The proposed microgrid frequency control is the result of the active power injection from the droop control implemented in the grid side converter (GSC) of the DFIG, and the BESS implemented in the DC link of the back-to-back converter also in the DFIG. This methodology guarantees the battery system charge during operation of the connected DFIG in the network, and the frequency control in microgrid operation after an intentional disturbance. In order for the DFIG to provide frequency support to the microgrid, the best-performing droop gain value is selected. Afterwards its performance is evaluated individually and together with the power injected by the battery. The power used for both battery charging and frequency support is managed and processed by the GSC without affecting the normal operation of the wind system. The simulation tests are performed using Matlab/Simulink toolbox.
A Wind Electric-Driven Combined Heating, Cooling, and Electricity System for an Office Building in Two Italian Cities
Authors: Roselli Carlo , Sasso Maurizio , Tariello Francesco
Published: February 2020

Electric air-conditioning systems driven by electricity from a wind turbine can be defined as wind electric and cooling systems according to the definition of solar-activated air-conditioners. They can potentially contribute to reduce primary energy demand and CO2 emission in the civil sector. In this paper, mini wind turbines are considered coupled with a ground source heat pump in order to serve an office building for air-conditioning and supply the electricity surplus for the pure electric load of the user. Different plant configurations are considered. First of all, assessments with two kinds of wind turbines (5–5.5 kW), vertical and horizontal axis, are performed, also considering the coupling with one and two identical wind generators. Secondly, to better use on-site electricity, a parametric study is proposed taking into account different battery storage system sizes (3.2–9.6 kWh). Finally, the plant is simulated in two locations: Naples and Cagliari. Simulation results demonstrate that the source availability mainly affects the system performance. In Cagliari, the primary energy reduction per kWh of final energy demand (for pure electric load, space heating, and cooling) is equal to 1.24, 54.8% more than in Naples. In addition, the storage system limits the interaction with the power grid, lowering the exported electricity from about 50% to about 27% for Naples and from 63% to 50% for Cagliari. The fraction of the load met by renewable energy accounts for up to 25% for Naples and 48% for Cagliari.
Experimental Investigations Conducted for the Characteristic Study of OM29 Phase Change Material and Its Incorporation in Photovoltaic Panel
Authors: Elavarasan Rajvikram , Velmurugan Karthikeyan , Subramaniam Umashankar , Kumar A , Almakhles Dhafer
Published: February 2020

The solar photovoltaic (PV) system is emerging energetically in meeting the present energy demands. A rise in PV module temperature reduces the electrical efficiency, which fails to meet the expected energy demand. The main objective of this research was to study the nature of OM29, which is an organic phase change material (PCM) used for PV module cooling during the summer season. A heat transfer network was developed to minimize the experimental difficulties and represent the working model as an electrical resistance circuit. Most existing PV module temperature (TPV) reduction technology fails to achieve the effective heat transfer from the PV module to PCM because there is an intermediate layer between the PV module and PCM. In this proposed method, liquid PCM is filled directly on the back surface of the PV module to overcome the conduction barrier and PCM attains the thermal energy directly from the PV module. Further, the rear side of the PCM is enclosed by tin combined with aluminium to avoid any leakages during phase change. Experimental results show that the PV module temperature decreased by a maximum of 1.2 °C using OM29 until 08:30. However, after 09:00, the OM29 PCM was unable to lower the TPV because OM29 is not capable of maintaining the latent heat property for a longer time and total amount of the PCM experimented in this study was not sufficient to store the PV module generated thermal energy for an entire day. The inability of the presented PCM to lower the temperature of the PV panel was attributed to the lower melting point of OM29. PCM back sheet was incapable of dissipating the stored PCM’s thermal energy to the ambient, and this makes the experimented PCM unsuitable for the selected location during summer.
Isolation and Characterization of Two Microalgal Isolates from Vietnam with Potential for Food, Feed, and Biodiesel Production
Authors: Nguyen Luu Thao Nguyen , Alsafra Zouheir , Corato Amélie , Corsaro Daniele , Le Hung Anh , Eppe Gauthier , Remacle Claire
Published: February 2020

Microalgae are promising feedstock for the production of biodiesel and diverse medium- and high-value products such as pigments and polyunsaturated fatty acids. The importance of strain selection adapted to specific environments is important for economical purposes. We characterize here two microalgal strains, isolated from wastewater of shrimp cultivation ponds in Vietnam. Based on the 18S rDNA-ITS region, one strain belongs to the Eustigmatophyceae class and is identical to the Nannochloropsis salina isolate D12 (JX185299.1), while the other is a Chlorophyceae belonging to the Desmodesmus genus, which possesses a S516 group I intron in its 18S rDNA gene. The N. salina strain is a marine and oleaginous microalga (40% of dry weight (DW) at stationary phase) whole oil is rich in saturated fatty acids (around 45% of C16:0) suitable for biodiesel and contains a few percent of eicosapentaenoic acid (C20:5). The Desmodesmus isolate can assimilate acetate and ammonium and is rich in lutein. Its oil contains around 40%–50% α-linolenic acid (C18:3), an essential fatty acid. Since they tolerate various salinities (10% to 35‰), both strains are thus interesting for biodiesel or aquaculture valorization in coastal and tropical climate where water, nutrient, and salinity availability vary greatly depending on the season.
Daily Photovoltaic Power Prediction Enhanced by Hybrid GWO-MLP, ALO-MLP and WOA-MLP Models Using Meteorological Information
Authors: Colak Medine , Yesilbudak Mehmet , Bayindir Ramazan
Published: February 2020

Solar energy is a safe, clean, environmentally-friendly and renewable energy source without any carbon emissions to the atmosphere. Therefore, there are many studies in the field of solar energy in order to obtain the maximum solar radiation during the day time, to estimate the amount of solar energy to be produced, and to increase the efficiency of solar energy systems. In this study, it was aimed to predict the daily photovoltaic power production using air temperature, relative humidity, total horizontal solar radiation and diffuse horizontal solar radiation parameters as multi-tupled inputs. For this purpose, grey wolf, ant lion and whale optimization algorithms were integrated to the multilayer perceptron. In addition, the effects of sigmoid, sinus and hyperbolic tangent activation functions on the prediction performance were analyzed in detail. As a result of overall accuracy indictors achieved, the grey wolf optimization algorithm-based multilayer perceptron model was found to be more successful and competitive for the daily photovoltaic power prediction. Furthermore, many meaningful patterns were revealed about the constructed models, input tuples and activation functions.
Modeling the Impact of Modified Inertia Coefficient (H) due to ESS in Power System Frequency Response Analysis
Authors: Saeed Uz Zaman Muhammad , Irfan Muhammad , Ahmad Muhammad , Mazzara Manuel , Kim Chul-Hwan
Published: February 2020

The advantages of increased penetration of distributed generation are also accompanied by several challenges, low inertia being one of them, which threatens the grid stability. An emerging approach to confront this problem is the introduction of so-called virtual inertia (VI) provided by energy storage systems (ESS). In contrast to the already available literature which considers a conventional load frequency control (LFC) model, this work concentrates on a modified LFC model as the integration of a large portion of ESS changes the inertia constant ( H ) of a power system. A sensitivity function is derived that shows the effects of changes in H on the power system’s frequency response. With the help of the developed mathematical model and simulation results, it is shown that a difference in the actual and calculated values of H can deteriorate the system performance and economy. As one of the reasons for this difference is improper modeling of ESS in the LFC model, therefore, the study signifies the accurate calculation of H in the power systems having enlarged penetration of ESS.
Power Generation from Concentration Gradient by Reverse Electrodialysis in Anisotropic Nanoporous Anodic Aluminum Oxide Membranes
Authors: Lee Yunhyun , Kim Hyun Jung , Kim Dong-Kwon
Published: February 2020

In this study, reverse electrodialysis power generation using an anisotropic anodic aluminum oxide membrane with nanopores of two different pore diameters is proposed and experimentally investigated for the first time. A number of experiments were carried out for various combinations of concentrations to show that the anisotropic anodic aluminum oxide membrane is superior to the conventional isotropic membrane. As a result, the highest power density that was measured from the anisotropic membrane was 15.0 mW/m2, and it was 7.2 times higher than that from the isotropic membrane. The reasons why the anisotropic membrane is superior to the isotropic membrane are explained in detail. The experiments on the anisotropic membranes with various active layer lengths and pore diameters were also conducted for exploring the effects of these engineering parameters on the power generation performance. As a result, it was shown that the length of the active layer is a more important engineering parameter than the pore diameter of the active layer. Additionally, it was also shown that a low concentration solution should be brought into contact with the active layer side of the membrane whenever an anisotropic membrane is used for reverse electrodialysis.
A Wireless Power Transfer Based Implantable ECG Monitoring Device
Authors: Kim Junho , Kim Hyeok , Kim Dongwook , Park Hun-Jun , Ban Kiwon , Ahn Seungyoung , Park Sung-Min
Published: February 2020

Implantable medical devices (IMDs) enable patients to monitor their health anytime and receive treatment anywhere. However, due to the limited capacity of a battery, their functionalities are restricted, and the devices may not achieve their intended potential fully. The most promising way to solve this limited capacity problem is wireless power transfer (WPT) technology. In this study, a WPT based implantable electrocardiogram (ECG) monitoring device that continuously records ECG data has been proposed, and its effectiveness is verified through an animal experiment using a rat model. Our proposed device is designed to be of size 24 × 27 × 8 mm, and it is small enough to be implanted in the rat. The device transmits data continuously using a low power Bluetooth Low Energy (BLE) communication technology. To charge the battery wirelessly, transmitting (Tx) and receiving (Rx) antennas were designed and fabricated. The animal experiment results clearly showed that our WPT system enables the device to monitor the ECG of a heart in various conditions continuously, while transmitting all ECG data in real-time.
A Method for the Optimization of Daily Activity Chains Including Electric Vehicles
Authors: Rizopoulos Dimitrios , Esztergár-Kiss Domokos
Published: February 2020

The focus of this article is to introduce a method for the optimization of daily activity chains of travelers who use Electric Vehicles (EVs) in an urban environment. An approach has been developed based on activity-based modeling and the Genetic Algorithm (GA) framework to calculate a suitable schedule of activities, taking into account the locations of activities, modes of transport, and the time of attendance to each activity. The priorities of the travelers concerning the spatial and temporal flexibility were considered, as well as the constraints that are related to the limited range of the EVs, the availability of Charging Stations (CS), and the elevation of the road network. In order to model real travel behavior, two charging scenarios were realized. In the first case, the traveler stays in the EV at the CS, and in the second case, the traveler leaves the EV to charge at the CS while conducting another activity at a nearby location. Through a series of tests on synthetic activity chain data, we proved the suitability of the method elaborated for addressing the needs of travelers and being utilized as an optimization method for a modern Intelligent Transportation System (ITS).
Parameters Affecting RDF-Based Pellet Quality
Authors: Jewiarz Marcin , Mudryk Krzysztof , Wróbel Marek , Frączek Jarosław , Dziedzic Krzysztof
Published: February 2020

Increasing production of waste has compelled the development of modern technologies for waste management. Certain fractions of municipal solid wastes are not suitable for recycling and must be utilised in other ways. Materials such as refuse-derived fuel (RDF) fractions are used as fuel in cement or CHP (combined heat and power) plants. The low bulk density leads to many problems pertaining to transportation and storage. In the case of biomass, these problems cause reduction in pelletisation. This paper therefore presents a comprehensive study on RDF pellet production, which is divided into three major areas. The first describes laboratory-scale tests and provides information on key factors that affect pellet quality (e.g., density and durability). Based on this, the second part presents a design of modified RDF dies to form RDF pellets, which are then tested via a semi-professional line test. The results show that RDF fraction can be compacted to form pellets using conventional devices. Given that temperature plays a key role, a special die must be used, and this ensures that the produced pellets exhibit high durability and bulk density, similar to biomass pellets.
Serial Laboratory Effective Thermal Conductivity Measurements of Cohesive and Non-cohesive Soils for the Purpose of Shallow Geothermal Potential Mapping and Databases—Methodology and Testing Procedure Recommendations
Authors: Łukawska Aleksandra , Ryżyński Grzegorz , Żeruń Mateusz
Published: February 2020

The article presents the methodology of conducting serial laboratory measurements of thermal conductivity of recompacted samples of cohesive and non-cohesive soils. The presented research procedure has been developed for the purpose of supplementing the Engineering–Geology Database and its part–Physical and Mechanical Properties of Soils and Rocks (abbr. BDGI-WFM) with a new component regarding thermal properties of soils. The data contained in BDGI-WFM are the basis for the development of maps and plans for the assessment of geothermal potential and support for the sustainable development of low enthalpy geothermal energy. Effective thermal conductivity of soils was studied at various levels of water saturation and various degrees of compaction. Cohesive soils were tested in initial moisture content and after drying to a constant mass. Non-cohesive soils were tested in initial moisture, fully saturated with water and after drying to a constant mass. Effective thermal conductivity of non-cohesive soils was determined on samples mechanically compacted to the literature values of bulk density. Basic physical parameters were determined for each of the samples. In total, 120 measurements of thermal conductivity were carried out, for the purposes of developing the guidelines which allowed statistical analysis of the results. The results were cross-checked with different measuring equipment and with the literature data.