bluuebunny/crossref_metadata_2025 huggingface dataset:
Keratinocyte-Expressed Podoplanin is Dispensable for Multi-Step Skin Carcinogenesis
Authors: Sesartić Marko , Ikenberg Kristian , Yoon Sun-Young , Detmar Michael
Published: June 2020

Podoplanin is a small transmembrane mucin-like glycoprotein that plays a crucial role in the development of the lung, heart and lymphatic vascular system. Its expression is upregulated in several types of human carcinomas and podoplanin levels in squamous cell carcinomas (SCCs) of the oral cavity and the lung correlate with cancer invasiveness, lymph node metastasis and shorter survival time of patients, indicating that podoplanin promotes tumor progression. However, its role during the early stages of carcinogenesis remain unclear. We generated mice with a specific deletion of podoplanin in epidermal keratinocytes (K5-Cre;Pdpnflox/flox mice) and subjected them to a multistep chemical skin carcinogenesis regimen. The rate of tumor initiation; the number, size and differentiation of tumors; and the malignant transformation rate were comparable in K5-Cre;Pdpnflox/flox mice and Pdpnflox/flox control mice. However, tumor cell invasion was reduced in K5-Cre;Pdpnflox/flox mice, in particular single cell invasion. Quantitative immunofluorescence analyses revealed that peritumoral lymphangiogenesis was reduced in K5-Cre;Pdpnflox/flox mice, whereas there were no major changes of tumor-associated immune cell subpopulations. Thus, keratinocyte-expressed podoplanin is dispensable for the early steps of skin carcinogenesis but contributes to the progression of established tumors.
Challenges for the Island of Barbuda: A Distinct Cultural and Ecological Island Ecosystem at the Precipice of Change
Authors: Hubbart Jason A. , Stephan Kirsten , Petersen Fritz , Heck Zachary , Horne Jason , Meade B. Jean
Published: June 2020

Barbuda is one of two major islands that comprise the Caribbean nation of Antigua and Barbuda. The island is known for its secluded pink and white sand beaches and, more recently, for Hurricane Irma (September 2017). The category five mega-storm decimated much of the island’s landscape and infrastructure, and the physical damage was widely publicized. Three years after Hurricane Irma, many challenges related to humanitarian aid, fiscal resources, and materials to rebuild remain. There are many natural resource commodity and human social challenges including those related to water resources, agriculture, marine ecosystems, feral animal populations, human health, tourism, and economics. This article includes some of Barbuda’s historical context and identifies a number of current critical challenges and recommendations for activities (approaches) that may advance a number of management practices. For example, the Integrated Watershed Management (IWM) and/or One Health approach(es) include social and fiscal mechanisms to implement programs, policies, legislation, and research in which multiple sectors of Barbuda could communicate and work together to achieve sustainable outcomes. Context is provided to substantiate humanitarian aid, scientific engagement, scientific progress, and political support for a semi-closed cultural socio-ecological island ecosystem at the precipice of change.
Influence of the PVC of Glass Fiber Powder on the Properties of a Thermochromic Waterborne Coating for Chinese Fir Boards
Authors: Yan Xiaoxing , Wang Lin , Qian Xingyu
Published: June 2020

A thermochromic waterborne coating with thermal insulation efficacy was prepared by adding thermochromic microcapsules and glass fiber powder. The influence of the pigment volume concentration (PVC) of a glass fiber powder on the performance of the thermochromic coating for Chinese fir boards was investigated. It was found that a coating with a PVC of glass fiber powder of 0–22.0% had better discoloration properties. When the PVC of the glass fiber powder was more than 4.0%, with the increase of the PVC, the gloss of the coating decreased gradually, while, the adhesion, impact resistance, and liquid resistance were not affected. When the PVC of the glass fiber powder was 10.0%–30.0%, it showed thermal insulation efficacy and high hardness. The coating with a PVC of 16.0% glass fiber powder had better wear resistance. The discoloration property of the coating with thermal insulation efficacy was not affected by time. These results exhibit great potential for the application of a wood surface thermochromic and thermal insulation coating.
Surface Modifications for Implants Lifetime extension: An Overview of Sol-Gel Coatings
Authors: Tranquillo Elisabetta , Bollino Flavia
Published: June 2020

The limited lifetime of implants entails having patients undergo replacement surgeries, several times throughout life in young patients, with significant risks for them and extensive cost for healthcare service. The overcoming of such inconvenience is still today a hard challenge for the scholars of the biomedical and biomaterial fields. The improvement of the currently employed implants through surface modification by coatings application is the main strategy proposed to avoid implants failure, and the sol-gel coating is an ideal technology to achieve this goal. Therefore, the present review aims to provide an overview of the most important problems leading to implant failure, the sol-gel coating technology, and its use as a strategy to overcome such issues.
Rebound Dynamics of Two Droplets Successively Impacting an Inclined Surface
Authors: Lin Dian-Ji , Zhang Ling-Zhe , Yi Meng-Chao , Wang Xin , Gao Shu-Rong , Yang Yan-Ru , Wang Xiao-Dong
Published: June 2020

The dynamic behaviors of two droplets successively impacting inclined surfaces are simulated by a three-dimensional pseudopotential lattice Boltzmann model based on multi-relaxation-time. The effect of velocity ratio of two successive droplets on the contact time is investigated and two rebounding regimes are identified depending on whether the coalesced droplet retouches the surface or not. Increasing the velocity ratio leads to a stronger interaction between the two droplets and the phenomenon of coalesced droplet retouching the surface is observed when the velocity ratio exceeds a threshold, resulting in a longer contact time. An outcome map of droplet rebounding is obtained at various velocity ratios and contact angles of surface. It is found that the coalesced droplet cannot rebound from the surface at a larger velocity ratio and a lower contact angle of surface. Furthermore, the effect of the length between impact points on the contact time is exhibited, and a longer length is beneficial to coalesced droplet rebounding.
Tribological and Anticorrosion Performance of Electroplated Zinc Based Nanocomposite Coatings
Authors: Klekotka Marcin , Zielińska Katarzyna , Stankiewicz Alicja , Kuciej Michal
Published: June 2020

This paper presents the results of corrosion and tribological analysis of pure and nanocomposite zinc coatings. Coatings were electroplated using commercially available products—zinc acidic bath and a nanoparticle carrying plating additive. Electrochemical measurements were carried out to compare the anticorrosion performance of coatings. An investigation into the influence of nanoparticles on the mechanical properties was performed. The zinc nanocomposite coating exhibited better wear resistance and higher hardness than the plain zinc coating. The application of confocal laser scanning microscopy (CLSM) allowed the detailed description of friction/wear marks. The electrochemical studies revealed that the introduction of nanoparticles into the coating did not compromise its protective properties—a similar resistance of plain and nanocomposite coatings to corrosion was obtained.
Properties of Fourier Syntheses and New Syntheses
Authors: Burla Maria Cristina , Carrozzini Benedetta , Cascarano Giovanni Luca , Giacovazzo Carmelo , Polidori Giampiero
Published: June 2020

In this study, the properties of observed, difference, and hybrid syntheses (hybrid indicates a combination of observed and difference syntheses) are investigated from two points of view. The first has a statistical nature and aims to estimate the amplitudes of peaks corresponding to the model atoms, belonging or not belonging to the target structure; the amplitudes of peaks related to the target atoms, missed or shared with the model; and finally, the quality of the background. The latter point deals with the practical features of Fourier syntheses, the special role of weighted syntheses, and their usefulness in practical applications. It is shown how the properties of the various syntheses may vary according to the available structural model and, in particular, how weighted hybrid syntheses may act like an observed and difference or a full hybrid synthesis. The theoretical results obtained in this paper suggest new Fourier syntheses using novel Fourier coefficients: their main features are first discussed from a mathematical point of view. Extended experimental applications show that they meet the basic mission of the Fourier syntheses, enhancing peaks corresponding to the missed target atoms, depleting peaks corresponding to the model atoms not belonging to the target, and significantly reducing the background. A comparison with the results obtained via the most popular modern Fourier syntheses is made, suggesting a role for the new syntheses in modern procedures for phase extension and refinement. The most promising new Fourier synthesis has been implemented in the current version of SIR2014.
Conservation Lessons from the Study of North American Boreal Birds at Their Southern Periphery
Authors: Ralston Joel , DeLuca William V.
Published: June 2020

Many North American boreal forest birds reach the southern periphery of their distribution in the montane spruce–fir forests of northeastern United States and the barren coastal forests of Maritime Canada. Because the southern periphery may be the first to be impacted by warming climates, these populations provide a unique opportunity to examine several factors that will influence the conservation of this threatened group under climate change. We discuss recent research on boreal birds in Northeastern US and in Maritime Canada related to genetic diversity, population trends in abundance, distributional shifts in response to climate change, community composition, and threats from shifting nest predators. We discuss how results from these studies may inform the conservation of boreal birds in a warming world as well as open questions that need addressing.
Technical Assessment of Ultrasonic Cerebral Tomosphygmography and New Scientific Evaluation of Its Clinical Interest for the Diagnosis of Electrohypersensitivity and Multiple Chemical Sensitivity
Authors: Greco Frédéric
Published: June 2020

Ultrasonic cerebral tomosphygmography (UCTS), also known as “encephaloscan”, is an ultrasound-based pulsatile echoencephalography for both functional and anatomical brain imaging investigations. Compared to classical imaging, UCTS makes it possible to locate precisely the spontaneous brain tissue pulsations that occur naturally in temporal lobes. Scientific publications have recently validated the scientific interest of UCTS technique but clinical use and industrial development of this ancient brain imaging technique has been stopped notably in France, not for scientific or technical reasons but due to a lack of financing support. UCTS should be fundamentally distinguished from transcranial Doppler ultrasonography (TDU), which, although it also uses pulsed ultrasounds, aims at studying the velocity of blood flow (hemodynamics) in the cerebral arteries by using Doppler effect, especially in the middle cerebral artery of both hemispheres. Instead, UCTS has the technical advantage of measuring and locating spontaneous brain tissue pulsations in temporal lobes. Recent scientific work has shown the possibility to make an objective diagnosis of electrohypersensitivity (EHS) and multiple chemical sensitivity (MCS) by using UCTS, in conjunction with TDU investigation and the detection of several biomarkers in the peripheral blood and urine of the patients. In this paper, we independently confirm the clinical interest of using UCTS for the diagnosis of EHS and MCS. Moreover, it has been shown that repetitive use of UCTS in EHS and/or MCS patients can contribute to the objective assessment of their therapeutic follow-up. Since classical CT scan and MRI are usually not contributive for the diagnosis and are poorly tolerated by these patients, UCTS should therefore be considered as one of the best imaging technique to be used for the diagnosis of these new disorders and the follow-up of patients.
Entropy-Based Estimation of Event-Related De/Synchronization in Motor Imagery Using Vector-Quantized Patterns
Authors: Velasquez-Martinez Luisa , Caicedo-Acosta Julián , Castellanos-Dominguez Germán
Published: June 2020

Assessment of brain dynamics elicited by motor imagery (MI) tasks contributes to clinical and learning applications. In this regard, Event-Related Desynchronization/Synchronization (ERD/S) is computed from Electroencephalographic signals, which show considerable variations in complexity. We present an Entropy-based method, termed VQEnt, for estimation of ERD/S using quantized stochastic patterns as a symbolic space, aiming to improve their discriminability and physiological interpretability. The proposed method builds the probabilistic priors by assessing the Gaussian similarity between the input measured data and their reduced vector-quantized representation. The validating results of a bi-class imagine task database (left and right hand) prove that VQEnt holds symbols that encode several neighboring samples, providing similar or even better accuracy than the other baseline sample-based algorithms of Entropy estimation. Besides, the performed ERD/S time-series are close enough to the trajectories extracted by the variational percentage of EEG signal power and fulfill the physiological MI paradigm. In BCI literate individuals, the VQEnt estimator presents the most accurate outcomes at a lower amount of electrodes placed in the sensorimotor cortex so that reduced channel set directly involved with the MI paradigm is enough to discriminate between tasks, providing an accuracy similar to the performed by the whole electrode set.
A Modified Artificial Bee Colony for Probabilistic Peak Shaving Technique in Generators Operation Planning: Optimal Cost–Benefit Analysis
Authors: Sasi Mohammed Daw Saleh , Othman Muhammad Murtadha , Elbarsha Ahmed
Published: June 2020

In the generation of operating system planning, saving utility cost (SUC) is customarily implemented to attain the forecasted optimal economic benefits in a generating system associated with renewable energy integration. In this paper, an improved approach for the probabilistic peak-shaving technique (PPS) based on computational intelligence is proposed to increase the SUC value. Contrary to the dispatch processing of the PPS technique, which mainly relies on the dispatching of each limited energy unit in sequential order, a modified artificial bee colony with a new searching mechanism (MABC-NSM) is proposed. The SUC is originated from the summation of the Saving Energy Cost and Saving Expected Cycling Cost of the generating system. In addition, further investigation for obtaining the optimal value of the SUC is performed between the SUC determined directly and indirectly estimated by referring to the energy reduction of thermal units (ERTU). Comparisons were made using MABC-NSM and a standard artificial bee colony and verified on the modified IEEE RTS-79 with different peak load demands. A compendium of the results has shown that the proposed method is constituted with robustness to determine the global optimal values of the SUC either obtained directly or by referring to the ERTU. Furthermore, SUC increments of 7.26% and 5% are achieved for 2850 and 3000 MW, respectively.
Phase Change Material Melting Process in a Thermal Energy Storage System for Applications in Buildings
Authors: Nascimento Porto Túlio , Delgado João M. P. Q. , Guimarães Ana Sofia , Fernandes Magalhães Hortência Luma , Moreira Gicelia , Brito Correia Balbina , Freire de Andrade Tony , Barbosa de Lima Antonio Gilson
Published: June 2020

The development of thermal energy storage systems is a possible solution in the search for reductions in the difference between the global energy supply and demand. In this context, the ability of some materials, the so-called phase change materials (PCMs), to absorb and release large amounts of energy under specific periods and operating conditions has been verified. The applications of these materials are limited due to their low thermal conductivity, and thus, it is necessary to associate them with high-conductivity materials, such as metals, to make the control of energy absorption and release times possible. Bearing this in mind, this paper presents a numerical analysis of the melting process of a PCM into a triplex tube heat exchanger (TTHX) with finned copper tubes, which allowed for the heat transfer between a heating fluid (water) and the phase change material to power a liquid-desiccant air conditioning system. Through the analysis of the temperature fields, liquid fractions, and velocities, as well as the phase transition, it was possible to describe the material charging process; then, the results were compared with experimental data, which are available in the specialized literature, and presented mean errors of less than 10%. The total required time to completely melt the PCM was about 105.5 min with the water being injected into the TTHX at a flow rate of 8.3 L/min and a temperature of 90 °C. It was observed that the latent energy that accumulated during the melting process was 1330 kJ, while the accumulated sensitive energy was 835 kJ. The average heat flux at the internal surface of the inner tube was about 3 times higher than the average heat flux at the outer surface of the TTHX intermediate tube due to the velocity gradients that developed in the internal part of the heat exchanger, and was about 10 times more intense than those observed in the external region of the equipment.
Multi-Objective Optimization Model EPLANopt for Energy Transition Analysis and Comparison with Climate-Change Scenarios
Authors: Prina Matteo Giacomo , Manzolini Giampaolo , Moser David , Vaccaro Roberto , Sparber Wolfram
Published: June 2020

The modeling of energy systems with high penetration of renewables is becoming more relevant due to environmental and security issues. Researchers need to support policy makers in the development of energy policies through results from simulating tools able to guide them. The EPLANopt model couples a multi-objective evolutionary algorithm to EnergyPLAN simulation software to study the future best energy mix. In this study, EPLANopt is applied at country level to the Italian case study to assess the best configurations of the energy system in 2030. A scenario, the result of the optimization, is selected and compared to the Italian integrated energy and climate action plan scenario. It allows a further reduction of CO2 emissions equal to 10% at the same annual costs of the Italian integrated energy and climate action plan scenario. Both these results are then compared to climate change scenarios through the carbon budget indicator. This comparison shows the difficulties to meet the Paris Agreement target of limiting the temperature increase to 1.5 °C. The results also show that this target can only be met through an increase in the total annual costs in the order of 25% with respect to the integrated energy and climate action plan scenario. However, the study also shows how the shift in expenditure from fossil fuels, external expenses, to investment on the national territory represents an opportunity to enhance the national economy.
Review of Online and Soft Computing Maximum Power Point Tracking Techniques under Non-Uniform Solar Irradiation Conditions
Authors: Ali Amjad , Almutairi K. , Malik Muhammad Zeeshan , Irshad Kashif , Tirth Vineet , Algarni Salem , Zahir Md. Hasan , Islam Saiful , Shafiullah Md , Shukla Neeraj Kumar
Published: June 2020

Significant growth in solar photovoltaic (PV) installation has been observed during the last decade in standalone and grid-connected power generation systems. However, the PV system has a non-linear output characteristic because of weather intermittency, which tends to a substantial loss in overall system output. Thus, to optimize the output of the PV system, maximum power point tracking (MPPT) techniques are used to track the global maximum power point (GMPP) and extract the maximum power from the PV system under different weather conditions with better precision. Since MPPT is an essential part of the PV system, to date, many MPPT methods have been developed by various researchers, each with unique features. A Google Scholar survey of the last five years (2015–2020) was performed to investigate the number of review articles published. It was found that overall, seventy-one review articles were published on different MPPT techniques; out of those, only four were on non-uniform solar irradiance, and seven review articles included shading conditions. Unfortunately, very few attempts were made in this regard. Therefore, a comprehensive review paper on this topic is needed, in which almost all the well-known MPPT techniques should be encapsulated in one document. This article focuses on online and soft-computing MPPT algorithm classifications under non-uniform irradiance conditions along with their mathematical expression, operating principles, and block diagram/flow charts. It will provide a direction for future research and development in the field of maximum power point tracking optimization.
Hour-Ahead Photovoltaic Power Forecasting Using an Analog Plus Neural Network Ensemble Method
Authors: Wang Jingyue , Qian Zheng , Wang Jingyi , Pei Yan
Published: June 2020

The common analog approach and ensemble methods in photovoltaic (PV) power forecasting are based on the forecasts from several numerical weather prediction (NWP) models. These may be not applicable to the very-short-term PV power forecasting, since forecasts based on NWP models are reliable in horizons longer than six hours. In this paper, a methodology for one-hour-ahead PV power forecasting is proposed. Instead of the NWP models, the persistence method is applied in the analog approach to produce meteorological forecasts. The historical data with meteorological predictions similar to the target forecast hour are identified to train the forecast model. Then, the feed forward neural networks (FNNs) act as the base predictors of the neural network ensemble method to replace the NWP-based PV power prediction methods. The forecast results produced by the FNNs are combined by the random forest (RF) algorithm. The performance of the proposed method is evaluated on a real grid-connected PV plant located in Southeast China. Results show that the proposed method outperforms six benchmark models: the persistence model, the support vector regression (SVR) model, the linear regression model, the RF model, the gradient boosting model, and XGBoost model. The improvements reach up to over 40% for the standard error metrics.
Circuit Model and Analysis of Multi-Load Wireless Power Transfer System Based on Parity-Time Symmetry
Authors: Luo Chengxin , Qiu Dongyuan , Lin Manhao , Zhang Bo
Published: June 2020

In the multi-load wireless power transfer (WPT) system, the output power and transfer efficiency will drop significantly with the change of distance between transmitter and receiver. Power distribution among multiple loads is also a major challenge. In order to solve these problems, a novel multi-load WPT system based on parity–time symmetry (PT-WPT) is proposed in this paper. Firstly, the multi-load PT-WPT system is modeled based on the circuit model. Then, the transmission characteristics of the multi-load PT-WPT system are analyzed. It is found that constant output power with constant transfer efficiency can be maintained against the variation of coupling coefficient, and the power distribution relationship among loads is only related to the coupling coefficient. Further, power distribution under different coupling situations is analyzed in detail to meet different power demands. Finally, taking a dual-load PT-WPT system as an example, the system parameters are designed and the circuit simulation is carried out. The simulation results are consistent with the theoretical analysis, which shows that PT symmetry can be applied to the multi-load WPT system to achieve constant output power, constant transfer efficiency, and power distribution simultaneously.
Transformerless Multilevel Voltage-Source Inverter Topology Comparative Study for PV Systems
Authors: Estévez-Bén Adyr A. , Alvarez-Diazcomas Alfredo , Rodríguez-Reséndiz Juvenal
Published: June 2020

At present, renewable energies represent 25% of the global power generation capacity. The increase in clean energy facilities is mainly due to the high levels of pollution generated by the burning of fossil fuels to satisfy the growing electricity demand. The global capacity of generating electricity from solar energy has experienced a significant increase, reaching 505 GW in 2018. Today, multilevel inverters are used in PV systems to convert direct current into alternating current. However, the use of multilevel inverters in renewable energies applications presents different challenges; for example, grid-connected systems use a transformer to avoid the presence of leakage currents. The grid-connected systems must meet at least two international standards analyzed in this work: VDE 0126-1-1 and VDE-AR-N 4105, which establish a maximum leakage current of 300 mA and harmonic distortion maximum of 5%. Previously, DC/AC converters have been studied in different industrial applications. The state-of-the-art presented in the work is due to the growing need for a greater use of clean energy and the use of inverters as an interface between these technologies and the grid. Also, the paper presents a comparative analysis of the main multilevel inverter voltage-source topologies used in transformerless PV systems. In each scheme, the advantages and disadvantages are presented, as well as the main challenges. In addition, current trends in grid-connected systems using these schemes are discussed. Finally, a comparative table based on input voltage, switching frequency, output levels, control strategy used, efficiency, and leakage current is shown.
Total Cost of Ownership Model and Significant Cost Parameters for the Design of Electric Bus Systems
Authors: Grauers Anders , Borén Sven , Enerbäck Oscar
Published: June 2020

Without experiences of electric buses, public transport authorities and bus operators have faced questions about how to implement them in a cost-effective way. Simple cost modelling cannot show how costs for different types of electric buses differ between different routes and timetables. Tools (e.g., HASTUS, PtMS, and optibus) which can analyse such details are complicated, time consuming to use, and provide insufficient insights into the mechanisms that influence the cost. This paper therefore proposes a method for how to calculate total cost of ownership, for different types of electric buses, in a way which can predict how the cost varies based on route and timetable. The method excludes factors which cause minor cost variations in an almost random manor, in order to better show the fundamental mechanisms influencing different costs. The method will help in finding ways to reduce the cost and help to define a few cases which deserve a deep analysis with more complete tools. Testing of the method in a Swedish context showed that the results are in line with other theoretical and practical studies, and how the total cost of ownership can vary depending on the variables.
EV Smart Charging with Advance Reservation Extension to the OCPP Standard
Authors: Orcioni Simone , Conti Massimo
Published: June 2020

An accurate management of the interactions among end user, electric vehicle, and charging station during recharge is fundamental for the diffusion of electric mobility. The paper proposes an extension of the Open Charge Point Protocol standard with the aim of including the user in the charging optimization process. The user negotiates with the central station a recharge reservation giving his/her preference and flexibility. The charging station management system provides different solutions based on user’s flexibility. This negotiation allows the optimization of the power grid management considering the user requests and constraints. The complete architecture has been designed, implemented on a web server and on a smartphone app, and tested. Results are reported in this work.
Rapid Wear Modelling in a Slurry Pump Using Soft 3D Impeller Material
Authors: Jiang C. , Fleck B. A. , Lipsett M. G.
Published: June 2020

Slurry transport systems are often limited in run length by the life of the pump internals, especially the impeller. The present work investigated abrasive wear of the impeller of a Hayward Gordon XR2(7) Torus Recessed Impeller slurry pump in a flow loop. The stock stainless steel impeller was replaced by a set of plastic test impellers with the same nominal geometry, fabricated by additive manufacturing (3D printing). A parametric set of abrasive wear experiments was conducted at five pump rotational speeds and three solid concentrations of garnet slurry in a pipe flow loop. Pump performance tests were conducted using impellers with progressive wear conditions, to investigate how a worn impeller affects hydraulic power delivery. A parabolic fit was imposed to describe the relationship between head and flow rate, and an empirical model was proposed to predict the pump head with damaged impellers. When the rotational speed is high, the damaged impeller has a larger effect on the pump’s performance than when the rotational speed is low. The head difference between the undamaged impeller and a 7.62%-mass-loss damaged impeller was 1.5 m at 1750 rpm rotational speed, however, for 850 rpm, the head difference was 1 m. Implications for pump diagnostics in other types of systems are discussed. This experiment gives a method for rapidly assessing wear locations, and provides a tool to predict wear rates on harder materials if scaling parameters are available. This first attempt at a scaling law is not reliable enough to accurately predict the wear rate for specific conditions, but shows the relative wear as a function of pertinent parameters.
A Study of Combustion Characteristics of Two Gasoline–Biodiesel Mixtures on RCEM Using Various Fuel Injection Pressures
Authors: Setiawan Ardhika , Wahono Bambang , Lim Ocktaeck
Published: June 2020

Experimental research was conducted on a rapid compression and expansion machine (RCEM) that has characteristics similar to a gasoline compression ignition (GCI) engine, using two gasoline–biodiesel (GB) blends—10% and 20% volume—with fuel injection pressures varying from 800 to 1400 bar. Biodiesel content lower than GB10 will result in misfires at fuel injection pressures of 800 bar and 1000 bar due to long ignition delays; this is why GB10 was the lowest biodiesel blend used in this experiment. The engine compression ratio was set at 16, with 1000 µs of injection duration and 12.5 degree before top dead center (BTDC). The results show that the GB20 had a shorter ignition delay than the GB10, and that increasing the injection pressure expedited the autoignition. The rate of heat release for both fuel mixes increased with increasing fuel injection pressure, although there was a degradation of heat release rate for the GB20 at the 1400-bar fuel injection rate due to retarded in-cylinder peak pressure at 0.24 degree BTDC. As the ignition delay decreased, the brake thermal efficiency (BTE) decreased and the fuel consumption increased due to the lack of air–fuel mixture homogeneity caused by the short ignition delay. At the fuel injection rate of 800 bar, the GB10 showed the worst efficiency due to the late start of combustion at 3.5 degree after top dead center (ATDC).
Measurement of Energy Access Using Fuzzy Logic
Authors: Seuret-Jimenez Diego , Robles-Bonilla Tiare , Cedano Karla G.
Published: June 2020

This paper describes an innovative method to evaluate energy access in any of size population by applying fuzzy logic. The obtained results allow ranking regions of Mexico according to their overall energy access. The regions were determined by the country’s political division (32 states). The results presented herein are in close correspondence with other studies undertaken. This method is recommended because it is possible to use as an assessment tool due to its representativeness—that is, it poses a heuristic alternative to quantify the level of Energy Access in a particular region through qualitative data. It is also efficient and cost-effective in terms of computer resources. This is extremely important to public policy makers that require more accurate, faster and cheaper methodologies to assess energy access as an indicator of well-being.
Enhanced Intelligent Energy Management System for a Renewable Energy-Based AC Microgrid
Authors: Dhifli Mehdi , Lashab Abderezak , Guerrero Josep M. , Abusorrah Abdullah , Al-Turki Yusuf A. , Cherif Adnane
Published: June 2020

This paper proposes an enhanced energy management system (EEMS) for a residential AC microgrid. The renewable energy-based AC microgrid with hybrid energy storage is broken down into three distinct parts: a photovoltaic (PV) array as a green energy source, a battery (BT) and a supercapacitor (SC) as a hybrid energy storage system (HESS), and apartments and electric vehicles, given that the system is for residential areas. The developed EEMS ensures the optimal use of the PV arrays’ production, aiming to decrease electricity bills while reducing fast power changes in the battery, which increases the reliability of the system, since the battery undergoes fewer charging/discharging cycles. The proposed EEMS is a hybrid control strategy, which is composed of two stages: a state machine (SM) control to ensure the optimal operation of the battery, and an operating mode (OM) for the best operation of the SC. The obtained results show that the EEMS successfully involves SC during fast load and PV generation changes by decreasing the number of BT charging/discharging cycles, which significantly increases the system’s life span. Moreover, power loss is decreased during passing clouds phases by decreasing the power error between the extracted power by the sources and the required equivalent; the improvement in efficiency reaches 9.5%.
Coordinated Flexibility Scheduling for Urban Integrated Heat and Power Systems by Considering the Temperature Dynamics of Heating Network
Authors: Wei Wei , Shi Yaping , Hou Kai , Guo Lei , Wang Linyu , Jia Hongjie , Wu Jianzhong , Tong Chong
Published: June 2020

The coordinated heat-electricity dispatch of the urban integrated energy system (UIES) helps to improve the system flexibility, thereby overcoming the adverse effects caused by the random fluctuations of renewable energy (RE) and promoting the penetration of RE. Among them, the dynamic characteristics of the urban heat network (UHN) are important features that need to be considered for the operating scheduling of the UIES. This paper aims to establish a flexibility scheduling model for UIES based on the dynamic characteristics of the UHN. First, the typical structure and key equipment model of the urban integrated heat and power system (UIHPS) with the dynamic characteristics of the UHN is proposed. Then, the definition and model of the UIHPS flexibility and the assessment index of the flexibility are developed. Moreover, a flexibility scheduling model for a UIHPS that considers the dynamic characteristics of a UHN is established. Finally, the validity of the proposed model is validated by case studies, and the applicability of flexibility scheduling and the effect of heat load (HL) are analyzed.
Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat Exchangers
Authors: Jahanbin Aminhossein , Semprini Giovanni , Natale Impiombato Andrea , Biserni Cesare , Rossi di Schio Eugenia
Published: June 2020

Given that the issue of variations in geometrical parameters of the borehole heat exchanger (BHE) revolves around the phenomenon of thermal resistance, a thorough understanding of these parameters is beneficial in enhancing thermal performance of BHEs. The present study seeks to identify relative changes in the thermal performance of double U-tube BHEs triggered by alterations in circuit arrangements, as well as the shank spacing and the borehole length. The thermal performance of double U-tube BHEs with different configurations is comprehensively analyzed through a 3D transient numerical code developed by means of the finite element method. The sensitivity of each circuit configuration in terms of the thermal performance to variations of the borehole length and shank spacing is investigated. The impact of the thermal interference between flowing legs, namely thermal short-circuiting, on parameters affecting the borehole thermal resistance is addressed. Furthermore, the energy exchange characteristics for different circuit configurations are quantified by introducing the thermal effectiveness coefficient. The results indicate that the borehole length is more influential than shank spacing in increasing the discrepancy between thermal performances of different circuit configurations. It is shown that deviation of the averaged-over-the-depth mean fluid temperature from the arithmetic mean of the inlet and outlet temperatures is more critical for lower shank spacings and higher borehole lengths.
Analysis of the Potential for Renewable Utilization in Kosovo Power Sector
Authors: Lajqi Shpetim , Đurin Bojan , Berisha Xhevat , Plantak Lucija
Published: June 2020

The reduction in greenhouse gas emissions and the decarbonization of the power sector through the utilization of available renewable technologies are challenging issues that Kosovo has to tackle right now, in order to fight the high pollution caused by a coal-based power system. Around 91.43% of installed capacities for electricity generation in Kosovo are based on coal-fired power plants. The aim of this paper is to show the potential for renewable utilization, using data measurements of wind, solar irradiation, biomass, and average water flows at different area locations to identify their utilization potential. Furthermore, a review on the currently available and future renewable energy projects integrated into the electricity sector is presented. A 54% carbon dioxide emission reduction potential was estimated in the power sector when considering maximum utilization potential of biomass, wind, solar renewable energies compared to a referent scenario. The results obtained from this review have shown the pathways for identifying the potential utilization of renewable as well as the actual and planned use of renewable implemented projects into the Kosovo Power Sector.
Analyzing the Biological and Structural Diversity of Hyrcanian Forests Dominated by Taxus baccata L.
Authors: Alavi Seyed Jalil , Veiskarami Razieh , Esmailzadeh Omid , Gadow Klaus v.
Published: June 2020

The Hyrcanian Forests, well-known for its World Heritage site in the South Caspian region of Northern Iran, are refugia for a special tree flora. Some areas in particular feature a concentration of large and numerous trees of Taxus baccata, a species that has attracted the interest of many researchers given its medicinal importance. The objective of this study was to analyze the biological and structural features of these unique ecosystems based on three large tree-mapped field plots using new methods. We developed a species abundance distribution and three species–area relations, and analyzed the small-scale structural patterns of each of the 15 tree species that occur in the plots. Species-specific details are presented for each of the three field plots, including the tree densities and average tree sizes, as well as the associated structural indices “species mingling”, “dominance”, and “size differentiation”. This includes non-linear relationships between tree density and neighborhood mingling, and between the average tree size and neighborhood dominance, and a linear relation between the neighborhood dominance and the mean neighborhood differentiation. Based on the findings, we recommend the use of these methods and indices for analyzing the structure of natural forests in other regions of the world.
Pollen Production of Quercus in the North-Western Iberian Peninsula and Airborne Pollen Concentration Trends during the Last 27 Years
Authors: Fernández-González María , González-Fernández Estefanía , Ribeiro Helena , Abreu Ilda , Rodríguez-Rajo F. Javier
Published: June 2020

Natural forests are considered a reservoir of great biological diversity constituting one of the most important ecosystems in Europe. Quercus study is essential to assess ecological conservation of forests, and also of economic importance for different industries. In addition, oak pollen can cause high sensitization rates of respiratory allergies in pollen-allergy sufferers. This study sought to know the pollen production of six oak species in the transitional area between the Eurosiberian and Mediterranean Bioclimatic Regions, and to assess the impact of climate change on airborne oak pollen concentrations. The study was conducted in Ourense (NW Spain) over the 1993–2019 period. A Lanzoni VPPS 2000 volumetric trap monitored airborne pollen. A pollen production study was carried out in ten trees randomly selected in several Quercus forest around the Ourense city. Oak pollen represented around 14% of annual total pollen registered in the atmosphere of Ourense, showing an increasing trend during the last decade. Pollen production of the six studied oak species follow the proportions 1:1:2:5:90:276 for Q. ilex, Q. faginea, Q. rubra, Q. suber, Q. pyrenaica, and Q. robur respectively. We detected a significant trend to the increase of the annual maximum temperature, whereas a decrease of the maximum and mean temperatures during three previous months to oak flowering. This could be related with the detected trend to a delay of the oak Main Pollen Season onset of 0.47 days per year. We also found significant trends to an increase of the annual pollen integral of 7.9% pollen grains per year, and the pollen peak concentration of 7.5% pollen grains per year. Quercus airborne pollen monitoring as well as the knowledge of the reproductive behavior of the main oak species, bring us an important support tool offering a promising bio-indicator to detect ecological variations induced by climate change.
Inducing Plant Defense Reactions in Tobacco Plants with Phenolic-Rich Extracts from Red Maple Leaves: A Characterization of Main Active Ingredients
Authors: Peghaire Elodie , Hamdache Samar , Galien Antonin , Sleiman Mohamad , ter Halle Alexandra , El Alaoui Hicham , Kocer Ayhan , Richard Claire , Goupil Pascale
Published: June 2020

Red maple leaf extracts (RME) were tested for their plant defense inducer (PDI) properties. Two extracts were obtained and compared by different approaches: RME1 using ethanol–water (30–70%, v/v, 0.5% HCl 1N) and RME2 using pure water. Both extracts titrated at 1.9 g L−1 in polyphenols and infiltrated into tobacco leaves efficiently induced hypersensitive reaction-like lesions with topical accumulation of auto-fluorescent compounds noted under UV and scopoletin titration assays. The antimicrobial marker PR1, β−1,3-glucanase PR2, chitinase PR3, and osmotin PR5 target genes were all upregulated in tobacco leaves following RME1 treatment. The alkaline hydrolysis of RME1 and RME2 combined with HPLC titration of gallic acid revealed that gallate functions were present in both extracts at levels comprised between 185 and 318 mg L−1. HPLC-HR-MS analyses and glucose assay identified four gallate derivatives consisting of a glucose core linked to 5, 6, 7, and 8 gallate groups. These four galloyl glucoses possessed around 46% of total gallate functions. Their higher concentration in RME suggested that they may contribute significantly to PDI activity. These findings define the friendly galloyl glucose as a PDI and highlight a relevant methodology for combining plant assays and chemistry process to their potential quantification in crude natural extracts.
Co-Creating Conceptual and Working Frameworks for Implementing Forest and Landscape Restoration Based on Core Principles
Authors: Chazdon Robin L. , Gutierrez Victoria , Brancalion Pedro H. S. , Laestadius Lars , Guariguata Manuel R.
Published: June 2020

Existing guidelines and best-practices documents do not satisfy, at present, the need for guiding implementation of Forest and Landscape Restoration (FLR) based on core principles. Given the wide range of FLR practices and the varied spectrum of actors involved, a single working framework is unlikely to be effective, but tailored working frameworks can be co-created based on a common conceptual framework (i.e., a common core set of principles and a generalized set of criteria and indicators). We present background regarding FLR concepts, definitions, and principles, and discuss the challenges that confront effective and long-term implementation of FLR. We enumerate the many benefits that a transformative criteria and indicators framework can bring to actors and different sectors involved in restoration when such framework is anchored in the FLR principles. We justify the need to co-develop and apply specifically tailored working frameworks to help ensure that FLR interventions bring social, economic, and environmental benefits to multiple stakeholders within landscapes and adjust to changing conditions over time. Several examples of working FLR frameworks are presented to illustrate the goals and needs of communities, donors and investors, and government agencies. Transparency, feedback, communication, assessment, and adaptive management are important components of all working frameworks. Finally, we describe existing FLR guidelines and what we can learn from them. Working frameworks can be developed and used by different actors who seek to initiate an FLR process and to align restoration actions at different scales and levels.
Personalized Early-Warning Signals during Progression of Human Coronary Atherosclerosis by Landscape Dynamic Network Biomarker
Authors: Ge Jing , Song Chenxi , Zhang Chengming , Liu Xiaoping , Chen Jingzhou , Dou Kefei , Chen Luonan
Published: June 2020

Coronary atherosclerosis is one of the major factors causing cardiovascular diseases. However, identifying the tipping point (predisease state of disease) and detecting early-warning signals of human coronary atherosclerosis for individual patients are still great challenges. The landscape dynamic network biomarkers (l-DNB) methodology is based on the theory of dynamic network biomarkers (DNBs), and can use only one-sample omics data to identify the tipping point of complex diseases, such as coronary atherosclerosis. Based on the l-DNB methodology, by using the metabolomics data of plasma of patients with coronary atherosclerosis at different stages, we accurately detected the early-warning signals of each patient. Moreover, we also discovered a group of dynamic network biomarkers (DNBs) which play key roles in driving the progression of the disease. Our study provides a new insight into the individualized early diagnosis of coronary atherosclerosis and may contribute to the development of personalized medicine.