bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbon Storage in Portland Cement Mortar: Influences of Hydration Stage, Carbonation Time and Aggregate Characteristics
Authors: Abidoye Luqman Kolawole , Das Diganta B.
Published: August 2021

This study elucidates the effects of the particle size, carbonation time, curing time and pressure on the efficiency of carbon storage in Portland cement mortar. Using pressure chamber experiments, our findings show how carbonation efficiency increases with a decrease in the particle size. Approximately 6.4% and 8.2% (w/w) carbonations were achieved in the coarse-sand and fine-sand based mortar samples, respectively. For the hydration/curing time of 7 h, up to 12% carbonation was achieved. This reduced to 8.2% at 40 h curing period. On the pressure effect, for comparable curing conditions, 2 bar at 7 h carbonation time gives 1.4% yield, and 8.2% at 5 bar. Furthermore, analysing the effect of the carbonation time, under comparable conditions, shows that 4 h of carbonation time gives up to 8.2% yield while 64 h of carbonation gives up to 18.5%. It can be reliably inferred that, under similar conditions, carbonation efficiency increases with lower-sized particles or higher-surface areas, increases with carbonation time and higher pressure but decreases with hydration/curing time. Microstructural analyses with X-ray diffraction (XRD) and scanning electron microscopy (SEM) further show the visual disappearance of calcium-silicate-hydrate (C-S-H) together with the inhibition of ettringite formation by the presence of CO2 and CaCO3 formation during carbonation.
An Exploration of Heart Failure Risk in Breast Cancer Patients Receiving Anthracyclines with or without Trastuzumab in Thailand: A Retrospective Study
Authors: Yoodee Jukapun , Sookprasert Aumkhae , Sanguanboonyaphong Phitjira , Chanthawong Suthan , Seateaw Manit , Subongkot Suphat
Published: August 2021

Anthracycline-based regimens with or without anti-human epidermal growth factor receptor (HER) 2 agents such as trastuzumab are effective in breast cancer treatment. Nevertheless, heart failure (HF) has become a significant side effect of these regimens. This study aimed to investigate the incidence and factors associated with HF in breast cancer patients treated with anthracyclines with or without trastuzumab. A retrospective cohort study was performed in patients with breast cancer who were treated with anthracyclines with or without trastuzumab between 1 January 2014 and 31 December 2018. The primary outcome was the incidence of HF. The secondary outcome was the risk factors associated with HF by using the univariable and multivariable cox-proportional hazard model. A total of 475 breast cancer patients were enrolled with a median follow-up time of 2.88 years (interquartile range (IQR), 1.59–3.93). The incidence of HF was 3.2%, corresponding to an incidence rate of 11.1 per 1000 person-years. The increased risk of HF was seen in patients receiving a combination of anthracycline and trastuzumab therapy, patients treated with radiotherapy or palliative-intent chemotherapy, and baseline left ventricular ejection fraction <65%, respectively. There were no statistically significant differences in other risk factors for HF, such as age, cardiovascular comorbidities, and cumulative doxorubicin dose. In conclusion, the incidence of HF was consistently high in patients receiving combination anthracyclines trastuzumab regimens. A reduced baseline left ventricular ejection fraction, radiotherapy, and palliative-intent chemotherapy were associated with an increased risk of HF. Intensive cardiac monitoring in breast cancer patients with an increased risk of HF should be advised to prevent undesired cardiac outcomes.
Evaluation of Adhesion Properties of Hard Coatings by Means of Indentation and Acoustic Emission
Authors: Drobný Peter , Mercier David , Koula Václav , Škrobáková Sára Ivana , Čaplovič Ľubomír , Sahul Martin
Published: August 2021

In general, the mechanical properties of hard thin coatings are investigated using indentation methods. Material characteristics of hard coatings, such as elastic modulus and hardness, are evaluated by means of nanoindentation and an appropriate evaluation methodology. The most popular method used to obtain the coating properties required using nanoindentation is the evaluation based on the Oliver and Pharr methodology. Adhesion and wear properties can be calculated using these data. In this study, we used a novel method to evaluate the wear and adhesion of coatings. A special measuring device combined with static indentation and acoustic emission signal detection was developed to evaluate the adhesion of coatings. The device consists of a macrohardness instrumental indentation device equipped with an acoustic emission measuring gauge. It was used to investigate crack formation and adhesion of coatings deposited on different substrates using acoustic emissions data. The results using both the existing and novel methods were compared and evaluated.
Novel Solid Silicon Oxycarbide Unmodified Carbon Nanotube Composite Coating: Structure, Topography and Mechanical Properties
Authors: Niemiec Wiktor , Owińska Maria , Ferenc Anna , Szuwarzyński Michał , Długoń Elżbieta
Published: August 2021

A silicon oxycarbide-carbon nanotube coating on steel was synthesized using a novel approach utilizing unmodified carbon nanotubes (CNT), silane surfactant and large monomer-based silsesquioxane sol. This enabled the creation of very stable carbon nanotube dispersion, which in turn resulted in homogenous layers obtained in a simple dip-coating process. The samples were annealed in 800 °C in argon to obtain a uniform glassy silicon oxycarbide-based composite from a silsesquioxane precursor. The layers’ morphology and nanomechanical properties were investigated using a number of methods, including infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), nanoindentation, Accelerated Property Mapping (XPM) and Quantitative Nanomechanical Mapping—an Atomic Force Microscopy method (QNM-AFM).
Effect of SiO2 and TiO2 Nanoparticles on the Performance of UV Visible Fluorescent Coatings
Authors: Mahović Poljaček Sanja , Tomašegović Tamara , Leskovšek Mirjam , Stanković Elesini Urška
Published: August 2021

In the present research, the properties of ultraviolet (UV) visible (daylight invisible) fluorescent coatings modified by the addition of SiO2 and TiO2 nanoparticles were studied. Structural, surface, and mechanical properties and changes in the coatings caused by accelerated ageing were analyzed. The results showed that the addition of nanoparticles caused the changes in unaged and aged printed coatings. Reflectance measurements of modified coatings showed that addition of TiO2 nanoparticles improved the visual effect of the unaged coatings. Furthermore, results have shown that the addition of SiO2 did not diminish the reflectance of the modified coatings after ageing. The results of roughness measurements showed that the addition of SiO2 decreased roughness after the ageing process, probably due to the degradation process indicated by Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy. The roughness of the coatings with TiO2 nanoparticles was increased after the ageing on the samples with higher concentrations of TiO2 due to the agglomerates of plastisol formed on the surface of the coatings, visible in SEM images. Surface analysis of coatings showed that TiO2 caused an increase in the polarity of the surface coatings. Results of the bending stiffness showed that the addition of the nanoparticles to the coating, especially of SiO2, significantly improved the bending stiffness of the unaged samples.
Int3D: A Data Reduction Software for Single Crystal Neutron Diffraction
Authors: Katcho Nebil A. , Cañadillas-Delgado Laura , Fabelo Oscar , Fernández-Díaz María Teresa , Rodríguez-Carvajal Juan
Published: August 2021

We describe a new software package for the data reduction of single crystal neutron diffraction using large 2D detectors. The software consists of a graphical user interface from which the user can visualize, interact with and process the data. The data reduction is achieved by sequentially executing a series of programs designed for performing the following tasks: peak detection, indexing, refinement of the orientation matrix and motor offsets, and integration. The graphical tools of the software allow visualization of and interaction with the data in two and three dimensions, both in direct and reciprocal spaces. They make it easy to validate the different steps of the data reduction and will be of great help in the treatment of complex problems involving incommensurate structures, twins or diffuse scattering.
Vortex Laser Based on a Plasmonic Ring Cavity
Authors: Wang Xingyuan , Hu Xiaoyong , Zhai Tianrui
Published: August 2021

The orbital angular momentum (OAM) of the structure light is viewed as a candidate for enhancing the capacity of information processing. Microring has advantages in realizing the compact lasers required for on-chip applications. However, as the clockwise and counterclockwise whispering gallery modes (WGM) appear simultaneously, the emitted light from the normal microring does not possess net OAM. Here, we propose an OAM laser based on the standing-wave WGMs containing clockwise and counterclockwise WGM components. Due to the inhomogeneous intensity distribution of the standing-wave WGM, the single-mode lasing for the OAM light can be realized. Besides, the OAM of the emitted light can be designed on demand. The principle and properties of the proposed laser are demonstrated by numerical simulations. This work paves the way for exploring a single-mode OAM laser based on the plasmonic standing-wave WGMs at the microscale, which can be served as a basic building block for on-chip optical devices.
Sol–Gel Method Applied to Crystalline Materials
Authors: Dell’Era Alessandro , Catauro Michelina
Published: August 2021

Sol–gel chemistry is a versatile synthesis used to produce modern materials at near-room temperature [...]
Fabrication of Nanosize ZnO and Zn1−xFexO Powder for Infrared Absorption by Flame Aerosol Synthesis
Authors: Tian Hui , Wang Lei , Yang Taisheng , Zhang Zili
Published: August 2021

In this study, nanosized ZnO and Zn1−xFexO powders were synthesized using the flame aerosol synthesis (FAS) method. The microstructure of the ZnO powder shows a significant difference with different precursor concentrations. By adding Fe to the precursor, nanosized Zn1−xFexO powder (x = 0~0.1) can be easily fabricated. The phase formation, microstructure, and infrared absorption properties were systematically investigated by XRD, SEM, TEM, and IR. With the substitution of Fe into the Zn site, lattice distortion occurred, resulting in excellent infrared absorption properties. Compared to other conventional synthesis methods, the FAS method has the advantages of high yield, high crystallinity, and low cost; furthermore, nanosized powder is easily obtained. The FAS method is believed to be one of the best choices for the large-scale production of ZnO and Zn1−xFexO powders.
Tutorial on Chemical Pressure Analysis: How Atomic Packing Drives Laves/Zintl Intergrowth in K3Au5Tl
Authors: Lu Erdong , Van Buskirk Jonathan S. , Cheng Jingxiang , Fredrickson Daniel C.
Published: August 2021

The tight atomic packing generally exhibited by alloys and intermetallics can create the impression of their being composed of hard spheres arranged to maximize their density. As such, the atomic size factor has historically been central to explanations of the structural chemistry of these systems. However, the role atomic size plays structurally has traditionally been inferred from empirical considerations. The recently developed DFT-Chemical Pressure (CP) analysis has opened a path to investigating these effects with theory. In this article, we provide a step-by-step tutorial on the DFT-CP method for non-specialists, along with advances in the approach that broaden its applicability. A new version of the CP software package is introduced, which features an interactive system that guides the user in preparing the necessary electronic structure data and generating the CP scheme, with the results being readily visualized with a web browser (and easily incorporated into websites). For demonstration purposes, we investigate the origins of the crystal structure of K3Au5Tl, which represents an intergrowth of Laves and Zintl phase domains. Here, CP analysis reveals that the intergrowth is supported by complementary CP features of NaTl-type KTl and MgCu2-type KAu2 phases. In this way, K3Au5Tl exemplifies how CP effects can drive the merging for geometrical motifs derived from different families of intermetallics through a mechanism referred to as epitaxial stabilization.
Optofluidic Platform Based on Liquid Crystals in X-Cut Lithium Niobate: Thresholdless All-Optical Response
Authors: Ciciulla Fabrizio , Zaltron Annamaria , Zamboni Riccardo , Sada Cinzia , Simoni Francesco , Reshetnyak Victor Yu. , Lucchetti Liana
Published: August 2021

In this study, we present a new configuration of the recently reported optofluidic platform exploiting liquid crystals reorientation in lithium niobate channels. In order to avoid the threshold behaviour observed in the optical control of the device, we propose microchannels realized in a x-cut crystal closed by a z-cut crystal on the top. In this way, the light-induced photovoltaic field is not uniform inside the liquid crystal layer and therefore the conditions for a thresholdless reorientation are realized. We performed simulations of the photovoltaic effect based on the well assessed model for Lithium Niobate, showing that not uniform orientation and value of the field should be expected inside the microchannel. In agreement with the re-orientational properties of nematic liquid crystals, experimental data confirm the expected thresholdless behaviour. The observed liquid crystal response exhibits two different regimes and the response time shows an unusual dependence on light intensity, both features indicating the presence of additional photo-induced fields appearing above a light intensity of 107 W/m2.
Bermuda’s Walsingham Caves: A Global Hotspot for Anchialine Stygobionts
Authors: Iliffe Thomas M. , Calderón-Gutiérrez Fernando
Published: August 2021

Bermuda is an Eocene age volcanic island in the western North Atlantic, entirely capped by Pleistocene eolian limestone. The oldest and most highly karstified limestone is a 2 km2 outcrop of the Walsingham Formation containing most of the island’s 150+ caves. Extensive networks of submerged cave passageways, flooded by saltwater, extend under the island. In the early 1980s, cave divers initially discovered an exceptionally rich and diverse anchialine community inhabiting deeper sections of the caves. The fauna inhabiting caves in the Walsingham Tract consists of 78 described species of cave-dwelling invertebrates, including 63 stygobionts and 15 stygophiles. Thus, it represents one of the world’s top hotspots of subterranean biodiversity. Of the anchialine fauna, 65 of the 78 species are endemic to Bermuda, while 66 of the 78 are crustaceans. The majority of the cave species are limited in their distribution to just one or only a few adjacent caves. Due to Bermuda’s high population density, water pollution, construction, limestone quarries, and trash dumping produce severe pressures on cave fauna and groundwater health. Consequently, the IUCN Red List includes 25 of Bermuda’s stygobiont species as critically endangered.
Testing a Deep Learning Algorithm for Detection of Diabetic Retinopathy in a Spanish Diabetic Population and with MESSIDOR Database
Authors: Baget-Bernaldiz Marc , Pedro Romero-Aroca , Santos-Blanco Esther , Navarro-Gil Raul , Valls Aida , Moreno Antonio , Rashwan Hatem A. , Puig Domenec
Published: August 2021

Background: The aim of the present study was to test our deep learning algorithm (DLA) by reading the retinographies. Methods: We tested our DLA built on convolutional neural networks in 14,186 retinographies from our population and 1200 images extracted from MESSIDOR. The retinal images were graded both by the DLA and independently by four retina specialists. Results of the DLA were compared according to accuracy (ACC), sensitivity (S), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic curve (AUC), distinguishing between identification of any type of DR (any DR) and referable DR (RDR). Results: The results of testing the DLA for identifying any DR in our population were: ACC = 99.75, S = 97.92, SP = 99.91, PPV = 98.92, NPV = 99.82, and AUC = 0.983. When detecting RDR, the results were: ACC = 99.66, S = 96.7, SP = 99.92, PPV = 99.07, NPV = 99.71, and AUC = 0.988. The results of testing the DLA for identifying any DR with MESSIDOR were: ACC = 94.79, S = 97.32, SP = 94.57, PPV = 60.93, NPV = 99.75, and AUC = 0.959. When detecting RDR, the results were: ACC = 98.78, S = 94.64, SP = 99.14, PPV = 90.54, NPV = 99.53, and AUC = 0.968. Conclusions: Our DLA performed well, both in detecting any DR and in classifying those eyes with RDR in a sample of retinographies of type 2 DM patients in our population and the MESSIDOR database.
Using Non-Contrast MRA to Discriminate between Obstructive and Nonobstructive Venous Diseases of the Legs
Authors: Chen Chien-Wei , Tseng Yuan-Hsi , Wong Min Yi , Lin Yu-Hui , Yang Teng-Yao , Hsu Yin-Chen , Lin Bor-Shyh , Huang Yao-Kuang
Published: August 2021

Background: Venous interventions of the legs are less predictable owing to a lock of objective tools. Methods: One hundred and twenty patients with lower extremity venous disease were evaluated anatomically using TRANCE MRI. Then, a QFlow analysis was performed in 53 patients with only one leg affected for hemodynamic evaluation. Those patients with complete QFlow were classified into obstructive and nonobstructive. Results: The QFlow—namely, stroke volume, forward flow volume, mean flux, stroke distance (SD), and mean velocity (MV) in the external iliac vein (EIV), femoral vein (FV), popliteal vein (PV), and great saphenous vein (GSV). The obstructed group had a shorter SD and lower MV in the EIV, EIV/FV, and GSV/PV (SD: p-values of 0.025, 0.05, and 0.043, respectively; MV: p-values of 0.02, 0.05, and 0.048, respectively). A good performance in discriminating obstructive venous disease was reported for SD in the EIV (area under the curve (AUC) = 67.9%, 95% confidence interval (CI) = 53.2–82.7%), EIV/FV (AUC = 72.4%, 95% CI = 58.2–86.5%), and GSV/PV (AUC = 67.9%, 95% CI = 51.7–84.1%). The SD in the EIV, EIV/FV, and GSV/PV had the ability to discriminate between obstructive and nonobstructive diseases (p-values of 0.025, 0.005, and 0.043). The MV in the EIV, EIV/FV, and GSV/PV had ability to discriminate between obstructive and nonobstructive venous diseases (p-values of 0.02, 0.005, and 0.048). Conclusions: The SD and MV were lower for obstructive than nonobstructive disease in the EIV.
Liver Injury and Use of Contrast-Enhanced Ultrasound for Evaluating Intrahepatic Recurrence in a Case of TACE-Refractory Hepatocellular Carcinoma Receiving Atezolizumab-Bevacizumab Combination Therapy: A Case Report
Authors: Komiyama Satoshi , Numata Kazushi , Ogushi Katsuaki , Chuma Makoto , Tanaka Reiko , Chiba Sawako , Otani Masako , Inayama Yoshiaki , Nakano Masayuki , Maeda Shin
Published: August 2021

A 67-year-old male with type 2 diabetes (T2DM) was diagnosed with postoperative intrahepatic recurrence for hepatocellular carcinoma (HCC). Nine sessions of transarterial chemoembolization (TACE) proved ineffective, and the patient was diagnosed as having TACE-refractory disease and received seven cycles of atezolizumab–bevacizumab combination therapy. After that, the patient developed hyperglycemia with the HbA1c elevation and the marked fasting serum C-peptide reduction and was diagnosed with developed immune-mediated diabetes (IMD) (T2DM exacerbation with insulin-dependent diabetes development). Subsequently, the hepatobiliary enzyme levels, which were high before the systemic therapy, worsened. Thus, we clinically diagnosed an exacerbation of liver injury due to TACE-induced liver injury complicated by drug-induced liver injury such as immune-mediated hepatotoxicity (IMH). Meanwhile, after contrast-enhanced computed tomography revealed complete response, contrast-enhanced ultrasound was performed to assess intrahepatic recurrence. We found that the latter modality allowed earlier and more definitive diagnosis of intrahepatic recurrence of HCC. Subsequently, despite systemic therapy discontinuation and steroids administration, the liver injury worsened, and the patient died. The autopsy revealed intrahepatic recurrence of HCC and extensive arterial obstruction by the beads used for TACE within the liver, which indicated that disturbed circulation was the primary cause of the liver injury and histopathologically confirmed IMD, but not IMH.
Coherent Superpositions of Photon Creation Operations and Their Application to Multimode States of Light
Authors: Biagi Nicola , Francesconi Saverio , Zavatta Alessandro , Bellini Marco
Published: August 2021

We present a concise review of recent experimental results concerning the conditional implementation of coherent superpositions of single-photon additions onto distinct field modes. Such a basic operation is seen to give rise to a wealth of interesting and useful effects, from the generation of a tunable degree of entanglement to the birth of peculiar correlations in the photon numbers and the quadratures of multimode, multiphoton, states of light. The experimental investigation of these properties will have an impact both on fundamental studies concerning, for example, the quantumness and entanglement of macroscopic states, and for possible applications in the realm of quantum-enhanced technologies.
C-GCN: A Flexible CSI Phase Feature Extraction Network for Error Suppression in Indoor Positioning
Authors: Liu Wen , Cheng Qianqian , Deng Zhongliang , Jia Mingjie
Published: August 2021

Channel state information (CSI) provides a fine-grained description of the signal propagation process, which has attracted extensive attention in the field of indoor positioning. However, considering the influence of environment and hardware, the phase of CSI is distorted in most cases. It is difficult to extract effective location features in multiple scenes only through the determined artificial experience model. Graph neural network has performed well in many fields in recent years, but there is still a lot of room to explore in the field of indoor positioning. In this paper, a phase feature extraction network based on multi-dimensional correlation is proposed, named Cooperation-Graph Convolution Network (C-GCN). The purpose of C-GCN is to extract new features of multiple correlation and to mine the relationship between antenna and subcarrier as much as possible. C-GCN is composed of convolution layer and graph convolution layer. In the graph convolution layer, C-GCN regards each subcarrier of each antenna as a node in the graph network, constructs the connection by the correlation between the antenna and the subcarrier, and aggregates the node vectors by graph convolution. In the convolution layer, there is a natural corresponding structure between data packets, C-GCN extracts the fluctuation with convolution in Euclidean space. C-GCN combines these two layers, and applies end-to-end supervised training to obtain effective features. Extensive experiments are conducted in typical indoor environments to verify the superior performance of C-GCN in restraining error tailing. The average positioning error of C-GCN is 1.29 m in comprehensive office and 1.71 m in garage. Combined with the amplitude feature, the average positioning error is 0.99 m in comprehensive office and 1.14 m in garage.
Market Choices Driven by Reference Groups: A Comparison of Analytical and Simulation Results on Random Networks
Authors: Ramsza Michał
Published: August 2021

The present paper reports simulation results for a simple model of reference group influence on market choices, e.g., brand selection. The model was simulated on three types of random graphs, Erdos–Renyi, Barabasi–Albert, and Watts–Strogatz. The estimates of equilibria based on the simulation results were compared to the equilibria of the theoretical model. It was verified that the simulations exhibited the same qualitative behavior as the theoretical model, and for graphs with high connectivity and low clustering, the quantitative predictions offered a viable approximation. These results allowed extending the results from the simple theoretical model to networks. Thus, by increasing the positive response towards the reference group, the third party may create a bistable situation with two equilibria at which respective brands dominate the market. This task is easier for large reference groups.
Ocean I3. Pedagogical Innovation for Sustainability
Authors: Rekalde-Rodríguez Itziar , Barrenechea Julieta , Hernandez Yannick
Published: August 2021

Universities are undertaking transformation projects that align their work with the Sustainable Development Goals. This paper describes how Ocean I3, an educational innovation project that aims to reduce plastic in the sea, has made an impact on its community over its three editions (2018/19 to 2020/21). Methodologically, it has been approached by the people who make up the technical team and academic coordination as an exploratory study using discrete, non-reactive techniques, mainly from the public domain (websites, blogs, press releases, etc.), and instruments, such as field notes and work material to manage, organize, and train within the project. The analytical procedure has represented a dynamic and systematic process of categorisation. The results highlight the repercussion of the project in terms of capstone projects, master’s thesis, coursework, etc., produced by the students involved; association with employability; collaborative work from the teaching teams; monitoring experience for research purposes, and social dissemination of the project. It concludes by suggesting lines for Ocean I3 to work on in the future to make its footprint sustainable in institutions over time.
Recent Meta-Heuristic Algorithms with a Novel Premature Covergence Method for Determining the Parameters of PV Cells and Modules
Authors: Abdel-Basset Mohamed , Mohamed Reda , Abouhawwash Mohamed , Nam Yunyoung , El-Fergany Attia
Published: August 2021

Currently, the incorporation of solar panels in many applications is a booming trend, which necessitates accurate simulations and analysis of their performance under different operating conditions for further decision making. In this paper, various optimization algorithms are addressed comprehensively through a comparative study and further discussions for extracting the unknown parameters. Efficient use of the iterations within the optimization process may help meta-heuristic algorithms in accelerating convergence plus attaining better accuracy for the final outcome. In this paper, a method, namely, the premature convergence method (PCM), is proposed to boost the convergence of meta-heuristic algorithms with significant improvement in their accuracies. PCM is based on updating the current position around the best-so-far solution with two-step sizes: the first is based on the distance between two individuals selected randomly from the population to encourage the exploration capability, and the second is based on the distance between the current position and the best-so-far solution to promote exploitation. In addition, PCM uses a weight variable, known also as a controlling factor, as a trade-off between the two-step sizes. The proposed method is integrated with three well-known meta-heuristic algorithms to observe its efficacy for estimating efficiently and effectively the unknown parameters of the single diode model (SDM). In addition, an RTC France Si solar cell, and three PV modules, namely, Photowatt-PWP201, Ultra 85-P, and STM6-40/36, are investigated with the improved algorithms and selected standard approaches to compare their performances in estimating the unknown parameters for those different types of PV cells and modules. The experimental results point out the efficacy of the PCM in accelerating the convergence speed with improved final outcomes.
Quadrature Demodulator-Assisted Estimation of Load Voltage and Resistance Based on Primary-Side Information of a Wireless Power Transfer Link
Authors: Trachtenberg Or , Kuperman Alon
Published: August 2021

This paper proposes an algorithm for the extraction of primary-side first harmonic voltage and current components for inductive wireless power transfer (WPT) links by employing quadrature demodulation. Such information allows for the accurate estimation of corresponding receiver-side components and hence permits the monitoring of the output voltage and resistance necessary for protection and/or control without using either sensors or feedback communication. It is shown that precision estimation is held as long as the parameter values of the system are known and the phasor-domain equivalent circuit is valid (i.e., in continuous conduction mode). On the other hand, upon light load operation (i.e., in discontinuous conduction mode), the proposed technique may still be employed if suitable nonlinear correction is employed. The methodology is applied to a 400 V, 1 kW inductive WPT link operating at a load-independent-voltage-output frequency and is well-verified both by simulations and experiments.
An Estimation of the Lightweight Potential of Battery Electric Vehicles
Authors: Nicoletti Lorenzo , Romano Andrea , König Adrian , Köhler Peter , Heinrich Maximilian , Lienkamp Markus
Published: August 2021

Although battery electric vehicles (BEVs) are locally emission-free and assist automakers in reducing their carbon footprint, two major disadvantages are their shorter range and higher production costs compared to combustion engines. These drawbacks are primarily due to the battery, which is generally the heaviest and most expensive component of a BEV. Lightweight measures (strategies to decrease vehicle mass, e.g., by changing materials or downsizing components) lower energy consumption and reduce the amount of battery energy required (and in turn battery costs). Careful selection of lightweight measures can result in their costs being balanced out by a commensurate reduction in battery costs. This leads to a higher efficiency vehicle, but without affecting its production and development costs. In this paper, we estimate the lightweight potential of BEVs, i.e., the cost limit below which a lightweight measure is fully compensated by the cost savings it generates. We implement a parametric energy consumption and mass model and apply it to a set of BEVs. Subsequently, we apply the model to quantify the lightweight potential range (in €/kg) of BEVs. The findings of this paper can be used as a reference for the development of cheaper, lighter, and more energy-efficient BEVs.
A Free-Market Environmentalist Transition toward Renewable Energy: The Cases of Germany, Denmark, and the United Kingdom
Authors: Wang William , Moreno-Casas Vicente , Huerta de Soto Jesús
Published: August 2021

Renewable energy (RE) is one of the most popular public policy orientations worldwide. Compared to some other countries and continents, Europe has gained an early awareness of energy and environmental problems in general. At the theoretical level, free-market environmentalism indicates that based on the principle of private property rights, with fewer state interventionist and regulation policies, entrepreneurs, as the driving force of the market economy, can provide better services to meet the necessity of offering RE to protect the environment more effectively. Previous studies have revealed that Germany, Denmark, and the United Kingdom have made some progress in using the market to develop RE. However, this research did not analyze the three countries’ RE conditions from the perspective of free-market environmentalism. Based on our review of the principles of free-market environmentalism, this paper originally provides an empirical study of how Germany, Denmark, and the United Kingdom have partly conducted free-market-oriented policies to successfully achieve their policy goal of RE since the 1990s on a practical level. In particular, compared with Germany and Denmark, the UK has maintained a relatively low energy tax rate and opted for more pro-market measures since the Hayekian-Thatcherism free-market reform of 1979. The paper also discovers that Fredrich A. Hayek’s theories have strongly impacted its energy liberalization reform agenda since then. Low taxes on the energy industry and electricity have alleviated the burden on the electricity enterprises and consumers in the UK. Moreover, the empirical results above show that the energy enterprises play essential roles in providing better and more affordable RE for household and industrial users in the three sampled countries. Based on the above results, the paper also warns that state intervention policies such as taxation, state subsidies, and industrial access restrictions can impede these three countries’ RE targets. Additionally, our research provides reform agendas and policy suggestions to policymakers on the importance of implementing free-market environmentalism to provide more efficient RE in the post-COVID-19 era.
A Comparison of Lane Marking Detection Quality and View Range between Daytime and Night-Time Conditions by Machine Vision
Authors: Babić Darko , Babić Dario , Fiolić Mario , Eichberger Arno , Magosi Zoltan Ferenc
Published: August 2021

Lateral support systems in vehicles have a high potential for reduction of lane departure crashes. To profit from their full potential, such systems should function properly in adverse conditions. Literature indicates that their accuracy varies between day and night-time. However, detailed quantifications of the systems’ performance in these conditions are rare. The aim of this study is to investigate the differences in detection quality and view range of Mobileye 630 in dry daytime and night-time conditions. On-road tests on four rural road sections in Croatia were conducted. Wilcoxon signed-rank test was used to test the difference between the number of quality rankings while absolute average, average difference and standard deviation were used to analyse the view range. Also, a paired samples t-test was used to test the difference between conditions for each line on each road. The overall results confirm that a significant difference in lane detection quality view range exists between tested conditions. “Medium” and “high” detection confidence (quality level 3 and 2), increased by 5% and 8% during night-time compared to daytime while level 0 (“nothing detected”) decreased by 12%. The view range increased (almost 16% for middle line) during daytime compared to night-time. The findings of this study expand the existing knowledge and are valuable for research and development of machine-vision systems but also for road authorities to optimize the markings’ quality performance.
Steady-State Control of Fuel Cell Based on Boost Mode of a Dual Winding Motor
Authors: Chang Cheng , Chang Weibin , Ma Jiangang , Zhou Yafu
Published: August 2021

In recent years, a dual winding motor drive has been proposed in the field of fuel cell vehicles due to its advantages of good performance and high robustness. This new topology and its basic control method have been widely investigated. However, the previous research has not considered the current dynamic property of a fuel cell when studying the power sharing control method, but this is an important research objective for fuel cell durability. Considering the current change principle of a fuel cell, an optimal steady-state control method based on a new dual winding motor architecture boost charging is proposed to optimize the fuel cell life. In addition, in view of the current circulation problem of the fuel cell side winding in the boost mode, a Bang-Bang-PI control algorithm with a relatively constant reference value is proposed to realize the current sharing control. On this basis, the optimized control of the output current ripple of the fuel cell is realized to ensure the steady-state of the proton exchange membrane fuel cell (PEMFC). Finally, the results show that this method can control the stability of the fuel cell efficiently.
Utility-Scale PV-Battery versus CSP-Thermal Storage in Morocco: Storage and Cost Effect under Penetration Scenarios
Authors: Bouramdane Ayat-allah , Tantet Alexis , Drobinski Philippe
Published: August 2021

In this study, we examine how Battery Storage (BES) and Thermal Storage (TES) combined with solar Photovoltaic (PV) and Concentrated Solar Power (CSP) technologies with an increased storage duration and rental cost together with diversification would influence the Moroccan mix and to what extent the variability (i.e., adequacy risk) can be reduced; this is done using recent (2013) cost data and under various penetration scenarios. To do this, we use MERRA-2 climate reanalysis to simulate hourly demand and capacity factors (CFs) of wind, solar PV and CSP without and with increasing storage capabilities—as defined by the CSP Solar Multiple (SM) and PV Inverter Loading Ratio (ILR). We adjust these time series to observations for the four Moroccan electrical zones over the year 2018. Our objective is to maximize the renewable (RE) penetration and minimize the imbalances between RE production and consumption considering three optimization strategies. We analyze mixes along Pareto fronts using the Mean-Variance Portfolio approach—implemented in the E4CLIM model—in which we add a maximum-cost constraint to take into account the different rental costs of wind, PV and CSP. We propose a method to calculate the rental cost of storage and production technologies taking into account the constraints on storage associated with the increase of SM and ILR in the added PV-BES and CSP-TES modules, keeping the mean solar CFs fixed. We perform some load bands-reduction diagnostics to assess the reliability benefits provided by each RE technology. We find that, at low penetrations, the maximum-cost budget is not reached because a small capacity is needed. The higher the ILR for PV, the larger the share of PV in the mix compared to wind and CSP without storage is removed completely. Between PV-BES and CSP-TES, the latter is preferred as it has larger storage capacity and thus stronger impact in reducing the adequacy risk. As additional BES are installed, more than TES, PV-BES is favored. At high penetrations, optimal mixes are impacted by cost, the more so as CSP (resp., PV) with high SM (resp., ILR) are installed. Wind is preferably installed due to its high mean CF compared to cost, followed by either PV-BES or CSP/CSP-TES. Scenarios without or with medium storage capacity favor CSP/CSP-TES, while high storage duration scenarios are dominated by low-cost PV-BES. However, scenarios ignoring the storage cost and constraints provide more weight to PV-BES whatever the penetration level. We also show that significant reduction of RE variability can only be achieved through geographical diversification. Technological complementarity may only help to reduce the variance when PV and CSP are both installed without or with a small amount of storage. However, the diversification effect is slightly smaller when the SM and ILR are increased and the covariances are reduced as well since mixes become less diversified.
Tactical Risk Assessment Method for Resilient Fuel Supply Chains for a Military Peacekeeping Operation
Authors: Ryczyński Jacek , Tubis Agnieszka A.
Published: August 2021

The article focuses on research on the functioning of liquid fuel supply chains, supplying troops carrying out peacekeeping and stabilisation operations in a foreign territory. Timely and complete supplies of fuels in war conditions determine the achievement of the assumed goals of a military operation. They often determine the health and life of soldiers. For this reason, the role of building the resilience of supply chains to disruptions, the type and frequency of which is entirely different from the undesirable events occurring in civil goods flows, is increasing. Therefore, the critical concept supporting building the resilience of fuel supply chains is risk management in these chains. The authors have developed a risk analysis method that integrates the Kaplan and Garrick approach and the fuzzy theory. The analysis identifies the existing disturbances and assigns them to the individual phases of the supply process. To illustrate the applicability of the proposed method, the authors analyse nine scenarios for the three most important stages of the procurement process in terms of building the resilience of the entire chain: Planning, delivery and storage. The fuzzy theory estimates the risk level for the analysed scenarios of adverse events. The proposed method is universal. It can be implemented to analyse the resistance of supply chains of other materials. It can also support the decision-making process for those responsible for planning, organisation and proper functioning of supply systems in all high-risk conditions, not only in the zone of war and stabilisation operations.
Transition Modeling for Low Pressure Turbines Using Computational Fluid Dynamics Driven Machine Learning
Authors: Akolekar Harshal D. , Waschkowski Fabian , Zhao Yaomin , Pacciani Roberto , Sandberg Richard D.
Published: August 2021

Existing Reynolds Averaged Navier–Stokes-based transition models do not accurately predict separation induced transition for low pressure turbines. Therefore, in this paper, a novel framework based on computational fluids dynamics (CFD) driven machine learning coupled with multi-expression and multi-objective optimization is explored to develop models which can improve the transition prediction for the T106A low pressure turbine at an isentropic exit Reynolds number of Re2is=100,000. Model formulations are proposed for the transfer and laminar eddy viscosity terms of the laminar kinetic energy transition model using seven non-dimensional pi groups. The multi-objective optimization approach makes use of cost functions based on the suction-side wall-shear stress and the pressure coefficient. A family of solutions is thus developed, whose performance is assessed using Pareto analysis and in terms of physical characteristics of separated-flow transition. Two models are found which bring the wall-shear stress profile in the separated region at least two times closer to the reference high-fidelity data than the baseline transition model. As these models are able to accurately predict the flow coming off the blade trailing edge, they are also able to significantly enhance the wake-mixing prediction over the baseline model. This is the first known study which makes use of ‘CFD-driven’ machine learning to enhance the transition prediction for a non-canonical flow.
Insulation Performance Comparison of Curtain Wall Systems with Existing Pipe Frames and Truss-Shaped Insulation Frames
Authors: Choi Bo-Hye , Song Seung-Yeong
Published: August 2021

The purpose of this study was to compare insulation performance between a base case that applied the existing steel pipe frame and an alternative case that reduced thermal bridging by applying a truss-shaped insulation frame (TIF) to a back frame type curtain wall. Insulation performance was compared by obtaining the effective U-factor and the lowest indoor surface temperature through a three-dimensional steady-state heat transfer simulation. In addition, mock-up tests were performed to compare the U-factors of the base case and alternative case. The simulation results showed that the effective U-factor of the alternative case was 36% lower than in the base case, a significant heat loss reduction. The lowest indoor surface temperature of the alternative case was 0.5 °C higher than in the base case, showing that the surface condensation risk also decreased. In the mock-up test results, the alternative case U-factor was 33% lower than in the base case, confirming the associated large heat loss reduction. For the base case, both the effective U-factor by simulation and the U-factor by the mock-up test were much higher than the design U-factor according to the Korean Design Standard, which neglects thermal bridging, indicating a significantly increased heat loss caused by this factor. For the alternative case, however, both U-factors were similar to the design U-factor.
Comparison of Semi-Empirical Single Point Wall Pressure Spectrum Models with Experimental Data
Authors: Thomson Nicholas , Rocha Joana
Published: August 2021

This study presents an evaluation of semi-empirical single-point wall pressure spectrum models by comparing model predictions with wind tunnel and flight test data. The mean squared error was used to compare the power spectral density of the wall pressure fluctuations predicted by semi-empirical models with a large amount of experimental data. Results show that the models proposed by Goody and Smol’yakov have the lowest mean squared error when predicting the power spectral density for wind tunnel experiments and the Rackl and Weston model has the lowest mean squared error when predicting the power spectral density for flight test data. In addition, although current studies of the power spectra obtained in the wind tunnel are similar, they are not generally an accurate representation of flight test experiments.
The Chemical, Structural, and Biological Properties of Crude Polysaccharides from Sweet Tea (Lithocarpus litseifolius (Hance) Chun) Based on Different Extraction Technologies
Authors: Guo Huan , Fu Meng-Xi , Zhao Yun-Xuan , Li Hang , Li Hua-Bin , Wu Ding-Tao , Gan Ren-You
Published: August 2021

Eight extraction technologies were used to extract sweet tea (Lithocarpus litseifolius (Hance) Chun) crude polysaccharides (STPs), and their chemical, structural, and biological properties were studied and compared. Results revealed that the compositions, structures, and biological properties of STPs varied dependent on different extraction technologies. Protein-bound polysaccharides and some hemicellulose could be extracted from sweet tea with diluted alkali solution. STPs extracted by deep-eutectic solvents and diluted alkali solution exhibited the most favorable biological properties. Moreover, according to the heat map, total phenolic content was most strongly correlated with biological properties, indicating that the presence of phenolic compounds in STPs might be the main contributor to their biological properties. To the best of our knowledge, this study reports the chemical, structural, and biological properties of STPs, and the results contribute to understanding the relationship between the chemical composition and biological properties of STPs.