bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced Anticorrosion Properties through Structured Particle Design of Waterborne Epoxy-Styrene-Acrylate Composite Emulsion
Authors: Zhang Kai , Chen Xifang , Xiao Yuling , Liu Rujia , Liu Jie
Published: November 2021

In order to develop a waterborne epoxy-styrene–acrylate composite latex with a better stability and anticorrosion resistance, a novel synthetic approach has been proposed. First, modified by methyl acrylic, epoxy resin containing terminal C=C double bonds was successfully synthesized, where epoxide groups were partially retained. Then, by structural design and multi-stage seed emulsion copolymerization, a stable waterborne epoxy-styrene-acrylate composite latex composed of a modified epoxy resin acrylate polymer as the core, inert polystyrene ester as the intermediate layer, and carboxyl acrylate polymer as the shell was successfully fabricated. The structure of the obtained latex was characterized by fourier transform infrared (FTIR) and transmission electron microscopy (TEM). The stability of the composite latex was tested based on the wet gel weight, Zeta potential, and storage stability, and the corrosion resistance of the composite latex films was analyzed by electrochemical measurements and salt spray tests. The thickness of each layer of the composite latex was calculated by the temperature random multi-frequency modulation DSC (TOPEM-DSC) technique. In addition to the successful emulsion copolymerization that occurred between the modified epoxy resin and acrylate monomer, the presence of carboxyl groups in the obtained latex was evidenced, while the epoxide groups were partially retained. The anticorrosion resistance and stability of the multilayer composite latex with the intermediate layer are better than that of the conventional core-shell latex. The outstanding stability and corrosion resistance is attributed to the multilayer core-shell structure. The TOPEM-DSC approach can accurately determine the thickness of the intermediate layer in the multilayer core-shell particles and is a new strategy for characterizing the core-shell structure of polymer particles with a similar monomer composition.
Investigation on Optimal Ta/Cr Ratio of a Single Crystal Ni-Base Superalloy in View of the Isothermal Oxidation Behavior
Authors: Chang Jianxiu , Feng Wenhao , Zhao Wenwen , Jia Hongmin , Liu Yanming , Luo Sheji , Wang Dong , Dong Jiasheng
Published: November 2021

The relative content of strengthening element tantalum (Ta) and oxidation-resistant element chromium (Cr) is an essential value for superalloys to obtain an excellent combination of oxidation resistance and mechanical properties. In the present paper, the isothermal oxidation behavior of several single crystal Ni-base superalloys with different Ta/Cr (wt. %, similarly hereinafter) ratios at 1000 °C in static air has been systematically investigated to explore the optimal Ta/Cr for excellent oxidation resistance. A detailed microstructure study using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and an electro-probe microanalyzer (EPMA) was performed to reveal the oxidation products and mechanisms. For all alloys, a three-layer structured scale consisting of an outer (Cr, Al, Ti, Ni, Ta)-O layer, an inner Al2O3 layer and an inner nitride layer was formed. As Ta/Cr increased, the amounts of Ta-containing products, cracks, holes and inner nitride increased. Meanwhile, the completeness of the Al2O3 layer got worse. It was shown that if Ta/Cr ≤ 0.5, Ta increased the growth rate of Cr2O3 via the doping effect induced by Ta cations. If Ta/Cr > 0.5, Ta reduced the completeness of Cr2O3 through competitive growth of Ta2O5 and Cr2O3. A good oxidation performance can be expected with the value Ta/Cr ≤ 0.5.
New Low-Dimensional Hybrid Perovskitoids Based on Lead Bromide with Organic Cations from Charge-Transfer Complexes
Authors: Nikovskiy Igor A. , Isakovskaya Kseniya L. , Nelyubina Yulia V.
Published: November 2021

We have obtained a series of low-dimensional hybrid perovskitoids (often referred to as perovskites) based on lead bromide. As organic cations, the derivatives of polyaromatic and conjugated molecules, such as anthracene, pyrene and (E)-stilbene, were chosen to form charge-transfer complexes with various organic acceptors for use as highly tunable components of hybrid perovskite solar cells. X-ray diffraction analysis showed these crystalline materials to be new 1D- and pseudo-layered 0D-perovskitoids with lead bromide octahedra featuring different sharing modes, such as in unusual mini-rods of four face- and edge-shared octahedra. Thanks to the low dimensionality, they can be of use in another type of optoelectronic device, photodetectors.
The Influence of Ni-Added Fe-Based Pre-Alloy on Microstructure Evolution and Lifetime Extension of Diamond Tools
Authors: Pu Juan , Sun Yubo , Long Weimin , Wu Mingfang , Liu Dashuang , Zhong Sujuan , Xue Songbai
Published: November 2021

Diamond tools were prepared by sintering Fe-Cu-Sn-Zn-Ni pre-alloyed powders and diamonds. The effects of Ni contents in pre-alloyed powders on microstructure evolution of Fe-based matrix, the properties of Fe-based matrix and the service life of diamond tools were investigated. The results showed that adding 3~15 wt.% Ni into the Fe-Cu-Sn-Zn pre-alloyed powders refined the microstructure of the Fe-based matrix and improved its density and hardness gradually. The addition of Ni reduced the loss of low melting liquid phase at a low sintered temperature, thus resulting in a decrease of the pores, an increase of the density and hardness of Fe-based matrix. When the Ni content is less than 9 wt.%, the bending strength of Fe-based matrix and diamond tools, together with the holding force of Fe-based matrix to diamonds increases sharply. They reached up to the optimal value with the Ni content of 9 wt.%. At this sintering powder ratio, the sufficient Fe-Cu-Sn-Zn-Ni liquid phase had a good wettability on the surface of diamonds, thus the optimal performance of sintered matrix and diamond tools was obtained. The service life of diamond tools was prolonged greatly owing to the excellent bonding capacity between matrix and diamonds. Once the Ni content exceeded 9 wt.%, the corresponding value decreased gradually. The fracture morphologies of the matrix changed from the brittle fracture into brittle-ductile fracture, then ductile fracture (with the Ni content of 9 wt.%), brittle-ductile mixed fracture and brittle fracture.
Screening for Colorectal Cancer Leading into a New Decade: The “Roaring ‘20s” for Epigenetic Biomarkers?
Authors: Almeida-Lousada Hélder , Mestre André , Ramalhete Sara , Price Aryeh J. , de Mello Ramon Andrade , Marreiros Ana D. , Neves Ricardo Pires das , Castelo-Branco Pedro
Published: November 2021

Colorectal cancer (CRC) has an important bearing (top five) on cancer incidence and mortality in the world. The etiology of sporadic CRC is related to the accumulation of genetic and epigenetic alterations that result in the appearance of cancer hallmarks such as abnormal proliferation, evasion of immune destruction, resistance to apoptosis, replicative immortality, and others, contributing to cancer promotion, invasion, and metastasis. It is estimated that, each year, at least four million people are diagnosed with CRC in the world. Depending on CRC staging at diagnosis, many of these patients die, as CRC is in the top four causes of cancer death in the world. New and improved screening tests for CRC are needed to detect the disease at an early stage and adopt patient management strategies to decrease the death toll. The three pillars of CRC screening are endoscopy, radiological imaging, and molecular assays. Endoscopic procedures comprise traditional colonoscopy, and more recently, capsule-based endoscopy. The main imaging modality remains Computed Tomography (CT) of the colon. Molecular approaches continue to grow in the diversity of biomarkers and the sophistication of the technologies deployed to detect them. What started with simple fecal occult blood tests has expanded to an armamentarium, including mutation detection and identification of aberrant epigenetic signatures known to be oncogenic. Biomarker-based screening methods have critical advantages and are likely to eclipse the classical modalities of imaging and endoscopy in the future. For example, imaging methods are costly and require highly specialized medical personnel. In the case of endoscopy, their invasiveness limits compliance from large swaths of the population, especially those with average CRC risk. Beyond mere discomfort and fear, there are legitimate iatrogenic concerns associated with endoscopy. The risks of perforation and infection make endoscopy best suited for a confirmatory role in cases where there are positive results from other diagnostic tests. Biomarker-based screening methods are largely non-invasive and are growing in scope. Epigenetic biomarkers, in particular, can be detected in feces and blood, are less invasive to the average-risk patient, detect early-stage CRC, and have a demonstrably superior patient follow-up. Given the heterogeneity of CRC as it evolves, optimal screening may require a battery of blood and stool tests, where each can leverage different pathways perturbed during carcinogenesis. What follows is a comprehensive, systematic review of the literature pertaining to the screening and diagnostic protocols used in CRC. Relevant articles were retrieved from the PubMed database using keywords including: “Screening”, “Diagnosis”, and “Biomarkers for CRC”. American and European clinical trials in progress were included as well.
Impact of Value Frameworks on the Magnitude of Clinical Benefit: Evaluating a Decade of Randomized Trials for Systemic Therapy in Solid Malignancies
Authors: Cusano Ellen , Wong Chelsea , Taguedong Eddy , Vaska Marcus , Abedin Tasnima , Nixon Nancy , Karim Safiya , Tang Patricia , Heng Daniel Y. C. , Ezeife Doreen
Published: November 2021

In the era of rapid development of new, expensive cancer therapies, value frameworks have been developed to quantify clinical benefit (CB). We assessed the evolution of CB since the 2015 introduction of The American Society of Clinical Oncology and The European Society of Medical Oncology value frameworks. Randomized clinical trials (RCTs) assessing systemic therapies for solid malignancies from 2010 to 2020 were evaluated and CB (Δ) in 2010–2014 (pre-value frameworks (PRE)) were compared to 2015–2020 (POST) for overall survival (OS), progression-free survival (PFS), response rate (RR), and quality of life (QoL). In the 485 studies analyzed (12% PRE and 88% POST), the most common primary endpoint was PFS (49%), followed by OS (20%), RR (12%), and QoL (6%), with a significant increase in OS and decrease in RR as primary endpoints in the POST era (p = 0.011). Multivariable analyses revealed significant improvement in ΔOS POST (OR 2.86, 95% CI 0.46 to 5.26, p = 0.02) while controlling for other variables. After the development of value frameworks, median ΔOS improved minimally. The impact of value frameworks has yet to be fully realized in RCTs. Efforts to include endpoints shown to impact value, such as QoL, into clinical trials are warranted.
Italian Vascular Flora: New Findings, Updates and Exploration of Floristic Similarities between Regions
Authors: Stinca Adriano , Musarella Carmelo Maria , Rosati Leonardo , Laface Valentina Lucia Astrid , Licht Wolfgang , Fanfarillo Emanuele , Wagensommer Robert Philipp , Galasso Gabriele , Fascetti Simonetta , Esposito Assunta , Fiaschi Tiberio , Nicolella Gianluca , Chianese Giuseppina , Ciaschetti Giampiero , Salerno Giovanni , Fortini Paola , Di Pietro Romeo , Perrino Enrico Vito , Angiolini Claudia , De Simone Leopoldo , Mei Giacomo
Published: November 2021

The tradition of floristic studies in Italy has made it possible to obtain a good knowledge of plant diversity both on a national and regional scale. However, the lack of knowledge for some areas, advances in plant systematics and human activities related to globalization, highlight the need for further studies aimed at improving floristic knowledge. In this paper, based on fieldwork and herbaria and literature surveys, we update the knowledge on the Italian vascular flora and analyze the floristic similarities between the administrative regions. Four taxa, all exotic, were recorded for the first time in Italy and Europe. In detail, Elaeodendron croceum, Kalanchoë blossfeldiana, and Sedum spathulifolium var. spathulifolium were found as casual aliens, while Oxalis brasiliensis was reported as historical record based on some herbarium specimens. Furthermore, Kalanchoë laxiflora was confirmed as a casual alien species for Italy and Europe. Status changes for some taxa were proposed at both national and regional levels, as well as many taxa were reported as new or confirmed at the regional level. Currently the Italian vascular flora comprises 9150 taxa of which 7547 are native (of which 1598 are Italian endemics) and 1603 are exotic at the national level. The multivariate analysis of updated floristic data on a regional scale showed a clear distribution along the latitudinal gradient, in accordance with the natural geographical location of the regions in Italy. This pattern of plants distribution was not affected by the introduction of alien species. Despite some taxonomic and methodological issues which are still open, the data obtained confirm the important role of floristic investigations in the field and in herbaria, as well as the collaborative approach among botanists, in order to improve the knowledge of the Italian and European vascular flora.
Range Shifts in the Worldwide Expansion of Oenothera drummondii subsp. drummondii, a Plant Species of Coastal Dunes
Authors: Castillo-Infante Frida R. , Mendoza-González Gabriela , Rioja-Nieto Rodolfo , Gallego-Fernández Juan B.
Published: November 2021

Oenothera drummondii is a coastal dunes plant species from the North American continent that has affected the natural structure and dynamics of Spanish, Israeli, and Chinese shores as an invasive species. In South Africa, Australia, New Zealand, and France, it is reported as a naturalized species. Ecological niche and species distribution modeling has been widely used as a tool to find potential global invasions and assess invasion effects. Herein, we modeled the ecological niche and the potential distribution of Oenothera drummondii, using the Köppen–Geiger climate classification, bioclimatic variables and occurrence records that have been validated in their native and non-native distribution. In the native area, the temperature and precipitation values are higher compared to non-native zones, where the low temperatures and the absence of humidity are the main climatic limitations for the species. In the environmental space, new distribution areas were identified and a partial overlap between the native and non-native niches detected. This suggests that climate matching is not occurring for the species, and that the potential invasion of coastal dune areas seems to be higher than previously observed. Therefore, new potential invasion areas, where the species is not yet distributed, were also identified. Our predictions could be used to establish ecosystem management measures to mitigate the invasion of Oenothera drummondii, helping to prevent possible negative impacts on fragile coastal ecosystems.
Diversity of Flower Visiting Beetles at Higher Elevations on the Yulong Snow Mountain (Yunnan, China)
Authors: Li Kai-Qin , Ren Zong-Xin , Li Qiang
Published: November 2021

Background: Flowers are one of the important microhabitats promoting beetle diversity, but little is known about variation in the diversity of these insects at higher elevations. We do not know how divergent habitats influence the distribution of beetles among montane flora. Methods: We sampled beetles systematically in angiosperm flowers at 12 sites at two elevations (2700 m and 3200 m) and in two habitats (meadows and forests) for two consecutive years (2018 and 2019) on the Yulong Snow Mountain in Yunnan, southwestern China. Beetle diversity among sites were compared. Their interactions with flowers of identified plant species were analyzed using bipartite networks approach. Results: We collected 153 species of beetles from 90 plant species recording 3391 interactions. While plant species richness was lower at the higher, 3200 m elevation regardless of habitat type, beetle species richness was not significantly different among sites. Plant-beetle interaction networks were strongly modular and specialized. The structure of networks showed greater differences between elevations than between habitats. The turnover of networks was determined by species composition showing a weak influence by interaction rewiring. Conclusion: Our study showed a high diversity of beetles in flowers at higher elevations within this mountain complex. The role of beetles in plant–insect interactions within some sections of temperate, montane sites appear to be underestimated and warrant further study.
The Influences of Omega-3 Polyunsaturated Fatty Acids on the Development of Skin Cancers
Authors: Minokawa Yoko , Sawada Yu , Nakamura Motonobu
Published: November 2021

Dietary nutrition intake is essential for human beings and influences various physiological and pathological actions in the human body. Among various nutritional factors, dietary intake of omega-3 polyunsaturated fatty acids (PUFAs) has been shown to have various beneficial effects against inflammatory diseases. In addition to their therapeutic potency against inflammation, omega-3 PUFAs have also been shown to have anti-tumor effects via various mechanisms, such as cell arrest and apoptosis. To date, limited information is available on these effects in cutaneous malignancies. In this review, we focused on the effect of omega-3 PUFAs on skin cancers, especially malignant melanoma, basal cell carcinoma, lymphoma, and squamous cell carcinoma and discussed the detailed molecular mechanism of the omega-3 PUFA-mediated anti-tumor response. We also explored the molecular mechanisms mediated by epigenetic modifications, cell adhesion molecules, and anti-tumor immune responses.
A Rare Case of Duodenal Pseudomelanosis
Authors: D’Ercole Marianna , Lopez Gianluca , Elli Luca , Ferrero Stefano , Croci Giorgio Alberto
Published: November 2021

A black-spotted duodenal mucosa was observed during endoscopy of a man with several comorbidities including hypertension and end-stage kidney disease. Histopathological examination revealed pigment-laden macrophages in the lamina propria of the duodenal villi, which was consistent with duodenal pseudomelanosis.
Detectability of Head and Neck Cancer via New Computed Tomography Reconstruction Tools including Iterative Reconstruction and Metal Artifact Reduction
Authors: Troeltzsch Daniel , Shnayien Seyd , Heiland Max , Kreutzer Kilian , Raguse Jan-Dirk , Hamm Bernd , Niehues Stefan M.
Published: November 2021

State-of-the-art technology in Computed Tomography (CT) includes iterative reconstruction algorithms (IR) and metal artefact reduction (MAR) techniques. The objective of the study is to show the benefits of this technology for the detection of primary and recurrent head and neck cancer. A total of 131 patients underwent contrast-enhanced CT for diagnosis of primary and recurrent Head and Neck cancer; 110 patients were included. All scans were reconstructed using iterative reconstruction, and metal artifact reduction was applied when indicated. Tumor detectability was evaluated dichotomously. Histopathological findings were used as a standard of reference. Data were analyzed retrospectively, statistics was performed through diagnostic test characteristics. State-of-the-art Head and Neck CT showed a sensitivity of 0.83 (95% CI; 0.61–0.95) with 0.93 specificity (95% CI; 0.84–0.98) for primary tumor detection. Recurrent tumors were identified with a 0.94 sensitivity (95% CI; 0.71–0.99) and 0.93 specificity (95% CI; 0.84–0.98) in this study. Conclusion: State-of-the-art reconstruction tools improve the diagnostic quality of Head and Neck CT, especially for recurrent tumor detection, compared with data published for standard CT. IR and MAR are easily implemented in routine clinical settings and improve image evaluation by reducing artifacts and image noise while lowering radiation exposure.
Using Ground-Based Passive Reflectors for Improving UAV Landing
Authors: Yasentsev Dmitry , Shevgunov Timofey , Efimov Evgeny , Tatarskiy Boris
Published: November 2021

The article reviews the problem of landing on hard-to-reach and poorly developed territories, especially in the case of unmanned aerial vehicles. Various landing systems and approaches are analyzed, and their key advantages and disadvantages are summarized; afterwards, an approach with passive reflectors is considered. A formal definition is provided for the main factors relative to the accuracy analysis, and a model is presented. The way to improve the landing procedure, while simultaneously meeting various practical constraints, is analyzed; the results of numerical simulation are presented, followed by the detailed conclusion describing still remaining challenges and subjects for further research.
Hierarchical Classification of Event-Related Potentials for the Recognition of Gender Differences in the Attention Task
Authors: Maciejewska Karina , Froelich Wojciech
Published: November 2021

Research on the functioning of human cognition has been a crucial problem studied for years. Electroencephalography (EEG) classification methods may serve as a precious tool for understanding the temporal dynamics of human brain activity, and the purpose of such an approach is to increase the statistical power of the differences between conditions that are too weak to be detected using standard EEG methods. Following that line of research, in this paper, we focus on recognizing gender differences in the functioning of the human brain in the attention task. For that purpose, we gathered, analyzed, and finally classified event-related potentials (ERPs). We propose a hierarchical approach, in which the electrophysiological signal preprocessing is combined with the classification method, enriched with a segmentation step, which creates a full line of electrophysiological signal classification during an attention task. This approach allowed us to detect differences between men and women in the P3 waveform, an ERP component related to attention, which were not observed using standard ERP analysis. The results provide evidence for the high effectiveness of the proposed method, which outperformed a traditional statistical analysis approach. This is a step towards understanding neuronal differences between men’s and women’s brains during cognition, aiming to reduce the misdiagnosis and adverse side effects in underrepresented women groups in health and biomedical research.
Age of Information of Parallel Server Systems with Energy Harvesting
Authors: Doncel Josu
Published: November 2021

Motivated by current communication networks in which users can choose different transmission channels to operate and also by the recent growth of renewable energy sources, we study the average Age of Information of a status update system that is formed by two parallel homogeneous servers and such that there is an energy source that feeds the system following a random process. An update, after getting service, is delivered to the monitor if there is energy in a battery. However, if the battery is empty, the status update is lost. We allow preemption of updates in service and we assume Poisson generation times of status updates and exponential service times. We show that the average Age of Information can be characterized by solving a system with eight linear equations. Then, we show that, when the arrival rate to both servers is large, the average Age of Information is one divided by the sum of the service rates of the servers. We also perform a numerical analysis to compare the performance of our model with that of a single server with energy harvesting and to study in detail the aforementioned convergence result.
What Does Vietnam Gain When Its Currency Depreciates?
Authors: Thi Thanh Binh Nguyen
Published: November 2021

The study investigates how the depreciation of the Vietnam dong (VND) against the US dollar (USD) affected export turnover and the stock market in Vietnam during the period from 2000 to 2020. A Markov triple regime-switching model is developed for time-series data involving multistructural breaks. Empirical results reveal that the impact of exchange rates on export turnover and stock price existed both in the long and short run. In the short run, the depreciation of VND led to (i) an increase in export turnover after 12 months; (ii) a decrease in export turnover of the high-growing regime in the short term; (iii) a reduction in stock returns in most cases. In addition, the common cycle from order receipt, preparation, production, and export is about 12 months for all states. The high volatility of export turnover was associated with high export growth. The commonly used phrase of “high risk, high return” seems to not be true for Vietnam’s stock market. The results of this study suggest the feasibility of a slight appreciation of VND against USD, which is the key to escape from being labeled a currency manipulator by the US Treasury.
Inclusive Educational Spaces and Social Pedagogical Recognition: Interaction- and Social-Pedagogy-Inspired Analysis of Space Dynamics in Compulsory, Upper-Secondary and Post-Secondary Education
Authors: Basic Goran , Lokareva Galina Vasylivna , Stadnichenko Nadiya Vasylivna
Published: November 2021

The purpose of this article is to provide a new understanding of the essence of inclusive educational spaces as a pedagogical phenomenon that presents different scientific approaches to the concept of educational space, and the importance of interpersonal interactions in educational spaces, and also presents the authors’ interpretations of their essence. The analytical basis is a literature review of various studies from the domains of symbolic interactionism, social constructivism, ethnomethodology, the sociology of knowledge, education, pedagogy and social pedagogy. Empirical sequences in the reviewed literature that exemplify inclusive educational spaces are derived from the organisational and practical work of compulsory and upper-secondary schools related to newly arrived students and students who use alcohol and narcotics, and from the context of the organisational and practical work of universities related to the education of future actors. The importance of recognizing the role of creative educational spaces as a leading requirement for the preparation of students for future communicative interactions in professional communication is revealed, and the structural characteristics of these spaces’ content and functional load are provided. Inclusive educational spaces and professionals’ inclusive approach demand that schools practically and collaboratively organise work with students in the educational space, show support for them and give them room to manoeuvre to ensure that professional actors in the school and university thrive in their practical work with students, both in relation to the expected normative right and deviant acting in the educational space and in relation to laws and governing documents that, to a certain extent, govern practical work in these educational spaces. The study contributes to the development of knowledge regarding (1) dealing with social interaction and inclusive educational spaces combining (a) the experiences of students in educational space, (b) the experiences of professional actors in educational space, and (c) the development of integration and social pedagogical recognition in educational space; (2) the significance of these social interactions and inclusive educational spaces in the creation and recreation of students’ and professionals’ identities; and (3) alternative social pedagogical approaches to analysing inclusive educational spaces in compulsory, upper-secondary and post-secondary education.
A Survey of Machine Learning Techniques for Video Quality Prediction from Quality of Delivery Metrics
Authors: Izima Obinna , de Fréin Ruairí , Malik Ali
Published: November 2021

A growing number of video streaming networks are incorporating machine learning (ML) applications. The growth of video streaming services places enormous pressure on network and video content providers who need to proactively maintain high levels of video quality. ML has been applied to predict the quality of video streams. Quality of delivery (QoD) measurements, which capture the end-to-end performances of network services, have been leveraged in video quality prediction. The drive for end-to-end encryption, for privacy and digital rights management, has brought about a lack of visibility for operators who desire insights from video quality metrics. In response, numerous solutions have been proposed to tackle the challenge of video quality prediction from QoD-derived metrics. This survey provides a review of studies that focus on ML techniques for predicting the QoD metrics in video streaming services. In the context of video quality measurements, we focus on QoD metrics, which are not tied to a particular type of video streaming service. Unlike previous reviews in the area, this contribution considers papers published between 2016 and 2021. Approaches for predicting QoD for video are grouped under the following headings: (1) video quality prediction under QoD impairments, (2) prediction of video quality from encrypted video streaming traffic, (3) predicting the video quality in HAS applications, (4) predicting the video quality in SDN applications, (5) predicting the video quality in wireless settings, and (6) predicting the video quality in WebRTC applications. Throughout the survey, some research challenges and directions in this area are discussed, including (1) machine learning over deep learning; (2) adaptive deep learning for improved video delivery; (3) computational cost and interpretability; (4) self-healing networks and failure recovery. The survey findings reveal that traditional ML algorithms are the most widely adopted models for solving video quality prediction problems. This family of algorithms has a lot of potential because they are well understood, easy to deploy, and have lower computational requirements than deep learning techniques.
2D Omni-Directional Wireless Power Transfer Modeling for Unmanned Aerial Vehicles with Noncollaborative Charging System Control
Authors: Allama Oussama , Habaebi Mohamed Hadi , Khan Sheroz , Elsheikh Elfatih A. A. , Suliman Fakher Eldin M.
Published: November 2021

Wireless power transfer (WPT) has been extensively studied from various aspects such as far field and near field, operating frequency, coil design, matched capacitance values, misaligned locations of transmitting and receiving coils, distance variance between them, target loads in the specific locations, environment, and operating conditions. This is due to the usefulness of WPT technology in many applications, including the revolutionary method of auto-recharging of unmanned aerial vehicles (UAVs). This paper presents analytical modeling of a WPT-link with two orthogonal transmitting coils arranged to produce an omnidirectional magnetic field suitable for charging a moving rotating load, maximizing energy transfer without any feedback from the receiving end. To achieve a suitable 2D WPT simulation system, as well as an accurate control design, the mutual coupling values in terms of receiver angular rotation are simulated using Ansys software. Power transfer is maximized by using extremum seeking control (ESC), making use of the input power as an objective function with specific parameter values that represent the WPT model to obtain the results. The results shown are those of the input power transmitted by the transmitting-end coils to a load of an orbiting mobile UAV. Based on the simulation results, the controller can achieve maximum power transfer in 100 µs of duration when the speed of the UAV is close to 314 rad/s.
A Bootstrap Structure Directly Charged by BUS Voltage with Threshold-Based Digital Control for High-Speed Buck Converter
Authors: Guo Yujie , Yuan Fang , Chang Yukuan , Kou Yuxia , Zhang Xu
Published: November 2021

This article proposes a high-frequency, area-efficient high-side bootstrap circuit with threshold-based digital control (TBDC) that is directly charged by BUS voltage (DCBV). In the circuit, the voltage of the bootstrap is directly obtained from the BUS voltage instead of the on-chip low dropout regulator (LDO), which is more suitable for a high operating frequency. An area-efficient threshold-based digital control structure is used to detect the bootstrap voltage, thereby effectively preventing bootstrap under-voltage or over-voltage that may result in insufficient driving capability, increased loss, or breakdown of the power device. The design and implementation of the circuit are based on CSMC 0.25 µm 60 V BCD technology, with an overall chip area of 1.4 × 1.3 mm2, of which the bootstrap area is 0.149 mm2 and the figure-of-merit (FOM) is 0.074. The experimental results suggest that the bootstrap circuit can normally operate at 5 MHz with a maximum buck converter efficiency of 83.6%. This work plays a vital role in promoting the development of a wide range of new products and new technologies, such as integrated power supplies, new energy vehicles, and data storage centers.
Study on Convective Heat Transfer of Supercritical Nitrogen in a Vertical Tube for Liquid Air Energy Storage
Authors: Yu Qinghua , Peng Yuxiang , Negoescu Ciprian Constantin , Wang Yi , Li Yongliang
Published: November 2021

The convective heat transfer behavior of supercritical nitrogen (S-N2) has played a significant role in optimizing the design of recently emerging cryogenic cold storage and recovery systems. However, studies on S-N2 heat transfer have been relatively scarce, not to mention that there is a legitimate urge for a robust numerical model to accurately predict and explain S-N2 heat transfer under various working conditions. In this paper, both experimental and numerical studies were conducted for convective heat transfer of S-N2 in a small vertical tube. The results demonstrated that the standard k-ε model performed better for predicting the key heat transfer characteristics of S-N2 than the SST k-ω model. The effects of heat flux and inlet pressure on the heat transfer characteristics under a large mass flux were evaluated. The variation mechanisms of local heat transfer performance were revealed by illustrating radial profiles of thermophysical properties and turbulent parameters of N2. It was found that the local performance variation along the flow direction was mainly determined by the radial profile of specific heat while the variation of the best local performance with the ratio of heat flux to mass flux was mainly determined by the radial profile of turbulent viscosity.
Machine-Learning-Based Carbon Footprint Management in the Frozen Vegetable Processing Industry
Authors: Scherer Magdalena , Milczarski Piotr
Published: November 2021

In the paper, we present a method of automatic evaluation and optimization of production processes towards low-carbon-emissions products. The method supports the management of production lines and is based on unsupervised machine learning methods, i.e., canopy, k-means, and expectation-maximization clusterization algorithms. For different production processes, a different clustering method may be optimal. Hence, they are validated by classification methods (k-nearest neighbors (kNN), multilayer perceptron (MLP), binary tree C4.5, random forest (RF), and support vector machine (SVM)) that identify the optimal clusterization method. Using the proposed method with real-time production parameters for a given process, we can classify the process as optimal or non-optimal on an ongoing basis. The production manager can react appropriately to sub-optimal production processes. If the process is not optimal, then during the process the manager or production technologist may change the production parameters, e.g., speed up or slow down certain batches, so that the process returns to the optimal path. This path is determined by a model trained via the proposed method based on the selected clustering method. The method is verified on an onion production line with more than a hundred processes and then applied to production lines with a smaller number of cases. We use data from real-world measurements from a frozen food production plant. Our research demonstrates that proper process management using machine learning can result in a lower carbon footprint per ton of the final product.
An Average Model of DC–DC Step-Up Converter Considering Switching Losses and Parasitic Elements
Authors: Faifer Marco , Piegari Luigi , Rossi Marco , Toscani Sergio
Published: November 2021

Power electronic converters represent a pillar of modern power systems, especially since generation from renewable energy sources, such as photovoltaics, have been introduced. One of their main characteristics consists of the high flexibility in converting different voltage levels and waveforms. As for all the conversion devices, they are subjected to unavoidable losses introduced by non-ideal components. For this reason, in the last few decades numerous research activities have been devoted to model their behavior and predicting the global efficiency. In spite of the number of scientific publications on the topic, the non-idealities have been rarely studied in terms of their impact on the input-output characteristics of the converter. In this paper, the conventional equivalent circuit of a step-up DC/DC converter has been upgraded in order to introduce the effects of both conduction and switching losses. The obtained formulation, applicable to all DC/DC converters, allows a more accurate average model that is particularly suitable for the study of multi-converter architectures, as for the most recent renewable energy sources applications. Finally, thanks to a dedicated test setup, the results of an experimental campaign demonstrate how the new formulation faithfully predicts its electrical behavior.
Unintended Effects of Energy Efficiency Policy: Lessons Learned in the Residential Sector
Authors: Blumberga Andra , Bazbauers Gatis , Vancane Selina , Ijabs Ivars , Nikisins Jurijs , Blumberga Dagnija
Published: November 2021

The European Union has set an ambitious goal to tackle climate change, and energy efficiency in the residential sector is among the measures required to close the gap between targeted and actual greenhouse gas emissions. While different policy tools have been applied, the diffusion rate of these measures remains low. A system dynamics simulation model of the residential sector was developed to assess the advantages and drawbacks of energy efficiency policy in the multi-family building sector based on experience accumulated over the last twelve years in Latvia. The model was validated in expert group model building sessions and with historical trends. Simulating the model, a hypothesis was tested that supported the idea that seemingly positive policy tools set the stage for a series of unintended adverse effects due to the complex interactions between different system components. The common assumption that information and financial support should result in significant energy efficiency diffusion proved to be wrong. It instead results in unintended long-term consequences that hamper national energy efficiency goals. The model carried out an analysis and brought insights for improving the effectiveness of government energy efficiency policy. It is concluded that models that broadly describe complex systems are needed to identify effective policies and foresee unintended side effects.
The Radial Growth of Picea wilsonii Was More Restricted by Precipitation Due to Climate Warming on Mt. Guandi, China
Authors: Huang Xiaoxia , Sun Xiaoneng , Jiang Yuan , Xue Feng , Cui Minghao , Zhao Shoudong , Kang Muyi
Published: November 2021

Transitional climate zones (TCZ) are characterized by instability due to rapid changes in climate and biological variables, and trees growing there are particularly sensitive to climate change. Therefore, knowledge about the shifted relationships of tree growth in response to climate warming will shape regional forest conservation and management strategies. China has experienced rapid warming in recent decades. However, how tree growth in semihumid to semiarid regions, such as the Guandi Mountains, responds to more sophisticated changes in the hydrothermal combination is not yet clear. In this study, we used tree-ring width data from three sites along an elevational gradient in the Guandi Mountains to present the response of Picea wilsonii Mast. radial growth to increasing temperature and elevational differences in the relationship between tree growth and climate. The results indicated that the Guandi Mountains have experienced rapid warming with a clear trend toward aridity. From 1959 to 1995, the radial growth of P. wilsonii was mainly influenced by temperature, while it was controlled by both temperature and precipitation after rapid warming in 1996. From 1959 to 2017, this species showed a generally consistent growth–climate relationship at different elevations in the Guandi Mountains. However, the radial growth of trees at higher elevations had a higher climatic correlation than at lower elevations, and it was more conditioned by higher summer temperatures and precipitation in December of the previous year. These results suggested that P. wilsonii was more susceptible to drought and high temperatures due to a warming climate and that more attention should be devoted to forest management, especially the adverse consequences of summer drought on P. wilsonii.
Reduced Combustion Mechanism for Fire with Light Alcohols
Authors: Mosisa Wako Fekadu , Pio Gianmaria , Salzano Ernesto
Published: November 2021

The need for sustainable energy has incentivized the use of alternative fuels such as light alcohols. In this work, reduced chemistry mechanisms for the prediction of fires (pool fire, tank fire, and flash fire) for two primary alcohols—methanol and ethanol—were developed, aiming to integrate the detailed kinetic model into the computational fluid dynamics (CFD) model. The model accommodates either the pure reactants and products or other intermediates, including soot precursors (C2H2, C2H4, and C3H3), which were identified via sensitivity and reaction path analyses. The developed reduced mechanism was adopted to predict the burning behavior in a 3D domain and for the estimation of the product distribution. The agreement between the experimental data from the literature and estimations resulting from the analysis performed in this work demonstrates the successful application of this method for the integration of kinetic mechanisms and CFD models, opening to an accurate evaluation of safety scenarios and allowing for the proper design of storage and transportation systems involving light alcohols.
Rheological Characterization of Non-Newtonian Mixtures by Pressure Pipe Tests
Authors: Carravetta Armando , Fecarotta Oreste , Martino Riccardo , Morani Maria Cristina
Published: November 2021

The rheological behavior of non-Newtonian fluids in turbulent conditions is an important topic in several fields of engineering. Nevertheless, this topic was not deeply investigated in the past due to the complexity of the experimental tests for the assessment of the constitutive parameters. Pressure pipe tests on Herschel-Bulkley mixtures were proven to be suitable for exploring turbulent conditions, but discrepancies with the results of tests performed in laminar flow were detected. These contradictions could be attributed to the inconsistencies of the Herschel-Bulkley model (HB) for high shear rate flows, proven by Hallbom and Klein, who suggested a more general “yield plastic” model (HK). Hence, in this study, a procedure for the estimation of the rheological parameters of both HB and HK models in pressure pipe tests is defined and rated on a complete set of experiments. The HK model performed much better than HB model in the turbulent range and slightly better than the HB model in the laminar range, confirming the consistency of the “yield plastic” model. The rheological parameters obtained by the proposed procedure were used to numerically model a dam-break propagation of a non-Newtonian fluid, showing significant differences in terms of process evolution depending on the constitutive model.
The Effect of Feeding Chicken and Geese Broilers with Different Cereals on the Fatty Acids Profile in Meat
Authors: Janiszewski Piotr , Lisiak Dariusz , Borzuta Karol , Grześkowiak Eugenia , Schwarz Tomasz , Siekierko Urszula , Andres Krzysztof , Świątkiewicz Sylwester
Published: November 2021

The research was conducted on the effect of bird broilers fed with different hybrid rye doses on the fatty acids profile in muscle. The first experiment was performed on 3 geese broilers groups fed with hybrid rye, oats or hybrid rye and oats mix in proportion 1:1. No effect of the hybrid rye feeding of geese on the SFA level in meat was observed, but the MUFA level was significantly higher and PUFA level and n-6/n-3 PUFA ratio were significantly lower than in geese fed with oats. The second experiment was performed on 3 chicken broiler groups fed with mix of corn, wheat, soybean meal and rapeseed oil (control group), and fed with an addition of 10% or 20% hybrid rye in diet (experimental groups). No effect of hybrid rye feeding of chicken broilers on the meat quality and SFA level was observed. However, the MUFA level was higher and the PUFA level and n-6/n-3 PUFA ratio were lower in meat of chicken broilers fed with hybrid rye. In conclusion hybrid rye is a healthy ingredient in the diet of studied birds and may be used up to 20% in chicken broilers and 50% in the diets of geese. A 100% hybrid rye in geese diet caused lower final body weight.
An Entropy Paradox Free Fractional Diffusion Equation
Authors: Ortigueira Manuel Duarte
Published: November 2021

A new look at the fractional diffusion equation was done. Using the unified fractional derivative, a new formulation was proposed, and the equation was solved for three different order cases: neutral, dominant time, and dominant space. The solutions were expressed by generalizations of classic formulae used for the stable distributions. The entropy paradox problem was studied and clarified through the Rényi entropy: in the extreme wave regime the entropy is −∞. In passing, Tsallis and Rényi entropies for stable distributions are introduced and exemplified.
Preparation of Electrospun Polyvinyl Alcohol/Nanocellulose Composite Film and Evaluation of Its Biomedical Performance
Authors: Ji Xinbin , Guo Jing , Guan Fucheng , Liu Yuanfa , Yang Qiang , Zhang Xin , Xu Yi
Published: November 2021

Using polyvinyl alcohol (PVA) and nanocellulose (NC) as raw materials, PVA/NC nanofiber membranes were prepared by electrospinning. The hydrogen bonding, crystalline properties and microscopic appearance of PVA/NC membranes with different NC contents were characterized. The mechanical properties, liquid absorption and cytotoxicity of the nanofiber membrane were evaluated. The results show that the free hydroxyl group of the PVA/NC nanofiber membranes have a maximum value of 9% at a mass fraction of 6% NC. The crystallinity of the PVA/NC nanofiber membranes and the average diameter of the nanofibers decreased and then increased as the NC content increased, with a minimum value of 38.23% and 272.03 nm, respectively, at 6% NC content. At this time, the contact angle was the smallest. The maximum strength of the PVA/NC nanofiber membranes is 75.8% higher than that of the PVA membrane at 2% NC content. With increasing NC content, the absorption of water, PBS sustained-release suspensions and artificial blood by PVA/NC nanofiber membranes increases. Cytotoxicity tests have shown that PVA/NC nanofiber membranes are non-toxic, have good cytocompatibility and are expected to be used in the field of medical dressings.