bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between Muscle Tone of the Erector Spinae and the Concave and Convex Sides of Spinal Curvature in Low-Grade Scoliosis among Children
Authors: Wilczyński Jacek
Published: December 2021

The objective of the present research was to assess the relationship between muscle tone of the erector spinae and the concave and convex sides of spinal curvature in low-grade scoliosis found among children. The study included 251 children, aged 7–8. Examination of the spine and body posture was carried out using the Diers Formetric III 4D optoelectronic method. Surface electromyography (sEMG) was used to assess erector spinae muscle tone. The trial was carried out using the 14-channel Noraxon TeleMyo DTS apparatus. The highest generalised tone (sEMG amplitude) of the erector spinae occurred in the case of scoliosis. The higher the angle of curvature, the greater the erector spinae muscle tone. Regardless of the position adopted during examination of the thoracic spine, greater erector spinae tone (sEMG amplitude) was exhibited on the convex side of the spinal curvature. However, in the area of the lumbar spine, greater tone (sEMG amplitude) of the erector spinae occurred on the curvature’s concave side. The exception was the test performed in a standing position, during which greater muscle tone was noted on the side of the convex curvature. In therapeutic practice, within the thoracic section, too tense erector spinae muscles should be stretched on the convex side of the scoliosis, while in the lumbar region, this should be performed on the concave side. However, each case of scoliosis requires individually tailored treatment. The current research has applicative value and does fill a research gap with regard to erector spinae muscle tone in young children experiencing low-grade scoliosis. The development of scoliosis is associated with asymmetry and an increase in erector spinae tone. The uneven distribution of its tone, occurring on both sides of the spine and in its various segments, causes destabilisation and its abnormal progression.
Preterm Infant Outcomes Following COVID-19 Lockdowns in Melbourne, Australia
Authors: Mulcahy Brendan , Rolnik Daniel L. , Matheson Alexia , Liu Yizhen , Palmer Kirsten R. , Mol Ben W. , Malhotra Atul
Published: December 2021

Background Community lockdowns during the coronavirus disease 2019 (COVID-19) pandemic may influence preterm birth rates, but mechanisms are unclear. Methods We compared neonatal outcomes of preterm infants born to mothers exposed to community lockdowns in 2020 (exposed group) to those born in 2019 (control group). Main outcome studied was composite of significant neonatal morbidity or death. Results Median gestational age was 35 + 4 weeks (295 infants, exposed group) vs. 35 + 0 weeks (347 infants, control group) (p = 0.108). The main outcome occurred in 36/295 (12.2%) infants in exposed group vs. 46/347 (13.3%) in control group (p = 0.69). Continuous positive airway pressure (CPAP) use, jaundice requiring phototherapy, hypoglycaemia requiring treatment, early neonatal white cell and neutrophil counts were significantly reduced in the exposed group. Conclusions COVID-19 community lockdowns did not alter composite neonatal outcomes in preterm infants, but reduced rates of some common outcomes as well as early neonatal inflammatory markers.
Low- and High-Attenuation Lung Volume in Quantitative Chest CT in Children without Lung Disease
Authors: Moutafidis Dimitrios , Gavra Maria , Golfinopoulos Sotirios , Kattamis Antonios , Chrousos George , Kanaka-Gantenbein Christina , Kaditis Athanasios G.
Published: December 2021

In contrast to studies of adults with emphysema, application of fixed thresholds to determine low- and high-attenuation areas (air-trapping and parenchymal lung disease) in pediatric quantitative chest CT is problematic. We aimed to assess age effects on: (i) mean lung attenuation (full inspiration); and (ii) low and high attenuation thresholds (LAT and HAT) defined as mean attenuation and 1 SD below and above mean, respectively. Chest CTs from children aged 6–17 years without abnormalities were retrieved, and histograms of attenuation coefficients were analyzed. Eighty examinations were included. Inverse functions described relationships between age and mean lung attenuation, LAT or HAT (p < 0.0001). Predicted value for LAT decreased from −846 HU in 6-year-old to −950 HU in 13- to 17-year-old subjects (cut-off value for assessing emphysema in adults). %TLCCT with low attenuation correlated with age (rs = −0.31; p = 0.005) and was <5% for 9–17-year-old subjects. Inverse associations were demonstrated between: (i) %TLCCT with high attenuation and age (r2 = 0.49; p < 0.0001); (ii) %TLCCT with low attenuation and TLCCT (r2 = 0.47; p < 0.0001); (iii) %TLCCT with high attenuation and TLCCT (r2 = 0.76; p < 0.0001). In conclusion, quantitative analysis of chest CTs from children without lung disease can be used to define age-specific LAT and HAT for evaluation of pediatric lung disease severity.
Anticorrosion Efficiency of Inhibitor Coatings Based on Ammonium Cation with Different Substituents: The Influence of Wettability and Molecular Structure
Authors: Pianka Hanna , Falah Sana , Zanna Sandrine , Bezborodov Vladimir , Mikhalyonok Sergei , Kuz’menok Nina , Chernik Alexander , Xue Yanpeng , Taleb Abdelhafed
Published: December 2021

In this work, different cationic surfactants with various aliphatic and aromatic ammonium cations were used to prepare inhibitor coatings and were characterized by different techniques such as IR spectroscopy and NMR. The inhibitor coatings were prepared by electrografting on the steel surface and their anticorrosion properties were evaluated in different media (HCl, H2SO4 and NaCl solutions). The electrochemical potentiodynamic polarization technique was used to study the inhibition efficiency of the prepared coatings. The dependence of the wetting properties of the electrografted layer and its homogeneity on the molecular structure of the prepared surfactants was studied. Particular attention was paid to the relationship between the properties of these surfactants in terms of critical micellar concentration, packing and wetting, and the anti-corrosion efficiency of their coatings. In this paper, we discuss the synergistic inhibition effect and the anticorrosion efficiency.
In Situ Reduction of Silver Nanoparticles on the Plasma-Induced Chitosan Grafted Polylactic Acid Nonwoven Fabrics for Improvement of Antibacterial Activity
Authors: Ren Yu , Fan Tingyue , Wang Xiaona , Guan Yongyin , Zhou Long , Cui Li , Li Meixian , Zhang Guangyu
Published: December 2021

An eco-friendly approach for improvement of antibacterial properties of polylactic acid (PLA) nonwoven fabrics was obtained by in situ reduction of silver nanoparticles (Ag NPs) on dielectric barrier discharge (DBD) plasma-induced chitosan grafted (DBD-CS-Ag NPs) PLA nonwoven fabrics. The surface morphology, surface element composition and the chemical state of silver of the PLA surfaces after the treatment were evaluated through scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), respectively. The antibacterial activity of DBD-CS-Ag NPs treated PLA against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was tested. The uniform dispersion of silver nanoparticles on the DBD-CS-Ag NPs treated PLA surface were confirmed by SEM images. The results of XPS and XRD showed that the concentration of silver element on the surface of PLA nonwoven fabrics was significantly improved after DBD-CS-Ag NPs treatment. The DBD-CS-Ag NPs treated PLA nonwoven fabrics also exhibited excellent antibacterial properties.
Anti-Reflection Coatings on 3D-Printed Components
Authors: Canning John , Clark Caspar , Dayao Monica , de LaMela Daniel , Logozzo Michael , Zhao Jing
Published: December 2021

The use of anti-reflection coatings on 3D-printed components to reduce both Fresnel reflections and scattering is explored. Two similar photo-initiated acrylic commercial material structures, known as Standard Clear (SC: T~60% @ λ = 800 nm) and VeroClear (VC: T~90% @ λ = 800 nm), used specifically for optical components, are examined. The refractive indices for slab samples~(5 × 5 × 0.7) cm are measured at λ = 650 nm and averaged over the slab area: n(SC)~(1.49 ± 0.04) and n(VC)~(1.42 ± 0.03). Within experimental error, novel Shore D mapping is used to show hardness distribution across the surface flats, with VC slightly harder than SC, where VC = 85.9 ± 0.3 and SC = 84.4 ± 1.3, indicating uniform hardness. A TiO2/MgF2 anti-reflection twin-layer coating is deposited onto one side of an unpolished SC slab and binds well, passing standard peeling and humidity tests. Shore hardness increases to SCCOATED = 87.5 ± 1.5. It is found to reduce the measured Fresnel reflection and surface scatter by~65% without requiring major polishing, paving the way for lower-cost high-quality optics. The demonstration of successful anti-reflection coatings will benefit all 3D-printed component finishes, permitting viable film deposition more broadly.
Electrostatic Charges of Abrasive Powders: The Role of Particle Size and Humidity
Authors: Tkach Alexander , Garcez Miguel , Vilarinho Paula M.
Published: December 2021

Electrostatically coated abrasives have drawn vast attention in many industrial applications. Therefore, influence of humidity on the electrical properties of α-SiC and α-Al2O3 abrasive powders with three μm-range particle sizes are here investigated using electrostatic charge and DC resistivity analysis. From the three particle size ranges used, 15–16 μm, 60–63 μm and 153–156 μm, the intermediate one (60–63 μm) is found to be associated with the highest charge values, measured using a double Faraday cup method, as well as the highest resistivity for both materials. However, comparing SiC and Al2O3 powders, the latter ones present about twice larger charges in dry and normal humidity states accompanied by several orders of magnitude larger resistivity. Under humid conditions all the powders reveal diminishing charge and resistivity values.
Optimization of the Rework of Bended OLED Displays by Surface-Energy Control
Authors: Kim Young-Gyun , Park Byung-Min , Choi Jong-Keun , Jang Dong-Hoon , Han Kwan-Young
Published: December 2021

Recent display technology has changed substantially from flat-type displays to bended displays. As a result, the lamination process for bonding the panel substrates and bended window glass has become difficult due to the changes in display shape, and the use of optically clear adhesive (OCA) makes it impossible to rework defective substrates due to residue problems. Therefore, it is necessary to research and develop a substrate-surface treatment that maintains the initial adhesion and is reusable via the complete removal of impurities during delamination in order to enable rework. In this paper, the possibility of maintaining adhesive force and reusing substrates was confirmed through the surface treatment of substrates and OCA using various materials. We found that a surface coating and a cooling treatment of additional substrates completely removed the impurities that remained on the substrates during reworking. These results could contribute to improving lamination-process technology and the productivity of the various forms of next-generation displays that are currently under development.
Fuzzy Mathematics-Based Outer-Loop Control Method for Converter-Connected Distributed Generation and Storage Devices in Micro-Grids
Authors: Castro Lorena , Bueno-López Maximiliano , Mora-Flórez Juan
Published: December 2021

The modern changes in electric systems present new issues for control strategies. When power converters and distributed energy resources are included in the micro-grid, its model is more complex than the simplified representations used, sometimes losing essential data. This paper proposes a unified fuzzy mathematics-based control method applied to the outer loop of a voltage source converter (VSC) in both grid-connected and islanded modes to avoid using simplified models in complex micro-grids and handle the uncertain and non-stationary behaviour of nonlinear systems. The proposed control method is straightforwardly designed without simplifying the controlled system. This paper explains the design of a fuzzy mathematics-based control method applied to the outer-loop of a VSC, a crucial device for integrating renewable sources and storage devices in a micro-grid. Simulation results validated the novel control strategy, demonstrating its capabilities for real field applications.
Salvage Surgical Resection after Linac-Based Stereotactic Radiosurgery for Newly Diagnosed Brain Metastasis
Authors: Matsuda Ryosuke , Morimoto Takayuki , Tamamoto Tetsuro , Inooka Nobuyoshi , Ochi Tomoko , Miyasaka Toshiteru , Hontsu Shigeto , Yamaki Kaori , Miura Sachiko , Takeshima Yasuhiro , Tamura Kentaro , Yamada Shuichi , Nishimura Fumihiko , Nakagawa Ichiro , Motoyama Yasushi , Park Young-Soo , Hasegawa Masatoshi , Nakase Hiroyuki
Published: December 2021

Background: This study aimed to assess the clinical outcomes of salvage surgical resection (SSR) after stereotactic radiosurgery and fractionated stereotactic radiotherapy (SRS/fSRT) for newly diagnosed brain metastasis. Methods: Between November 2009 and May 2020, 318 consecutive patients with 1114 brain metastases were treated with SRS/fSRT for newly diagnosed brain metastasis at our hospital. During this study period, 21 of 318 patients (6.6%) and 21 of 1114 brain metastases (1.9%) went on to receive SSR after SRS/fSRT. Three patients underwent multiple surgical resections. Twenty-one consecutive patients underwent twenty-four SSRs. Results: The median time from initial SRS/fSRT to SSR was 14 months (range: 2–96 months). The median follow-up after SSR was 17 months (range: 2–78 months). The range of tumor volume at initial SRS/fSRT was 0.12–21.46 cm3 (median: 1.02 cm3). Histopathological diagnosis after SSR was recurrence in 15 cases, and radiation necrosis (RN) or cyst formation in 6 cases. The time from SRS/fSRT to SSR was shorter in the recurrence than in the RNs and cyst formation, but these differences did not reach statistical significance (p = 0.067). The median survival time from SSR and from initial SRS/fSRT was 17 and 74 months, respectively. The cases with recurrence had a shorter survival time from initial SRS/fSRT than those without recurrence (p = 0.061). Conclusions: The patients treated with SRS/fSRT for brain metastasis need long-term follow-up. SSR is a safe and effective treatment for the recurrence, RN, and cyst formation after SRS/fSRT for brain metastasis.
Deep Neural Network Models for the Prediction of the Aggregate Base Course Compaction Parameters
Authors: Othman Kareem
Published: December 2021

Laboratory tests for the estimation of the compaction parameters, namely the maximum dry density (MDD) and optimum moisture content (OMC) are time-consuming and costly. Thus, this paper employs the artificial neural network technique for the prediction of the OMC and MDD for the aggregate base course from relatively easier index properties tests. The grain size distribution, plastic limit, and liquid limits are used as the inputs for the development of the ANNs. In this study, multiple ANNs (240 ANNs) are tested to choose the optimum ANN that produces the best predictions. This paper focuses on studying the impact of three different activation functions: number of hidden layers, number of neurons per hidden layer on the predictions, and heatmaps are generated to compare the performance of every ANN with different settings. Results show that the optimum ANN hyperparameters change depending on the predicted parameter. Additionally, the hyperbolic tangent activation is the most efficient activation function as it outperforms the other two activation functions. Additionally, the simplest ANN architectures results in the best predictions, as the performance of the ANNs deteriorates with the increase in the number of hidden layers or the number of neurons per hidden layers.
Utilization of the Evaluation System for Spatial Comfort toward Multi-Layered Public Hanok Facilities
Authors: Lee Mi-Hyang , Han Seung-Hoon
Published: December 2021

This study aims to present evaluation methods that can evaluate thermal comfort reflecting traditional values of the vernacular architecture in Korea called Hanok, especially focused on modernized public facilities. For this purpose, representative vertically-sectional structures of Hanok has been categorized by the spatial configuration used for public buildings such as school, museum, library and so on. Next, a comfort assessment index was derived to evaluate the spatial comfort performance of Hanok especially with certified domestic standards and indices. Then, predicted mean vote (PMV) has further been selected as the method for the thermal assessment for their interior spaces. As a result, the surrounding conditions showed the least influence on the Hanok comfort and the adjacency type mostly affected the performance of thermal control in the aspects of the habitual sustainability. Finally, Hanok designs could positively be considered and utilized by surroundings and adjacency types that have the most advantages in terms of thermal environment.
Special Issue “Advances in Breast MRI”
Authors: Galati Francesca , Trimboli Rubina Manuela , Pediconi Federica
Published: December 2021

We thank all the authors, reviewers and the editorial staff who contributed to this Special Issue [...]
Clinical Evaluation of a New Antigen-Based COVID-19 Rapid Diagnostic Test from Symptomatic Patients
Authors: Sazed Saiful Arefeen , Kibria Mohammad Golam , Hossain Mohammad Sharif , Zamil Md Fahad , Adhikary Pranob Chandra , Hossain Mohammad Enayet , Ahmed Dilruba , Haque Rashidul , Alam Mohammad Shafiul
Published: December 2021

Accurate diagnosis at the right moment is the prerequisite for treatment of any disease. Failure to correctly diagnose a disease can result in highly detrimental effects, unmistakably a crucial factor during the COVID-19 pandemic. RT-PCR is the gold standard for COVID-19 detection while there are other test procedures available, such as LAMP, X-Ray, and ELISA. However, these tests are expensive, require sophisticated equipment and a highly trained workforce, and multiple hours or even days are often required to obtain the test results. A rapid and cheap detection system can thus render a solution to the screening system on a larger scale and be added as an aid to the current detection processes. Recently, some rapid antigen-based COVID-19 tests devices have been developed and commercialized. In this study, we evaluated the clinical performance of a new rapid detection device (OnSite® COVID-19 Ag Rapid Test by CTK Biotech Inc., Poway, CA, USA) on COVID-19 symptomatic patients (n = 380). The overall sensitivity and specificity were 91.0% (95% CI: 84.8–95.3%) and 99.2% (95% CI: 97.1–99.9), against gold standard RT-PCR. The kit was capable of detecting patients even after 06 days of onset of symptoms and the sensitivity can be maximized to 98% in samples with an average RT-PCR Ct ≤ 26.48, demonstrating a high potential of the kit for clinical diagnosis of symptomatic patients in healthcare facilities.
Integrated Genomic, Transcriptomic and Proteomic Analysis for Identifying Markers of Alzheimer’s Disease
Authors: Madrid Laura , Labrador Sandra C. , González-Pérez Antonio , Sáez María E. ,   The Alzheimer’s Disease Neuroimaging Initiative (ADNI)
Published: December 2021

There is an urgent need to identify biomarkers for Alzheimer’s disease (AD), but the identification of reliable blood-based biomarkers has proven to be much more difficult than initially expected. The current availability of high-throughput multi-omics data opens new possibilities in this titanic task. Candidate Single Nucleotide Polymorphisms (SNPs) from large, genome-wide association studies (GWAS), meta-analyses exploring AD (case-control design), and quantitative measures for cortical structure and general cognitive performance were selected. The Genotype-Tissue Expression (GTEx) database was used for identifying expression quantitative trait loci (eQTls) among candidate SNPs. Genes significantly regulated by candidate SNPs were investigated for differential expression in AD cases versus controls in the brain and plasma, both at the mRNA and protein level. This approach allowed us to identify candidate susceptibility factors and biomarkers of AD, facing experimental validation with more evidence than with genetics alone.
Error Propagation in the Simulation of Atherosclerotic Plaque Growth and the Prediction of Atherosclerotic Disease Progression
Authors: Sakellarios Antonis I. , Siogkas Panagiotis , Kigka Vassiliki , Tsompou Panagiota , Pleouras Dimitrios , Kyriakidis Savvas , Karanasiou Georgia , Pelosi Gualtiero , Nikopoulos Sotirios , Naka Katerina K. , Rocchiccioli Silvia , Michalis Lampros K. , Fotiadis Dimitrios I.
Published: December 2021

Assessments of coronary artery disease can be achieved using non-invasive computed tomography coronary angiography (CTCA). CTCA can be further used for the 3D reconstruction of the coronary arteries and the development of computational models. However, image acquisition and arterial reconstruction introduce an error which can be propagated, affecting the computational results and the accuracy of diagnostic and prognostic models. In this work, we investigate the effect of an imaging error, propagated to a diagnostic index calculated using computational modelling of blood flow and then to prognostic models based on plaque growth modelling or binary logistic predictive modelling. The analysis was performed utilizing data from 20 patients collected at two time points with interscan period of six years. The collected data includes clinical and risk factors, biological and biohumoral data, and CTCA imaging. The results demonstrated that the error propagated and may have significantly affected some of the final outcomes. The calculated propagated error seemed to be minor for shear stress, but was major for some variables of the plaque growth model. In parallel, in the current analysis SmartFFR was not considerably affected, with the limitation of only one case located into the gray zone.
Hierarchical Boosting Dual-Stage Feature Reduction Ensemble Model for Parkinson’s Disease Speech Data
Authors: Yang Mingyao , Ma Jie , Wang Pin , Huang Zhiyong , Li Yongming , Liu He , Hameed Zeeshan
Published: December 2021

As a neurodegenerative disease, Parkinson’s disease (PD) is hard to identify at the early stage, while using speech data to build a machine learning diagnosis model has proved effective in its early diagnosis. However, speech data show high degrees of redundancy, repetition, and unnecessary noise, which influence the accuracy of diagnosis results. Although feature reduction (FR) could alleviate this issue, the traditional FR is one-sided (traditional feature extraction could construct high-quality features without feature preference, while traditional feature selection could achieve feature preference but could not construct high-quality features). To address this issue, the Hierarchical Boosting Dual-Stage Feature Reduction Ensemble Model (HBD-SFREM) is proposed in this paper. The major contributions of HBD-SFREM are as follows: (1) The instance space of the deep hierarchy is built by an iterative deep extraction mechanism. (2) The manifold features extraction method embeds the nearest neighbor feature preference method to form the dual-stage feature reduction pair. (3) The dual-stage feature reduction pair is iteratively performed by the AdaBoost mechanism to obtain instances features with higher quality, thus achieving a substantial improvement in model recognition accuracy. (4) The deep hierarchy instance space is integrated into the original instance space to improve the generalization of the algorithm. Three PD speech datasets and a self-collected dataset are used to test HBD-SFREM in this paper. Compared with other FR algorithms and deep learning algorithms, the accuracy of HBD-SFREM in PD speech recognition is improved significantly and would not be affected by a small sample dataset. Thus, HBD-SFREM could give a reference for other related studies.
Current Status of Genetic Counselling for Rare Diseases in Spain
Authors: Álvaro-Sánchez Sara , Abreu-Rodríguez Irene , Abulí Anna , Serra-Juhe Clara , Garrido-Navas Maria del Carmen
Published: December 2021

Genetic Counselling is essential for providing personalised information and support to patients with Rare Diseases (RD). Unlike most other developed countries, Spain does not recognize geneticists or genetic counsellors as healthcare professionals Thus, patients with RD face not only challenges associated with their own disease but also deal with lack of knowledge, uncertainty, and other psychosocial issues arising as a consequence of diagnostic delay. In this review, we highlight the importance of genetic counsellors in the field of RD as well as evaluate the current situation in which rare disease patients receive genetic services in Spain. We describe the main units and strategies at the national level assisting patients with RD and we conclude with a series of future perspectives and unmet needs that Spain should overcome to improve the management of patients with RD.
The Refined Composite Downsampling Permutation Entropy Is a Relevant Tool in the Muscle Fatigue Study Using sEMG Signals
Authors: Ravier Philippe , Dávalos Antonio , Jabloun Meryem , Buttelli Olivier
Published: December 2021

Surface electromyography (sEMG) is a valuable technique that helps provide functional and structural information about the electric activity of muscles. As sEMG measures output of complex living systems characterized by multiscale and nonlinear behaviors, Multiscale Permutation Entropy (MPE) is a suitable tool for capturing useful information from the ordinal patterns of sEMG time series. In a previous work, a theoretical comparison in terms of bias and variance of two MPE variants—namely, the refined composite MPE (rcMPE) and the refined composite downsampling (rcDPE), was addressed. In the current paper, we assess the superiority of rcDPE over MPE and rcMPE, when applied to real sEMG signals. Moreover, we demonstrate the capacity of rcDPE in quantifying fatigue levels by using sEMG data recorded during a fatiguing exercise. The processing of four consecutive temporal segments, during biceps brachii exercise maintained at 70% of maximal voluntary contraction until exhaustion, shows that the 10th-scale of rcDPE was capable of better differentiation of the fatigue segments. This scale actually brings the raw sEMG data, initially sampled at 10 kHz, to the specific 0–500 Hz sEMG spectral band of interest, which finally reveals the inner complexity of the data. This study promotes good practices in the use of MPE complexity measures on real data.
Double-Layer Micro Porous Media Burner from Lean to Rich Fuel Mixture: Analysis of Entropy Generation and Exergy Efficiency
Authors: Ismail Nazmi Che , Abdullah Mohd Zulkifly , Mustafa Khairil Faizi , Mazlan Nurul Musfirah , Gunnasegaran Prem , Irawan Agustinus Purna
Published: December 2021

Porous media burner (PMB) is widely used in a variety of practical systems, including heat exchangers, gas propulsion, reactors, and radiant burner combustion. However, thorough evaluations of the performance of the PMB based on the usefulness of entropy generation, thermal and exergy efficiency aspects are still lacking. In this work, the concept of a double-layer micro PMB with a 23 mm cylindrical shape burner was experimentally demonstrated. The PMB was constructed based on the utilization of premixed butane-air combustion which consists of an alumina and porcelain foam. The tests were designed to cover lean to rich combustion with equivalence ratios ranging from ϕ = 0.6 to ϕ = 1.2. It was found that the maximum thermal and exergy efficiency was obtained at ϕ = 1.2 while the lowest thermal and exergy efficiency was found at ϕ = 0.8. Furthermore, the findings also indicated that the total entropy generation, energy loss, and exergy destroyed yield the lowest values at ϕ = 1.0 with 0.0048 W/K, 98.084 W, and 1.456 W, respectively. These values can be stated to be the suitable operating conditions of the PMB. The findings provided useful information on the design and operation in a double-layer PMB.
The Development of Electromobility in the European Union: Evidence from Poland and Cross-Country Comparisons
Authors: Łuszczyk Marcin , Sulich Adam , Siuta-Tokarska Barbara , Zema Tomasz , Thier Agnieszka
Published: December 2021

The article presents the current situation with the implementation of electric cars in Poland against the background of pan-European trends and the current energy sector condition in Poland. The aim of the study was to show the ecological, economic, social, and technical difficulties and controversies related to the use of electric cars in Poland. The authors used statistical analysis and identified the main factors of electromobility development in Poland. Despite the declared electromobility in the Strategy of Responsible Development program, the degree of its implementation is far from the previously established goals. The article analyzes the feasibility of the above plan and indicates the factors inhibiting the development of electromobility in Poland. The strategy and decisions to further implement electric cars cannot be purely political. In justifying the need to promote the use of electric cars in Poland, one should take into account the specificity of the Polish economy, its energy system, the condition of its infrastructure, and real social needs. The authors formulated a hypothesis that the aforementioned program is based on simplistic assumptions and marginalizes or ignores significant barriers to the development of electricity-based transport in Poland. The successful implementation of that program is conditioned by comprehensive and costly activities aimed to transform the whole energy system and introduce an effective system of incentives for the buyers of electric cars.
Combined Light and Electron Scattering for Exploring Proximity Effects on Hydrogen Absorption in Vanadium
Authors: Huang Wen , Xiao Xin , Steichen Parker , Droulias Sotirios A. , Brischetto Martin , Wolff Max , Li Xing’ao , Hjörvarsson Björgvin
Published: December 2021

We investigate proximity effects on hydrogen absorption in ultra-thin vanadium layers through combing light transmission and electron scattering. We compare the thermodynamic properties of the vanadium layers, which are based on the superlattice structure of Cr/V (001) and Fe/V (001). We find an influence of the proximity effects on the finite-size scaling of the critical temperatures, which can be explained by a variation of dead layers in the vanadium. In addition to this, the proximity effects on hydrogen absorption are also verified from the changes of excess resistivity.
Technology for Improving the Efficiency of Fractured Reservoir Development Using Gel-Forming Compositions
Authors: Mardashov Dmitry , Duryagin Victor , Islamov Shamil
Published: December 2021

Increasing the field development efficiency of fractured reservoirs is a contemporary issue. This paper presents fundamental and exploratory research results in this field using modern high-tech experimental equipment from the “Arctic” Scientific Centre at the Saint Petersburg Mining University. Oil reserves in fractured reservoirs are enormous; however, they are classified as hard-to-recover. The before-mentioned reservoirs require a specific approach when selecting technologies to improve the efficiency of their development. In this paper, as a solution to the problem under discussion, we propose the use of a physicochemical method of developing fractured reservoirs based on the injection of a water shut-off agent to exclude highly permeable water-conducting fractures from the drainage process. This technology makes it possible to effectively include and develop previously undrained reservoir areas by directly controlling their filtration properties with the use of new highly efficient and ecologically safe chemical reagents and process fluids.
Variable Speed Drive DC-Bus Voltage Dip Proofing
Authors: Chiranga Freeman , Masisi Lesedi
Published: December 2021

This paper proposes a power electronic module that uses a switched capacitor for retaining the integrity of the dc-link voltage of a variable speed drive (VSD) during a 0.2 s short-term power interruption (STPI). Ride-through was achieved through switched capacitor onto the dc bus. However, this technique presents a challenge of the high inrush currents during a ride through compensation. In this work both analytical and experimental investigations were conducted in order to reduce the in-rush currents and its impact on the performance of the VSD during the STPI. Inrush peak currents were reduced by approximately 90%. Experimental results showed torque pulsations of 12.8% and 14.3% at the start and end of dc-link voltage compensation, respectively. A method for sizing the switched capacitor and the inrush limiting resistors is proposed. This methodology is based on the use of readily available nameplate information of the VSD and the electric motor. The proposed module can be retrofitted to existing VSDs that are based on v/f control.
Characterization of Pd60Cu40 Composite Membrane Prepared by a Reverse Build-Up Method for Hydrogen Purification
Authors: Shinoda Yasunari , Takeuchi Masakazu , Mizukami Hikaru , Dezawa Norikazu , Komo Yasuhiro , Harada Takuya , Takasu Hiroki , Kato Yukitaka
Published: December 2021

A thin Pd-based H2-permeable membrane is required to produce high-purity H2 with high efficiency. In this study, a porous Ni-supported Pd60Cu40 composite H2-permeable membrane was developed using a reverse build-up method to produce economical H2 purification. The thickness of the Pd60Cu40 alloy layer produced by the improved membrane production process reached 1.0 μm; it was thinner than the layer obtained in a previous study (3.7 μm). The membrane was characterized by scanning electron microscope, inductively coupled plasma optical emission spectrometer, H2 permeation test, and Auger microprobe analysis. The permeation tests were performed at 300–320 °C and 50–100 kPa with H2 introduced from the primary side. The H2 permeation flux was stable up to ~320 °C. The n-value was determined to be 1.0. The H2 permeance of the membrane was 2.70 × 10−6 mol m−2 s−1 Pa−1.0 at 320 °C, after 30 h, similar to those of other 2.2-µm-thick and 3.7-µm-thick Pd60Cu40 composite membranes, suggesting that the adsorption and dissociation reaction processes on the PdCu alloy surface were rate-limiting. The Pd cost of the membrane was estimated to be ~1/30 of the Pd cost of the pure Pd60Cu40 membrane.
The Health Impact and External Cost of Electricity Production
Authors: Zyśk Janusz , Wyrwa Artur , Pluta Marcin , Olkuski Tadeusz , Suwała Wojciech , Raczyński Maciej
Published: December 2021

The use of fossil fuels, which still dominate global primary energy consumption, results not only in emissions of greenhouse gas but also in emissions of pollutants such as SO2, NOx, and PM. Damage caused by air pollution can be expressed in monetary terms in the form of external costs to society. The goal of this paper is to answer the following questions: How much will the energy sector’s emissions change as a result of decarbonization? What is the estimated level of external costs related to human health in future energy scenarios? How large are the estimated external costs compared to the planned investments in this sector? The study conducted for the period 2018–2050 used the impact pathway approach and covered the centralized power and heat generation sector in Poland. The reported values of the concentration–response functions that relate human exposure to air pollution with health impact were reviewed. The results show that external costs decrease from an estimated annual level in the range of EUR 782–1911 million in 2018 to EUR 36–876 million in 2050. The cumulative value of avoided external costs between 2018 and 2050 is significantly lower than the planned capital expenditures in the energy sector in Poland.
Modeling and Fault Tolerance Analysis of ZigBee Protocol in IoT Networks
Authors: Dymora Paweł , Mazurek Mirosław , Smalara Krzysztof
Published: December 2021

This paper presents the essence of IoT (Internet of Things) works and design challenges, discusses its principles of operation, and presents IoT development concepts. WSN (Wireless Sensor Network) was characterized in detail as an essential component of IoT infrastructure. The various faults that can occur at all levels of the IoT architecture, such as sensor nodes, actuators, network links, as well as processing and storage components clearly demonstrate that fault-tolerance (FT) has become a key issue for IoT systems. A properly applied routing algorithm has a direct impact on the power consumption of sensors, which in extreme cases is the reason why nodes shut down due to battery degradation. To study the fault tolerance of IoT infrastructure, a ZigBee network topology was created, and various node failure scenarios were simulated. Furthermore, the results presented showed the impact and importance of choosing the right routing scheme, based on the correlation of throughput to the number of rejected packets, as well as the proportionality of the value of management traffic to the other including the ratio of rejected packets.
On the Flow Structure and Dynamics of Methane and Syngas Lean Flames in a Model Gas-Turbine Combustor
Authors: Dulin Vladimir , Chikishev Leonid , Sharaborin Dmitriy , Lobasov Aleksei , Tolstoguzov Roman , Liu Zundi , Shi Xiaoxiang , Li Yuyang , Markovich Dmitriy
Published: December 2021

The present paper compares the flow structure and flame dynamics during combustion of methane and syngas in a model gas-turbine swirl burner. The burner is based on a design by Turbomeca. The fuel is supplied through injection holes between the swirler blades to provide well-premixed combustion, or fed as a central jet from the swirler’s centerbody to increase flame stability via a pilot flame. The measurements of flow structure and flame front are performed by using the stereo particle image velocimetry and OH planar laser-induced fluorescence methods. The measurements are performed for the atmospheric pressure without preheating and for 2 atm with the air preheated up to 500 K. The flow Reynolds numbers for the non-reacting flows at these two conditions are 1.5 × 103 and 1.0 × 103, respectively. The flame dynamics are analyzed based on a high-speed OH* chemiluminescence imaging. It is found that the flame dynamics at elevated conditions are related with frequent events of flame lift-off and global extinction, followed by re-ignition. The analysis of flow structure via the proper orthogonal decomposition reveals the presence of two different types of coherent flow fluctuations, namely, longitudinal and transverse instability modes. The same procedure is applied to the chemiluminescence images for visualization of bulk movement of the flame front and similar spatial structures are observed. Thus, the longitudinal and transverse instability modes are found in all cases, but for the syngas at the elevated pressure and temperature the longitudinal mode is related to strong thermoacoustic fluctuations. Therefore, the present study demonstrates that a lean syngas flame can become unstable at elevated pressure and temperature conditions due to a greater flame propagation speed, which results in periodic events of flame flash-back, extinction and re-ignition. The reported data is also useful for the validation of numerical simulation codes for syngas flames.
Hybrid Renewable Energy Systems’ Optimisation. A Review and Extended Comparison of the Most-Used Software Tools
Authors: Kavadias Kosmas A. , Triantafyllou Panagiotis
Published: December 2021

To help stakeholders plan, research, and develop Hybrid Renewable Energy Systems (HRES), the elaboration of numerous modelling techniques and software simulation tools has been reported. The thorough analysis of these undoubtedly complex systems is strongly correlated with the efficient utilisation of the potential of renewable energy and the meticulous development of pertinent designs. In this context, various optimisation constraints/targets have also been utilised. This specific work initially carries out a thorough review of the modelling techniques and simulation software developed in an attempt to define a commonly accepted categorisation methodology for the various existing HRES simulation methods. Moreover, the widely utilised optimisation targets are analysed in detail. Finally, it identifies the sensitivity of two commercial software tools (HOMER Pro and iHOGA) by examining nine case studies based on different wind and solar potential combinations. The results obtained by the two commercial tools are compared with the ESA Microgrid Simulator, a software developed by the Soft Energy Applications and Environmental Protection Laboratory of the Mechanical Engineering Department of the University of West Attica. The evaluation of the results, based on the diversification of the renewable energy potential used as input, has led to an in-depth assessment of the deviances detected in the software tools selected.
Design of Hardware Setup Based on IEC 61850 Communication Protocol for Detection & Blocking of Harmonics in Power Transformer
Authors: Azeem Abdul , Jamil Majid , Qamar Shamimul , Malik Hasmat , Thokar Rayees Ahmad
Published: December 2021

In this paper, the authors have developed a hardware model for blocking even and odd harmonics of a power transformer. In the proposed hardware model, intelligent differential & over-current relays are used for the blocking of harmonics of a power transformer. The harmonic restraint function on the differential relay (7UT61) prevents the relay from tripping during transformer magnetizing inrush current. However, the over-current relays which are used for back up protection does not have a harmonic restraint element, and over-current relay trips due to magnetizing inrush current, causes unwanted interruptions and power failures. The establishment of harmonic blocking scheme for over-current protection in power transformers is an important finding of this research study. IEC61850 standard-Based GOOSE (Generic Object Oriented Substation Event) applications used in power transformer protection for fast detecting and clearing of faults is an interested study presented in the proposed work.
Method for Tuning the Parameters of Active Force Reducing Building Vibrations—Numerical Tests
Authors: Dymarek Andrzej , Dzitkowski Tomasz , Herbuś Krzysztof , Ociepka Piotr , Niedworok Andrzej , Orzech Łukasz
Published: December 2021

The paper formulates a method of active reduction of structure vibrations in the selected resonance zones of the tested object. The method ensures reduction of vibrations of the selected resonance zones by determining the parameters of the active force that meets the desired dynamic properties. The paper presents a method for determining the parameters of the active force by reducing the vibrations of the structure in its resonance zones to a given vibration amplitude. For this purpose, an analytical form was formulated, which will clearly define the dynamic properties of the tested object and the force reducing the vibrations in the form of a mathematical model. The formulated mathematical model is a modified object input function, which in its form takes into account the properties of the active force reducing the vibrations. In such a case, it is possible to use the methods of mechanical synthesis to decompose the modified characteristic function into the parameters of the system and the parameters of the force being sought. In the formulated method, the desired dynamic properties of the system and the vibration reducing force were defined in such a way that the determined parameters of the active force (velocity-dependent function) had an impact on all forms of natural vibrations of the tested system. Based on the formalized method, the force reducing the vibrations of the four-story frame to the desired displacement amplitude was determined. Two cases of determining the active force reducing the vibrations to the desired vibration amplitude of the system by modifying the dynamic characteristics describing the object together with the active force were considered. For both cases, the system’s responses to the oscillation generated by harmonic force of frequencies equal to the first two forms of natural vibrations of the tested system were determined. In order to verify the determined force reducing the vibrations of the object and to create a visualization of the analyzed phenomenon, the building structure dynamics were analyzed with the use of PLM Siemens NX 12 software. The determined force parameters were implemented into the numerical model, in which the tested system was modelled, and the response time waveforms were generated with regard to the considered story. The generated waveforms were compared with the waveforms obtained in the formalized mathematical model for determining the active force reducing the vibrations. The vibrations of the tested numerical model were induced by the kinematic excitation with the maximum amplitude equal to 100 mm, which corresponds to the vibration amplitude during the earthquake with a force equal to level 5 on the Richter scale.
Review of MVDC Applications, Technologies, and Future Prospects
Authors: Coffey Sophie , Timmers Victor , Li Rui , Wu Guanglu , Egea-Àlvarez Agustí
Published: December 2021

This paper presents a complete review of MVDC applications and their required technologies. Four main MVDC applications were investigated: rail, shipboard systems, distribution grids, and offshore collection systems. For each application, the voltage and power levels, grid structures, converter topologies, and protection and control structure were reviewed. Case studies of the varying applications as well as the literature were analyzed to ascertain the common trends and to review suggested future topologies. For rail, ship, and distribution systems, the technology and ability to implement MVDC grids is available, and there are already a number of case studies. Offshore wind collection systems, however, are yet able to be implemented. Across the four applications, the MVDC voltages ranged from 5–50 kV DC and tens of MW, with some papers suggesting an upper limit of 100 kV DC and hundreds of MV for distribution networks and offshore wind farm applications. This enables the use of varying technologies at both the lower and high voltage ranges, giving flexibility in the choice of topology that is required required.
Design of Hybrid (PV-Diesel) System for Tourist Island in Karimunjawa Indonesia
Authors: Hiron Nurul , Busaeri Nundang , Sutisna Sutisna , Nurmela Nurmela , Sambas Aceng
Published: December 2021

The main problem with electricity supply on densely populated islands is reliable, low-carbon, and sustainable electricity. The availability of potential energy needs in-depth observation to ensure that the system can be built sustainably. This paper examines the integration of PV systems and diesel power systems on Karimunjawa Island to meet the need for reliable systems from economic, ecological, and technological aspects. Using the DigSilent Power Factory program to obtain the system response interference and penetration of the Photovoltaic (PV) system. Furthermore, this paper also tests short circuit analysis and economic feasibility analysis while validating the Levelized Cost of Electricity (LCOE) and Electric Production Cost (EPC) approaches. The results show that the availability of irradiation can handle the electricity needs on Karimunjawa Island. In addition, it proposes the designed requirements for an integrated PV power system and Diesel Power Plant (DPP) system. The research has also captured the synergistic profile of PV and DPP working coordination within 24 h.