bluuebunny/crossref_metadata_2025 huggingface dataset:
Alberta Infant Motor Scale (AIMS) Performance of Early-Term Greek Infants: The Impact of Shorter Gestation on Gross Motor Development among “Term-Born” Infants
Authors: Syrengelas Dimitris , Nikaina Eirini , Kleisiouni Paraskevi , Siahanidou Tania
Published: February 2022

Early-term birth (37+0 to 38+6 gestational weeks) may have a negative impact on infants’ neurodevelopment compared to delivery at 39 weeks or beyond. The purpose of this study was to evaluate the gross motor development of early-term infants using the Alberta Infant Motor Scale (AIMS). A total of 1087 healthy infants (559 early-term and 528 full-term infants born at 39+0 to 41+6 weeks of gestation) were studied. Mean AIMS scores were compared between the two groups at monthly intervals. The impact of gestational age on total AIMS scores was assessed by linear regression, after adjustment for chronological age, sex and SGA. Mean total AIMS scores, albeit within normal range, were significantly lower in early-term than full-term infants at the 2nd, 6th, 7th, 8th and 12th month of age; differences between groups were within three points. In multivariate regression analysis, a longer gestation by one week had a positive impact on total AIMS score during the first year of life (β = 0.90; 95% CI 0.45, 1.35). In conclusion, early-term infants exhibit worse gross motor performance during the first year of life in comparison with their full-term peers; however, the differences between the two groups are small.
The Importance of Sleep and Circadian Rhythms for Vaccination Success and Susceptibility to Viral Infections
Authors: Schmitz Nina C. M. , van der Werf Ysbrand D. , Lammers-van der Holst Heidi M.
Published: February 2022

Sleep and circadian rhythms are closely involved in the immune system and its regulation. Here, we describe this relationship and provide recommendations regarding the influence of sleep and circadian rhythms on vaccination success. We review studies investigating how viral susceptibility is influenced by changes in immunological parameters as a consequence of sleep deprivation. Short sleep duration and poor sleep efficiency both appear to be strong factors leading to greater vulnerability. In addition, both sleep duration and the time of day of the vaccination seem to be associated with the magnitude of the antibody response after vaccination. Based on these findings, a recommendation would consist of a sleep duration of 7 h or more every night to both reduce the risk of infection and to optimize the efficacy of vaccination with respect to circadian timing. Improving sleep quality and its circadian timing can potentially play a role in preventing infection and in vaccination benefits. In conclusion, sufficient (or longer) sleep duration is important in both reducing susceptibility to infection and increasing antibody response after vaccination.
MOCVD of II-VI HRT/Emitters for Voc Improvements to CdTe Solar Cells
Authors: Clayton Andrew J. , Abbas Ali , Siderfin Peter J. , Jones Stephen , Teloeken Ana , Oklobia Ochai , Walls John M. , Irvine Stuart J. C.
Published: February 2022

CdTe solar cells were produced using metal organic chemical vapour deposition (MOCVD), which employed a (Zn,Al)S (AZS) high resistant transparent (HRT) layer at the transparent conducting oxide (TCO)/Cd(Zn)S emitter interface, to enable the higher annealing temperature of 440 °C to be employed in the chlorine heat treatment (CHT) process. The AZS HRT remained intact with conformal coverage over the TCO after performing the high CHT annealing, confirmed by cross-section scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy (STEM-EDX) characterisation, which also revealed the Cd(Zn)S emitter layer having been consumed by the CdTe absorber via interdiffusion. The more aggressive CHT resulted in large CdTe grains. The combination of AZS HRT and aggressive CHT increased open circuit voltage (Voc) and improved solar cell performance.
Effect of Ammonia Addition on the Growth of an AlO(OH) Film during Steam Coating Process
Authors: Itano Naotaka , Lee So Yoon , Serizawa Ai
Published: February 2022

Al alloys possess excellent physical and mechanical properties, such as low density, high specific strength, and good ductility. However, their low corrosion resistance limits their use in corrosive environments. The steam coating process has attracted considerable attention as a new coating technology that can improve the corrosion resistance of Al alloys. This surface treatment technology uses steam to form a corrosion-resistant film on Al alloys. However, a decrease in the processing time, which can result in a lower cost, is needed for the practical application of the steam coating process. In this study, an Al-Mg-Si alloy is used as the base material, and ammonia is added to the steam source to increase the film formation rate. By adding ammonia (0.5 mol/L) to the steam source, the rate constant, K, for film formation increases 1.82 times compared to that of the pure-water-only treatment. Field emission scanning electron micrographs of the film surface confirms that the crystal morphologies of the crystals change from rectangular to parallelepiped shape with increasing process time by ammonia addition. Furthermore, X-ray diffraction patterns show that AlO(OH) crystals are successfully synthesized without byproducts, even when ammonia is added.
Effect of Gas Propellant Temperature on the Microstructure, Friction, and Wear Resistance of High-Pressure Cold Sprayed Zr702 Coatings on Al6061 Alloy
Authors: Ralls Alessandro M. , Kasar Ashish K. , Daroonparvar Mohammadreza , Siddaiah Arpith , Kumar Pankaj , Kay Charles M. , Misra Manoranjan , Menezes Pradeep L.
Published: February 2022

For the first time, Zr702 coatings were deposited onto an Al6061 alloy using a high-pressure cold spray (HPCS) system. In this work, five different N2 process gas temperatures between 700 and 1100 °C were employed to understand the formation of cold sprayed (CS) Zr coatings and their feasibility for enhanced wear resistance. Results indicated that the N2 processing gas temperature of about 1100 °C enabled a higher degree of particle thermal softening, which created a dense, robust, oxide- and defect-free Zr coating. Across all CS Zr coatings, there was a refinement of crystallinity, which was attributed to the severe localized plastic deformation of the powder particles. The enhanced thermal boost up zone at the inter-particle boundaries and decreased recoverable elastic strain were accountable for the inter-particle bonding of the coatings at higher process gas temperatures. The flattening ratio (ε) increased as a function of temperature, implying that there was a greater degree of plastic deformation at higher N2 gas temperatures. The microhardness readings and wear volume of the coatings were also improved as a function of process gas temperature. In this work, the wear of the Al6061 alloy substrate was mainly plowing-based, whereas the Zr CS substrates demonstrated a gradual change of abrasive to adhesive wear. From our findings, the preparation of CS Zr coatings was a feasible method of enhancing the wear resistance of Al-based alloys.
A Cross-Sectional Study for Association between Periodontitis and Benign Prostatic Hyperplasia Using the Korean Genome and Epidemiology Study Data
Authors: Byun Soo-Hwan , Min Chanyang , Bang Woojin , Yang Byoung-Eun , Hong Seok Jin , Park Sang Chul , Choi Hyo Geun
Published: February 2022

Recently, several studies have suggested the relationship between periodontitis and prostatic disease. However, epidemiological studies on the association between periodontitis and benign prostatic hyperplasia (BPH) are scarce. Hence, we aimed to identify the association between the two diseases using data from the Korean Genome and Epidemiology Study. Among the 173,209 participants, 3297 men with periodontitis and 35,292 controls (without periodontitis) were selected. The history of BPH in participants with periodontitis and the controls were also investigated. Two-tailed analyses, independent t-tests, and chi-square tests were used for statistical analysis. The adjusted odds ratio (OR) for BPH was 1.50 (95% confidence interval, 1.35–1.68; p < 0.001) after adjusting for past medical histories. The adjusted OR for BPH was 1.57 (95% confidence interval, 1.41–1.76; p < 0.001) after adjusting for anthropometric and laboratory data. Collectively, this study provides evidence that periodontitis is associated with BPH. This finding supports the use of regular dental checkups and periodontal treatments to reduce the prevalence and progression of BPH.
Deep Learning (CNN, RNN) Applications for Smart Homes: A Systematic Review
Authors: Yu Jiyeon , de Antonio Angelica , Villalba-Mora Elena
Published: February 2022

In recent years, research on convolutional neural networks (CNN) and recurrent neural networks (RNN) in deep learning has been actively conducted. In order to provide more personalized and advanced functions in smart home services, studies on deep learning applications are becoming more frequent, and deep learning is acknowledged as an efficient method for recognizing the voices and activities of users. In this context, this study aims to systematically review the smart home studies that apply CNN and RNN/LSTM as their main solution. Of the 632 studies retrieved from the Web of Science, Scopus, IEEE Explore, and PubMed databases, 43 studies were selected and analyzed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. In this paper, we examine which smart home applications CNN and RNN/LSTM are applied to and compare how they were implemented and evaluated. The selected studies dealt with a total of 15 application areas for smart homes, where activity recognition was covered the most. This study provides essential data for all researchers who want to apply deep learning for smart homes, identifies the main trends, and can help to guide design and evaluation decisions for particular smart home services.
Crystal Plasticity Simulation of the Microstructural Effect in Powder Metallurgy Superalloys under Dwell Fatigue Loading
Authors: Zheng Zebang , Peng Zichao
Published: February 2022

The microstructural effect, including γ’ precipitate morphology and twin grains, of dwell fatigue behavior in a powder metallurgy nickel-based superalloy, was studied using crystal plasticity modeling. Strain rate and dwell sensitivities of 923 K were quantitatively investigated. The strain accumulations, under normal and dwell fatigue loading, showed γ’ precipitate size-dependence. Strong load shedding can be observed between parent and twin grains, which was attributed to local plastic heterogeneity. Local stress and strain evolution are both faster than the macroscopic values, which threatens the safety of engine components.
Superplastic Deformation Behaviors and Power Dissipation Rate for Fine-Grained Ti-6Al-4V Titanium Alloy Processed by Direct Rolling
Authors: Wang Xin , Zhou Ge , Men Yue , Zhang Siqian , Zhang Haoyu , Li Feng , Chen Lijia
Published: February 2022

Fine-grained Ti-6Al-4V titanium alloy plates were manufactured using a direct rolling approach, and a series of superplastic tensile tests were conducted at varying temperatures and strain rates. The maximum tensile elongation of 816% was obtained at 810 °C and 5 × 10−4 s−1, and the superplastic flow behavior was dominated by a strain-induced grain boundary slip. In addition, the superplastic behaviors of the alloy were investigated, and the α-and β-phase Gibbs free energy was calculated. The vital role of phase β in the transformation was discussed from a thermodynamical perspective. A power dissipation rate model of Ti-6Al-4V during the superplastic deformation was built and used to predict the energy changing laws in the dynamic recrystallization and grain boundary sliding during the superplastic deformation.
Moving beyond Definitive Therapy: Increasing Physical Activity in Survivors of Cancers of the Head and Neck
Authors: Nehlsen Anthony D. , Sindhu Kunal K. , Jones Brianna M. , Lehrer Eric J. , Rowley Jared P. , Bakst Richard L.
Published: February 2022

As chemotherapeutic, radiation, and surgical techniques have improved, there has been a dramatic improvement in survival in patients diagnosed with cancers of the head and neck. As a result, a heightened focus on survivorship by clinicians will increasingly prove necessary. In particular, medical care teams will have to pay special attention to mitigating the long-term sequelae of definitive cancer treatments, many of which act as barriers to exercise. This is unfortunate, as the benefits of exercise in patients with cancer have become increasingly recognized. In this review, we discuss the potential benefits of and barriers to exercise in survivors of cancers of the head and neck. We also review existing exercise guidelines and strategies by which clinicians can promote exercise in this unique patient population.
Small Bowel Adenocarcinoma: From Molecular Insights to Clinical Management
Authors: Gelsomino Fabio , Balsano Rita , De Lorenzo Stefania , Garajová Ingrid
Published: February 2022

Small bowel adenocarcinoma (SBA) is a rare malignancy, with a rising incidence in recent decades, and accounts for roughly 40% of all cancers of the small bowel. The majority of SBAs arise in the duodenum and are associated with a dismal prognosis. Surgery remains the mainstay of treatment for localized disease, while systemic treatments parallel those used in colorectal cancer (CRC), both in the adjuvant and palliative setting. In fact, owing to the lack of prospective data supporting its optimal management, SBA has historically been treated in the same way as CRC. However, recent genetic and molecular data suggest a distinct profile from other gastrointestinal malignancies and support a more nuanced approach to its management. Herein, we briefly review the state-of-the-art in the clinical management of early-stage and advanced disease and recent discoveries of potentially actionable genetic alterations or pathways along with the most promising ongoing clinical trials, which will hopefully revolutionize the treatment landscape of this orphan disease in the foreseeable future.
Small Mammal Diversity in Response to Land Transformation and Seasonal Variation in South Africa
Authors: Ramahlo Mmatsawela , Somers Michael John , Hart Daniel William , Ganswindt Andre
Published: February 2022

Anthropogenic land transformation is a consequence of human population growth and the associated agricultural, residential, and industrial needs. This study aimed to investigate the effects of anthropogenic activity and human-mediated land transformation on capture/recapture frequencies, species richness, and diversity of native small mammal community assemblages in the Magaliesberg Biosphere, North West province, South Africa. Five anthropogenically transformed land-use types were investigated: an animal rehabilitation and ecotourism center, an agricultural farmstead, a residential farmstead, a mine-adjacent agricultural farmstead, and a protected nature conservancy. We used live traps to sample small mammals during the dry and wet seasons over three consecutive years and compared population numbers and species composition across study sites and seasons. Capture/recapture frequencies differed significantly between sites and seasons, with the highest capture frequencies recorded at the agricultural and residential farmsteads. Species richness and diversity were highest at the residential and mine-adjacent farmsteads, both of which experienced intermediate levels of anthropogenic disturbance throughout the sampling period. The study shows that while natural and protected landscapes with low levels of disturbance are preferred, transformed landscapes can also be managed effectively to benefit native small mammal populations by regulating the frequency and intensity of human-mediated activities.
Microbial Diversity Associated with Photosynthetic Organisms
Authors: Li Zhun , Kim Song-Gun
Published: February 2022

Photosynthetic organisms (e.g., algae and plants) can produce organic substancesfrom inorganic nutrients based on energy harvested from light as the primary producers inboth the aquatic and terrestrial ecosystems [...]
Diversity and Molecular Phylogeny of Pagurid Hermit Crabs (Anomura: Paguridae: Pagurus)
Authors: Sultana Zakea , Babarinde Isaac Adeyemi , Asakura Akira
Published: February 2022

Species of the genus Pagurus have diversified into a wide variety of marine habitats across the world. Despite their worldwide abundance, the genus diversity and biogeographical relationship are relatively less understood at species-level. We evaluated the phylogenetic relationship and genetic diversity among the Pagurus species based on publicly available mitochondrial and nuclear markers. While independent analyses of different markers allowed for larger coverage of taxa and produced largely consistent results, the concatenation of 16S and COI partial sequences led to higher confidence in the phylogenetic relationships. Our analyses established several monophyletic species clusters, substantially corresponding to the previously established morphology-based species groups. The comprehensive species inclusion in the molecular phylogeny resolved the taxonomic position of a number of recently described species that had not been assigned to any morpho-group. In mitochondrial markers-based phylogenies, the “Provenzanoi” group was identified as the basal lineage of Pagurus. The divergence time estimation of the major groups of Pagurus revealed that the Pacific species originated and diversified from the Atlantic lineages around 25–51 MYA. The molecular results suggested a higher inter-regional species diversity and complex phylogenetic relationships within the diverse and heterogeneous members of the genus Pagurus. The study presents a comprehensive snapshot of the diversity of pagurid hermit crabs across multiple geographic regions.
A Rare Case of Radiation-Induced Liver Disease in Treated Abdominal Lymphoma Showing High [18F]FDG Avidity and Low EOB Uptake Proportional to the Irradiation Dose
Authors: Usami Aya , Yokoyama Kota , Tsuchiya Junichi , Umezawa Yoshihiro , Toda Kazuma , Tateishi Ukihide , Yoshimura Ryoichi
Published: February 2022

A 44-year-old woman presented with high [18F]FDG uptake liver lesion after six courses of R-CHOP and radiotherapy for abdominal DLBCL, which was misdiagnosed as a hepatic invasion. EOB–MRI showed slight T2 hyperintensity, low-intensity DWI, and decreased EOB uptake in the hepatocellular phase. Compared with the pretreatment planning CT, the liver lesion coincided with the area of >40.5 Gy, resulting in the diagnosis of RILD. At the follow-up [18F]FDG PET/CT 7 months after irradiation, the abnormal liver uptake disappeared. Comparing [18F]FDG PET/CT, EOB–MRI, and planning CT can lead to the correct diagnosis of RILD and avoid unnecessary biopsies and treatment changes.
Analysis of Multi-Path Fading and the Doppler Effect for Reconfigurable-Intelligent-Surface-Assisted Wireless Networks
Authors: Wu Guilu
Published: February 2022

The randomness property of wireless channels restricts the improvement of their performance in wireless networks. As a novel solution for overcoming this, a reconfigurable intelligent surface (RIS) was introduced to reshape wireless physical environments. Initially, the multi-path and Doppler effects are discussed in a case in which a reflector was considered to reflect the incident signal for wireless communication. Subsequently, the results for the transmission signal were analyzed when a reflector was coated with an RIS. Specifically, the multi-path fading stemming from the movement of the mobile transmitter was eliminated or mitigated by utilizing an RIS. Meanwhile, the Doppler effect was also reduced to restrain the rapid fluctuations in the transmission signal by using a tunable RIS in real time. The simulation results demonstrate that the magnitude and spectrum of the received signal can be regulated by an RIS. The multi-path fading and Doppler effect can be effectively mitigated when the reflector is coated with an RIS in wireless networks.
Timescape: A Novel Spatiotemporal Modeling Tool
Authors: Ciolfi Marco , Chiocchini Francesca , Pace Rocco , Russo Giuseppe , Lauteri Marco
Published: February 2022

We developed a novel approach in the field of spatiotemporal modeling, based on the spatialisation of time, the Timescape algorithm. It is especially aimed at sparsely distributed datasets in ecological research, whose spatial and temporal variability is strongly entangled. The algorithm is based on the definition of a spatiotemporal distance that incorporates a causality constraint and that is capable of accommodating the seasonal behavior of the modeled variable as well. The actual modeling is conducted exploiting any established spatial interpolation technique, substituting the ordinary spatial distance with our Timescape distance, thus sorting, from the same input set of observations, those causally related to each estimated value at a given site and time. The notion of causality is expressed topologically and it has to be tuned for each particular case. The Timescape algorithm originates from the field of stable isotopes spatial modeling (isoscapes), but in principle it can be used to model any real scalar random field distribution.
An Overview of Medical Electronic Hardware Security and Emerging Solutions
Authors: Taheri Shayan , Asadizanjani Navid
Published: February 2022

Electronic healthcare technology is widespread around the world and creates massive potential to improve clinical outcomes and transform care delivery. However, there are increasing concerns with respect to the cyber vulnerabilities of medical tools, malicious medical errors, and security attacks on healthcare data and devices. Increased connectivity to existing computer networks has exposed the medical devices/systems and their communicating data to new cybersecurity vulnerabilities. Adversaries leverage the state-of-the-art technologies, in particular artificial intelligence and computer vision-based techniques, in order to launch stronger and more detrimental attacks on the medical targets. The medical domain is an attractive area for cybercrimes for two fundamental reasons: (a) it is rich resource of valuable and sensitive data; and (b) its protection and defensive mechanisms are weak and ineffective. The attacks aim to steal health information from the patients, manipulate the medical information and queries, maliciously change the medical diagnosis, decisions, and prescriptions, etc. A successful attack in the medical domain causes serious damage to the patient’s health and even death. Therefore, cybersecurity is critical to patient safety and every aspect of the medical domain, while it has not been studied sufficiently. To tackle this problem, new human- and computer-based countermeasures are researched and proposed for medical attacks using the most effective software and hardware technologies, such as artificial intelligence and computer vision. This review provides insights to the novel and existing solutions in the literature that mitigate cyber risks, errors, damage, and threats in the medical domain. We have performed a scoping review analyzing the four major elements in this area (in order from a medical perspective): (1) medical errors; (2) security weaknesses of medical devices at software- and hardware-level; (3) artificial intelligence and/or computer vision in medical applications; and (4) cyber attacks and defenses in the medical domain. Meanwhile, artificial intelligence and computer vision are key topics in this review and their usage in all these four elements are discussed. The review outcome delivers the solutions through building and evaluating the connections among these elements in order to serve as a beneficial guideline for medical electronic hardware security.
Soft Load Shedding Based Demand Control of Residential Consumers
Authors: Gull Muhammad S. , Mehmood Nasir , Rauf Huzaifa , Khalid Muhammad , Arshad Naveed
Published: February 2022

Power generation and consumption is an instantaneous process and maintaining the balance between demand and supply is crucial since the demand and supply mismatch leads to various risks like over-investment, over-generation, under-generation, and the collapse of the power system. Therefore, the reduction in demand and supply mismatch is critical to ensure the safety and reliability of power system operation and economics. A typical and common approach, called full load shedding (FLS), is practiced in cases where electric power demand exceeds the available generation. FLS operation alleviates the power demand by cutting down the load for an entire area or region, which results in several challenges and problems for the utilities and consumers. In this study, a demand-side management (DSM) technique, called Soft-load shedding (SLS), is proposed, which uses data analytics and software-based architecture, and utilizes the real-world time-series energy consumption data available at one-minute granularity for a diversified group of residential consumers. The procedure is based on pattern identification extracted from the dataset and allocates a certain quota of power to be distributed on selected consumers such that the excessive demand is reduced, thereby minimizing the demand and supply mismatch. The results show that the proposed strategy obtains a significant reduction in the demand and supply mismatch such that the mismatch remains in the range of 10–15%, especially during the period where demand exceeds generation, operating within the utility constraints, and under the available generation, to avoid power system failure without affecting any lifeline consumer, with a minimum impact on the consumer’s comfort.
Hybrid Converter with Multiple Sources for Lithium Battery Charger Applications
Authors: Tseng Sheng-Yu , Fan Jun-Hao , Huang Hong-Kai
Published: February 2022

This paper proposes a hybrid converter with multiple sources for lithium battery charger applications. Since the output voltage of a lithium battery charger is very low, its charger needs a higher step-down voltage for a utility line source or a step-down voltage for PV arrays. In order to implement the battery charger with utility line and PV arrays sources to simultaneously supply power to battery, a flyback converter is selected for utility line sources, and a buck converter is adopted for PV arrays source. Due to leakage inductor of transformer in flyback converter, an active clamp circuit is introduced into flyback converter to recover the energy stored in leakage inductor. In addition, flyback and buck converters can adopt switch integration techniques to simplify circuit structure. With this approach, the proposed hybrid converter has less components, is lighter weight and has smaller size and higher conversion efficiency. Finally, a prototype of the proposed hybrid converter with output voltage of 5 V~8.4 V and output maximum current of 12 A has been implement to verify its feasibility. It is suitable for the lithium battery charger applications.
Optimization of Heat Exchange Plate Geometry by Modeling Physical Processes Using CAD
Authors: Korobiichuk Igor , Mel’nick Viktorij , Shybetskyi Vladyslav , Kostyk Sergii , Kalinina Myroslava
Published: February 2022

This article presents the possibility of evaluating the efficiency of the heat exchange element with a special stamping plate, which is based on the results of computer simulation. The method is based on a comparative analysis of convective heat transfer models implemented in ANSYS using a k-ε turbulence model. To conduct the study, 3D models of three different types of cavity geometry formed between two heat exchange plates (flat plate, chevron plate, and plate with conical stampings) were built. Simulation was performed by finite element analysis in ANSYS for channels formed by the three types of plates, one of which is a new configuration. The results of hydrodynamic and heat exchange parameters allowed for establishing the efficiency of convective heat exchange for plates of known structures and to compare them with the proposed one. It was found that the plates with conical stamping form the smallest channels through which the fluid moves. The velocity of the coolant is uniform throughout the cross section of the channel and equal to 0.294 m/s; the value of the heat transfer coefficient is the largest of the three models and is 5339 W/(m K), while the pressure drop is 1060 Pa. Taking into account the simulation results, the best heat transfer parameters were shown by the channel formed by plates with conical stamping and the highest pressure drop. To increase the efficiency, indicated by the ratio of heat transfer coefficients to hydraulic resistance, the geometry of the plate with conical stamping was optimized. As a result of optimization, it was found that the optimal geometric parameters of the heat exchange plate with conical stamping were achieved at a 55° inclination angle and 1.5 mm height for the cone. The results of this study can be used in the design of heat exchange elements of new structures with optimal parameters for highly efficient heating of liquid coolants.
The Hydrodynamics of Translational−Rotational Motion of Incompressible Gas Flow within the Working Space of a Vortex Heat Generator
Authors: Nikolsky Valeriy , Dychkovskyi Roman , Cabana Edgar Cáceres , Howaniec Natalia , Jura Bartłomiej , Widera Katarzyna , Smoliński Adam
Published: February 2022

The paper presents the results of analytical and experimental studies of the hydrodynamics of the translational−rotational motion of incompressible gas flow within a working space of a variable-geometry vortex heat generator. The terminal velocity and pressure have been identified analytically. The effect of vortex generation on the ratio of the parameters has been analyzed. A mathematical model has been developed with a simplified design scheme that simulates the movement inside a vortex channel with fixed elements. On the basis of mathematical modelling, the influence of the apparatus-constructive (AC) design of the working space of a vortex heat generator on the generation of vortices inside the apparatus has been analyzed. The influence of the main geometric and hydrodynamic parameters of the device on the indicators of its energy efficiency has been investigated. The obtained models show the critical regions where the most intense cavitation zones are possible. An analysis of the hydrodynamics of the incompressible gas motion within the working space of the newly designed vortex heat generator with variable geometry has helped define both the terminal velocity and pressure. In addition, the effect of the facility geometry on the generation of vortices favoring cavitation was determined. The model studies have been carried out in terms of liquid loading changes in the 0.001–0.01 m3/s range. The changes in a velocity field within a working channel have been analyzed for the channel geometry, where a cone angle γ is 0° to 25°, with 130, 70, and 40 mm widths for the working channel. It has been identified that a sufficient axial symmetry of the heat carrier along a vortex accelerator enables the heat carrier inlet through a turbulizing nozzle. The dependence of the nozzle area, the effect on the efficiency of the vortex heat generator angle of attack of the vortex accelerator, and the ratio of the length and diameter of the vortex zone of the heat generator to its energy efficiency in general have been defined experimentally. These studies could be instrumental in the design of vortex heat generators whose geometry corresponds to the current requirements concerning energy efficiency. It has been found that the geometry of the vortex accelerator improves the operation of the heat generator by 35% in comparison with similar available designs.
A Hybrid Approach in Design of Building Energy Management System with Smart Readiness Indicator and Building as a Service Concept
Authors: Ożadowicz Andrzej
Published: February 2022

Improving energy efficiency and increasing the level of intelligence are two main factors determining the current development trends for new and modernized buildings. They are especially important in the perspective of development of prosumer installations and local microgrids. A key tool to achieve these goals is a well-designed and implemented Building Automation and Control System (BACS). This paper presents a new hybrid approach to the design and technical organization of BACS based on the provisions of the EN 15232 standard and the guidelines of the Smart Readiness Indicator (SRI) defined in the Energy Performance of Buildings Directive 2018 (EPBD 2018). The main assumptions of this hybrid approach along with examples of functional BACS designs for small prosumer installations organized according to them are provided. Potential impact on building energy performance is discussed as well. Finally, a SWOT analysis of the possibility of merging the EN 15232 standard guidelines and the SRI assessment methodology to develop uniform technical guidelines for the BACS functions design and evaluation of their impact on the buildings’ energy efficiency are discussed.
Design and Real-Time Implementation of a Control System for SiC Off-Board Chargers of Battery Electric Buses
Authors: Rasool Haaris , Verbrugge Boud , Jaman Shahid , Abramushkina Ekaterina , Geury Thomas , El Baghdadi Mohamed , Hegazy Omar
Published: February 2022

Emerging wide bandgap (WBG) semiconductors, such as silicon carbide (SiC), will enable chargers to operate at higher switching frequencies, which grants the ability to deliver high power and enhances efficiency. This paper addresses the modeling of a double-sided cooling (DSC) SiC technology-based off-board charger for battery electric buses (BEBs) and the design of its control and real-time (RT) implementation. A three-phase active front-end (AFE) rectifier topology is considered in the modeling and control system design for the active part of the DC off-board charger. The control system consists of a dual-loop voltage–current controller and is used to ensure AC to DC power conversion for charging and to achieve the targeted grid current total harmonic distortion (THD) and unity power factor (PF). Linear and nonlinear simulation models are developed in MATLAB/Simulink for optimum control design and to validate the voltage and current control performances. Four types of controllers (i.e., proportional–integral (PI), lead–lag, proportional–resonant (PR), and modified proportional–resonant (MPR)) are designed as current controllers, and a comparative analysis is conducted on the simulation model. In addition, the final design of the dual-loop controller is implemented on the RT–FPGA platform of dSpace MicroLabBox. It is then tested with the charger to validate the control performance with experimental data. The simulation and experimental results demonstrate the correct operation of the converter control performance by tracking the reference commands.
The Rule-Based Model of Negentropy for Increasing the Energy Efficiency of the City’s Digital Transformation Processes into a Smart City
Authors: Orłowski Cezary , Cofta Piotr , Orlowski Aleksander
Published: February 2022

The aim of the article is to build a rule-based model (RMFDN) for increasing the energy efficiency of Smart Cities’ digital transformation processes. The problem that arises during the implementation of digital transformation processes concerns the measures that should be assigned to estimate the duration of the digital transformation. Previous studies of digital transformation have been based on the analysis of design processes based on key performance indicators (KPIs), their place and role in the digital transformation processes, and their monitoring with the use of information architecture. The analysis of the digital transformation processes of cities into Smart Cities shows that they seem inappropriate to the complexity and uncertainty of the digital transformation carried out. The new approach presented in the article is based on three key aspects: rule-based description of the state of digital transformation processes enabling their energy assessment, introducing energy maturity capsules to describe the state of these processes and application of measures based on project negentropy increments for maturity capsules.
Drivers of Digitalization in the Energy Sector—The Managerial Perspective from the Catching Up Economy
Authors: Światowiec-Szczepańska Justyna , Stępień Beata
Published: February 2022

This article attempts to identify the key forces driving the successful digitalization of the energy sector, ensuring improvements in the energy triangle including sustainability, stability, and economic performance. The article sheds light on the diverse energy priorities at supra-, national, and managerial levels, and the role of digitalization in achieving these objectives. Catching up economies (such as Poland), being post-socialist EU member states, in order to transform its energetic sector, must overcome a number of infrastructural and social shortcomings retained as a legacy of the socialist economy. As such, sustainability (as the core priority at EU energy agenda) may not be the leading objective at both national and company level in the energy sector transformation. This article presents the results of empirical research carried out through distribution of e-questionnaire addressed to Polish managers from the energy sector. The results were analyzed using the fsQCA method. The findings suggest that, for managers, the most important drivers of digitalization and transformation of the energy sector in Poland are its high economic performance, together with support for energy prosumers and consumers. The prerequisites for a successful digitalization are alternatively the absence of management barriers, or a combination of high economic performance and a strong focus on environmental protection. Surprisingly, according to managers surveyed, the rapid implementation of new technologies is not considered a vital condition for successful digital transformation of the energy sector, which implies either or managerial lack of knowledge in this area and/or a reluctance to introduce digital rapid technologies.
A Study on the Preprocessing Method for Power System Applications Based on Polynomial and Standard Patterns
Authors: Kim Jun-Hyeok , Joung Jong-Man , Lee Byung-Sung
Published: February 2022

Data-based decisions have been being made in various fields due to the development of sensors throughout the industries. Likewise, in the power system field, data-based decisions are being made in various tasks, including establishing distribution investment plans. However, in order for it to have validity, it is necessary to get rid of abnormal data or data with low representativeness of a temporary nature. Although in general, such a series of processes are done by preprocessing, the those of power system data should be handled not only noise but also data fluctuations caused by temporary change in operations such as load transfers, as mentioned above. In addition, the characteristics of load data of distribution lines (DLs) can be different depending on the characteristics of the load itself, the characteristics of the connected DLs, and regional characteristics of each DLs, so it is essential to propose and apply the optimized preprocessing method for each DL. In this study, therefore, an optimal preprocessing algorithm for each DL was proposed by mixing standard pattern calculations and polynomials based statistical method, and its appropriateness was verified by comparing the results with actual load transfer records. As a result of the verification, it was confirmed that the load transfer detection accuracy of the proposed method was 88.89%, and the maximum load of the target DL can be reduced up to 11.59% by removing the load transfer data.
Optimization Control of Oilfield Waterflooding Systems Based on Different Zone and Pressure
Authors: Wang Yan , Wen Jingqiang , Zhang Ruijie , Gao Sheng , Ren Yongliang
Published: February 2022

The scrapping of old waterflooding wells and the increase in new waterflooding wells results in mixed flooding of high–low pressure wells in various oil layers in waterflooding systems. In order to meet production operation requirements, the whole system is in a state of high pressure, which leads to an increase in energy consumption and complicates the operation of waterflooding networks. According to the pressure distribution of wells, proceeding with regional accurate waterflooding can reduce operation costs and improve development efficiency. Considering the technical constraints of waterflooding networks, a method was proposed, which can quantitatively optimize classification and zoning for waterflooding of high–low pressure wells according to the pressure of networks and wells. At the same time, the ant colony algorithm and genetic algorithm were fused to form a new adaptive ant colony genetic hybrid algorithm, which can effectively determine the best pumping scheme of the waterflooding station, the pumping flow and optimize the low-pressure area. The K-means algorithm was used to optimize the topology of the pipe network in the high-pressure area to reduce the overall waterflooding pressure. Finally, the method was successfully applied to the large-scale waterflooding system including 2200 wells and 10 waterflooding stations in sites in China. The results show that the method is effective for the operation and reconstruction of waterflooding pipe networks with large-scale and serious mixed high–low pressure.
Effect of Chordwise Struts and Misaligned Flow on the Aerodynamic Performance of a Leading-Edge Inflatable Wing
Authors: Viré Axelle , Lebesque Geert , Folkersma Mikko , Schmehl Roland
Published: February 2022

Leading-edge inflatable (LEI) kites use a pressurized tubular frame to structurally support a single skin membrane canopy. The presence of the tubes on the pressure side of the wing leads to characteristic flow phenomena for this type of kite. In this paper, we present steady-state Reynolds-Averaged Navier-Stokes (RANS) simulations for a LEI wing for airborne wind energy applications. Expanding on previous work where only the leading-edge tube was considered, eight additional strut tubes that support the wing canopy are now included. The shape of the wing is considered to be constant. The influence of the strut tubes on the aerodynamic performance of the wing and the local flow field is assessed, considering flow configurations with and without side-slip. The simulations show that the aerodynamic performance of the wing decreases with increasing side-slip component of the inflow. On the other hand, the chordwise struts have little influence on the integral lift and drag of the wing, irrespective of the side-slip component. The overall flow characteristics are in good agreement with previous studies. In particular, it is confirmed that at a low Reynolds number of Re=105, a laminar separation bubble exists on the suction side of this hypothetical rigid wing shape with perfectly smooth surface. The destruction of this bubble at low angles of attack impacts negatively on the aerodynamic performance.
The Application of Open Capillary Modules for Sweeping Gas Membrane Distillation
Authors: Gryta Marek
Published: February 2022

The paper presents the sweeping gas membrane distillation realised by using the capillary module (length 1.1 m and area 0.1 m2) without housing (module shell). During the tests, the feed was flowing inside the hydrophobic polypropylene membranes. The studies were performed for two variants of process: with pre-heating (313–330 K) and without heating of the feed (brines). Under low gas flow (0.005 m/s) the evaporation performance varied in the range of 0.15–0.25 L/m2h, depending on the relative humidity (42–63%) and the air temperature (293–300 K). The application of feed pre-heating to 330 K led to an increase in the evaporation performance to 2.4 L/m2h. The permeate flux increased by 60% when the air flow velocities between the capillaries increased to 1.8–2.5 m/s. Increasing the feed flow rate from 0.1 to 0.59 m/s led to increase the permeate flux about 20% for feed temperature 293–310 K, and over 55% for feed temperature higher than 323 K.
Thermal Management in Electrical Machines
Authors: Micallef Christopher
Published: February 2022

Apart from protecting electrical machines from temperature related failures, thermal management of electrical machines is employed in the design phase of electrical machines to achieve higher efficiencies and higher power densities [...]
A Parameter Estimation Method for a Photovoltaic Power Generation System Based on a Two-Diode Model
Authors: Huang Chao-Ming , Chen Shin-Ju , Yang Sung-Pei
Published: February 2022

This study presents a parameter estimation method that uses an enhanced gray wolf optimizer (EGWO) to optimize the parameters for a two-diode photovoltaic (PV) power generation system. The proposed method consists of three stages. The first stage converts seven parameters for the two-diode model into 17 parameters for different environmental conditions, which provides more precise parameter estimation for the PV model. A PV power generation model is then established to represent the nonlinear relationship between inputs and outputs. The second stage involves a parameter sensitivity analysis and uses the overall effect method to remove the parameters that have smaller effect on the output. The final stage uses an enhanced GWO that is associated with measurement data to optimally estimate the parameters that are selected in the second stage. When the parameters are estimated, the predicted value for the PV power output is calculated for specific values of solar irradiation and module temperature. The proposed method is verified on a 200 kWp PV power generation system. To confirm the feasibility of the proposed method, the parameter estimation before and after optimization are compared, and these results are compared with other optimization algorithms, as well as those for a single-diode PV model.
The Impact of the COVID-19 Pandemic on the Development of Electromobility in Poland. The Perspective of Companies in the Transport-Shipping-Logistics Sector: A Case Study
Authors: Figura Janusz , Gądek-Hawlena Teresa
Published: February 2022

Negative processes occurring in the natural environment, under dynamic economy development, have become a factor for taking actions limiting destructive human activity. An important area in which initiatives are taken to improve the state of the natural environment is that of companies in the Transport-Shipping-Logistics Sector (TSL sector). The main objective of this article was to analyse the impact of the COVID-19 pandemic on the development of electromobility among companies in the Polish TSL sector, and identify factors that positively influenced or hindered its development during this time. For this purpose, qualitative and quantitative data analyses were carried out based on a literature review, statistical data, and direct research results. Descriptive statistics, chi-square test of concordance, and contingency coefficients were used to process the data. The results showed that the pandemic period did not affect the development of electromobility among TSL companies. Only a few companies own electric cars in Poland. Many of them did not plan to purchase this type of vehicle during the pandemic. The main factors influencing the decisions of entrepreneurs during the study period were the availability of charging infrastructure and electricity price uncertainty. The results of the study can be used by stakeholders of this sector in Poland.