bluuebunny/crossref_metadata_2025 huggingface dataset:
Revitalization of Residential Buildings Dating Back to the Late 19th and Early 20th Century on the Example of “Willa Halina” in Sopot (Poland)
Authors: Taraszkiewicz Antoni
Published: June 2021

Residential buildings dating back to the late 19th and early 20th century constitute an important element of the urban composition of many European cities, often determining their overall spatial expression. These buildings often require revitalization and sometimes also reconstruction or extension. Such activities make it possible to restore historical buildings to their former glory, but also to create new architecture, inscribed in the context of the place, yet bearing witness to modern times. Revitalization of historically and architecturally valuable but technically degraded residential buildings is one of the important elements of maintaining and sometimes rebuilding the image of modern cities and their sustainable development. However, revitalization activities require solving many problems of conservational nature, especially issues related to preserving the authenticity of the existing tissue, ways of reconstructing lost elements, and connecting historical architecture with contemporary architecture. Historic residential buildings of Sopot, a city located in Poland on the shores of the Baltic Sea, dating back to the late 19th and early 20th century, provide excellent research material for such considerations. In the article, the historical center of Sopot was examined, with particular emphasis on the historic Willa Halina from 1896 located there, which was revitalized (according to the design of the author of the article). Using such research methods as analysis of historical source material (iconography), observation (operationalization of preserved historical objects), comparative analysis of contemporary investments, and analysis of the revitalization design of “Willa Halina”, an attempt was made to present spatial and technical solutions leading to the desired effects in the revitalization process. This work aims to show (on the example of Willa Halina in Sopot) the author’s method of revitalizing valuable, historical residential buildings, complying with international conservation standards, including the Venice Charter, adopted in 1964 by the Second International Congress of Architects and Technicians of Historical Monuments. The paper also aims to present spatial and technical solutions leading to desired effects in the revitalization process, consistent with the idea of sustainable development.
The Role of Blockchain Technology in Augmenting Supply Chain Resilience to Cybercrime
Authors: Bayramova Aya , Edwards David J. , Roberts Chris
Published: June 2021

Using a systematic review of literature, this study identifies the potential impact of blockchain solutions for augmenting supply chain resilience (SCR) to cybercrime. This rich literature synthesis forms the basis of a novel theoretical framework that provides guidance and insight for blockchain adopters and vendors as well as delineate palpable benefits of this novel technology. An interpretivist philosophical design and inductive reasoning are adopted to conduct the systematic review of literature. A total of 867 papers were retrieved from Scopus database between the years of 2016 and 2020 and subsequently analysed via abductive reasoning, grounded theory and a thematic meta-analysis; where the latter was achieved using a scientometric approach and software tools such as VOS viewer and NVivo. Scientometric analysis revealed the most prolific countries, sources, publications and authors who reside at the vanguard of blockchain developments and adoption. Subsequent grounded theory analysis identified six main clusters of research endeavour viz: “case study”, “challenges and opportunity”, “traceability”, “smart contract” “blockchain and IoT” and “data security”. From 28 SCR metrics identified within literature, five were found to have been positively impacted by blockchain technology solutions, namely: “visibility”, “collaboration”, “integration”, “risk management” and “information sharing.” Prominent applications of blockchain technology in practice were “traceability systems” and “smart contracts” which are often implemented separately or in combination and primarily in food supply chains. This research constitutes the first study to critically synthesise extant literature for evaluation of blockchain solutions’ implication on SCR metrics. New perspectives obtained provided a basis for the novel theoretical framework for implementation that will be valued by software developers and adopting organizations, whilst creating new direction for researchers interested in blockchain technology.
Effect of the Metal Deposition Order on Structural, Electronic and Catalytic Properties of TiO2-Supported Bimetallic Au-Ag Catalysts in 1-Octanol Selective Oxidation
Authors: Kotolevich Yulia , Pakrieva Ekaterina , Kolobova Ekaterina , Farías Mario H. , Bogdanchikova Nina , Cortés Corberán Vicente , Pichugina Daria , Nikitina Nadezhda , Carabineiro Sónia A. C. , Pestryakov Alexey
Published: June 2021

Au and Ag were deposited on TiO2 modified with Ce, La, Fe or Mg in order to obtain bimetallic catalysts to be used for liquid-phase oxidation of 1-octanol. The effects of the deposition order of gold and silver, and the nature of the support modifying additives and redox pretreatments on the catalytic properties of the bimetallic Au-Ag catalysts were studied. Catalysts were characterized by low-temperature nitrogen adsorption–desorption, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and ultraviolet-visible diffuse reflectance spectroscopy. It was found that pretreatments with hydrogen and oxygen at 300 °C significantly decreased the activity of AuAg catalysts (silver was deposited first) and had little effect on the catalytic properties of AgAu samples (gold was deposited first). The density functional theory method demonstrated that the adsorption energy of 1-octanol increased for all positively charged AuxAgyq (x + y = 10, with a charge of q = 0 or +1) clusters compared with the neutral counterparts. Lanthanum oxide was a very effective promoter for both monometallic and bimetallic gold and silver catalysts in the studied process.
V2O5-Activated Graphite Felt with Enhanced Activity for Vanadium Redox Flow Battery
Authors: Wang Yi-Hung , Hung I-Ming , Wu Cheng-Yeou
Published: June 2021

In this study, a simple and environment-friendly method of preparing activated graphite felt (GF) for a vanadium redox flow battery (VRFB) by depositing the vanadium precursor on the GF surface and calcining vanadium oxide was explored. The intermediate material, VO2, generated carbon oxidation during the calcination. In contrast to the normal etching method, this method was simple and without a pickling process. On the surface of the activated GF, multiple pores and increased roughness were noted after the calcination temperature and surface area of the activated GF reached 350 °C to 400 °C and 17.11 m2/g, respectively. Additionally, the polarization of the activated GF decreased with resistance to the charge transfer at 0.27 Ω. After a single-cell test at current density of 150 mA/cm2 was performed, the capacity utilization and the capacity retention after 50 cycles reached 70% and 84%, respectively. These results indicated the potential use of activated GF as an VRFB electrode.
Databases Selection in a Systematic Review of the Association between Anthropometric Measurements and Dental Caries among Children in Asia
Authors: Mamikutty Rokiah , Aly Ameera Syafiqah , Marhazlinda Jamaludin
Published: June 2021

A comprehensive search for primary studies using a sufficient number and relevant databases is critical to minimise bias and increase the validity of a systematic review. We examined the frequency and choices of databases commonly used to provide an efficient search of primary studies for a systematic review of anthropometric measurements and dental caries among children in Asia. Twelve previous systematic reviews on a similar topic were retrieved from six databases. The frequency and choice of databases used by reviewers were determined from the methods sections. We also identified the lists of other databases usually searched in other reviews. Eligibility criteria for final databases selection were the database’s scope, the topic of interest, design of the study, type of article, and the accessibility of the databases. Of the 77 databases identified, previous reviews on this topic used 21 databases, ranging from 2 to 12 databases in each review. Medline, Cochrane Library, Web of Science, and PubMed were employed most frequently. Twenty-six databases were eligible and selected for the present review. Twelve were regional databases to provide comprehensive coverage of primary studies. A systematic approach in selecting appropriate databases for searching primary studies is paramount to reduce errors, ensure coverage, and increase the validity of systematic reviews’ conclusions.
Effect of Shellac Waterborne Coating Microcapsules on the Optical, Mechanical and Self-Healing Properties of Waterborne Primer on Tilia europaea L. Wood
Authors: Yan Xiaoxing , Tao Yu , Chang Yijuan
Published: June 2021

Microcapsules of melamine formaldehyde-coated shellac and waterborne coating were prepared by in situ polymerization at 400, 600, 800 and 1000 rpm. The microcapsules prepared at four different stirring rates were added into the waterborne primer at a concentration of 5.0%, 10.0%, 15.0%, 20.0% and 25.0%. The effects of microcapsules prepared at different stirring rates and the concentration of microcapsules added into the paint film on the optical, mechanical and liquid resistance properties of the paint film were investigated. The results showed that the comprehensive performance of Tilia europaea L. waterborne primer film was the best when the concentration of microcapsules obtained at 600 rpm was 5.0%. On this basis, the aging resistance and self-healing performance of waterborne primer film on Tilia europaea L. with the best comprehensive performance were explored to lay the foundation for optimizing the preparation process of self-healing coating.
Dendritic Growth in Si1−xGex Melts
Authors: Takakura Genki , Arivanandhan Mukannan , Maeda Kensaku , Chuang Lu-Chung , Shiga Keiji , Morito Haruhiko , Fujiwara Kozo
Published: June 2021

We investigated the types of dendrites grown in Si1−xGex (0 < x < 1) melts, and also investigated the initiation of dendrite growth during unidirectional growth of Si1-xGex alloys. Si1−xGex (0 < x < 1) is a semiconductor alloy with a completely miscible-type binary phase diagram. Therefore, Si1−xGex alloys are promising for use as epitaxial substrates for electronic devices owing to the fact that their band gap and lattice constant can be tuned by selecting the proper composition, and also for thermoelectric applications at elevated temperatures. On the other hand, regarding the fundamentals of solidification, some phenomena during the solidification process have not been clarified completely. Dendrite growth is a well-known phenomenon, which appears during the solidification processes of various materials. However, the details of dendrite growth in Si1−xGex (0 < x < 1) melts have not yet been reported. We attempted to observe dendritic growth in Si1−xGex (0 < x < 1) melts over a wide range of composition by an in situ observation technique. It was found that twin-related dendrites appear in Si1−xGex (0 < x < 1) melts. It was also found that faceted dendrites can be grown in directional solidification before instability of the crystal/melt interface occurs, when a growing crystal contains parallel twin boundaries.
Diagnosis of Ion-Exchange Resin Depositions in Paraffin Sections Using Corrective Light and Electron Microscopy-NanoSuit Method
Authors: Ooishi Mako , Yamada Satoshi , Itoh Toshiya , Meguro Shiori , Yagi Haruna , Kosugi Isao , Iwashita Toshihide , Shinmura Kazuya , Misawa Kiyoshi , Hariyama Takahiko , Kawasaki Hideya
Published: June 2021

Ion-exchange resins are commonly used to treat complications such as hyperkalemia, hyperphosphatemia, and hypercholesterolemia. Gastrointestinal complications may occur as side effects of such treatments. Sodium and calcium polystyrene sulfonate (PS-Ca) are cation-exchange resins comprising an insoluble structure that binds to potassium ions in the digestive tract and exchanges them with sodium and calcium ions, respectively, to promote their elimination. PS crystals are rhomboid, refractive, and basophilic in hematoxylin and eosin staining. To differentiate PS crystals from other ion-exchange resin crystals such as sevelamer and cholestyramine, periodic acid–Schiff, Ziehl–Neelsen, and Congo red staining are usually performed. Here, correlative light and electron microscopy (CLEM)-energy-dispersive X-ray spectroscopy and the NanoSuit method (CENM) was applied to perform a definitive identification of ion-exchange resins. CENM could detect sulfur in PS crystals without destroying the glass slides. Notably, PS retained its ion-exchange ability to bind potassium in paraffin sections. Differential diagnosis of anion-exchange resins, such as sevelamer and cholestyramine, was possible using these characteristics. The phosphorus:carbon ratio was higher in sevelamer than in cholestyramine after soaking paraffin sections in a phosphate solution. Therefore, CENM may be used for the differential pathological diagnosis of ion-exchange resins in paraffin sections.
Impact of Endoscopic Ultrasound-Guided Tissue Acquisition on Decision-Making in Precision Medicine for Pancreatic Cancer: Beyond Diagnosis
Authors: Imaoka Hiroshi , Sasaki Mitsuhito , Hashimoto Yusuke , Watanabe Kazuo , Miyazawa Shoichi , Shibuki Taro , Mitsunaga Shuichi , Ikeda Masafumi
Published: June 2021

Precision medicine in cancer treatment refers to targeted therapy based on the evaluation of biomarkers. Although precision medicine for pancreatic cancer (PC) remains challenging, novel biomarker-based therapies, such as pembrolizumab, olaparib, and entrectinib, have been emerging. Most commonly, endoscopic ultrasound-guided tissue acquisition (EUS-TA) had been used for the diagnosis of PC until now. However, advances in EUS-TA devices and biomarker testing, especially next-generation sequencing, have opened up the possibility of sequencing of various genes even in limited amounts of tissue samples obtained by EUS-TA, and identifying potential genetic alterations as therapeutic targets. Precision medicine benefits only a small population of patients with PC, but biomarker-based therapy has shown promising results in patients who once had no treatment options. Now, the role of EUS-TA has extended beyond diagnosis into decision-making regarding the treatment of PC. In this review, we mainly discuss tissue sampling by EUS-TA for biomarker testing and the current status of precision medicine for PC.
COVID-19-Associated Cardiovascular Complications
Authors: Lee Clement C. E. , Ali Kashan , Connell David , Mordi Ify R. , George Jacob , Lang Elizabeth MSL , Lang Chim C.
Published: June 2021

Coronavirus disease 2019 (COVID-19) has been reported to cause cardiovascular complications such as myocardial injury, thromboembolic events, arrhythmia, and heart failure. Multiple mechanisms—some overlapping, notably the role of inflammation and IL-6—potentially underlie these complications. The reported cardiac injury may be a result of direct viral invasion of cardiomyocytes with consequent unopposed effects of angiotensin II, increased metabolic demand, immune activation, or microvascular dysfunction. Thromboembolic events have been widely reported in both the venous and arterial systems that have attracted intense interest in the underlying mechanisms. These could potentially be due to endothelial dysfunction secondary to direct viral invasion or inflammation. Additionally, thromboembolic events may also be a consequence of an attempt by the immune system to contain the infection through immunothrombosis and neutrophil extracellular traps. Cardiac arrhythmias have also been reported with a wide range of implicated contributory factors, ranging from direct viral myocardial injury, as well as other factors, including at-risk individuals with underlying inherited arrhythmia syndromes. Heart failure may also occur as a progression from cardiac injury, precipitation secondary to the initiation or withdrawal of certain drugs, or the accumulation of des-Arg9-bradykinin (DABK) with excessive induction of pro-inflammatory G protein coupled receptor B1 (BK1). The presenting cardiovascular symptoms include chest pain, dyspnoea, and palpitations. There is currently intense interest in vaccine-induced thrombosis and in the treatment of Long COVID since many patients who have survived COVID-19 describe persisting health problems. This review will summarise the proposed physiological mechanisms of COVID-19-associated cardiovascular complications.
A Multilevel Architecture for Autonomous UAVs
Authors: Bigazzi Luca , Basso Michele , Boni Enrico , Innocenti Giacomo , Pieraccini Massimiliano
Published: June 2021

In this paper, a multilevel architecture able to interface an on-board computer with a generic UAV flight controller and its radio receiver is proposed. The computer board exploits the same standard communication protocol of UAV flight controllers and can easily access additional data, such as: (i) inertial sensor measurements coming from a multi-sensor board; (ii) global navigation satellite system (GNSS) coordinates; (iii) streaming video from one or more cameras; and (iv) operator commands from the remote control. In specific operating scenarios, the proposed platform is able to act as a “cyber pilot” which replaces the role of a human UAV operator, thus simplifying the development of complex tasks such as those based on computer vision and artificial intelligence (AI) algorithms which are typically employed in autonomous flight operations.
An Objective Prior from a Scoring Rule
Authors: Walker Stephen G. , Villa Cristiano
Published: June 2021

In this paper, we introduce a novel objective prior distribution levering on the connections between information, divergence and scoring rules. In particular, we do so from the starting point of convex functions representing information in density functions. This provides a natural route to proper local scoring rules using Bregman divergence. Specifically, we determine the prior which solves setting the score function to be a constant. Although in itself this provides motivation for an objective prior, the prior also minimizes a corresponding information criterion.
Causal Reasoning and Event Cognition as Evolutionary Determinants of Language Structure
Authors: Gärdenfors Peter
Published: June 2021

The aim of this article is to provide an evolutionarily grounded explanation of central aspects of the structure of language. It begins with an account of the evolution of human causal reasoning. A comparison between humans and non-human primates suggests that human causal cognition is based on reasoning about the underlying forces that are involved in events, while other primates hardly understand external forces. This is illustrated by an analysis of the causal cognition required for early hominin tool use. Second, the thinking concerning forces in causation is used to motivate a model of human event cognition. A mental representation of an event contains two vectors representing a cause as well as a result but also entities such as agents, patients, instruments and locations. The fundamental connection between event representations and language is that declarative sentences express events (or states). The event structure also explains why sentences are constituted of noun phrases and verb phrases. Finally, the components of the event representation show up in language, where causes and effects are expressed by verbs, agents and patients by nouns (modified by adjectives), locations by prepositions, etc. Thus, the evolution of the complexity of mental event representations also provides insight into the evolution of the structure of language.
Clifford Wavelet Entropy for Fetal ECG Extraction
Authors: Jallouli Malika , Arfaoui Sabrine , Ben Mabrouk Anouar , Cattani Carlo
Published: June 2021

Analysis of the fetal heart rate during pregnancy is essential for monitoring the proper development of the fetus. Current fetal heart monitoring techniques lack the accuracy in fetal heart rate monitoring and features acquisition, resulting in diagnostic medical issues. The challenge lies in the extraction of the fetal ECG from the mother ECG during pregnancy. This approach has the advantage of being a reliable and non-invasive technique. In the present paper, a wavelet/multiwavelet method is proposed to perfectly extract the fetal ECG parameters from the abdominal mother ECG. In a first step, due to the wavelet/mutiwavelet processing, a denoising procedure is applied to separate the noised parts from the denoised ones. The denoised signal is assumed to be a mixture of both the MECG and the FECG. One of the well-known measures of accuracy in information processing is the concept of entropy. In the present work, a wavelet/multiwavelet Shannon-type entropy is constructed and applied to evaluate the order/disorder of the extracted FECG signal. The experimental results apply to a recent class of Clifford wavelets constructed in Arfaoui, et al. J. Math. Imaging Vis. 2020, 62, 73–97, and Arfaoui, et al. Acta Appl. Math. 2020, 170, 1–35. Additionally, classical Haar–Faber–Schauder wavelets are applied for the purpose of comparison. Two main well-known databases have been applied, the DAISY database and the CinC Challenge 2013 database. The achieved accuracy over the test databases resulted in Se = 100%, PPV = 100% for FECG extraction and peak detection.
Upper Bounds for the Capacity for Severely Fading MIMO Channels under a Scale Mixture Assumption
Authors: Ferreira Johannes T.
Published: June 2021

A cornerstone in the modeling of wireless communication is MIMO systems, where a complex matrix variate normal assumption is often made for the underlying distribution of the propagation matrix. A popular measure of information, namely capacity, is often investigated for the performance of MIMO designs. This paper derives upper bounds for this measure of information for the case of two transmitting antennae and an arbitrary number of receiving antennae when the propagation matrix is assumed to follow a scale mixture of complex matrix variate normal distribution. Furthermore, noncentrality is assumed to account for LOS scenarios within the MIMO environment. The insight of this paper illustrates the theoretical form of capacity under these key assumptions and paves the way for considerations of alternative distributional choices for the channel propagation matrix in potential cases of severe fading, when the assumption of normality may not be realistic.
Small-Signal Stability Analysis for Multi-Terminal LVDC Distribution Network Based on Distributed Secondary Control Strategy
Authors: Lv Zhenyu , Zhou Min , Wang Qi , Hu Wenqiang
Published: June 2021

This paper presents a detailed and accurate small-signal analysis model for a four-terminal low-voltage direct current (LVDC) distribution network with distributed secondary control strategy. To tackle the contradiction between power sharing accuracy and average voltage recovery ability of voltage source converters (VSCs), a distributed secondary control strategy is adopted, which is based on average consensus algorithm and local voting protocol. Furthermore, to analyze the stability of LVDC distribution network based on the proposed distributed secondary control strategy, a detailed and accurate small-signal analysis model is formulated which is derived from various non-linear state-space sub-models. The time-domain simulation and electromagnetic simulation are carried out to verify the validity and accuracy of the proposed model. Based on this model, the influence rules of main eigenvalues are summarized with the variation of PI control and DC line parameters. Time-domain simulations conducted in PSCAD are used to validate the operational limits of the secondary controllers and DC line obtained from the small-signal stability analysis.
Forecasting of Tomato Yields Using Attention-Based LSTM Network and ARMA Model
Authors: Cho Wanhyun , Kim Sangkyuoon , Na Myunghwan , Na Inseop
Published: June 2021

Nonlinear autoregressive exogenous (NARX), autoregressive integrated moving average (ARIMA) and multi-layer perceptron (MLP) networks have been widely used to predict the appearance value of future points for time series data. However, in recent years, new approaches to predict time series data based on various networks of deep learning have been proposed. In this paper, we tried to predict how various environmental factors with time series information affect the yields of tomatoes by combining a traditional statistical time series model and a deep learning model. In the first half of the proposed model, we used an encoding attention-based long short-term memory (LSTM) network to identify environmental variables that affect the time series data for tomatoes yields. In the second half of the proposed model, we used the ARMA model as a statistical time series analysis model to improve the difference between the actual yields and the predicted yields given by the attention-based LSTM network at the first half of the proposed model. Next, we predicted the yields of tomatoes in the future based on the measured values of environmental variables given during the observed period using a model built by integrating the two models. Finally, the proposed model was applied to determine which environmental factors affect tomato production, and at the same time, an experiment was conducted to investigate how well the yields of tomatoes could be predicted. From the results of the experiments, it was found that the proposed method predicts the response value using exogenous variables more efficiently and better than the existing models. In addition, we found that the environmental factors that greatly affect the yields of tomatoes are internal temperature, internal humidity, and CO2 level.
Analysis of Hybrid Meander Structures with Additional Shields
Authors: Belova-Plonienė Diana , Krukonis Audrius , Katkevičius Andrius
Published: June 2021

Models of hybrid meander structures with additional shields are presented in this paper. The influence of additional shields and their grounding positions on the electromagnetic characteristics of the hybrid meander structures was investigated. Three-dimensional models were created and analyzed using the method of moments (MoM) in the Sonnet® and finite-difference time-domain (FDTD) method in CST Microwave Studio® commercial software packages. The computer-based modeling was verified by physical experiment. The analysis showed that it is possible to control the delay time characteristic using different values of lumped inductive elements without the need to change the overall size of the hybrid meander structure. The delay time varied by 1.2 ns in the range of 1.3 ns to 2.5 ns when the inductivity changed from 1 nH to 10 nH in our investigation. On the other hand, the passband decreased from 2.384 GHz to 0.508 GHz. The additional shields and their grounding positions allowed for increasing the passband by up to 1.6%.
Blockchain-Based Pseudonym Management Scheme for Vehicular Communication
Authors: George Sonia Alice , Stephen Steffie Maria , Jaekel Arunita
Published: June 2021

A vehicular ad hoc network (VANET) consists of vehicles, roadside units, and other infrastructures that communicate with each other with the goal of improving road safety, reducing accidents, and alleviating traffic congestion. For safe and secure operation of critical applications in VANET, it is essential to ensure that only authenticated vehicles can participate in the network. Another important requirement for VANET communication is that the privacy of vehicles and their users must be protected. Privacy can be improved by using pseudonyms instead of actual vehicle identities during communication. However, it is also necessary to ensure that these pseudonyms can be linked to the real vehicle identities if needed, in order to maintain accountability. In this paper, we propose a new blockchain-based decentralized pseudonym management scheme for VANET. This allows the vehicles to maintain conditional anonymity in the network. The blockchain is used to maintain a record of each vehicle and all of its pseudo-IDs. The information in the blockchain can only be accessed by authorized entities and is not available to all vehicles. The proposed distributed framework maintains an immutable record of the vehicle data, which is not vulnerable to a single point of failure. We compared the performance of the proposed approach with a traditional PKI scheme and shown that it significantly reduces the authentication delay.
Demonstration of a Top-Lit Updraft Based Pyrolytic Burner with Low Emission Operation and Automatic Process Control
Authors: Krüger Dennis , Mutlu Özge Çepelioğullar
Published: June 2021

In this study, a small-scale (4.7 kWfuel) biomass burner based on “top-lit updraft” (TLUD) technology with automatic process control was developed for process heat generation. The combustion experiments were performed using wood pellets to gain more insights on the process, its repeatability and the behaviors of the emitted gaseous and particulate emissions under different combustion phases. The emission values were compared with similar small-scale combustion technologies as well as the emission limits defined in official regulations. The results showed that the average emissions (based on standardized 13 vol. % O2 content in the dry flue gas (STP)) over the entire process from start-up to switch-off were 29.4 mg/m3 for CO, 80 mg/m3 for NOx, and 3.6 mg/m3 for total particle matter (TPM) measured within the hot gas. These results were below the official limits for wood-fueled small-scale systems. The developed process control approach resulted in very low residual O2 content in the flue gas (approx. 2 vol. %), high flue gas temperatures and repetition accuracy. Thus, the process offers potential for further development in terms of process control, scale-up, and application in different areas.
BioLPG for Clean Cooking in Sub-Saharan Africa: Present and Future Feasibility of Technologies, Feedstocks, Enabling Conditions and Financing
Authors: Chen Kimball C. , Leach Matthew , Black Mairi J. , Tesfamichael Meron , Kemausuor Francis , Littlewood Patrick , Marker Terry , Mwabonje Onesmus , Mulugetta Yacob , Murphy Richard J. , Diaz-Chavez Rocio , Hauge John , Saleeby Derek , Evans Alex W. , Puzzolo Elisa
Published: June 2021

Energy supply for clean cooking is a priority for Sub-Saharan Africa (SSA). Liquefied petroleum gas (LPG, i.e., propane or butane or a mixture of both) is an economically efficient, cooking energy solution used by over 2.5 billion people worldwide and scaled up in numerous low- and middle-income countries (LMICs). Investigation of the technical, policy, economic and physical requirements of producing LPG from renewable feedstocks (bioLPG) finds feasibility at scale in Africa. Biogas and syngas from the circular economic repurposing of municipal solid waste and agricultural waste can be used in two groundbreaking new chemical processes (Cool LPG or Integrated Hydropyrolysis and Hydroconversion (IH2)) to selectively produce bioLPG. Evidence about the nature and scale potential of bioLPG presented in this study justifies further investment in the development of bioLPG as a fuel that can make a major contribution toward enabling an SSA green economy and universal energy access. Techno-economic assessments of five potential projects from Ghana, Kenya and Rwanda illustrate what might be possible. BioLPG technology is in the early days of development, so normal technology piloting and de-risking need to be undertaken. However, fully developed bioLPG production could greatly reduce the public and private sector investment required to significantly increase SSA clean cooking capacity.
Ground-Source Heat Pump Systems: The Effects of Variable Trench Separations and Pipe Configurations in Horizontal Ground Heat Exchangers
Authors: Zhou Yu , Bidarmaghz Asal , Makasis Nikolas , Narsilio Guillermo
Published: June 2021

Ground-source heat pump systems are renewable and highly efficient HVAC systems that utilise the ground to exchange heat via ground heat exchangers (GHEs). This study developed a detailed 3D finite element model for horizontal GHEs by using COMSOL Multiphysics and validated it against a fully instrumented system under the loading conditions of rural industries in NSW, Australia. First, the yearly performance evaluation of the horizontal straight GHEs showed an adequate initial design under the unique loads. This study then evaluated the effects of variable trench separations, GHE configurations, and effective thermal conductivity. Different trench separations that varied between 1.2 and 3.5 m were selected and analysed while considering three different horizontal loop configurations, i.e., the horizontal straight, slinky, and dense slinky loop configurations. These configurations had the same length of pipe in one trench, and the first two had the same trench length as well. The results revealed that when the trench separation became smaller, there was a minor increasing trend (0.5 °C) in the carrier fluid temperature. As for the configuration, the dense slinky loop showed an average that was 1.5 °C lower than those of the horizontal straight and slinky loop (which were about the same). This indicates that, when land is limited, compromises on the trench separation should be made first in lieu of changes in the loop configuration. Lastly, the results showed that although the effective thermal conductivity had an impact on the carrier fluid temperature, this impact was much lower compared to that for the GHE configurations and trench separations.
Transposition of European Guidelines for Energy Communities into Austrian Law: A Comparison and Discussion of Issues and Positive Aspects
Authors: Fina Bernadette , Fechner Hubert
Published: June 2021

The Renewable Energy Directive and the Electricity Market Directive, both parts of the Clean Energy for all Europeans Package (issued in 2019), provide supranational rules for renewable energy communities and citizen energy communities. Since national transpositions need to be completed within two years, Austria has already drafted corresponding legislation. This article aims at providing a detailed comparison of the European guidelines and the transposition into Austrian law. The comparison not only shows how, and to what extent, the European guidelines are transposed into Austrian law, but also helps to identify loopholes and barriers. The subsequent discussion of these issues as well as positive aspects of the Austrian transposition may be advantageous for legislators and policy makers worldwide in their process of designing a coherent regulatory framework. It is concluded that experts from different areas (i.e., project developers, scientists concerned with energy communities, energy suppliers and grid operators) should be closely involved in the law-making process in order to introduce different perspectives so that a consistent and supportive regulatory framework for energy communities is created.
Link between Technically Derived Energy Efficiency and Ecological Footprint: Empirical Evidence from the ASEAN Region
Authors: Khan Dilawar , Nouman Muhammad , Popp József , Khan Muhammad Asif , Ur Rehman Faheem , Oláh Judit
Published: June 2021

The sustainable environment has been a desired situation around the world for the last few decades. Environmental contaminations can be a consequence of various economic activities. Different socio-economic factors influence the environment positively or negatively. Many previous studies have resulted in the efficient allocation of inputs as an environment-friendly component. This paper investigates the effects of energy efficiency on ecological footprint in the ASEAN region using balanced panel data from 2001 to 2019. First, this paper technically derives the energy efficiency, using the stochastic frontier analysis (SFA) of the translog production type of single output and multiple inputs. Findings of the SFA show that the Philippines and Singapore have the highest energy efficiency (94%) and Laos has the lowest energy efficiency (85%) in the ASEAN region. The estimated average efficiency score of the ASEAN region was around 90%, ranging from 85% to 96%, indicating that there is still 10% room for improvement in energy efficiency. Second, this study employed the panel autoregressive distributed lag (ARDL) model to explore the short run and long run impact of technically derived energy efficiency on ecological footprint in the ASEAN region. Results of the panel ARDL model show that energy efficiency is a reducing factor of ecological footprint in the long run. Moreover, energy efficiency plays a significant role to control the environmental contaminations. In addition, results of this study also explored that urbanization is an increasing factor of ecological footprint, and investment in agriculture is also beneficial for the environment. Moreover, to obtain the directional nature of the associations between the ecological footprint and its independent variables, this paper has employed the paired-panel Granger causality test. The results of the paired wise panel Granger causality test also confirm that the energy efficiency, urbanization, and investment in agriculture cause ecological footprint. Finally, this study recommends that efficient utilization of energy resources as well as investment in agriculture are necessary for sustainable environment.
Response Identification in a Vibration Energy-Harvesting System with Quasi-Zero Stiffness and Two Potential Wells
Authors: Iwaniec Joanna , Litak Grzegorz , Iwaniec Marek , Margielewicz Jerzy , Gąska Damian , Melnyk Mykhaylo , Zabierowski Wojciech
Published: June 2021

In this paper, the frequency broadband effect in vibration energy harvesting was studied numerically using a quasi-zero stiffness resonator with two potential wells and piezoelectric transducers. Corresponding solutions were investigated for system excitation harmonics at various frequencies. Solutions for the higher voltage output were collected in specific branches of the power output diagram. Both the resonant solution synchronized with excitation and the frequency responses of the subharmonic spectra were found. The selected cases were illustrated and classified using a phase portrait, a Poincaré section, and recurrence plot (RP) approaches. Select recurrence quantification analysis (RQA) measures were used to characterize the discussed solutions.
Dynamic Characteristics of Oil Attributes and Their Market Effects
Authors: Hu Qingqing , Li Tinghui , Li Xue , Dong Hao
Published: June 2021

The commercial and financial attributes of oil have significantly changed the evolution characteristics of prices and returns of the international crude oil market. Using monthly data from April 2003 to October 2020, this paper identifies dynamic characteristics of oil’s commercial and financial attributes based on the structural vector autoregressive model (SVAR) and further analyzes their market effects with different attributes. The result shows that there are situations of commercial and financial attributes dominating, and dual attributes co-dominating for oil. Furthermore, their durations account for 51%, 23%, and 26% respectively, of the full sample. Besides, the reactions of crude oil price or return to the different properties of oil are heterogeneous. Specifically, the dual attributes of oil play the most important role in the price evolution of the international crude oil market, which is 80.851. There are significant differences among the impact of different attributes of oil on the evolution of international crude oil market returns, which are 0.009, −0.008, and −0.004, respectively. Then, some relevant recommendations for policy-makers and investors based on the above research conclusions are also put forward.
Operation and Control of a Hybrid Power Plant with the Capability of Grid Services Provision
Authors: Attya Ayman B. , Vickers Adam
Published: June 2021

The integration of distributed power plants that rely on renewable energy sources (RESs) is a major challenge for system operators (SOs) due to the variable nature of the input energy (e.g., wind and solar irradiation) to these power sources. A key solution to such a challenge is to coordinate and combine the power generation of these sources such that their behavior is closer to a conventional and dispatchable power station, taking into account the limitations imposed by the battery storage system (BESS), so it is seen as a hybrid power plant (HPP) from the SOs’ viewpoint. This paper develops a model of HPP that encompasses two generation technologies, wind and photovoltaic farms, which are assisted by a BESS. The paper proposes a comprehensive control method that can smooth the HPP output with minimized energy rejection whilst enabling the HPP to provide synthetic inertia and primary frequency response, which are grid-code compliant. The proposed control method is validated through various scenarios, which are implemented on a detailed electromechanical test system modeled in MATLAB/Simulink. The results show and quantify the achieved improvement on stabilizing the HPP capacity factor under variable wind speed. The HPP also enhances the system response to frequency events.
One-Dimensional Analysis of Double Annular Combustor for Reducing Harmful Emissions
Authors: Jeong Gijeong , Ahn Kyubok
Published: June 2021

The number of aircraft flights worldwide has increased steadily since the introduction of air transportation to the public. Accordingly, environmental issues caused by the exhaust gases of aircraft engines have emerged. In particular, international organizations have crafted emission regulations since gases exhausted during takeoff and landing have been identified as the direct cause of air pollution near airports. Nitrogen oxides (NOx) produced at high combustion temperatures and carbon monoxide (CO) due to incomplete combustion affect the performance of the combustion chamber. Therefore, annular combustors comprising two annular zones have been developed to reduce the emissions of these two substances, which occur under different conditions. Parameters that should be considered when modifying a conventional single annular (SAC) to a double annular combustor (DAC) are discussed herein. In this paper, an optimization algorithm for obtaining the main design parameters of the DAC is presented to minimize NOx and CO emissions and an operation solution for reducing carbon monoxide emission is identified. A thermodynamic model of a high-bypass turbofan engine (PS-90A) is used to establish the inlet and outlet conditions of the combustor. Analysis results show that NOx emissions can be effectively reduced by adjusting the design parameters and CO emissions can be significantly decreased by partially turning off the fuel supply based on the engine cycle.
Constrained Optimization as the Allocation Method in Local Flexibility Markets
Authors: Zeiselmair Andreas , Köppl Simon
Published: June 2021

Local flexibility markets or smart markets are new tools used to harness regional flexibility for congestion management. In order to benefit from the available flexibility potential for grid-oriented or even grid-supportive applications, complex but efficient and transparent allocation is necessary. This paper proposes a constrained optimization method for matching the flexibility demand of grid operators to the flexibility supply using decentralized flexibility options located in the distribution grid. Starting with a definition of the operational and stakeholder environment of smart market design, various existing approaches are analyzed based on a literature review and a resulting meta-analysis. In the next step, a categorization of the allocation method is conducted followed by the definition of the optimization goal. The optimization problem, including all relevant input parameters, is identified and formulated by introducing the relevant boundary conditions and constraints of flexibility demand and offers. A proof of concept of the approach is presented using a case study and the Altdorfer Flexmarkt (ALF) field test within the project C/sells. In this paper, we analyze the background of the local flexibility market, provide the methodology (including publishing the code of the matching mechanism), and provide the results of the field test.
System Identification of Mosques Resting on Soft Soil. The Case of the Suleiman Mosque in the Medieval City of Rhodes, Greece
Authors: Karatzetzou Anna , Pitilakis Dimitris , Karafagka Stella
Published: June 2021

The present study focuses on the dynamic system identification of the Suleiman Mosque minaret in the medieval city of Rhodes, Greece. Suleiman Mosque was built in 1522 at the site of the destroyed Christian Church of the Apostles. First, we performed sets of ambient vibration measurements at the minaret of the monument. Based on these data, we calculated the eigenproperties of the minaret. Next, we modeled the monument in three dimensions, using the finite element method. Six numerical models were considered. Model Ι is the simplest one (isolated, fixed base minaret). Model VI is the most complicated one (simulation of the whole mosque also considering soil–structure interaction and foundation flexibility). The calculated predominant periods and mode shapes of Models I–VI are validated against the microtremor field measurements, recorded on the minaret’s two floors and ground level. We elaborate on the reliability of finite element models for earthquake response evaluation, considering soil–structure interaction and foundation flexibility on the mode shape eigenfrequencies. Additionally, we discuss the seismic response of the minaret compared to the whole monument. We observed no significant difference in the first two modes of response, implying that the minaret’s dynamic behavior is slightly affected by the entire mosque’s presence.
Mental Health and Social Development Effects of the Abecedarian Approach
Authors: Sparling Joseph , Ramey Sharon Landesman , Ramey Craig T.
Published: June 2021

The Abecedarian Approach is an early intervention and contains a broad-spectrum adult/child curriculum. The Approach has been studied in three longitudinal randomized controlled trials in the USA, starting in 1972 and continuing today. Recent research studies in multiple countries have examined the Abecedarian Approach during the first three years of life. The collective findings from these studies lead to the conclusion that human development is malleable, especially in the years before school entry, and that high-quality early intervention exerts positive, early, and long-lasting influences on human development, including social development and mental health.
Influence of Self-Esteem of Middle School Students for Mental Care on Academic Achievement: Based on the Mediation Effect of GRIT and Academic Enthusiasm
Authors: Kim Jhong Yun (Joy) , Kim EunBee , Lee InSu
Published: June 2021

The purpose of this study is to identify how self-esteem of middle school students for mental care influences their academic achievement and to verify the mediation effect of GRIT on academic enthusiasm. Data of 2590 first graders in middle school from the Kora Children and Youth Panel Survey 2019 was used to support this study. Data analysis was performed by using SPSS21.0, AMOS22.0, and PROCESS macro program. The results are as follows. Comparison of the model fits of each full mediation model and partial mediation model with χ2 showed that the full mediation model was more suitable for this study. In more detail, the influence of self-esteem on GRIT and the influence of GRIT on academic enthusiasm were significantly positive. Lastly, the study identified that there was a mediation effect between self-esteem and academic achievement through GRIT and academic enthusiasm. It indicates that self-esteem is the key to improve academic achievement and that specific programs should be supplemented in order to enhance self-esteem, GRIT, and academic enthusiasm.