bluuebunny/crossref_metadata_2025 huggingface dataset:
Research and Measuring Technology Needs to Better Model and Measure Fatigue Crack Development of Thinly Surfaced Asphalt Road Pavements
Authors: Horak Emile , De Beer Morris , van Zyl Gerrie , Maina James , Fakra Damien Ali Hamada
Published: May 2022

The root cause of premature failures in relatively thin (<50 mm) asphalt surfaced roads is often a challenge to solve during forensic investigations in South Africa (SA). This description is based on peer review type discussions with forensic investigations experts as well as published research papers. The areas of ignorance or areas where research effort is needed are identified. These observations serve to identify areas of new knowledge needed in terms of actual verification with measurements, measurement technology, and modeling of the observed phenomena. The main objectives of this discussion paper are to highlight the evolution of distress development in asphalt layers starting from the identification and description of the kind of microcracks, effects of microcracks in the debonding of the asphalt layer from lower layer, and vehicle–pavement interactions (VPI) of moving truck wheels focusing on the thin asphalt layer. Specific reference is made to the need to measure and model the effects of bow waves in front of and next to the loaded rolling wheel.
Characteristics of Temperature Field of Rammed Earth Wall in Arid Environment
Authors: Pei Qiangqiang , Zhang Bo , Shang Dongjuan , Guo Qinglin , Huang Jinjing , Zhu Jing
Published: May 2022

The rammed earth walls were greatly affected by the change of temperature fields in arid environments, particularly the swell-shrink stress caused by gradient variations of the temperature fields was one of the main factors leading to surface weathering of rammed earth sites. While heat conduction, convection, and radiation were the main factors resulting in temperature variations of rammed earth walls. In this study, the thermocouple sensors were embedded in a rammed-earth test wall, to continuously monitor the temperature gradient field of the rammed earth wall from the near-surface area to the interior. The results revealed that the wall was greatly influenced by seasonal temperature fields together with significant changes in daily temperature differences. The top and the surface of the wall were affected by thermal radiation and convection, while the interior and the foundation were affected by heat conduction. The annual temperature difference reached 62.99 °C, and the maximum daily temperature difference on the surface of the wall was 24.3 °C, which mainly appeared during the spring and autumn seasons. The near-surface thickness of the temperature-sensitive area of the wall was less than 32 cm, within which the temperature varied dramatically at depths of 0–18 cm. The temperature variations at depths of 18–32 cm were somewhat significant with no obvious changes at depths exceeding 32 cm. These trends indicate that the rammed earth wall has an outstanding function of thermal preservation and insulation. This study is expected to be of guidance and reference for multi-field coupling environmental condition setting for surface weathering of rammed earth site bodies, stress and strain caused by temperature field, surface weathering mechanism and strengthening technology as well as the related researches of modern rammed earth building designs.
Facile and Eco-Friendly Preparation of Mild Steel Based Superhydrophobic Surfaces without Chemical Modifications
Authors: Jiang Wenxuan , Liu Yujun , Wang Ji , Li Rui , Liu Xiao , Ai Shaohua
Published: May 2022

The fabrication of superhydrophobic coatings on mild steel has attracted considerable attention. However, some methods are cumbersome and unsuitable for large-scale preparation, limiting industrial applications. Furthermore, the extensive use of fluorinated compounds to achieve low surface energy is not environmentally friendly. This paper proposed a facile method based on electrodeposition and annealing to prepare mild steel-based superhydrophobic surfaces without chemical modifications. Subsequently, SEM images were analyzed, and it was observed that the plating parameter (current and time) significantly affected surface morphology. At optimum process parameters, a rough surface with a multi-level structure was formed on the plated surface, contributing to superhydrophobic properties. XPS, EDS, and XRD were utilized to analyze surface composition. The results indicated the presence of copper oxides, zinc oxides, and a large number of hydrocarbons on the prepared superhydrophobic surface. These transition metal oxides on the surface adsorbed hydrocarbons in the air during the annealing process, which lowered the surface energy. Combined with the obtained multi-level morphology, a superhydrophobic surface was achieved. Finally, the corrosion behavior was evaluated in 3.5 wt% NaCl solution by AC impedance spectroscopy. Results showed that the obtained superhydrophobic surface, compared with the untreated coating and the steel substrate, showed a substantial improvement in corrosion resistance. A mild steel-based superhydrophobic surface with a contact angle greater than 150 degrees and excellent corrosion resistance was finally obtained. We hope this study will facilitate the industrial preparation of superhydrophobic coatings, especially in marine engineering, since this method does not require complex processes or expensive equipment and does not require fluorinated substances.
Energy-Efficient Deterministic Approach for Coverage Hole Detection in Wireless Underground Sensor Network: Mathematical Model and Simulation
Authors: Sharma Priyanka , Singh Rishi Pal
Published: May 2022

Wireless underground sensor networks (WUSNs) are being used in agricultural applications, in border patrol, and in the monitoring of remote areas. Coverage holes in WUSNs are an issue which needs to be dealt with. Coverage holes may occur due to random deployment of nodes as well as the failure of nodes with time. In this paper, a mathematical approach for hole detection using Delaunay geometry is proposed which divides the network region into Delaunay triangles and applies the laws of triangles to identify coverage holes. WUSNs comprise static nodes, and replacing underground nodes is a complex task. A simplistic algorithm for detecting coverage holes in static WSNs/WUSNs is proposed. The algorithm was simulated in the region of interest for the initially randomly deployed network and after energy depletion of the nodes with time. The performance of the algorithm was evaluated by varying the number of nodes and the sensing radius of the nodes. Our scheme is advantageous over other schemes in the following aspects: (1) it builds a mathematical model and polynomial-time algorithm for detecting holes, and (2) the scheme does not work on centralized computation and therefore provides better scalability, (3) is energy-efficient, and (4) provides a cost-effective solution to detect holes with great accuracy and a low detection time. The algorithm takes less than 0.1 milliseconds to detect holes in a 100 m × 100 m-size network with 100 sensor nodes having a sensing radius of 8 m. The detection time shows only a linear change with an increase in the number of nodes in the network, which makes the algorithm applicable for every network size from small to large.
Features of the Process Obtaining of Mg-Zn-Y Master Alloy by the Metallothermic Recovery Method of Yttrium Fluoride Melt
Authors: Savchenkov Sergey , Beloglazov Ilia
Published: May 2022

At present, magnesium master alloys with such rare earth metals (REM) as yttrium are used in the production of alloys of magnesium and aluminum. These alloys especially the system Mg-6Zn-1Y-0,5Zr are commonly used in the aircraft and automotive industries. The article is devoted to the exploration of the synthesis process features for ternary magnesium master alloys with yttrium and zinc. The authors used X-ray fluorescence analysis (XRF), differential thermal analysis (DTA), and X-ray spectral analysis (XRD). Optical microscopy was used to conduct microstructural studies. The thermal effects that occur during metallothermic reactions of yttrium reduction from the YF3-NaCl-KCl-CaCl2 salt mixture with a melt of magnesium and zinc were investigated, and the temperatures of these effects were determined. It has been confirmed that the metallothermic reaction of yttrium reduction proceeds from the precursors of the composition: Na1.5Y2.5F9, NaYF4, Na5Y9F32, and KY7F22, and starts at a temperature of 471 °C. The results of experimental studies of the process of metallothermic reduction of yttrium from the salt mixture YF3-NaCl-KCl-CaCl2 are presented in detail. These experiments were carried out in a pit furnace at temperatures ranging from 650 to 700 °C, and it was found that, at a synthesis temperature of 700 °C, the yttrium yield is up to 99.1–99.8%. The paper establishes rational technological regimes for the synthesis (temperature 700 °C, exposure for 25 min, the ratio of chlorides to yttrium fluoride 6:1, periodic stirring of the molten metal) at which the yttrium yield reaches up to 99.8%. The structure of the master alloy samples obtained during the experiments was studied. That structure can be distinguished by a uniform distribution of ternary intermetallic compounds (Mg3YZn6) in the bulk of the double magnesium–zinc eutectic. Studies have been carried out on testing the obtained ternary master alloy as an alloying material in the production of alloys of the Mg-6Zn-1Y-0.5Zr system, while the digestibility of yttrium ranged from 91 to 95%.
Pt-Modified Interfacial Engineering for Enhanced Photocatalytic Performance of 3D Ordered Macroporous TiO2
Authors: Dong Shunhong , Wu Juan , Huang Lanlan , Wang Hong-En
Published: May 2022

Narrowing the band gap and increasing the photodegradation efficiency of TiO2-based photocatalysts are very important for their wide application in environment-related fields such as photocatalytic degradation of toxic pollutants in wastewater. Herein, a three-dimensionally ordered macroporous Pt-loaded TiO2 photocatalyst (3DOM Pt/TiO2) has been successfully synthesized using a facile colloidal crystal-template method. The resultant composite combines several morphological/structural advantages, including uniform 3D ordered macroporous skeletons, high crystallinity, large porosity and an internal electric field formed at Pt/TiO2 interfaces. These unique features enable the 3DOM Pt/TiO2 to possess a large surface for photocatalytic reactions and fast diffusion for mass transfer of reactants as well as efficient suppression of recombination for photogenerated electron-hole pairs in TiO2. Thus, the 3DOM Pt/TiO2 exhibits significantly enhanced photocatalytic activity. Typically, 88% of RhB can be degraded over the 3DOM Pt/TiO2 photocatalyst under visible light irradiation (λ ≥ 420 nm) within 100 min, much higher than that of the commercial TiO2 nanoparticles (only 37%). The underlying mechanism for the enhanced photocatalytic activity of 3DOM Pt/TiO2 has been further analyzed based on energy band theory and ascribed to the formation of Schottky-type Pt/TiO2 junctions. The proposed method herein can provide new references for further improving the photocatalytic efficiency of other photocatalysts via rational structural/morphological engineering.
Effects of Waste-Derived ZnO Nanoparticles against Growth of Plant Pathogenic Bacteria and Epidermoid Carcinoma Cells
Authors: Jaithon Titiradsadakorn , Ruangtong Jittiporn , T-Thienprasert Jiraroj , T-Thienprasert Nattanan Panjaworayan
Published: May 2022

Green synthesis of zinc oxide nanoparticles (ZnO NPs) has recently gained considerable interest because it is simple, environmentally friendly, and cost-effective. This study therefore aimed to synthesize ZnO NPs by utilizing bioactive compounds derived from waste materials, mangosteen peels, and water hyacinth crude extracts and investigated their antibacterial and anticancer activities. As a result, X-ray diffraction analysis confirmed the presence of ZnO NPs without impurities. An ultraviolet–visible absorption spectrum showed a specific absorbance peak around 365 nm with an average electronic band gap of 2.79 eV and 2.88 eV for ZnO NPs from mangosteen peels and a water hyacinth extract, respectively. An SEM analysis displayed both spherical shapes of ZnO NPs from the mangosteen peel extract (dimension of 154.41 × 172.89 nm) and the water hyacinth extract (dimension of 142.16 × 160.30 nm). Fourier transform infrared spectroscopy further validated the occurrence of bioactive molecules on the produced ZnO NPs. By performing an antibacterial activity assay, these green synthesized ZnO NPs significantly inhibited the growth of Xanthomonas oryzae pv. oryzae, Xanthomonas axonopodis pv. citri, and Ralstonia solanacearum. Moreover, they demonstrated potent anti-skin cancer activity in vitro. Consequently, this study demonstrated the possibility of using green-synthesized ZnO NPs in the development of antibacterial or anticancer agents. Furthermore, this research raised the prospect of increasing the value of agricultural waste.
Patient and Physician Satisfaction with Telemedicine in Cancer Care in Saskatchewan: A Cross-Sectional Study
Authors: Gondal Hurria , Abbas Tahir , Choquette Heather , Le Duc , Chalchal Haji Ibraheem , Iqbal Nayyer , Ahmed Shahid
Published: May 2022

Background: Telemedicine is a useful tool that connects patients to their care team remotely and improves access to medical care for rural residents. This study aimed to determine the telemedicine experience of both rural patients with cancer and their physicians, and to explore factors associated with a positive patient experience. Methods: In this cross-sectional study, cancer patients and physicians in Saskatchewan completed a paper-based survey composed of 32 items or an electronic survey of 18 items, respectively. Logistic regression analysis was performed to assess patient satisfaction in relation to various sociodemographic and cancer-related factors. Results: Overall, 25 physicians and 165 patients participated in the study. Among the physicians, 94% were confident in their telemedicine assessment, 58% agreed that telemedicine improved clinical efficiency, and 73% agreed that doctor–patient rapport was unimpaired with telemedicine. Of 165 patients, 61% had used telemedicine for the first time, 81% felt that their needs were met, 83% were satisfied with the quality of their care, and 88% had a positive experience. Overall, 83% patients vs. 45% physicians preferred telemedicine to a face-to-face clinic visit (p = 0.005). On univariate analysis, patients ≥ 65 years old had a greater positive telemedicine experience compared to patients < 65 years old (odds ratio 4.1 [1.2–13.8], p = 0.02). Conclusion: Both patients and physicians have a high rate of positive experiences with telemedicine. However, patients have a higher preference for telemedicine over face-to-face visits compared to physicians. In addition, elderly patients have more positive telemedicine experiences compared to younger patients.
Responses of Vegetation and Soil to Artificial Restoration Measures in Abandoned Gold Mining Areas in Altai Mountain, Northwest China
Authors: Xu Qiao , Xia Guozhu , Wei Yan , Aili Aishajiang , Yuan Kaiye
Published: May 2022

Gold mining plays an essential role on the social and economic development. However, mining activities leads to destructive changes in ground structure and biodiversity, triggering considerable environmental problems. This study proposed a field observation to evaluate the short-term efforts of the artificial restoration measures taken by the Two-River Source Nature Reserve Administration from 2010 to 2015 in an abandoned gold mining area in Altai Mountain, Northwest China. The effects of different ecological restoration measures on soil and vegetation recovery were examined by calculating the richness index, dominance index, diversity index, evenness index, aboveground biomass, vegetation coverage, species number and soil-rock ratio index of the recovered area. Further, a principal component analysis (PCA) was used to compare the efficiency of each artificial measure. The results showed that gold mining activities cause serious environmental degradation in natural landscapes. The soil-rock ratio of the abandoned mining area was reduced by 98% compared with the original grassland. The surface vegetation was destructively destroyed, and the surface soil was stripped. Restoration measures considerably improved ecological conditions, which were reflected by surface biomass, diversity index and the soil-rock ratio, as well as accelerated ecological rebuilding processes in abandoned mining areas. The ecological efficiency of the single restoration measures assessed, such as soil measures, water replenishment measures and biological measures, was not significant. The average values of various indexes of these measures showed lower values of 0.12–0.45. The combination of various measures can not only improve the soil environment but can also lead to changes in plant community diversity and significant ecological efficiency. This was reflected by the values of various indexes, which reached higher values of 0.4–1.21. As far as the same kind of restoration measure is considered, the longer the restoration period, the better the recovery effect.
Circulating Calprotectin as a Predictive and Severity Biomarker in Patients with COVID-19
Authors: Norman Gary L. , Navaz Sherwin A. , Kanthi Yogendra , Albesa Roger , Mahler Michael , Knight Jason S. , Zuo Yu
Published: May 2022

Background: New tools for the assessment and prediction of the severity of hospitalized COVID-19 patients can help direct limited resources to patients with the greatest need. Circulating levels of calprotectin (S100A8/S100A9) reflect inflammatory activity in multiple conditions, and have been described as being elevated in COVID-19 patients, but their measurement is not routinely utilized. The aim of our study was to assess the practical and predictive value of measuring circulating calprotectin levels in patients at admission and during their hospitalization. Methods: Circulating calprotectin levels were measured in 157 hospitalized patients with COVID-19 using an automated quantitative chemiluminescent assay. Results: Circulating calprotectin levels were strongly correlated with changing respiratory supplementation needs of patients. The overall trajectory of circulating calprotectin levels generally correlated with patient improvement or deterioration. Conclusions: Routine measurement of circulating calprotectin levels may offer a valuable tool to assess and monitor hospitalized patients with COVID-19, as well as other acute inflammatory conditions.
Research on Soil and Nutrient Losses through Liquid Runoff, in Order to Mitigate the Climate Risks to Which Romania Is Exposed, in the Context of CAP
Authors: Chiurciu Irina-Adriana , Dana Daniela , Chereji Aurelia-Ioana , Chereji Ioan , Voicu Valentina , Firățoiu Andreea-Roxana
Published: May 2022

The current paper presents the monitoring of soil and nutrient losses through runoff as the result of the climate change. The experimental results were recorded on the standard plots for runoff and erosion control. The results of the studies carried out highlight that total nitrogen losses range from 0.05 kg/ha to 12.60 kg/ha, potassium displaced from the plots has values between 0.02 and 1.35 kg/ha, the humus associated with the eroded soil includes values between 0.51 and 176.5 kg/ha, phosphorus is recorded with maximum values of 0.39 kg/ha, the total iron losses have values between 3.14 and 431.16 g/ha, manganese has losses from 1.69 to 290.82 g/ha, copper losses range from 0.15 to 7.62 g/ha, and, regarding zinc, the values are within the limits of 0.25–57.22 g/ha. The maximum values of the displacement of fertilizing elements from the sloping agricultural lands, by means of liquid and solid leaks, are registered at the plots left as permanent black fields, the plots practically unprotected against the rain erosion. The experiments were performed at the Soil Erosion Research and Development Station “Mircea Moțoc”, Perieni/Staţiunea de Cercetare Dezvoltare pentru Combaterea Eroziunii Solului “Mircea Moţoc”, Perieni (SCDCES—MM, Perieni), Vaslui County, an institution strategically located in an area subject to erosion soil. Additionally, the paper envisages how the National Rural Development Programme (NRDP) and the Common Agricultural Policy (CAP) can be of use in this area by analysing past lessons and providing an overview of what was done.
Exploring the Relationship between New Bank Debt and Earnings Management: Evidence from Italian SMEs
Authors: Palumbo Riccardo , Rosati Pierangelo
Published: May 2022

This paper investigates the relationship between bank debt and earnings management in private SMEs in a bank-oriented economy. In this study, we leverage a sample of 4866 Italian private SMEs from 2005 to 2012 and propose a new metric to isolate the annual increase in bank debt. The results of our OLS regression suggest that, even though bank monitoring is an effective mechanism to constrain firms’ earnings management, firms engage in higher income-increasing earnings management, as proxied by discretionary accruals, in the fiscal year prior to a new bank loan application. The results are robust to different econometric specifications and are not affected by endogeneity.
The Barometer of Agency: Reconceptualising the ‘Guided Reading’ Teaching Approach
Authors: Nicholas Maria
Published: May 2022

The guided reading teaching approach is a commonly utilised practice that teachers have employed for over 20 years, both in Australia and abroad. What the approach entails, however, can be open to interpretation—an outcome that highlights the challenge of describing and conceptualising the approach in clear and unambiguous terms. This study addressed this issue of ambiguity by exploring whether guided reading, rather than being a singular teaching strategy in-and-of-itself, can more accurately be reconceptualised as comprising a range of teaching strategies that educators move between from lesson beginning to lesson’s end. Following thematic analysis of the six most commonly prescribed texts used in Australian Initial Teacher Education literacy units, a new model was devised as presented in this paper; a model that teachers and researchers in Australia and abroad can draw upon to better understand, apply and/or evaluate their own and other’s use of the guided reading teaching approach in everyday practice.
Differences in Health-Related Quality of Life in Older People with and without Sarcopenia Covered by Long-Term Care Insurance
Authors: Kitamura Masahiro , Izawa Kazuhiro P. , Ishihara Kodai , Brubaker Peter H. , Matsuda Hiroaki , Okamura Soichiro , Fujioka Koji
Published: May 2022

Background: As a result of the increase in older people covered by long-term care insurance (LTCI), prevention of sarcopenia and maintenance and improvement of health-related quality of life (HRQOL) have become important themes. This study aimed to clarify both the differences in HRQOL in older people with and without sarcopenia covered by LTCI and the correlation between HRQOL and physical function. Methods: Participants were 101 older people with LTCI at a daycare center in Japan. We investigated clinical factors using the EuroQol five-dimension three-level questionnaire (EQ-5D-3L). Analysis was by unpaired t-test, Mann–Whitney U test, chi-square test, analysis of covariance, Pearson’s correlation coefficient, and Spearman’s rank correlation coefficient. Results: Compared to the no sarcopenia group (n = 40), the sarcopenia group (n = 24) had significantly lower body mass index, skeletal muscle mass index, gait speed, EQ-5D-3L, and adjusted EQ-5D-3L (p < 0.05). The EQ-5D-3L showed a significant correlation with handgrip strength in the sarcopenia group (p = 0.02) and significant correlations with gait speed and one-leg standing time (both, p = 0.01) in the no sarcopenia group. Conclusion: We clarified differences in HRQOL in older people with and without sarcopenia covered by LTCI. This information on the interrelationship between HRQOL and physical function may help maintain and improve HRQOL in these people.
Dark Triad Psychopathy Outperforms Self-Control in Predicting Antisocial Outcomes: A Structural Equation Modeling Approach
Authors: Pechorro Pedro , Curtis Shelby , DeLisi Matt , Maroco João , Nunes Cristina
Published: May 2022

Dark Triad traits and self-control are considered viable causal precursors to antisocial and criminal outcomes in youth. The purpose of the present study is to concurrently compare how Dark Triad traits and self-control differ in terms of predicting self-reported juvenile delinquency, CD symptoms, proactive overt aggression, and crime seriousness. The sample consisted of 567 (M = 15.91 years, SD = 0.99 years, age range = 14–18 years) Southern European youth from Portugal. Structural-equation-modelling procedures revealed that the psychopathy factor of Dark Triad traits presented the strongest significant hypothetical causal associations with the antisocial/criminal outcomes, followed by self-control. Machiavellianism and narcissism presented the lowest causal associations. Our findings indicate that psychopathy, as operationalized in the Dark Triad, concurrently surpasses self-control and the remaining factors of the Dark Triad in terms of predicting antisocial/criminal outcomes in youth. This suggests that behavioral disinhibition, or a core incapacity to regulate one’s conduct, is central for understanding delinquency and externalizing psychopathology. Comparatively, the interpersonal component of dark personality features, such as Machiavellianism and narcissism, are secondary for understanding crime.
Efficient and Accurate CORDIC Pipelined Architecture Chip Design Based on Binomial Approximation for Biped Robot
Authors: Chung Rih-Lung , Hsueh Yen , Chen Shih-Lun , Abu Patricia Angela R.
Published: May 2022

Recently, much research has focused on the design of biped robots with stable and smooth walking ability, identical to human beings, and thus, in the coming years, biped robots will accomplish rescue or exploration tasks in challenging environments. To achieve this goal, one of the important problems is to design a chip for real-time calculation of moving length and rotation angle of the biped robot. This paper presents an efficient and accurate coordinate rotation digital computer (CORDIC)-based efficient chip design to calculate the moving length and rotation angle for each step of the biped robot. In a previous work, the hardware cost of the accurate CORDIC-based algorithm of biped robots was primarily limited by the scale-factor architecture. To solve this problem, a binomial approximation was carefully employed for computing the scale-factor. In doing so, the CORDIC-based architecture can achieve similar accuracy but with fewer iterations, thus reducing hardware cost. Hence, incorporating CORDIC-based architecture with binomial approximation, pipelined architecture, and hardware sharing machines, this paper proposes a novel efficient and accurate CORDIC-based chip design by using an iterative pipelining architecture for biped robots. In this design, only low-complexity shift and add operators were used for realizing efficient hardware architecture and achieving the real-time computation of lengths and angles for biped robots. Compared with current designs, this work reduced hardware cost by 7.2%, decreased average errors by 94.5%, and improved average executing performance by 31.5%, when computing ten angles of biped robots.
Application of Generator Capacity Design Technique Considering the Operational Characteristics of Container Ships
Authors: Lee Jong-Hak , Oh Ji-Hyun , Oh Jin-Seok
Published: May 2022

The advantages of economies of scale in marine logistics and transportation can be obtained by building bigger ships. As ship sizes increase, so do their propulsion systems, requiring that stable and high-efficiency power must continuously be supplied. In general, ships’ operations require power lower than the installed generator capacity. However, when the generator is operated at a low load, its efficiency decreases. In this study, based on actual operation data, the load requirements for each operation mode were analyzed, and a diesel-generator-based power system was designed. We present a generator capacity optimization calculation method through generator capacity. The proposed strategy maximizes the space utilization and efficiency of the ship while minimizing the generator’s power consumption. The generator’s fuel consumption, operating time, and efficiency were compared and analyzed to verify the proposed strategy’s efficacy. In conclusion, the proposed strategy demonstrated the effect of reducing fuel consumption by 2.2%, increasing generator efficiency by 8.4%, and reducing costs by 5.14% compared to the existing onboard generator capacity for the same vessel.
A Self-Flux-Biased NanoSQUID with Four NbN-TiN-NbN Nanobridge Josephson Junctions
Authors: Faley M. I. , Dunin-Borkowski R. E.
Published: May 2022

We report the development of a planar 4-Josephson-junction nanoscale superconducting quantum interference device (nanoSQUID) that is self-biased for optimal sensitivity without the application of a magnetic flux of Φ0/4. The nanoSQUID contains novel NbN-TiN-NbN nanobridge Josephson junctions (nJJs) with NbN current leads and electrodes of the nanoSQUID body connected by TiN nanobridges. The optimal superconducting transition temperature of ~4.8 K, superconducting coherence length of ~100 nm, and corrosion resistance of the TiN films ensure the hysteresis-free, reproducible, and long-term stability of nJJ and nanoSQUID operation at 4.2 K, while the corrosion-resistant NbN has a relatively high superconducting transition temperature of ~15 K and a correspondingly large energy gap. FIB patterning of the TiN films and nanoscale sculpturing of the tip area of the nanoSQUID’s cantilevers are performed using amorphous Al films as sacrificial layers due to their high chemical reactivity to alkalis. A cantilever is realized with a distance between the nanoSQUID and the substrate corner of ~300 nm. The nJJs and nanoSQUID are characterized using Quantum Design measurement systems at 4.2 K. The technology is expected to be of interest for the fabrication of durable nanoSQUID sensors for low temperature magnetic microscopy, as well as for the realization of more complex circuits for superconducting nanobridge electronics.
Three-Dimensional Direct Numerical Simulation of Near-Field Ozone-Enhanced Lean Premixed Syngas Turbulent Jet Flame
Authors: Xu Cong , Lin Junguang , Wang Zhihua , Wan Kaidi , Sun Shien , Zhou Zhijun
Published: May 2022

Due to its enhancement in the flame speed, ozone added in lean premixed syngas turbulent jet flame was investigated by the three-dimensional direct numerical simulation method in the near field of the flame. In the present study, numerical simulations were conducted in the lean premixed syngas turbulent jet flame configuration to explore the effects of ozone addition on freely-propagating turbulent flames. It was seen that turbulence began to significantly affect the flame surface to produce wrinkles in lean premixed gas flame with ozone added after 4D; ozone started to affect the composition field and temperature field after 8D; it accelerated the generation of intermediate products, OH and O radicals; and it will promote the production of CO2 in the near field range. Ozone will increase the flame surface area of the lean premixed syngas flame during the ignition period and can promote the ignition process and make the combustion occur earlier. The flame surface of the case with ozone added is more easily stretched by turbulence, and ozone can improve the stability of combustion. Ozone does not affect the effective radius of the flame curvature but will broaden the distribution of the curvature term because of the enhancement effect on the displacement speed of the flame surface.
Harmonic Modeling and Analysis for Parallel 12-Pulse Rectifier under Unbalanced Voltage Condition in Frequency-Domain
Authors: Qian Guochao , Wang Qianggang , He Shun , Dai Weiju , Wei Nengqiao , Zhou Niancheng
Published: May 2022

This paper treats a parallel 12-pulse rectifier as the study subject. The influence of unbalanced terminal voltage, the triggering angle, as well as the commutation angle of a thyristor-controlled rectifier circuit are considered in switching functions. Then, a frequency-domain harmonic coupled admittance matrix under the effect of positive sequence and negative sequence voltages are proposed, respectively. With the integration of the above matrices, a harmonic coupled admittance matrix model of a parallel 12-pulse rectifier under unbalanced voltage is proposed. On this basis, a simplified harmonic model of a 12-pulse rectifier is established, which only considers the effect of major elements through analyzing the elements’ distribution and magnitude of the harmonic coupled admittance matrix, as well as the AC current harmonic producing mechanism. All the models proposed in this paper are verified with high accuracy through simulation in MATLAB/Simulink. The models proposed in this paper can be used to guide the selection of harmonic suppression measures and equipment.
Is the Renewable Portfolio Standard in China Effective? Research on RPS Allocation Efficiency in Chinese Provinces Based on the Zero-Sum DEA Model
Authors: Wang Shangjia , Zhao Wenhui , Fan Shuwen , Xue Lei , Huang Zijuan , Liu Zhigang
Published: May 2022

As one of the countries with the most rapid development of new energy, China has been committed to exploring countermeasures to the challenges of new energy consumption. After more than ten years of consideration and consultation, the “renewable portfolio standard“(RPS) for “renewable energy power consumption responsibility weighting” has landed in China. However, in the official affirmation issued by the National Energy Administration, theoretical support for the basis of the initial quota allocation is still lacking. In this study, we examine the efficiency of the weight allocation scheme for renewable energy power consumption responsibilities, which was announced by the National Energy Administration in 2018 and which is based on the BCC-DEA efficiency model. The results indicate that most provinces have low allocation efficiency under this allocation scheme. Therefore, we propose an optimal allocation scheme for a renewable energy consumption quota, based on the ZSG-DEA model. With the achievement of its target, this study’s allocation scheme would ensure 100% efficiency in all provinces, improve provincial economic efficiency, and simultaneously bring economic growth. After analyzing the fairness before and after adjustment of the RPS, our findings suggest that the adjusted RPS allocation scheme can promote equity in per capita renewable electricity consumption.
Energy Consumption by DHW System with a Circulation Loop as an Energy Efficiency Component, Based on an Example of a Residential Building
Authors: Klimczak Marcin , Bartnicki Grzegorz , Ziembicki Piotr
Published: May 2022

In the EU countries, almost 50% of the produced energy is used in residential buildings. More than 25% of this energy is used to produce domestic hot water, of which almost 80% is used to heat water in domestic hot water circulation systems. This is due to high expectations on the part of residents based on their comfort, in particular regarding the supply of heat for heating and domestic hot water. In the course of their long-term research conducted on real systems, the authors confirmed that the operation of domestic hot water distribution systems causes significant costs, mainly due to heat losses. Therefore, typical variants of energy optimization of such systems were analyzed. Tests have shown that selected solutions, such as the use of control automation, are not sufficient, and recommended additional thermal insulation may not be applicable due to technical reasons. With an aim of finding a solution to the problem, the publication analyzes operational data from an existing heat source and domestic hot water circulation system in a residential building. On the basis of these analyses, a solution was proposed to reduce energy consumption within the installation by means of its hydraulic optimization. The reduction of heat losses in domestic hot water installation by means of a method presented by the authors is estimated at approximately 20%.
Influence of Measurement Methodologies for the Volumetric Air Flow Rate of Mobile Positive Pressure Fans on Drive Unit Performance
Authors: Kaczmarzyk Piotr , Warguła Łukasz , Janik Paweł , Krawiec Piotr
Published: May 2022

Since there are no legally defined testing requirements for mobile positive pressure fans, they may be tested based on methods that do not correspond to their actual operating conditions. Adequate assessment of the technical and operating conditions for this type of equipment is particularly important for equipment used in rescue operations. Such units should be characterized by efficient and reliable operation. This article investigates the influence of measurement methods of the volumetric airflow rate on the performance of a power unit. The article shows that the applied measurement method, whether it is PN-EN ISO 5801 (test conditions in a pipe duct—Method A) or other methods, i.e., ANSI/AMCA 240-15 and testing of the characteristics of the velocity profile (tests in open flow—Method B), can cause differences in the power demand of fans of from 3.2% to 4.5%. The differences in the requirements of propulsion power translate into fuel consumption and emissions of harmful exhaust gases generated by the combustion drive units (4 kW). It was also observed that fans with conventional impellers (W1) show a lower power demand when applying Method B (open flow) tests, while fans with turbo impellers (W2) show a lower power demand when Method A (duct) tests are applied. Comparative analysis of the parameters of the drive unit in the test group of fans without taking into account the measurement method can cause errors of up to about 7.7%, 6.4%, and 2.4% for the power, torque, and speed, respectively.
Study on Influencing Factors of Temperature Variation Displacement Compensation Behavior of Gas Insulated Switchgear Shell Bellows
Authors: Li Xin , Bi Teng , Xu Haiwei , Shen Xiaojun
Published: May 2022

Bellows are the key structures that compensate for and absorb the temperature-dependent displacement of a gas insulated switchgear (GIS) shell. It is of great engineering value to master the relationship between the temperature-dependent displacement behavior and various influencing factors. Based on the analysis of the influencing factors of the temperature variation displacement compensation ability of the GIS bellows, a bellows model was established. By coupling it with a shell having different degrees of bending through two layout methods, finite element simulation was carried out based on ABAQUS software to obtain the regular relationship between the temperature variation displacement compensation behavior of the bellows and various influencing factors. The results of the case study show that the temperature change displacement compensation ability of the bellows is most significantly affected by their own structural size. Reducing the wall thickness and increasing the wave height of the bellows can effectively improve the temperature change displacement compensation ability of the bellows and reduce the stress concentration in the compensation process. The change in the GIS shell shape is the second-most important influence; when the sliding support base of the bus barrel is lower than the fixed support base, the amount of temperature change displacement compensation of the bellows increases and the compensation capacity decreases, and, on the contrary, the temperature compensation capacity increases. Within the operating temperature range, the compensation ability of bellows with a distributed arrangement is better than that of a centralized arrangement, and can alleviate the initial deformation caused by gravity and gas pressure in GIS equipment.
A Photovoltaic System Fault Identification Method Based on Improved Deep Residual Shrinkage Networks
Authors: Cui Fengxin , Tu Yanzhao , Gao Wei
Published: May 2022

With the increasing installed capacity of photovoltaic (PV) power generation, it has become a significant challenge to detect abnormalities and faults of PV modules in a timely manner. Considering that all the fault information of the PV module is contained in the current-voltage (I-V) curve, this pioneering study takes the I-V curve as the input and proposes a PV-fault identification method based on improved deep residual shrinkage networks (DRSN). This method can not only identify single faults (e.g., short-circuit, partial-shading, and abnormal aging), but also effectively identify the simultaneous existence of hybrid faults. Moreover, it can achieve end-to-end fault diagnosis. The diagnostic accuracy of the proposed method on the measured data reaches 97.73%, is better than the convolutional neural network (CNN), the support vector machine (SVM), the deep residual network (ResNet), and the stage-wise additive modeling using multi-class exponential loss function based on the classification and regression tree (SAMME-CART). In addition, the possibility of the aforementioned method running on the Raspberry Pi has been verified in this study, which is of great significance for realizing the edge diagnosis of PV fault.
Starmerella bacillaris Strains Used in Sequential Alcoholic Fermentation with Saccharomyces cerevisiae Improves Protein Stability in White Wines
Authors: Moreira Luiza de Paula Dias , Nadai Chiara , da Silva Duarte Vinícius , Brearley-Smith Edward John , Marangon Matteo , Vincenzi Simone , Giacomini Alessio , Corich Viviana
Published: May 2022

Haze can appear in white wines as a result of the denaturation and subsequent aggregation of grape pathogenesis-related (PR) proteins. Yeast cell-wall polysaccharides, particularly mannoproteins, represent a promising strategy to reduce the incidence of this phenomenon. The aim of this study was to evaluate the effects of 13 Starmerella bacillaris strains, in sequential fermentation with Saccharomyces cerevisiae, on wine protein stability of three white wines (Sauvignon blanc, Pinot grigio, and Manzoni bianco). The resulting wines were characterized in terms of their chemical composition, content of PR proteins and polysaccharides, and heat stability. In addition, the mannoprotein fraction was purified from six wines, five produced with S. bacillaris and one with S. cerevisiae EC1118 used as control. Generally, wines produced with S. bacillaris strains were more heat-stable, despite generally containing higher amounts of PR proteins. The increased heat stability of Starmerella wines was attributed to the stabilizing effect resulting from their higher concentrations of both total polysaccharides and mannoprotein fractions. In particular, for the most heat unstable wine (Manzoni bianco), the low MW mannoprotein fraction resulted to be the most involved in wine stability. The ability to produce wines with different heat stability was demonstrated to be strain-dependent and was more evident in the most unstable wines. By reducing fining waste, the use of S. bacillaris as an enological starter can be proposed as a new tool to manage wine protein stability for a more sustainable winemaking.
Optimization of the System of Allocation of Overdue Loans in a Sub-Saharan Africa Microfinance Institution
Authors: Araújo Andreia , Portela Filipe , Alvelos Filipe , Ruiz Saulo
Published: May 2022

In microfinance, with more loans, there is a high risk of increasing overdue loans by overloading the resources available to take actions on the repayment. So, three experiments were conducted to search for a distribution of the loans through the officers available to maximize the probability of recovery. Firstly, the relation between the loan and some characteristics of the officers was analyzed. The results were not that strong with F1 scores between 0 and 0.74, with a lot of variation in the scores of the good predictions. Secondly, the loan is classified as paid/unpaid based on what prediction could result of the analysis of the characteristics of the loan. The Support Vector Machine had potential to be a solution with a F1 score average of 0.625; however, when predicting the unpaid loans, it showed to be random with a score of 0.55. Finally, the experiment focused on segmentation of the overdue loans in different groups, from where it would be possible to know their prioritization. The visualization of three clusters in the data was clear through Principal Component Analysis. To reinforce this good visualization, the final silhouette score was 0.194, which reflects that is a model that can be trusted. This way, an implementation of clustering loans into three groups, and a respective prioritization scale would be the best strategy to organize and assign the loans to maximize recovery.
The Robustness of Detecting Known and Unknown DDoS Saturation Attacks in SDN via the Integration of Supervised and Semi-Supervised Classifiers
Authors: Khamaiseh Samer , Al-Alaj Abdullah , Adnan Mohammad , Alomari Hakam W.
Published: May 2022

The design of existing machine-learning-based DoS detection systems in software-defined networking (SDN) suffers from two major problems. First, the proper time window for conducting network traffic analysis is unknown and has proven challenging to determine. Second, it is unable to detect unknown types of DoS saturation attacks. An unknown saturation attack is an attack that is not represented in the training data. In this paper, we evaluate three supervised classifiers for detecting a family of DDoS flooding attacks (UDP, TCP-SYN, IP-Spoofing, TCP-SARFU, and ICMP) and their combinations using different time windows. This work represents an extension of the runner-up best-paper award entitled ‘Detecting Saturation Attacks in SDN via Machine Learning’ published in the 2019 4th International Conference on Computing, Communications and Security (ICCCS). The results in this paper show that the trained supervised models fail in detecting unknown saturation attacks, and their overall detection performance decreases when the time window of the network traffic increases. Moreover, we investigate the performance of four semi-supervised classifiers in detecting unknown flooding attacks. The results indicate that semi-supervised classifiers outperform the supervised classifiers in the detection of unknown flooding attacks. Furthermore, to further increase the possibility of detecting the known and unknown flooding attacks, we propose an enhanced hybrid approach that combines two supervised and semi-supervised classifiers. The results demonstrate that the hybrid approach has outperformed individually supervised or semi-supervised classifiers in detecting the known and unknown flooding DoS attacks in SDN.
The Economics of Consensus in Algorand
Authors: Dimitri Nicola
Published: May 2022

In the paper we investigate consensus formation, from an economic perspective, in a Proof-of-Stake (PoS) based platform inspired by the Algorand blockchain. In particular, we consider PoS in relation to governance, focusing on two main issues. First we discuss alternative sampling schemes, which can be adopted to select voting committees and to define the number of votes of committee members. The selection probability is proportional to one’s stake and increases with it. Participation in governance allows users to affect the platform’s decisions as well as to obtain a reward. Then, based on such preliminary analysis, we introduce a microeconomic model to investigate the optimal stake size for a generic user. In the model we conceptualize an optimal stake, for a user, as striking the balance between having Algos immediately available for transactions and setting aside currency units to increase the probability of becoming a committee member. Our main findings suggest that the optimal stake can be quite sensitive to the user’s preferences and to the rules for selecting committees. We believe the findings may support policy decisions in PoS based platforms.