bluuebunny/crossref_metadata_2025 huggingface dataset:
Winging It: Key Issues and Perceptions around Regulation and Practice of Aircraft Maintenance in Australian General Aviation
Authors: Naweed Anjum , Kourousis Kyriakos I.
Published: June 2020

The very diverse character of General Aviation (GA) within Australia poses challenges for its effective management of risk and safety in the sector. Improvements for human performance and perceptions of safety within the maintenance environment are among the areas which regulators have targeted for continuous improvement. This paper provides a timely empirical exploration of maintenance engineer perspectives around: (1) Changes in the role of the regulator/regulation that have impacted the sector and diminished safe operations; and (2) specific practical and operational challenges that the GA industry must deal with to sustain safe operations going forward. A thematic analysis of transcribed qualitative data revealed five key themes and identified a number of key issues from sector changes including a decline in training and education, drift in working practices, and wider power-distance gap. Issues with auditing and bureaucratization, negative safety climate, and underlying values and philosophies were also found. Practical and operational challenges going forward included an array of concerns associated with safety, the mismatch between GA and commercial aviation, workforce development and the financial burden in the sector. The results draw attention to the interconnectedness between various components of the GA system, and carry timely implications for regulation in the GA sector. Future research directions are discussed.
Effects of Harvest Time on the Yield and Quality of Winter Wheat Hay Produced in Northern Italy
Authors: Ronga Domenico , Dal Prà Aldo , Immovilli Alessandra , Ruozzi Fabrizio , Davolio Roberto , Pacchioli Maria Teresa
Published: June 2020

The aim of this work was to study the yield and nutritional characteristics of winter wheat hay. A selection of cultivars recommended for three main purposes: grain, whole plant (biomass) and dual purpose (grain and biomass) production were cultivated and harvested from heading to grain dough stages. Yield dry weight (YDW), dry matter (DM) and undigested neutral detergent fiber (uNDF) increased with advancing maturity, ranging from 9 t ha−1, 20 and 11% of DM to 16 t ha−1, 43 and 17% of DM, respectively; while crude protein (CP) and neutral detergent fiber (NDF) decreased from 11 and 59% of DM to 6 and 54% of DM, respectively. Our study showed that dual purpose winter wheat cultivars displayed similar performance of CP, NDF and net energy for lactation, when harvested at heading or grain milk stages. In addition, winter wheat recommended to be harvested as whole plant showed similar values of YDW, sugar and starch contents, when harvested at grain dough and milk stages. These characteristics are strategic in hay production, allowing a more flexible harvesting strategy. These results might be useful to improve the hay production, given useful information on harvest time and improving agricultural sustainability covering the soil in autumn and winter.
Strip-Till One-Pass Technology in Central and Eastern Europe: A MZURI Pro-Til Hybrid Machine Case Study
Authors: Jaskulska Iwona , Jaskulski Dariusz
Published: June 2020

The non-inversion tillage systems, including strip-till (ST), are the key element of conservation agriculture (CA). The aim of the 2012–2018 study has been to demonstrate the application of strip-till one-pass technology (ST-OP) on the farms of Central and Eastern Europe based on the use of Mzuri Pro-Til machines. There has also been an evaluation of the effect of that technology on the soil properties and the effects of crops growing. The scientific observations and field experiments were made, e.g., in Poland, Ukraine, Lithuania, the Czech Republic, Slovakia, the Eastern states of Germany, Belarus, Serbia, and Romania. ST-OP case study with the use of Mzuri Pro-Til machine can be applied for growing all the basic crops. Tillage with a simultaneous basic fertilization application and seeding made regularly for a few years in given field leads to favorable changes in the soil properties. As compared with the soil under conventional plough tillage (CT), the soil moisture, especially in the periods of rainfall deficit, the content of organic carbon and its fraction, the count of microorganisms and earthworms, as well as the enzymatic activity, are higher. This technology saves over 20–30 L ha−1 of fuel, respectively, compared to reduced tillage (RT) and CT. Plant emergence is uniform, dense canopies and crop yields—not lower and even higher than for tillage and seeding commonly applied in Central and Eastern Europe. ST-OP can be thus an important element of field plant production as part of CA and sustainable development.
Expected Changes to Alpine Pastures in Extent and Composition under Future Climate Conditions
Authors: Dibari Camilla , Costafreda-Aumedes Sergi , Argenti Giovanni , Bindi Marco , Carotenuto Federico , Moriondo Marco , Padovan Gloria , Pardini Andrea , Staglianò Nicolina , Vagnoli Carolina , Brilli Lorenzo
Published: June 2020

As the basis of livestock feeding and related performances, pastures evolution and dynamics need to be carefully monitored and assessed, particularly in the Alps where the effects of land abandonment are further amplified by climate change. As such, increases in temperature associated with changes in precipitation patterns and quantity are leading to modifications of grassland extent and composition with consequences on the pastoral systems. This study applied a machine learning approach (Random Forest) and GIS techniques to map the suitability of seven pasture macro types most representative of the Italian Alps and simulated the impact of climate change on their dynamics according to two future scenarios (RCP4.5, 8.5), two time-slices (2011–2040, 2041–2070), and three RCMs (Aladin, CMCC, ICTP). Results indicated that (i) the methodology was robust to map the current suitability of pasture macro types (mean accuracy classification = 98.7%), so as to predict the expected alterations due to climate change; (ii) future climate will likely reduce current extend of suitable pasture (−30% on average) and composition, especially for most niche ecosystems (i.e., pastures dominated by Carex firma and Festuca gr. Rubra); (iii) areas suited to hardier but less palatable pastures (i.e., dominated by Nardus stricta and xeric species) will expand over the Alps in the near future. These impacts will likely determine risks for biodiversity loss and decreases of pastoral values for livestock feeding, both pivotal aspects for maintaining the viability and profitability of the Alpine pastoral system as a whole.
Effect of Gibberellin Responsive Reduced Height Allele Rht13 on Agronomic Traits in Spring Bread Wheat in Field Experiment in Non-Black Soil Zone
Authors: Divashuk Mikhail G. , Kroupin Pavel Yu. , Shirnin Sergey Yu. , Vukovic Milena , Kroupina Aleksandra Yu. , Karlov Gennady I.
Published: June 2020

The introduction of gibberellin-responsive reduced height (GAR Rht) alleles is a promising tool for breeding semi-dwarf, high-input varieties of wheat. We have compared recombinant isogenic lines F2:3 carrying dwarfing allele Rht13 and without dwarfing alleles, obtained from the cross of isogenic lines and selected from F2 using molecular markers. After phenotyping and statistical analysis, we found that the Rht13 allele reduces total plant height by 13.0 cm (17.4%), while the proportions between the internodes in tall and short plants remain similar. The greatest decrease in length in plants with Rht13 in comparison to wild-type plants is observed for the second internode (5.3 cm, or 31.9%). Due to the presence of Rht13, semi-dwarf plants, compared to the wild type, had a higher grain number per main spike, grain number per spikelet and higher number of productive tillers, and a slightly higher harvest index, although thousand grain weight and grain weight in the main spike were lower. Our results indicate the possibility of using Rht13 in the breeding of wheat varieties without dramatic negative effects on yield and plant development.
Expression of DOCK9 and DOCK11 Analyzed with Commercial Antibodies: Focus on Regulation of Mutually Exclusive First Exon Isoforms
Authors: Parrado Antonio
Published: June 2020

Dedicators of cytokinesis 9 and 11 (DOCK9 and DOCK11) are members of the dedicator of cytokinesis protein family encoding the guanosine nucleotide exchange factors for Rho GTPases. Together with DOCK10, they constitute the DOCK-D or Zizimin subfamily. Two alternative full-length amino terminal isoforms of DOCK9 are known, which we will call DOCK9.1 and DOCK9.2. In order to investigate the relevance of the presence of the alternative first exon isoforms within this family, and to lay the groundwork for future studies that seek to investigate their potential role as biomarkers of disease, the expression levels of DOCK9 and DOCK11 were measured by qRT-PCR in 26 human tissues and 23 human cell lines, and by Western blot analysis, using commercial antibodies in cell lines. DOCK9.1 and DOCK9.2 were widely distributed. High levels of expression of both isoforms were found in the lungs, placenta, uterus, and thyroid gland. However, only DOCK9.1 was significantly expressed in the neural and hematopoietic tissues. The unique first exon form of DOCK11 was highly expressed in hematopoietic tissues, such as the peripheral blood leukocytes, spleen, thymus, or bone marrow, and in others such as the lungs, placenta, uterus, or thyroid gland. In contrast to tissues, the expression of DOCK9.1 and DOCK9.2 differed from one another and also from total DOCK9 in cell lines, suggesting that the amino terminal isoforms of DOCK9 may be differentially regulated. This study demonstrates the usefulness of antibodies in investigating the regulation of the expression of DOCK9.1, total DOCK9, and DOCK11.
Platelet-Rich Fibrin Can Neutralize Hydrogen Peroxide-Induced Cell Death in Gingival Fibroblasts
Authors: Kargarpour Zahra , Nasirzade Jila , Di Summa Francesca , Panahipour Layla , Miron Richard J. , Gruber Reinhard
Published: June 2020

Hydrogen peroxide is a damage signal at sites of chronic inflammation. The question arises whether platelet-rich fibrin (PRF), platelet-poor plasma (PPP), and the buffy coat can neutralize hydrogen peroxide toxicity and thereby counteract local oxidative stress. In the present study, gingival fibroblasts cells were exposed to hydrogen peroxide with and without lysates obtained from PRF membranes, PPP, heated PPP (75 °C for 10 min), and the buffy coat. Cell viability was examined by trypan blue staining, live-dead staining, and formazan crystal formation. Cell apoptosis was assessed by cleaved caspase-3 Western blot analysis. Reverse transcription-quantitative polymerase chain reaction (RT-PCR) was utilized to determine the impact of PRF lysates on the expression of catalase in fibroblasts. It was reported that lysates from PRF, PPP, and the buffy coat—but not heated PPP—abolished the hydrogen peroxide-induced toxicity in gingival fibroblasts. Necrosis was confirmed by a loss of membrane integrity and apoptosis was ruled out by the lack of cleavage of caspase-3. Aminotriazole, an inhibitor of catalase, reduced the cytoprotective activity of PRF lysates yet blocking of glutathione peroxidase by mercaptosuccinate did not show the same effect. PRF lysates had no impact on the expression of catalase in gingival fibroblasts. These findings suggest that PRF, PPP, and the buffy coat can neutralize hydrogen peroxide through the release of heat-sensitive catalase.
Carotenoids, Fatty Acids, and Volatile Compounds in Apricot Cultivars from Romania—A Chemometric Approach
Authors: Pintea Adela , Dulf Francisc Vasile , Bunea Andrea , Socaci Sonia Ancuța , Pop Elena Andreea , Opriță Vlăduț-Alexandru , Giuffrida Daniele , Cacciola Francesco , Bartolomeo Giovanni , Mondello Luigi
Published: June 2020

Lipophilic constituents are important for the color and aroma of apricots, but also for their health benefits. In the present study, carotenoids, fatty acids, and volatiles were analyzed in 11 apricot cultivars, from which nine were obtained in Romania. High performance liquid chromatography coupled to a diode array detector with atmospheric pressure chemical ionization and mass spectrometry (HPLC-DAD-APCI-MS methodology applied on unsaponified carotenoid extracts allowed the identification and quantification of 19 compounds. The predominant carotenoids in all cultivars were all-trans-β-carotene and its cis isomers. Lutein was present exclusively in non-esterified form, while β-cryptoxanthin was predominantly esterified, mainly with oleic, palmitic, lauric, and stearic acid. Moreover, β-cryptoxanthin linoleate, linolenate, and stearate were detected for the first time in Harogem cultivar. Variation in carotenoid content and composition was observed, with the highest carotenoid content being recorded in Tudor, Harogem, and Mamaia cultivars. The predominant fatty acids determined by gas chromatography–mass spectrometry (GC-MS) were linoleic (up to 47%), palmitic (up to 32.7%), and linolenic (up to 17.16%), with small variations among cultivars. In-tube extraction technique (ITEX)/GC-MS was applied for profiling the volatiles in apricot fruits and 120 compounds were identified, with terpenoids and esters as the most abundant classes. Principal component analysis (PCA) revealed that the carotenoids and the fatty acids profile can be used for variety authentication and discrimination in apricots.
Outcomes Assessment of Sustainable and Innovatively Simple Lifestyle Modification at the Workplace-Drinking Electrolyzed-Reduced Water (OASIS-ERW): A Randomized, Double-Blind, Placebo-Controlled Trial
Authors: Choi Young Ah , Lee Dong Hyeon , Cho Doo-Yeoun , Lee Yong-Jae
Published: June 2020

Oxidative stress has been associated with many diseases as well as aging. Electrolyzed-reduced water (ERW) has been suggested to reduce oxidative stress and improve antioxidant potential. This study investigated the effects of drinking ERW on biomarkers of oxidative stress and health-related indices in healthy adults. We conducted a randomized, double-blind, placebo-controlled clinical trial on 65 participants, who were allocated into two groups. Of these, 61 received intervention (32 with ERW and 29 MW [mineral water]). All participants were instructed to drink 1.5 L/day of ERW or MW for eight weeks. Biomarkers of oxidative stress and health-related indices were assessed at baseline as well as after 4 weeks and 8 weeks of intervention. Of the primary outcome variables assessed, diacron-reactive oxygen metabolites (d-ROMs) and biological antioxidant potential showed a significant interaction between the groups and time, with d-ROMs levels significantly decreased at 8 weeks in ERW compared to those in MW. Among the secondary outcome variables, total, visceral, and subcutaneous fat mass significantly changed over time, with a significant association observed between the group and time. Thus, daily ERW consumption may be a potential consideration for a sustainable and innovatively simple lifestyle modification at the workplace to reduce oxidative stress, increase antioxidant potential, and decrease fat mass.
Appraisal of the Spatial Resolution of 2D Electrical Resistivity Tomography for Geotechnical Investigation
Authors: Hung Yin Chun , Chou Ho Shu , Lin Chih Ping
Published: June 2020

In the past decade, the 2D electrical resistivity tomography (ERT) has been extensively used in the investigation and monitoring of geotechnical engineering and environment engineering, but there are many uncertainties hidden behind its vivid color earth-resistivity profiles. In order to use the 2D ERT in the scale of geotechnical engineering effectively, the accuracy and spatial resolution capability of measurements must be enhanced, or at least these uncertainties should be mastered to avoid overreading the measurement results. There were seven common geological models built in this study to discuss the variance in spatial analysis capability of 2D electrical resistivity profiles under different geologic conditions. The findings show that the resolution capability of 2D electrical resistivity profiles was influenced by depth, and in different strata, it may be influenced by the resistivity ratio, layer depth, covering depth, interlayer thickness, tilt angle, medium size, and noise intensity. Generally speaking, the relatively low resistance stratum had better resolution capability; if the relatively high resistance stratum was located under the relatively low resistance stratum, its resolution capability declined. In different strata, the resolution capability may be degraded under the effect of different factors. In addition, any noise in the course of measurement resulted in a random jump of the electrical resistivity profile, which worsened as the noise increased. These circumstances should be paid special attention to avoid misrecognition of electrical resistivity profile images.
The Elastic Wave Propagation in Rectangular Waveguide Structure: Determination of Dispersion Curves and Their Application in Nondestructive Techniques
Authors: Groth Eduardo Becker , Clarke Thomas Gabriel Rosauro , Schumacher da Silva Guilherme , Iturrioz Ignacio , Lacidogna Giuseppe
Published: June 2020

The use of mechanic waves for assessing structural integrity is a well-known non-destructive technique (NDT). The ultrasound applied in the guided wave in particular requires significant effort in order to understand the complexities of the propagation so as to develop new methods in damage detection, in this case, knowing the interaction between the wave propagation and the geometry of the waveguides is mandatory. In the present work, the wave propagation in rectangular steel rod is presented. In this study, the section dimensions were fixed as 5 × 15 [mm], a typical element of the flexible riser structural amour commonly used in the offshore oil industry. The studies here presented were restricted to [0, 100 KHz] frequencies. This frequency interval is in the range of commercial waveguide equipment commonly applied in ducts in NDT applications. The computation of the dispersion curves is performed by using three different methodologies: (i) analytical solutions, (ii) a method that combines analytical approaches with finite element methods (SAFE), and (iii) experimental method that extracted information from the rod using laser vibrometers and piezoelectric actuators. Finally, two applications based on the dispersion curves determined in the rectangular waveguide are presented to illustrate the possibilities of the curve dispersion knowledge related to the specific geometry in the development and application linked to NDT. The first application consists on showing the possibilities of the techniques that use a fiber grating Bragg cell (FGB) to measure the wave displacement and the second application involves the simulation of pre-fissured prismatic waveguide aimed at searching to induce three characteristic acoustic events. The model was built combining the finite element method and a version of the discrete element method.
Approaches for Detailed Investigations on Transient Flow and Spray Characteristics during High Pressure Fuel Injection
Authors: Kawaharada Noritsune , Thimm Lennart , Dageförde Toni , Gröger Karsten , Hansen Hauke , Dinkelacker Friedrich
Published: June 2020

High pressure injection systems have essential roles in realizing highly controllable fuel injections in internal combustion engines. The primary atomization processes in the near field of the spray, and even inside the injector, determine the subsequent spray development with a considerable impact on the combustion and pollutant formation. Therefore, the processes should be understood as much as possible; for instance, to develop mathematical and numerical models. However, the experimental difficulties are extremely high, especially near the injector nozzle or inside the nozzle, due to the very small geometrical scales, the highly concentrated optical dense spray processes and the high speed and drastic transient nature of the spray. In this study, several unique and partly recently developed techniques are applied for detailed measurements on the flow inside the nozzle and the spray development very near the nozzle. As far as possible, the same three-hole injector for high pressure diesel injection is used to utilize and compare different measurement approaches. In a comprehensive section, the approach is taken to discuss the measurement results in comparison. It is possible to combine the observations within and outside the injector and to discuss the entire spray development processes for high pressure diesel sprays. This allows one to confirm theories and to provide detailed and, in parts, even quantitative data for the validation of numerical models.
Agglomerative Clustering and Residual-VLAD Encoding for Human Action Recognition
Authors: Butt Ammar Mohsin , Yousaf Muhammad Haroon , Murtaza Fiza , Nazir Saima , Viriri Serestina , Velastin Sergio A.
Published: June 2020

Human action recognition has gathered significant attention in recent years due to its high demand in various application domains. In this work, we propose a novel codebook generation and hybrid encoding scheme for classification of action videos. The proposed scheme develops a discriminative codebook and a hybrid feature vector by encoding the features extracted from CNNs (convolutional neural networks). We explore different CNN architectures for extracting spatio-temporal features. We employ an agglomerative clustering approach for codebook generation, which intends to combine the advantages of global and class-specific codebooks. We propose a Residual Vector of Locally Aggregated Descriptors (R-VLAD) and fuse it with locality-based coding to form a hybrid feature vector. It provides a compact representation along with high order statistics. We evaluated our work on two publicly available standard benchmark datasets HMDB-51 and UCF-101. The proposed method achieves 72.6% and 96.2% on HMDB51 and UCF101, respectively. We conclude that the proposed scheme is able to boost recognition accuracy for human action recognition.
The Influence of Surfactants, Dynamic and Thermal Factors on Liquid Convection after a Droplet Fall on Another Drop
Authors: Misyura Sergey Y. , Morozov Vladimir S. , Gobyzov Oleg A.
Published: June 2020

The regularities of the processes and characteristics of convection in a sessile drop on a hot wall after the second drop fall are investigated experimentally. The movement of a particle on a drop surface under the action of capillary force and liquid convection is considered. The particle motion is realized by a complex curvilinear trajectory. The fall of droplet with and without surfactant additives is considered. Estimates of the influence of the thermal factor (thermocapillary forces) and the dynamic factor (inertia forces) on convection are given. The scientific novelty of the work is the investigation of the simultaneous influence of several factors that is carried out for the first time. It is shown that in the presence of a temperature jump for the time of about 0.01–0.1 s thermocapillary convection leads to a 7–8 times increase in the mass transfer rate in drop. The relative influence of inertial forces is found to be no more than 5%. The fall of drops with surfactant additives (water + surfactant) reduces the velocity jump inside the sessile drop 2–4 times, compared with the water drop without surfactant. Thermocapillary convection leads to the formation of a stable vortex in the drop. The dynamic factor and surfactant additive lead to the vortex breakdown into many small vortices, which results in the suppression of convection. The obtained results are of great scientific and practical importance for heat transfer enhancement and for the control of heating and evaporation rates.
tribAIn—Towards an Explicit Specification of Shared Tribological Understanding
Authors: Kügler Patricia , Marian Max , Schleich Benjamin , Tremmel Stephan , Wartzack Sandro
Published: June 2020

Within the domain of tribology, the science and technology for understanding and controlling friction, lubrication, and wear of relatively moving interacting surfaces, countless experiments are carried out and their results are published worldwide. Due to the variety of test procedures and a lack of consistency in the terminology as well as the practice of publishing results in the natural language, accessing and reusing tribological knowledge is time-consuming and experiments are hardly comparable. However, for the selection of potential tribological pairings according to given requirements and to enable comparative evaluations of the behavior of different tribological systems or testing conditions, a shared understanding is essential. Therefore, we present a novel ontology tribAIn (derived from the ancient Greek word “tribein” (= rubbing) and the acronym “AI” (= artificial intelligence)), designed to provide a formal and explicit specification of knowledge in the domain of tribology to enable semantic annotation and the search of experimental setups and results. For generalization, tribAIn is linked to the intermediate-level ontology EXPO (ontology of scientific experiments), supplemented with subject-specific concepts meeting the needs of the domain of tribology. The formalization of tribAIn is expressed in the W3C standard OWL DL. Demonstrating the ability of tribAIn covering tribological experience from experiments, it is applied to a use case with heterogeneous data sources containing natural language texts and tabular data.
An Early Warning System to Detect At-Risk Students in Online Higher Education
Authors: Bañeres David , Rodríguez M. Elena , Guerrero-Roldán Ana Elena , Karadeniz Abdulkadir
Published: June 2020

Artificial intelligence has impacted education in recent years. Datafication of education has allowed developing automated methods to detect patterns in extensive collections of educational data to estimate unknown information and behavior about the students. This research has focused on finding accurate predictive models to identify at-risk students. This challenge may reduce the students’ risk of failure or disengage by decreasing the time lag between identification and the real at-risk state. The contribution of this paper is threefold. First, an in-depth analysis of a predictive model to detect at-risk students is performed. This model has been tested using data available in an institutional data mart where curated data from six semesters are available, and a method to obtain the best classifier and training set is proposed. Second, a method to determine a threshold for evaluating the quality of the predictive model is established. Third, an early warning system has been developed and tested in a real educational setting being accurate and useful for its purpose to detect at-risk students in online higher education. The stakeholders (i.e., students and teachers) can analyze the information through different dashboards, and teachers can also send early feedback as an intervention mechanism to mitigate at-risk situations. The system has been evaluated on two undergraduate courses where results shown a high accuracy to correctly detect at-risk students.
Estuarine Mapping and Eco-Geomorphological Characterization for Potential Application in Conservation and Management: Three Study Cases along the Iberian Coast
Authors: Aranda María , Gracia Francisco Javier , Peralta Gloria
Published: June 2020

Geomorphological changes in recent decades in three estuaries along the Iberian coast were analysed using aerial orthophotographs. A hierarchical classification scheme, based on a literature review representing 26 estuarine eco-geomorphological features relevant to estuarine dynamics and functioning, is described. The estuaries selected were San Vicente de la Barquera (N Spain), Guadiana River (SW border between Spain and Portugal) and the Ebro River Delta mouth (NE Spain). For these systems, a 60-year time series of high-resolution maps was developed, analysing the changes in feature surfaces. The main subsystems analysed were beach, dunes, saltmarshes and the drainage network. The results of the cartographies showed general behaviour common to all transitional systems, relationships among main subsystems and processes inherent to each one. This work illustrates how beaches and dunes serve as a protective barrier for the tidal flats, acting as a sediment buffer for the entire system. The subsystems are connected by the drainage network responsible for the exchange of matter and energy between them. Furthermore, an accuracy assessment was performed in one of the study zones to identify the limitations of mapping with aerial photographs. The results explain the changes with time but also the processes and relationships between the estuarine features at a long-term scale. This work adds an important perspective towards a general understanding of their dependence on intrinsic and boundary conditions.
Power Transformer Fault Diagnosis Based on Dissolved Gas Analysis by Correlation Coefficient-DBSCAN
Authors: Liu Yongxin , Song Bin , Wang Linong , Gao Jiachen , Xu Rihong
Published: June 2020

The transformers work in a complex environment, which makes them prone to failure. Dissolved gas analysis (DGA) is one of the most important methods for oil-immersed transformers’ internal insulation fault diagnosis. In view of the high correlation of the same fault data of transformers, this paper proposes a new method for transformers’ fault diagnosis based on correlation coefficient density clustering, which uses density clustering to extrapolate the correlation coefficient of DGA data. Firstly, we calculated the correlation coefficient of dissolved gas content in the fault transformers oil and enlarged the correlation of the same fault category by introducing the amplification coefficient, and finally we used the density clustering method to cluster diagnosis. The experimental results show that the accuracy of clustering is improved by 32.7% compared with the direct clustering judgment without using correlation coefficient, which can effectively cluster different types of transformers fault modes. This method provides a new idea for transformers fault identification, and has practical application value.
Hierarchical Transformer Network for Utterance-Level Emotion Recognition
Authors: Li Qingbiao , Wu Chunhua , Wang Zhe , Zheng Kangfeng
Published: June 2020

While there have been significant advances in detecting emotions in text, in the field of utterance-level emotion recognition (ULER), there are still many problems to be solved. In this paper, we address some challenges in ULER in dialog systems. (1) The same utterance can deliver different emotions when it is in different contexts. (2) Long-range contextual information is hard to effectively capture. (3) Unlike the traditional text classification problem, for most datasets of this task, they contain inadequate conversations or speech. (4) To better model the emotional interaction between speakers, speaker information is necessary. To address the problems of (1) and (2), we propose a hierarchical transformer framework (apart from the description of other studies, the “transformer” in this paper usually refers to the encoder part of the transformer) with a lower-level transformer to model the word-level input and an upper-level transformer to capture the context of utterance-level embeddings. For problem (3), we use bidirectional encoder representations from transformers (BERT), a pretrained language model, as the lower-level transformer, which is equivalent to introducing external data into the model and solves the problem of data shortage to some extent. For problem (4), we add speaker embeddings to the model for the first time, which enables our model to capture the interaction between speakers. Experiments on three dialog emotion datasets, Friends, EmotionPush, and EmoryNLP, demonstrate that our proposed hierarchical transformer network models obtain competitive results compared with the state-of-the-art methods in terms of the macro-averaged F1-score (macro-F1).
High-Power Broadband Frequency Chirped Intensity-Modulated Single-Frequency 1064-nm Laser
Authors: Li Kun , Yang Suhui , Wang Xin , Li Zhuo
Published: June 2020

Optical carried microwave radar (OCMR), combining the advantages of lidar and microwave radar, uses an intensity-modulated laser beam as the medium to detect the distance and velocity of objects. In order to achieve a high ranging resolution at long distance, a high-power frequency chirped intensity-modulated light source at a 1064-nm wavelength was developed. A low-power narrow-linewidth 1064-nm laser beam was input to a Mach-Zehnder electro-optic modulator (EOM), and the frequency of the EOM was tuned from 10 MHz to 2.1 GHz. The output from the EOM was coupled to a laser-diode-pumped ytterbium-doped fiber amplifier (YDFA). A maximum output power of 29.5 W was achieved from the YDFA. We measured the frequency characteristics of the modulated laser beams before and after amplification, respectively. The amplification process did not bring any obvious degeneration of the modulation in terms of the bandwidth, frequency stability, chirping linearity, and modulation depth. Our research presents a new approach of obtaining a high-power broad-band intensity-modulated light source for OCMR.
An Innovative Construction Technique for Curved Structures
Authors: Cascardi Alessio , Micelli Francesco , Aiello Maria Antonietta
Published: June 2020

In the present paper, an innovative, recently patented technique for the construction of a curved structural member without scaffolds is proposed and illustrated. It consists of a Hinged Lifting Arch (HLA), using Fiber-Reinforced Polymer (FRP) bonded strips. In detail, a series of blocks are cut following an arch geometry and then aligned on the ground floor to bond a composite on their top surface. Moreover, impregnation of the polymeric adhesive is not allowed at the extremities of each block. The fiber sheet is applied continuously along the entire extrados. In this context, hinges are introduced, and the FRP-connected blocks can easily rotate in the opposite direction around the contact ends (i.e., hinges). Finally, the middle block is lifted up, and the arch takes the desired shape. Moreover, an analytical model is proposed and discussed for designing the proper aspect ratio of the blocks in order to ensure full mutual contact when the HLA is completely lifted. The advantages of the proposed technique relate to the absence of scaffolds and improved seismic strength against horizontal loads, thanks to the presence of the FRP, which limits the occurrence of hinges at the extrados.
Impact of Tungsten on Thermomechanically Induced Precipitation of Laves Phase in High Performance Ferritic (HiperFer) Stainless Steels
Authors: Pöpperlová Jana , Fan Xiuru , Kuhn Bernd , Bleck Wolfgang , Krupp Ulrich
Published: June 2020

High-chromium ferritic stainless steels strengthened by Laves phase precipitates were developed for a high-temperature application in steam power plants. The impact of tungsten content on the precipitation of the intermetallic Laves phase during the newly developed thermomechanical process route was investigated. Due to rapid thermomechanically induced precipitation, a considerable reduction in processing time in comparison to the conventional solely thermal two-step processing of high chromium ferritic steels was achieved. Nevertheless, comparable mechanical properties at room temperature, i.e., the ultimate tensile strength of 712 MPa and the yield strength of 434 MPa, were obtained. The microstructure was analyzed by scanning electron microscopy (SEM) in combination with digital particle analysis, to estimate the particle size and the phase fraction of the Laves phase. The mean particle size of 52 nm and the volume fraction of 4.11% were achieved. Due to the tungsten content, an increase in the volume fraction and particle size was observed, giving rise to the higher strengthening effect.
Assessment and Mitigation of Heavy Metals Uptake by Edible Vegetables Grown in a Turin Contaminated Soil Used as Vegetable Garden
Authors: Gaggero Elisa , Calza Paola , Fabbri Debora , Fusconi Anna , Mucciarelli Marco , Bordiglia Giorgio , Abollino Ornella , Malandrino Mery
Published: June 2020

In this study we evaluated the concentration of 22 elements, namely Al, As, Ba, Ca, Cd, Ce, Co, Cr, Cu, Fe, K, La, Mg, Mn, Na, Ni, P, Pb, Sr, Ti, V, Zn, and their uptake by edible plants in soils collected in a green urban area. The results highlighted a high yield of those heavy metals typical for anthropic pollution, such as Pb, Zn, Cu, Ba and Co, likely due to the intensive vehicular traffic. The uptake of metals by edible plants was analyzed on two broadleaf plants, Lactuca sativa and Brassica oleracea, grown in this soil and in an uncontaminated Turin soil in a growth chamber with and without the addition of a soil improver, provided by a local Organic Waste Treatment Plant. The subsequent analysis of their aerial part and roots highlighted the absorption of the main potentially toxic elements (PTEs) by the vegetables grown in the contaminated soil, whereas their concentration was lower if cultivated in the comparison soil, which was free of pollutants. The use of a soil amendment did not decrease the uptake of PTEs by Lactuca sativa and Brassica oleracea, but it caused a strong reduction in their translocation from the roots to the edible part, which consisted of the aerial part.
Platelet-Rich Plasma (PRP) in Dental Extraction of Patients at Risk of Bisphosphonate-Related Osteonecrosis of the Jaws: A Two-Year Longitudinal Study
Authors: Mauceri Rodolfo , Panzarella Vera , Pizzo Giuseppe , Oteri Giacomo , Cervino Gabriele , Mazzola Giuseppina , Di Fede Olga , Campisi Giuseppina
Published: June 2020

Dental extraction has often been described as the main trigger event of osteonecrosis of the jaws (ONJ). This longitudinal hospital-based study aimed to evaluate the outcome at 2 years of a standardized medical-surgical protocol for dental extraction, combined with platelet rich-plasma (PRP) application, compared with conventional protocol not combined with PRP or any other autologous platelet concentrate in cancer (ONC) and osteometabolic (OST) patients, at risk of bisphosphonate (BP)-related ONJ. Twenty patients were consecutively recruited: six received BPs for cancer skeletal-related events (34.17 ± 19.97 months), while fourteen received BPs for metabolic bone disease (74.5 ± 34.73 months). These patients underwent a standardized protocol for dental extraction, combined with autologous PRP application in the post-extraction socket. A total of 63 dental extractions were performed (24 and 39 in ONC and OST groups, respectively). As controls, historical cases, derived from the literature and including 171 ONC and 734 OST patients, were considered. The outcome of the surgical treatment was successful in all patients treated with PRP: two years after extraction, no patient had clinical or radiological signs of ONJ. When this datum was compared with historical controls, no statistically significant differences were found (p > 0.1). The combination of a standardized medical-surgical protocol with PRP application may contribute to limit the occurrence of BP-related ONJ, in both ONC and OST patients. Additional prospective studies with a larger patient sample are necessary to confirm this datum.
Ce- and B-Doped Silica Fibers for Monitoring Low-Energy Proton Beams on a Medical Cyclotron
Authors: Hoehr Cornelia , Hanna Matthew , Zeisler Stefan , Penner Crystal , Stokely Matthew , Dehnel Morgan
Published: June 2020

Many medical isotopes can be produced on a small cyclotron. The alignment and profiles of low-energy proton beams from cyclotrons used for medical radioisotope production, such as the TR13 cyclotron at TRIUMF, Canada, cannot be directly quantified during dose delivery with simultaneous constant feedback and sharp spatial resolutions. Doped silica fibers are a potential solution that has been tested at TRIUMF. To measure the effects of irradiation inside an isotope production target, we attached fibers to the outside of an 18O gas target and measured the light output during irradiation. Different dopants, fiber diameters, and target materials were investigated. It was found that 200 µm diameter Ce- and B-doped fibers produce signals linearly proportional to the beam current. This only deviated when the target was moved such that the beam was steered into the target wall, increasing the production of prompt radiation and causing the beam current to decrease but the fiber signal to increase. With the technique described here, the beam can be monitored on the target, including its steering and its overall alignment with the target.
Evaluation of Cross-Sectional Root Canal Shape and Presentation of New Classification of Its Changes Using Cone-Beam Computed Tomography Scanning
Authors: Razumova Svetlana , Brago Anzhela , Howijieh Ammar , Barakat Haydar , Kozlova Yuliya , Baykulova Malina
Published: June 2020

The root canal system is considering the most important factor in endodontic treatment, due to the complexity of its anatomy and morphology. The aim of this study was to evaluate the cross-sectional root canal shape in three thirds (coronal, middle, apical) in different age groups using cone-beam computed tomography scanning (CBCT) and to present a new classification for root canal shape changes. This cross-sectional study included 300 CBCT scans for patient aged 20–70, and these scans were evaluated to study the morphology of the cross-sectional root canal shape in coronal, middle, and apical thirds among three age groups, namely the young (20–44), middle (45–59), and elderly (60–70). The root canal shape was classified as round, oval, long oval, and ribbon (with or without isthmus). The cross-sectional root canal shape was identified in two groups: canals with an unchanging (constant) shape and canals with changing shape. In turn, in canals with changing shape, the change could be identified in the region of the middle or apical thirds of the canal. The results showed that root canal shape changes in two cases: (1) the presence of one or more canals in the root (with or without isthmus between them), and (2) with age, as it was observed that the cross-sectional shape of the root canal becomes round in the apical third with age. A new classification of the changes of root canal shape in three thirds (coronal, middle, apical) was presented in this study.
Topology and Parametric Optimization-Based Design Processes for Lightweight Structures
Authors: Tyflopoulos Evangelos , Steinert Martin
Published: June 2020

Topology and Parametric Optimization are two of the most implemented material optimization approaches. However, it is not clear in the literature which optimization procedure, or possible combination of them, can lead to the best results based on material reduction and optimization time. In this paper, a quantitative comparison of different topology and parametric optimization design processes is conducted using three benchmark examples: A Hollow Plate, an L-Bracket, and a Messerschmitt–Bölkow–Blohm Beam (MBB-Beam). Ten different design processes that were developed in each case study resulted in 30 simulations in total. The design processes were clustered in three main design workflows: The Topology Optimization, the Parametric Optimization, and the Simultaneous Parametric and Topology Optimization. Their results were compared with respect to mass, stress, and time. The Simultaneous Parametric and Topology Optimization approach gave the lightest design solutions without compromising their initial strength but also increased the optimization time. The findings of this paper will help the designers in the pursuit of lightweight structures and will create the basis for the identification of the ideal material optimization procedure.
Experimental and Numerical Study on Dynamics of Two Footbridges with Different Shapes of Girders
Authors: Banas Anna , Jankowski Robert
Published: June 2020

The paper presents the experimental and numerical results of the dynamic system identification and verification of the behavior of two footbridges in Poland. The experimental part of the study involved vibration testing under different scenarios of human-induced load, impulse load, and excitations induced by vibration exciter. Based on the results obtained, the identification of dynamic parameters of the footbridges was performed using the peak-picking method. With the impulse load applied to both structures, determination of their natural vibration frequencies was possible. Then, based on the design drawings, detailed finite element method (FEM) models were developed, and the numerical analyses were carried out. The comparison between experimental and numerical results obtained from the modal analysis showed a good agreement. The results also indicated that both structures under investigation have the first natural bending frequency of the deck in the range of human-induced excitation. Therefore, the risk of excessive structural vibrations caused by pedestrian loading was then analysed for both structures. The vibration comfort criteria for both footbridges were checked according to Sétra guidelines. In the case of the first footbridge, the results showed that the comfort criteria are fulfilled, regardless of the type of load. For the second footbridge, it was emphasized that the structure meets the assumptions of the guidelines for vibration severability in normal use; nevertheless, it is susceptible to excitations induced by synchronized users, even in the case of a small group of pedestrians.
Collaborative Use of a Shared System Interface: The Role of User Gaze—Gaze Convergence Index Based on Synchronous Dual-Eyetracking
Authors: Tchanou Armel Quentin , Léger Pierre-Majorique , Boasen Jared , Senecal Sylvain , Taher Jad Adam , Fredette Marc
Published: June 2020

Gaze convergence of multiuser eye movements during simultaneous collaborative use of a shared system interface has been proposed as an important albeit sparsely explored construct in human-computer interaction literature. Here, we propose a novel index for measuring the gaze convergence of user dyads and address its validity through two consecutive eye-tracking studies. Eye-tracking data of user dyads were synchronously recorded while they simultaneously performed tasks on shared system interfaces. Results indicate the validity of the proposed gaze convergence index for measuring the gaze convergence of dyads. Moreover, as expected, our gaze convergence index was positively associated with dyad task performance and negatively associated with dyad cognitive load. These results suggest the utility of (theoretical or practical) applications such as synchronized gaze convergence displays in diverse settings. Further research perspectives, particularly into the construct’s nomological network, are warranted.