bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in the Spectrum of Free Fatty Acids in Blood Serum of Dairy Cows during a Prolonged Summer Heat Wave
Authors: Mylostyvyi Roman , Sejian Veerasamy , Izhboldina Olena , Kalinichenko Olena , Karlova Lina , Lesnovskay Olena , Begma Natalia , Marenkov Oleh , Lykhach Vadym , Midyk Svitlana , Cherniy Nikolay , Gutyj Bogdan , Hoffmann Gundula
Published: November 2021

This experiment was conducted to study the effect of a prolonged hot period on the fatty acid (FA) composition in blood serum of dairy cows. Eighteen multiparous Holstein cows were randomly assigned to the hyperthermia group (HYP, n = 8) in August (summer season) and the control group (CON, n = 10) in October (autumn season). Blood from animals of the HYP group was collected in one heat wave, which was preceded by a long period of heat stress (HS, temperature-humidity index (THI ≥ 72)). Blood from cows of the CON group was collected under thermal comfort conditions (THI < 68). The spectrum of free fatty acids (FFA) in the blood serum was analyzed by gas chromatography. The concentration of FFA increased, including saturated FAs and monounsaturated FAs, in the blood serum of cows under conditions of prolonged HS. This was associated with the mobilization of FA into the bloodstream from adipose tissue, as a consequence of negative energy balance. An increase in the ratio of n-6/n-3 polyunsaturated FAs may indicate biomembrane dysfunction and adversely affect dairy cows. This study showed that prolonged periods of heat can affect the FA composition of blood. How much this leads to changes in the FA composition of milk and the quality of food products remains to be seen in further research.
Production and Health Management from Grazing to Confinement Systems of Largest Dairy Bovine Farms in Azores: A Farmers’ Perspective
Authors: Medeiros Ivo , Fernandez-Novo Aitor , Astiz Susana , Simões João
Published: November 2021

The intensification of bovine milk production in the Azores has led farmers to increase farm size and specialization in grasslands, implementing confined and semi-confined production systems. Fixed milking parlours (FMP) have progressively gained more popularity, at the expense of conventional mobile milking systems (MMS). The present study aimed to evaluate the associations between production and health management in dairy cattle farms, with FMP or MMS, in grasslands (São Miguel, Azores), according to the farmers’ perspective. A total of 102 questions about production and health management were surveyed in 105 farms with >30 dairy cows each. Farms with FMP were associated (p ≤ 0.05) with larger herd size, better facilities, and specialized management, however, the adoption of preventive and biosecurity measures should be improved by these farmers. MMS farms implemented a lower level of disease prevention or control programs, less frequent transhumance, and showed a wider vocation to dual-purpose (milk and cross beef) than FMP farms. In conclusion, MMS and FMP farms tried to optimize yield and economic viability in different ways using grasslands. Several biosecurity and health prevention constraints were identified for improvement.
Flaxseed Oil as a Source of Omega n-3 Fatty Acids to Improve Semen Quality from Livestock Animals: A Review
Authors: Ngcobo Jabulani Nkululeko , Ramukhithi Fhulufhelo Vincent , Nephawe Khathutshelo Agree , Mpofu Takalani Judas , Chokoe Tlou Caswell , Nedambale Tshimangadzo Lucky
Published: November 2021

The demand to conserve indigenous species through the cryo-gene bank is increasing. Spermatozoa remain sensitive to cryopreservation damages especially that of avian species thus limiting the use of reproductive biotechnologies such as artificial insemination in the conservation programs. Long-chain polyunsaturated fatty acid (LCPUFAs), specifically omega n-3, expanded a research interest to improve animal reproductive efficiency through improving spermatozoa quality. This is driven by the fact that mammals cannot synthesize omega-3 de-novo because they lack delta-12 and delta-15 desaturase enzymes thus supplemented in the diet is mandatory. Delta-12 and delta-15 add a double bond at the 12th and 15th carbon-carbon bond from the methyl end of fatty acids, lengthening the chain to 22 carbon molecules. Fish oil is a pioneer source of omega n-3 and n-6 fatty acids. However, there is a report that numerous fisheries are over-exploited and could collapse. Furthermore, processing techniques used for processing by-products could complement alterations of the amino acid profile and reduce protein retrieval. Alternatively, flaxseed oil contains ±52–58% of total fatty acids and lignans in the form of α-linolenic and linoleic acid. Alpha-linolenic acid (ALA,18:3n-3) is enzymatically broken-down de-novo by delta-6 desaturase and lengthened into a long-chain carbon molecule such as eicosapentaenoic acid (C20:5n-3). Nevertheless, controversial findings following the enrichment of diet with flaxseed oil have been reported. Therefore, this paper is aimed to postulate the role of flaxseed oil as an alternative source of omega n-3 and n-6 fatty acids to improve semen quality and quantity from livestock animals. These include the interaction between docosahexaenoic acid (DHA) and spermatogenesis, the interaction between docosahexaenoic acid (DHA) and testicular cells, and the effect of flaxseed oil on semen quality. It additionally assesses the antioxidants to balance the level of PUFAs in the semen.
From the Point of View of the Chickens: What Difference Does a Window Make?
Authors: Sans Elaine Cristina de Oliveira , Tuyttens Frank André Maurice , Taconeli Cesar Augusto , Pedrazzani Ana Silvia , Vale Marcos Martinez , Molento Carla Forte Maiolino
Published: November 2021

We aimed to investigate what broiler chickens prefer when given free choice between a barn side with artificial lighting only as opposed to the other barn side with natural light through glass windows and artificial light. Eighty-five 1 day-old male Cobb 500 broiler chickens were divided into 10 pens; half of each pen area was provided with only artificial light (OAL) and the other half with natural and artificial light (NAL), and birds were free to move across sides. Environmental indicators and external conditions such as temperature, relative humidity, air velocity, ammonia and illuminance were monitored inside and outside the barn. Chickens’ preference was registered each three days, divided in categories: I (at 9, 12, and 15 days), II (at 18, 21, 24, and 27 days), and III (at 30, 33 and 36 days). The effect of the interaction between environmental indicators and week was statistically different only for illuminance. Chickens preferred NAL to OAL from 18 days onwards (II p < 0.001; III p = 0.016). Drinking (p = 0.034) and exploration or locomotion (p = 0.042) behaviours were more frequent, and “not visible” behaviours (p < 0.001) were less frequent, in NAL. Foraging was the only behaviour with an interaction effect between age category and light treatment, as birds during period II expressed this behaviour more frequently in NAL than OAL (p = 0.003). For our experimental conditions, the chickens preferred NAL from 18 days of age onwards, when the confounding effect of the heating light was removed, and their behavioural repertoire was also different according to each side of the barn and to their ages.
Penicillins’ Solubility in Supercritical Carbon Dioxide: Modeling by Cubic Equations of States Revisited
Authors: Nasri Loubna
Published: November 2021

Development of processes using green solvents as supercritical fluids (SCFs) depends on the accuracy of modeling and predicting phase equilibrium which is of considerable importance to exploit the use of SCF process at the level of pharmaceutical industries. Solid-Fluid equilibrium modeling is associated to many drawbacks when compressed gas-based models as cubic equations of states (cEoSs) are used. The unavailability of experimental values of solute’s sublimation pressure presents one of the major obstacles to the solubility modeling with this type of models, and thus, its estimation is essential and inevitable. This work is an attempt to address a question regarding “accurate estimated value” of sublimation pressure of two antibiotics Penicillin G (benzyl penicillin) and Penicillin V (phenoxymethyl penicillin). Toward that, first, cEoSs are provided as the thermodynamics modeling framework and fundamental approach. Second, a discussion and a review of some literature results are given. Third, results are invoked to present a criticism analysis that comes from the use of modified form of Peng-Robinson (PR) equation of states. Finally, considerable improvement of modeling results by using a new sublimation pressure is shown.
Antimicrobial Impact of Different Air-Polishing Powders in a Subgingival Biofilm Model
Authors: Wenzler Johannes-Simon , Krause Felix , Böcher Sarah , Falk Wolfgang , Birkenmaier Axel , Conrads Georg , Braun Andreas
Published: November 2021

Subgingival air-polishing devices (SAPD) can reduce bacterial biofilms and thus support periodontal healing. The authors of this study evaluated the effectiveness of the glycine-based and trehalose-based air-polishing powders in removing pathogenic bacteria in a subgingival biofilm model. We treated 56 subgingival pockets in porcine jaws with SAPD. Subgingival air polishing was performed in three groups of 13 pockets each: I, glycine-based powder; II, trehalose-based powder; and III, water alone. Another group (IV) served as untreated controls. Prior to air polishing, inoculated titanium bars were inserted into the pockets containing periopathogenic bacteria such as Porphyromonas gingivalis and Tannerella forsythia. Remaining bacteria were evaluated using real-time PCR. The numbers of remaining bacteria depended on the treatment procedure, with the lowest number of total bacteria in group I (median: 1.96 × 106 CFU; min: 1.46 × 105; max: 9.30 × 106). Both polishing powders in groups I and II (median: 1.36 × 107 CFU; min: 5.22 × 105; max: 7.50 × 107) showed a statistically significantly lower total bacterial load in comparison to both group IV (median: 2.02 × 108 CFU; min: 5.14 × 107; max: 4.51 × 108; p < 0.05) and group III (median: 4.58 × 107 CFU; min: 2.00 × 106; max: 3.06 × 108; p < 0.05). Both subgingival air-polishing powders investigated can reduce periopathogenic bacteria and thus support antimicrobial therapy approaches in periodontal treatment regimens.
An Improved VGG16 Model for Pneumonia Image Classification
Authors: Jiang Zhi-Peng , Liu Yi-Yang , Shao Zhen-En , Huang Ko-Wei
Published: November 2021

Image recognition has been applied to many fields, but it is relatively rarely applied to medical images. Recent significant deep learning progress for image recognition has raised strong research interest in medical image recognition. First of all, we found the prediction result using the VGG16 model on failed pneumonia X-ray images. Thus, this paper proposes IVGG13 (Improved Visual Geometry Group-13), a modified VGG16 model for classification pneumonia X-rays images. Open-source thoracic X-ray images acquired from the Kaggle platform were employed for pneumonia recognition, but only a few data were obtained, and datasets were unbalanced after classification, either of which can result in extremely poor recognition from trained neural network models. Therefore, we applied augmentation pre-processing to compensate for low data volume and poorly balanced datasets. The original datasets without data augmentation were trained using the proposed and some well-known convolutional neural networks, such as LeNet AlexNet, GoogLeNet and VGG16. In the experimental results, the recognition rates and other evaluation criteria, such as precision, recall and f-measure, were evaluated for each model. This process was repeated for augmented and balanced datasets, with greatly improved metrics such as precision, recall and F1-measure. The proposed IVGG13 model produced superior outcomes with the F1-measure compared with the current best practice convolutional neural networks for medical image recognition, confirming data augmentation effectively improved model accuracy.
Direct Measurements of Cosmic Rays (TeV and beyond) Using an Ultrathin Calorimeter: Lessening Fluctuation Method
Authors: Lebedev Igor , Fedosimova Anastasia , Mayorov Andrey , Krassovitskiy Pavel , Dmitriyeva Elena , Ibraimova Sayora , Bondar Ekaterina
Published: November 2021

In this paper, we propose a method that makes it possible to use an ultrathin calorimeter for direct measurements of cosmic rays with energies of TeV and higher. The problems of determining the primary energy with a thin calorimeter, due to large fluctuations in shower development, the low statistics of analyzed events and the large size required for the calorimeter, are considered in detail. A solution to these problems is proposed on the basis of a lessening fluctuation method. This method is based on the assumption of the universality of the development of cascades initiated by particles of the same energy and mass. For energy reconstruction, so-called correlation curves are used. The main analyzed quantities are the size of the cascade and the rate of its development. The method was tested using the calorimeter of the PAMELA collaboration. Based on simulations, it is shown that the primary energy can be determined on the ascending branch of the cascade curve. This fact solves the problems associated with the need to increase the calorimeter thickness with an increase in primary energy and with the limitation of the analyzed events. The proposed technique is universal for different energies and different nuclei.
A Novel Adaptive Sparrow Search Algorithm Based on Chaotic Mapping and T-Distribution Mutation
Authors: Yang Xiaoxu , Liu Jie , Liu Yi , Xu Peng , Yu Ling , Zhu Lei , Chen Huayue , Deng Wu
Published: November 2021

Aiming at the problems of the basic sparrow search algorithm (SSA) in terms of slow convergence speed and the ease of falling into the local optimum, the chaotic mapping strategy, adaptive weighting strategy and t-distribution mutation strategy are introduced to develop a novel adaptive sparrow search algorithm, namely the CWTSSA in this paper. In the proposed CWTSSA, the chaotic mapping strategy is employed to initialize the population in order to enhance the population diversity. The adaptive weighting strategy is applied to balance the capabilities of local mining and global exploration, and improve the convergence speed. An adaptive t-distribution mutation operator is designed, which uses the iteration number t as the degree of freedom parameter of the t-distribution to improve the characteristic of global exploration and local exploration abilities, so as to avoid falling into the local optimum. In order to prove the effectiveness of the CWTSSA, 15 standard test functions and other improved SSAs, differential evolution (DE), particle swarm optimization (PSO), gray wolf optimization (GWO) are selected here. The compared experiment results indicate that the proposed CWTSSA can obtain higher convergence accuracy, faster convergence speed, better diversity and exploration abilities. It provides a new optimization algorithm for solving complex optimization problems.
Fat Graft in Surgical Treatment of Medication-Related Osteonecrosis of the Jaws (MRONJ)
Authors: De Cicco Davide , Tartaro Gianpaolo , Colella Giuseppe , Dell’Aversana Orabona Giovanni , Santagata Mario , Ferrieri Ivo , Troiano Antonio , Staglianò Samuel , Volgare Andrea Salvatore , D’Amato Salvatore
Published: November 2021

Background: Although the published literature has grown exponentially during the last few decades, managing medication-related osteonecrosis of the jaws (MRONJ) remains challenging. Since the first description of adipose-derived stem cells, cell therapy showed promising perspectives in surgical treatment of MRONJ. In this study, the beneficial effect of fat graft in surgical treatment of stage 2 and 3 MRONJ patients was assessed. Methods: A retrospective analysis of the evolution pattern of the disease was conducted comparing the outcomes of MRONJ patients who underwent sequestrectomy followed by fat graft (n = 9) and those who received sequestrectomy alone (n = 12). Results: Improvement of the disease stage was observed in 77.8% vs. 22.2% cases in group A and B, respectively (p = 0.030); disease stability was documented in 11.1% vs. 25.0% cases in group A and B, respectively (p = 0.603); worsening of MRONJ stage was observed in 11.1% vs. 50.0% cases in group A and B, respectively (p = 0.159). Conclusions: Despite the small sample size, this study suggests that fat graft may represent a promising low-risk and cost-efficient adjunctive therapy in the surgical treatment of MRONJ patients.
Analysis of Heat and Mass Transfer Features of Hybrid Casson Nanofluid Flow with the Magnetic Dipole Past a Stretched Cylinder
Authors: Ahmad Shafiq , Naveed Khan Muhammad , Rehman Aysha , Felemban Bassem F. , Alqurashi Maram S. , Alharbi Fahad M. , Alotaibi Fakhirah , Galal Ahmed M.
Published: November 2021

The main purpose of this research is to scrutinize the heat and mass transfer in the Casson hybrid nanofluid flow over an extending cylinder in the presence of a magnetic dipole and double stratification. The nanofluid contained chemically reactive hybrid nanoparticles (Ag, MgO) in the conventional fluids (water). The effects of viscous dissipation, radiation, and concentration stratification were taken into consideration. In the presence of gyrotactic microorganisms and the Non-Ficks Model, the flow was induced. Incorporating microorganisms into a hybrid nanofluid flow is thought to help stabilize the dispersed nanoparticles. For viscosity and thermal conductivity, experimental relations with related dependence on nanoparticle concentration were used. To acquire the nonlinear model from the boundary layer set of equations, suitable similarity transformations were employed. The built-in function bvp4c of Matlab software was utilized to solve the transformed equation numerically. The graphical results were obtained for temperature, velocity, concentration, and microorganism distribution for various parameters. The numerical amounts of drag friction, heat transport rate, and motile density number for different parameters are presented through tables. It is seen that the fluid velocity is augmented by the increase of the curvature parameter, while a decrease occurs in the fluid velocity with an increase in the magnetic and slips parameters. The comparison of the present study with previously available studies is discussed, which shows a good agreement with published results.
Evaluation of Sambucus nigra L. Biopotential as an Unused Natural Resource
Authors: Radojković Marija , Vujanović Milena , Majkić Tatjana , Zengin Gokhan , Beara Ivana , Catauro Michelina , Montesano Domenico
Published: November 2021

An unbreakable relationship between plants, nutrition, and health has directed researchers to deeply investigate and characterize the biopotential and medicinal properties of traditional foods. The aim of this study is to analyze and compare the phytochemical composition and biological potential of plant extracts with the idea of defining the most potent extracts as a natural source of bioactive molecules and their application in different industries. We evaluated unused plant species Sambucus nigra L. for investigation of bioactivities as potential natural products. Extracts of fresh elderberry fruits were obtained by modern (microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE)) and traditional (maceration (MAC)) extraction techniques, using 50% ethanol (50% EtOH) and water (H2O) of different polarities. In analyzed extracts, rutin and chlorogenic acid were dominant compounds in both 50% EtOH and H2O extracts, while ursolic acid was identified in 50% EtOH extracts as a terpenic compound with notable concentration. Elderberry extracts were evaluated regarding antioxidant, neuroprotective, antityrosinase, and antidiabetic abilities: MAE extracts had the best overall activity, and in general, 50% EtOH extracts were more potent than water extracts. The correlation of the dominant compound—rutin with all biological activities, indicates the importance of its presence in elderberries. S. nigra fruits showed excellent biopotential and opened possibilities of creating new food products or remedies, which are not present on the market because elderberry extracts are an exceptional source of rutin, chlorogenic acid, and ursolic acid.
Vibration Responses of a Coaxial Dual-Rotor System with Supporting Misalignment
Authors: Zhang Hongxian , Li Xuejun , Yang Dalian , Jiang Lingli
Published: November 2021

In order to improve the thrust-weight ratio, modern aeroengines generally adopt a coaxial dual-rotor system. Factors such as manufacturing errors, assembly errors, bearing wear, and structural deformation can cause misalignment failures in a dual-rotor system. Supporting misalignment is one of the common types of misalignments in a dual-rotor system. To analyze the vibration characteristics of misalignment faults, in this study, we aim to build a finite element model of a dual-rotor system with supporting misalignment. The bearing loads caused by supporting misalignment are calculated using the three-bending moment equation method. Bearing loads are introduced into the dynamic model of the dual-rotor system. The influence of supporting misalignment at different bearings on the dynamic characteristics of the rotor system is investigated based on the supporting misalignment model. Studies have shown that supporting misalignment at different bearings has similar effects on the dynamic characteristics of the dual-rotor system. The proposed supporting misalignment model is more adaptable than the coupling misalignment model. It indicates that the damping of a rolling bearing should be considered in the dynamic analysis of a dual-rotor system although the value of the damping is not large. An experimental analysis is carried out. The simulation results are in good agreement with the experimental results.
A Study of the Effects of Geosynthetic Reinforced Soil and Reinforcement Length on GRS Bridge Abutment
Authors: Won Myoung-Soo , Langcuyan Christine Patinga
Published: November 2021

The geosynthetic reinforced soil (GRS) bridge abutment with a staged-construction full height rigid (FHR) facing and an integral bridge (IB) system was developed in Japan in the 2000s. This technology offers several advantages, especially concerning the deformation behavior of the GRS-IB abutment. In this study, the effects of GRS in the bridge abutment with FHR facing and the effects of geosynthetics reinforcement length on the deformation behavior of the GRS–IB are presented. The numerical models are analyzed using the finite element method (FEM) in Plaxis 2D program. The results showed that the GRS–IB model exhibited the least lateral displacements at the wall facing compared to those of the IB model without geosynthetics reinforcement. The geosynthetics reinforcement in the bridge abutment with FHR facing has reduced the vertical displacement increments by 4.7 times and 1.3 times (maximum) after the applied general traffic loads and railway loads, respectively. In addition, the numerical results showed that the increase in the length-to-height (L/H) ratio of reinforcement from 0.3H to 1.1H decreases the maximum lateral displacements by 29% and the maximum vertical displacements by 3% at the wall facing by the end of construction. The effect of the reinforcement length on the wall vertical displacements is minimal compared to the effect on the wall lateral displacements.
The Analysis of the Applications of Crop Seed Tape Sowing Technology and Equipment: A Review
Authors: Zhang Baofeng , Liu Dan , Xi Xiaobo , Zhang Yifu , Chen Chao , Qu Jiwei , Dong Hao , Zhang Ruihong
Published: November 2021

Seed tape sowing technology is a kind of crop cultivation technology based on a carrier. This technology first wraps crop seeds in a kind of carrier materials and makes them into seed tape. The seed tape is then laid down in farmland with special equipment. Seed tape planting has the advantages of accurate control of hill spacing, simplification of field sowing process and helps to implement order agriculture. Seed tape manufacturing and laying equipment are the core equipment of the technology and their working reliability directly affects the advantages of seed tape planting technology. Based on the research status of seed tape planting technology and equipment, this article made comparisons between the key technologies which include the method for seed tape manufacturing, seed tape sowing, furrowing, seed tape guiding technology, etc. In this paper, the basic problems of seed tape technology that still need further study are put forward. The future development of tape sowing technology and equipment are predicted as follows: the intelligent high precision and high-speed seed tape manufacturing equipment, the large intelligent integrated seed tape planter of “land preparation-seeding tape making-sowing”, the small and medium-sized mobile walk-behind planters, the application on the agricultural landscape and the crop transplanting. This study will be helpful to promote the further development of seed tape planting technology and provide a reference for the research of tape planting technology and equipment.
Synthesis of Zeolitic Material with High Cation Exchange Capacity from Paper Sludge Ash Using EDTA
Authors: Wajima Takaaki
Published: November 2021

Paper sludge ash (PSA) typically has a low Si abundance and significant Ca content because of the presence of calcite fillers, which interfere with the zeolitic conversion of PSA. Ca-masking with ethylenediaminetetraacetic acid (EDTA) was used to reduce Ca interference during zeolite synthesis so that a zeolitic product with a high cation exchange capacity (CEC) could be synthesized. Hydroxysodalite, zeolite-P, hydroxycancrinite, tobermorite, and zeolite-A can be synthesized from PSA by an alkali reaction with EDTA. With the addition of EDTA, calcium ions in the solution were trapped by chelation, and the number of zeolitic crystals with low Si/Al (Si/Al = 1), zeolite-A, increased owing to the promotion of the synthesis reaction. A product with a high CEC that has a high zeolite-A content was obtained. The chelating agent can inhibit Ca interference for zeolite synthesis by Ca-masking, and a product with a high zeolite-A content can be obtained from PSA using EDTA.
A Numerical Study of the Wind Speed Effect on the Flow and Acoustic Characteristics of the Minor Cavity Structures in a Two-Wheel Landing Gear
Authors: Huang Longlong , Zhao Kun , Liang Junbiao , Kopiev Victor , Belyaev Ivan , Zhang Tian
Published: November 2021

The landing gear is widely concerned as the main noise source of airframe noise. The flow characteristics and aerodynamic noise characteristics of the landing gear were numerically simulated based on Large Eddy Simulation and Linearized Euler Equation, and the feasibility of the simulation model was verified by experiments. Then the wind speed effect on the flow and acoustic characteristics of the minor cavity structures in a two-wheel landing gear were analyzed. The results show that the interaction of vortices increases with the increase of velocity at the brake disc, resulting in a slight increase in the amplitude of pressure fluctuation at 55 m·s−1~75 m·s−1. With the increase of speed, the obstruction at the lower hole of torque link decreases, and many vortical structures flow out of the lower hole and are dissipated, so that the pressure fluctuation amplitude of 75 m·s−1 almost does not increase relative to 55 m·s−1. The contribution of each part in the landing gear to the overall noise is as follows: shock strut > tire > torque link > brake disc. At the speed of 34 m·s−1~55 m·s−1, the contribution of each component to the total noise increases with the increase of speed, and the small components such as torque link and brake disc contribute more to the total noise. At the speed of 55 m·s−1~75 m·s−1, the increase of overall noise mainly comes from the main components such as shock strut and tire, and the brake disc and torque link contribute very little to the overall noise. It provides a reference for the further noise reduction optimization design of the landing gear.
A Hard Example Mining Approach for Concealed Multi-Object Detection of Active Terahertz Image
Authors: Li Ling , Xue Fei , Liang Dong , Chen Xiaofei
Published: November 2021

Concealed objects detection in terahertz imaging is an urgent need for public security and counter-terrorism. So far, there is no public terahertz imaging dataset for the evaluation of objects detection algorithms. This paper provides a public dataset for evaluating multi-object detection algorithms in active terahertz imaging. Due to high sample similarity and poor imaging quality, object detection on this dataset is much more difficult than on those commonly used public object detection datasets in the computer vision field. Since the traditional hard example mining approach is designed based on the two-stage detector and cannot be directly applied to the one-stage detector, this paper designs an image-based Hard Example Mining (HEM) scheme based on RetinaNet. Several state-of-the-art detectors, including YOLOv3, YOLOv4, FRCN-OHEM, and RetinaNet, are evaluated on this dataset. Experimental results show that the RetinaNet achieves the best mAP and HEM further enhances the performance of the model. The parameters affecting the detection metrics of individual images are summarized and analyzed in the experiments.
Psychoacoustic Principle, Methods, and Problems with Perceived Distance Control in Spatial Audio
Authors: Xie Bosun , Yu Guangzheng
Published: November 2021

One purpose of spatial audio is to create perceived virtual sources at various spatial positions in terms of direction and distance with respect to the listener. The psychoacoustic principle of spatial auditory perception is essential for creating perceived virtual sources. Currently, the technical means for recreating virtual sources in different directions of various spatial audio techniques are relatively mature. However, perceived distance control in spatial audio remains a challenging task. This article reviews the psychoacoustic principle, methods, and problems with perceived distance control and compares them with the principles and methods of directional localization control in spatial audio, showing that the validation of various methods for perceived distance control depends on the principle and method used for spatial audio. To improve perceived distance control, further research on the detailed psychoacoustic mechanisms of auditory distance perception is required.
Seismic Analysis Method for Underground Structure in Loess Area Based on the Modified Displacement-Based Method
Authors: Zhang Ruijie , Ye Dan , Zhou Jianting , Quan Dengzhou
Published: November 2021

At present, the seismic design research of underground structures in loess areas is lagging behind compared with practical engineering requirements. The selection of seismic calculation methods and parameters does not consider the influences of the special geological conditions in various regions, so their usefulness is limited. Based on the above problems, a modified displacement-based method (DBM) was proposed and its application was compared with the most commonly used methods of analysis (force-based design method, displacement-based design method, detailed equivalent static analysis numerical method, and the full dynamic time-history method). The results were also validated by considering data from shaking table tests conducted on a case study involving the underground Feitian Road subway station in Xi’an. The results show that compared with DBM, the average accuracy of the modified DBM technique is improved by 41.65%. The modified DBM offers good accuracy, simplicity in its model, a rapid analysis time, and easy convergence.
Seismic Risk Assessment of Chania, Greece, Using an Integrated Computational Approach
Authors: Koutsoupakis Ioannis , Tsompanakis Yiannis , Soupios Pantelis , Kirmizakis Panagiotis , Kaka SanLinn , Providakis Costas
Published: November 2021

This study develops a comprehensive seismic risk model for the city of Chania, in Greece, which is located ina highly seismic-prone region due to the occurrenceof moderate to large earthquakes because of the nearby major subduction zone between African and Eurasian tectonic plates. The main aim is to reduce the seismic risk for the study area by incorporating the spatial distribution of the near-surface shear wave velocity model and the soil classification, along with all possible seismic sources, taking into account historical events. The study incorporates and correlates various ground motion scenarios and geological fault zones as well as information on existing buildings to develop a seismic risk model using QuakeIST software, and then the seismic hazard and a realistic prediction of resulting future adverse effects are assessed. The developed model can assist the municipal authorities of Chania to be prepared for potential seismic events, as well as city planners and decisionmakers, who can use the model as an effective decision-making tool to identify the seismic vulnerability of the city buildings and infrastructure. Thus, this study enables the implementation of an appropriate and viable earthquake-related hazards strategy to mitigate damage and losses in future earthquakes.
Deleterious Effect of Participant Positioning on the Acceptability and Acceptance of a Wellness Management System under Development
Authors: Lemoine Fabien , Nadarajah Kévin , Carrault Guy , Guguen-Allain Anaïs , Somat Alain
Published: November 2021

Managing everyday wellness using sensors requires user buy-in and acceptance. The Unified Theory of Acceptance and Use of Technology (UTAUT) was used to measure at D-0 the acceptability (a priori), and at D-21 the acceptance of an ambulatory monitoring system under development, the SHERPAM system. Interviews with the participants revealed that they no longer viewed the system in the same way at the different stages of the study. The results of the qualitative analysis suggest that the time of the research led the participants to stop seeing themselves as potential future users and to take on the role of critical testers of the technology (which corresponds more to a user test). This role change led participants to question the usefulness of the technology, which affected their intention to use the technology in the future (5.30 vs. 4.24; t = 2.58 *). This research identified the reasons why it was crucial to have a fully functional device in the second phase (acceptance study). The results of this study suggest that it is inappropriate to undertake an acceptability study when the technology is under development. While the SHERPAM platform has been the subject of several user tests, none have been carried out in a situation of use. Thus, this study seems to suggest that the dysfunctions observed are more related to the absence of a development phase in the daily activity of the users. Thus, to ensure a good appropriation of the technology and to predict its use, the technology must not only be in perfect working order, but must also have been developed according to the daily activities of the individuals.
Ensemble Voting-Based Multichannel EEG Classification in a Subject-Independent P300 Speller
Authors: Mussabayeva Ayana , Jamwal Prashant Kumar , Akhtar Muhammad Tahir
Published: November 2021

Classification of brain signal features is a crucial process for any brain–computer interface (BCI) device, including speller systems. The positive P300 component of visual event-related potentials (ERPs) used in BCI spellers has individual variations of amplitude and latency that further changse with brain abnormalities such as amyotrophic lateral sclerosis (ALS). This leads to the necessity for the users to train the speller themselves, which is a very time-consuming procedure. To achieve subject-independence in a P300 speller, ensemble classifiers are proposed based on classical machine learning models, such as the support vector machine (SVM), linear discriminant analysis (LDA), k-nearest neighbors (kNN), and the convolutional neural network (CNN). The proposed voters were trained on healthy subjects’ data using a generic training approach. Different combinations of electroencephalography (EEG) channels were used for the experiments presented, resulting in single-channel, four-channel, and eight-channel classification. ALS patients’ data represented robust results, achieving more than 90% accuracy when using an ensemble of LDA, kNN, and SVM on four active EEG channels data in the occipital area of the brain. The results provided by the proposed ensemble voting models were on average about 5% more accurate than the results provided by the standalone classifiers. The proposed ensemble models could also outperform boosting algorithms in terms of computational complexity or accuracy. The proposed methodology shows the ability to be subject-independent, which means that the system trained on healthy subjects can be efficiently used for ALS patients. Applying this methodology for online speller systems removes the necessity to retrain the P300 speller.
A Study on Anti-Shock Performance of Marine Diesel Engine Based on Multi-Body Dynamics and Elastohydrodynamic Lubrication
Authors: Chen Liang , Xue Dongxin , Song Xigeng , He Zhaoqi , Huang Dongjie
Published: November 2021

Diesel engine anti-shock performance is important for navy ships. The calculation method is a fast and economic way compared to underwater explosion trial in this field. Researchers of diesel engine anti-shock performance mainly use the spring damping model to simulate the main bearings of a diesel engine. The elastohydrodynamic lubrication method has been continuously used in the main bearings of diesel engines in normal working conditions. This research aims at using the elastohydrodynamic lubrication method in the main bearings of the diesel engine in external shock conditions. The main bearing elastohydrodynamic lubrication and diesel engine multi-body dynamics analysis is based on AVL EXCITE Power Unite software. The external shock is equivalent to the interference on the elastohydrodynamic lubrication calculation. Whether the elastohydrodynamic lubrication algorithm can complete the calculation under interference is the key to the study. By adopting a very small calculation step size, a high number of iterations, and increasing the stiffness of the thrust bearing, the elastohydrodynamic lubrication algorithm can be successfully completed under the external impact environment. The calculation results of the accelerations on engine block feet have a similar trend as the experiment results. Diesel engines with and without shock absorbers in external shock conditions are calculated. This calculation model can also be used for diesel engine dynamics calculations and main bearing lubrication calculations under normal working conditions.
An Integrated Cybernetic Awareness Strategy to Assess Cybersecurity Attitudes and Behaviours in School Context
Authors: Antunes Mário , Silva Carina , Marques Frederico
Published: November 2021

Digital exposure to the Internet among the younger generations, notwithstanding their digital abilities, has increased and raised the alarm regarding the need to intensify the education on cybersecurity in schools. Understanding of the human factor and its influence on children, namely their attitudes and behaviors online, is pivotal to reinforce their awareness towards cyberattacks, and to promote their digital citizenship. This paper aims to present an integrated cybersecurity and cyberawareness strategy composed of three major steps: (1) Cybersecurity attitude and behavior assessment, (2) self-diagnosis, and (3) teaching/learning activities. The following contributions are made: Two questionnaires to assess risky attitudes and behaviors regarding cybersecurity; a self-diagnosis to measure students’ skills on cybersecurity; a lesson plan addressing cyberawareness to be applied on Information and Communications Technology (ICT) and citizenship education curricular units. Cybersecurity risky attitudes and behaviors were evaluated in a junior high school population of 164 students attending the sixth and ninth grades. The assessment focused on two main subjects: To identify the attitudes and behaviors that raise the risk on cybersecurity among the participating students; to characterize the acquired students’ cybersecurity and cyberawareness skills. Global and individual scores and the histograms for attitudes and behaviors are presented. The items in which we have observed significant differences between sixth and ninth grades are depicted and quantified by their corresponding p-values obtained through the Mann–Whitney non-parametric test. Regarding the results obtained on the assessment of attitudes and behaviors, although positive, we observed that the attitudes and behaviors in ninth grade students are globally inferior compared to those attained by sixth grade students. The deployed strategy for cyberawareness was applied in a school context; however, the same approach is suitable to be applied in other types of organizations, namely enterprises, healthcare institutions and public sector.
Effect of Aggregate Size on Recycled Aggregate Concrete under Equivalent Mortar Volume Mix Design
Authors: Jang Haneol , Kim Jeonghyun , Sicakova Alena
Published: November 2021

In this paper, the effect of the original aggregate size of the recycled aggregate on the mechanical properties of the recycled aggregate concrete was evaluated. A series of concretes were produced in which natural aggregates, recycled aggregates, and original aggregates in recycled aggregates were matched for a single particle size distribution curve. The replacement levels of recycled aggregate were 25% and 50%, and equivalent mortar volume mix design was applied for recycled aggregate concrete. The results show that the mechanical strength of recycled aggregate concrete increases with increasing original aggregate size. This effect was observed to be greater in concrete using recycled aggregate with a high residual mortar content.
Mixed Reality-Enhanced Intuitive Teleoperation with Hybrid Virtual Fixtures for Intelligent Robotic Welding
Authors: Su Yun-Peng , Chen Xiao-Qi , Zhou Tony , Pretty Christopher , Chase Geoffrey
Published: November 2021

This paper presents an integrated scheme based on a mixed reality (MR) and haptic feedback approach for intuitive and immersive teleoperation of robotic welding systems. By incorporating MR technology, the user is fully immersed in a virtual operating space augmented by real-time visual feedback from the robot working space. The proposed robotic tele-welding system features imitative motion mapping from the user’s hand movements to the welding robot motions, and it enables the spatial velocity-based control of the robot tool center point (TCP). The proposed mixed reality virtual fixture (MRVF) integration approach implements hybrid haptic constraints to guide the operator’s hand movements following the conical guidance to effectively align the welding torch for welding and constrain the welding operation within a collision-free area. Onsite welding and tele-welding experiments identify the operational differences between professional and unskilled welders and demonstrate the effectiveness of the proposed MRVF tele-welding framework for novice welders. The MRVF-integrated visual/haptic tele-welding scheme reduced the torch alignment times by 56% and 60% compared to the MRnoVF and baseline cases, with minimized cognitive workload and optimal usability. The MRVF scheme effectively stabilized welders’ hand movements and eliminated undesirable collisions while generating smooth welds.
A High-Resolution (20 m) Simulation of Nighttime Low Temperature Inducing Agricultural Crop Damage with the WRF–LES Modeling System
Authors: Noh Ilseok , Lee Seung-Jae , Lee Seoyeon , Kim Sun-Jae , Yang Sung-Don
Published: November 2021

In Korea, sudden cold weather in spring occurs repeatedly every year and causes severe damage to field crops and fruit trees. Detailed forecasting of the daily minimum or suddenly decreasing temperature, closely related to the local topography, has been required in the farmer community. High-resolution temperature models based on empirical formulas or statistical downscaling have fundamental limitations, making it difficult to perform biophysical application and mechanism explanation on small-scale complex terrains. Weather Research and Forecasting–Large Eddy Simulation (WRF–LES) can provide a dynamically and physically scientific tool to be easily applied for farm-scale numerical weather predictions. However, it has been applied mainly for urban areas and in convective boundary layer studies until now. In this study, 20 m resolution WRF–LES simulation of nighttime near-surface temperature and wind was performed for two cold spring weather events that induced significant crop damages in the apple production area and the results were verified with automatic weather station observation data. The study showed that the maximum mean bias of temperature was −1.75 °C and the minimum was −0.68 °C in the spring, while the root mean square error varied between 2.13 and 3.00 °C. The minimum temperature and its duration significantly affected the crop damage, and the WRF–LES could accurately simulate both features. This implies that the application of WRF–LES, with proper nest-domain configuration and harmonized physical options, to the prediction of nighttime frost in rural areas has promising feasibility for orchard- or farm-scale frost prevention and low-temperature management.
Statistical Modeling to Predict Climate Change Effects on Watershed Scale Evapotranspiration
Authors: Khanal Rajendra , Dhungel Sulochan , Brewer Simon C. , Barber Michael E.
Published: November 2021

Estimation of satellite-based remotely sensed evapotranspiration (ET) as consumptive use has been an integral part of agricultural water management. However, less attention has been given to future predictions of ET at watershed-scales especially since with a changing climate, there are additional challenges to planning and management of water resources. In this paper, we used nine years of total seasonal ET derived using a satellite-based remote sensing model, Mapping Evapotranspiration at Internalized Calibration (METRIC), to develop a Random Forest machine learning model to predict watershed-scale ET into the future. This statistical model used topographic and climate variables in agricultural areas of Lower Yakima, Washington and had a prediction accuracy of 88% for the region. This model was then used to predict ET into the future with changed climatic conditions under RCP4.5 and RCP8.5 emission scenarios expected by 2050s. The model result shows increases in seasonal ET across some areas of the watershed while decreases in other areas. On average, growing seasonal ET across the watershed was estimated to increase by +5.69% under the low emission scenario (RCP4.5) and +6.95% under the high emission scenario (RCP8.5).