bluuebunny/crossref_metadata_2025 huggingface dataset:
Trajectory and causes of decline in the botanical composition of dairy-grazed pasture in the Waikato
Authors: Lee J.M. , Thom E.R. , Waugh C.D. , Bell N.L. , Mcneill M.R. , Wilson D.J. , Chapman D.F.
Published: June 2020

Abstract Herbage accumulation, botanical composition, tiller density and insect pest populations were monitored over 6 years for four perennial ryegrass functional types grazed by dairy cows in the Waikato. The aim was to identify genotypic and environmental factors contributing to ryegrass persistence failure in the upper North Island. Perennial ryegrass content of pastures declined as low as 60% of total herbage mass (HM) in summer of the first 3 years but recovered in autumn to at least 75%. However, following two successive severe summer/autumn droughts in Years 2 and 3, and subsequent grass grub larvae populations exceeding the damage threshold of 200/m2, by 4 years after sowing (autumn 2015), ryegrass had fallen to 20% of HM. This pattern was repeated in the following 2 years, and was not prevented by any combination of ryegrass functional type, endophyte, seeding rate, or best-practice dairy cattle grazing and soil nutrient management. The abiotic and biotic environmental stresses dominated all other factors. Keywords: pasture persistence, perennial ryegrass, drought, insects, black beetle, dairy systems
Modelling options to increase milk production while reducing N leaching for an irrigated dairy farm in Canterbury
Authors: Beukes P.C. , Edwards P. , Coltman T.
Published: June 2020

Abstract The Forages for Reduced Nitrate Leaching programme (FRNL) aims to address the challenge of presenting farmers with alternatives for forage production that will sustain milk production and farm profit, but simultaneously reduce nitrogen leaching by 20% from current levels. This paper describes the improvements made to a dairy model comprising three software packages, and how this model was used to evaluate proposed farm system changes on a Canterbury dairy farm (Canlac Holdings) associated with the FRNL programme. After a baseline scenario was sensechecked against actual farm physical and financial data for the 2014-2015 season, alternative options were modelled in an additive way by expanding the effluent area, growing fodder beet on the platform, replacing some pasture with maize silage, growing diverse pastures on 7% of the milking platform, and including a feed pad. The cumulative effect of these changes was an increase of 3 and 13% in production and profit respectively, but only a 5% decrease in nitrogen leaching as estimated for the combined platform and support block areas over 3 climate years. A hypothetical scenario, of a third of the platform in diverse pastures, less nitrogen fertiliser, all fodder beet grown on the milking platform, lifted and fed on the feed pad, and with an oats catch crop following fodder beet, increased production and profit by 2 and 10%, respectively, with a reduction in N leaching of 19%. This result indicates that high-performing farmers have scope to reduce N leaching by ~20% and still increase profit by implementing some of the options emanating from the FRNL programme. Keywords: diverse pastures, dairy farm system, fodder beet, effluent block, feed pad, catch crop
Winter rotation length effect on pasture production and animal performance
Authors: Matthew C. , Osborne M.A. , Liu Y. , Duan X. , Hou F.
Published: June 2020

Abstract Data comparing pasture production in winter pastures subject to 16, 48 or 72-day rotation lengths were recovered from experiments at Massey University to support teaching of grazing management. 'Farmlets' with 16 breeding ewes on 0.8 ha were run from 2011- 2016, and herbage production estimated from metabolic energy budgeting (MEB). The data illustrate: the roles of pasture cover and animal body weight as buffers to neutralise the impact of weather variability, the use of controlled cover release via the grazing rotation to partially meet winter feed deficit, and the potential value of MEB in systems research. Grass grown from May to September (early pregnancy to mid-lactation) was 3850, 4220 and 4840 kg DM/ha for 16, 48 and 72- day rotations, respectively. As a result of a reduction in herbage accumulation and the premature release of autumn-saved pasture to animals, the 16-day rotation failed to overwinter the animals in five of the 6 years, the exception being a winter with high pasture growth. Keywords: winter rotation length, pasture growth rate, teaching pedagogy
An Alternative Perfusion Approach for the Intensification of Virus-Like Particle Production in HEK293 Cultures
Authors: Lavado-García Jesús , Cervera Laura , Gòdia Francesc
Published: June 2020

Virus-like particles (VLPs) have gained interest over the last years as recombinant vaccine formats, as they generate a strong immune response and present storage and distribution advantages compared to conventional vaccines. Therefore, VLPs are being regarded as potential vaccine candidates for several diseases. One requirement for their further clinical testing is the development of scalable processes and production platforms for cell-based viral particles. In this work, the extended gene expression (EGE) method, which consists in consecutive media replacements combined with cell retransfections, was successfully optimized and transferred to a bioreactor operating in perfusion. A process optimization using design of experiments (DoE) was carried out to obtain optimal values for the time of retransfection, the cell specific perfusion rate (CSPR) and transfected DNA concentration, improving 86.7% the previously reported EGE protocol in HEK293. Moreover, it was successfully implemented at 1.5L bioreactor using an ATF as cell retention system achieving concentrations of 6.8·1010 VLP/mL. VLP interaction with the ATF hollow fibers was studied via confocal microscopy, field emission scanning electron microscopy, and nanoparticle tracking analysis to design a bioprocess capable of separating unassembled Gag monomers and concentrate VLPs in one step.
Prediction and Characterization of Cationic Arginine-Rich Plant Antimicrobial Peptide SM-985 From Teosinte (Zea mays ssp. mexicana)
Authors: Qutb Abdelrahman M. , Wei Feng , Dong Wubei
Published: June 2020

Antimicrobial peptides (AMPs) are effective against different plant pathogens and newly considered as part of plant defense systems. From prokaryotes to eukaryotes, AMPs can exist in all forms of life. SM-985 is a cationic AMP (CAMP) isolated from the cDNA library of Mexican teosinte (Zea mays ssp. mexicana). A computational prediction server running with different algorithms was used to screen the teosinte cDNA library for AMPs, and the SM-985 peptide was predicted as an AMP with high probability prediction values. SM-985 is an arginine-rich peptide and composed of 21 amino acids (MW: 2671.06 Da). The physicochemical properties of SM-985 are very promising as an AMP, including the net charge (+8), hydrophobicity ratio of 23%, Boman index of 5.19 kcal/mol, and isoelectric point of 12.95. The SM-985 peptide has amphipathic α-helix conformations. The antimicrobial activity of SM-985 was confirmed against six bacterial plant pathogens, and the MIC of SM-985 against Gram-positive indicators was 8 μM, while the MIC of SM-985 against Gram-negative indicators was 4 μM. The SM-985 interacting with the bacterial membrane and this interaction were examined by treatment of the bacterial indicators with FITC-SM-985 peptide, which showed a high binding affinity of SM-985 to the bacterial membrane (whether Gram-positive or Gram-negative). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of the treated bacteria with SM-985 demonstrated cell membrane damage and cell lysis. In vivo antimicrobial activity was examined, and SM-985 prevented leaf spot disease infection caused by Pst DC3000 on Solanum lycopersicum. Moreover, SM-985 showed sensitivity to calcium chloride salt, which is a common feature of CAMPs.
Laying Hens Biochar Diet Supplementation—Effect on Performance, Excreta N Content, NH3 and VOCs Emissions, Egg Traits and Egg Consumers Acceptance
Authors: Kalus Kajetan , Konkol Damian , Korczyński Mariusz , Koziel Jacek A. , Opaliński Sebastian
Published: June 2020

Sustainable solutions for intensive poultry production can help farmers, rural communities, consumers, and regulatory agencies. This study assessed supplementation of laying hens diet with beechwood biochar (BC, 1~2%) and BC–aluminosilicates–glycerin mixture (BCM, 1.5~3%) to lower the environmental impact while maintaining egg quality. The effect on feed intake, laying performance, egg quality, the sensory quality of hardboiled eggs, ammonia (NH3) and volatile organic compound (VOC) emissions from excreta, and the excreta composition, were evaluated. A total of 90 hens were distributed into 30 cages and divided into five groups (n=6 replications). BC addition increased daily feed intake, while 1.5% BCM addition reduced it. The influence on egg parameters was positive, with a 6% increase in laying performance, up to 10% and 6% increase in shell resistance to crushing and shell thickness, respectively. The sensory analysis demonstrated no significant differences between all treatments. Excreta total N content was numerically lower due to the treatments (by 4~20%); its pH increased (not significantly), while no effect on ammoniacal N and dry matter content was observed. Most of the investigated treatments had a numerically positive (not statistically significant) effect on NH3 reduction. The reduction of VOC emissions was ambiguous and not statistically significant.
Pathogenic and Non-Pathogenic Fungal Communities in Wheat Grain as Influenced by Recycled Phosphorus Fertilizers: A Case Study
Authors: Jastrzębska Magdalena , Wachowska Urszula , Kostrzewska Marta K.
Published: June 2020

Waste-based fertilizers provide an alternative to fertilizers made from non-renewable phosphate rock. Fungal communities colonizing the grain of spring wheat fertilized with preparation from sewage sludge ash and dried animal blood (Rec) and the same fertilizer activated by Bacillus megaterium (Bio) were evaluated against those resulting from superphosphate (SP) and no phosphorus (control, C0) treatments. The Illumina MiSeq sequencing system helped to group fungal communities into three clades. Clade 1 (communities from C0, Bio 60 and 80, Rec 80 and SP 40 kg P2O5 ha−1 treatments) was characterized by a high prevalence of Alternaria infectoria, Monographella nivalis and Gibberella tricincta pathogens. Clade 2 (Bio 40 kg, Rec 40 and 60 kg, and SP 60 kg P2O5 ha−1) was characterized by the lowest amount of the identified pathogens. Commercial SP applied at 80 kg P2O5 ha−1 (clade 3) induced the most pronounced changes in the fungal taxa colonizing wheat grain relative to non-fertilized plants. The above was attributed mainly to the lower amount of A. infectoria and higher counts of species of the family Nectriaceae, mostly epiphytic pathogens Fusarium culmorum and Fusarium poae.
Crop Water Production Functions for Winter Wheat with Drip Fertigation in the North China Plain
Authors: Shen Xiaojun , Wang Guangshuai , Tilahun Zeleke Ketema , Si Zhuanyun , Chen Jinsai , Gao Yang
Published: June 2020

During four consecutive growing seasons (2014–2018), field experiments were conducted in the North China to determine winter wheat production function. The field experiments were carried out using winter wheat subjected to four N levels (N120, N180, N240, and N300) and three irrigation levels (If, I0.8f, and I0.6f). The main aims were to characterize winter wheat productivity, drought response factor Ky, and the winter wheat grain yield production functions in relation to water supply under the different N fertilizer levels. The amount of water supply (rain + irrigation) were 326–434, 333–441, 384–492, and 332–440 mm in 2014–2015, 2015–2016, 2016–2017, and 2017–2018 growing seasons, respectively. Similarly, the values of ETa (including the contribution from soil water storage) were 413–466, 384–468, 401–466, and 417–467 mm in 2014–2015, 2015–2016, 2016–2017, and 2017–2018, respectively. ETa increased as the amount of irrigation increased. The average values of If, I0.8f, and I0.6f over the four growing seasons were 459–465, 432–446, and 404–413 mm, respectively. For the same amount of irrigation, there was only small difference in ETa among different nitrogen levels; for the three irrigation levels, the values of ETa in N120, N180, N240, and N300 ranged from 384 to 466, 384 to 466, 385 to 467, and 407 to 468 mm, respectively. Water productivity values ranged from 1.69 to 2.50 kg m−3 for (rain + irrigation) and 1.45 to 2.05 kg·m−3 for ETa. The Ky linearly decreased with the increase in nitrogen amount, and the values of r were greater than 0.92. The values of Ky for winter wheat in N120, N180, N240, and N300 were 1.54, 1.41, 1.28, and 1.25, respectively. The mean value of Ky for winter wheat over the three irrigation levels and the four nitrogen levels was 1.37 (r = 0.95). In summary, to gain higher grain yield and WUE, optimal combination of N fertilizer of 180–240 kg·ha−1 and irrigation quota of 36–45 mm per irrigation should be applied for winter wheat with drip fertigation in the North China Plain.
Affordable Phenotyping of Winter Wheat under Field and Controlled Conditions for Drought Tolerance
Authors: Kumar Dhananjay , Kushwaha Sandeep , Delvento Chiara , Liatukas Žilvinas , Vivekanand Vivekanand , Svensson Jan T. , Henriksson Tina , Brazauskas Gintaras , Chawade Aakash
Published: June 2020

Drought stress is one of the key plant stresses reducing grain yield in cereal crops worldwide. Although it is not a breeding target in Northern Europe, the changing climate and the drought of 2018 have increased its significance in the region. A key challenge, therefore, is to identify novel germplasm with higher drought tolerance, a task that will require continuous characterization of a large number of genotypes. The aim of this work was to assess if phenotyping systems with low-cost consumer-grade digital cameras can be used to characterize germplasm for drought tolerance. To achieve this goal, we built a proximal phenotyping cart mounted with digital cameras and evaluated it by characterizing 142 winter wheat genotypes for drought tolerance under field conditions. The same genotypes were additionally characterized for seedling stage traits by imaging under controlled growth conditions. The analysis revealed that under field conditions, plant biomass, relative growth rates, and Normalized Difference Vegetation Index (NDVI) from different growth stages estimated by imaging were significantly correlated to drought tolerance. Under controlled growth conditions, root count at the seedling stage evaluated by imaging was significantly correlated to adult plant drought tolerance observed in the field. Random forest models were trained by integrating measurements from field and controlled conditions and revealed that plant biomass and relative growth rates at key plant growth stages are important predictors of drought tolerance. Thus, based on the results, it can be concluded that the consumer-grade cameras can be key components of affordable automated phenotyping systems to accelerate pre-breeding for drought tolerance.
Exploration of Environmental DNA (eDNA) to Detect Kirtland’s Snake (Clonophis kirtlandii)
Authors: Ratsch Rikki , Kingsbury Bruce A. , Jordan Mark A.
Published: June 2020

Environmental DNA (eDNA) surveys utilize DNA shed by organisms into their environment in order to detect their presence. This technique has proven effective in many systems for detecting rare or cryptic species that require high survey effort. One potential candidate for eDNA surveying is Kirtland’s Snake (Clonophis kirtlandii), a small natricine endemic to the midwestern USA and threatened throughout its range. Due to its cryptic and fossorial lifestyle, it is also a notoriously difficult snake to survey, which has limited efforts to understand its ecology. Our goal was to utilize eDNA surveys for this species to increase detection probability and improve survey efficiency to assist future conservation efforts. We conducted coverboard surveys and habitat analyses to determine the spatial and temporal activity of snakes, and used this information to collect environmental samples in areas of high and low snake activity. In addition, we spiked artificial crayfish burrows with Kirtland’s Snake feces to assess the persistence of eDNA under semi-natural conditions. A quantitative PCR (qPCR) assay using a hydrolysis probe was developed to screen the environmental samples for Kirtland’s Snake eDNA that excluded closely related and co-occurring species. Our field surveys showed that snakes were found in the spring during the first of two seasons, and in areas with abundant grass, herbaceous vegetation, and shrubs. We found that eDNA declines within a week under field conditions in artificial crayfish burrows. In environmental samples of crayfish burrow water and sediment, soil, and open water, a single detection was found out of 380 samples. While there may be physicochemical and biological explanations for the low detection observed, characteristics of assay performance and sampling methodology may have also increased the potential for false negatives. We explored these outcomes in an effort to refine and advance the successful application of eDNA surveying in snakes and groundwater microhabitats.
Owner-Related Reasons Matter more than Behavioural Problems—A Study of Why Owners Relinquished Dogs and Cats to a Danish Animal Shelter from 1996 to 2017
Authors: Jensen Janne B. H. , Sandøe Peter , Nielsen Søren Saxmose
Published: June 2020

Every year, dogs and cats are relinquished to animal shelters by their owners in large numbers. Reasons for relinquishment of dogs and cats to a large Danish shelter from 1996 to 2017 were obtained and characterised. The reasons were available for 86% of the owner-relinquished animals, including 3204 dog relinquishments (90%) and 2755 cat relinquishments (82%). They were allocated to 59 categories, which were further merged into four owner-related and three animal-related reasons. The most commonly reported of these seven reasons for relinquishment of dogs were owner health (29%), animal behavioural problems (23%), housing issues (21%) and lack of time (14%). For cats, the figures were: owner health (32%), housing issues (26%), and animal behavioural problems (25%). No systematic changes in these patterns were found over time. The number of relinquished cats was roughly stable, whereas the number of relinquished dogs decreased on average by 3% per annum. Owner issues were the primary reason for relinquishment in both species, but nearly one-quarter of the animals were relinquished as a result of behavioural problems. As the latter are often connected with the owner in some way, the results emphasise the importance of a focus on owners when addressing pet relinquishment challenges.
Considerations for Optimizing Dosing of Immunoglobulins Based on Pharmacokinetic Evidence
Authors: Mahmood Iftekhar , Tegenge Million A. , Golding Basil
Published: June 2020

Immunoglobulins (IGs) are widely used for the treatment of immunodeficiency syndromes and several autoimmune diseases. In neonates, IGs have been used for the treatment of alloimmune thrombocytopenia, in neonatal infections and in the rare cases of neonatal Kawasaki disease. This review aims to examine the various dosing regimens of IGs following intravenous (IV) and subcutaneous (SC) administration, pharmacokinetics (PK) of IGs, and the importance of trough values for the prevention of infections in patients with primary immune deficiency (PID). The review also focuses on the mechanism of catabolism of IGs and the impact on the half-life of IGs. Data and reviews were obtained from the literature and the FDA package inserts. The authors suggest that for dosing, the PK of IGs should be evaluated on the baseline-corrected concentrations since this approach provides an accurate estimate of half-life and clearance of IGs. We also suggest employing clearance as a primary PK parameter for dosing determination of IGs. We suggest that IV dosing would be more effective if given more frequently to adjust for the increased clearance at high doses and because the baseline-corrected half-life is much shorter than the baseline-uncorrected half-life. Regarding SC administration, the dose should be adjusted based on the absolute bioavailability (determined against IV dosing) of the product. Finally, we highlight clinical and PK data gaps for optimum and individualized dosing of IGs.
Humans, Animals, Food and Environment: One Health Approach against Global Antimicrobial Resistance
Authors: Iriti Marcello , Vitalini Sara , Varoni Elena Maria
Published: June 2020

Antimicrobial resistance represents one of the most relevant threats to global public health and food security, affecting anyone, of any age, in any country and is responsible for longer hospital stays, higher medical costs and increased mortality. Resistant microorganisms are present in humans, animals, food and the environment, and, therefore, the One Health approach is very promising to counteract antimicrobial resistance, since human health and animal health are connected to each other and with the environment and the latter a potential source of resistant microorganisms. In this context, the need for novel antimicrobial drugs has stimulated the exploration of plant products as a source of novel phytotherapeutics able to reverse antimicrobial resistance when used in combination with conventional antibiotic drugs.
Investigation of the Effect of Operational Factors on Conveyor Belt Mechanical Properties
Authors: Rudawska Anna , Madleňák Radovan , Madleňáková Lucia , Droździel Paweł
Published: June 2020

This paper aims to present the effect of specific operational factors (temperature and humidity) on the selected mechanical properties of a conveyor belt. The tests were conducted in a climatic chamber, simulating the effect of both minus and plus temperatures −30 °C to 80 °C (243 K to 353 K) at specific humidity, and in a thermal shock chamber where a varying number of ageing cycles was applied for a specific range of thermal shocks. Six different tests in the climatic chamber and four different tests in a thermal shock chamber were conducted. The results of the climatic chamber tests demonstrate that many strength parameters have undesired values at a temperature of 10 °C (283 K) and 80 °C (353 K) at a relative humidity of 80%. Interestingly, the results revealed that tensile strength, tensile modulus and yield strength are higher at below 0 °C temperature than at above 0 °C temperature. For example, comparing the temperature −30 °C (243 K) and +30 °C (303 K) obtained a difference of tensile modulus of nearly 10%, and comparing the temperature −30 °C (243 K) and +10 °C (283 K) the differences were 22%.
Hash-Chain-Based Cross-Regional Safety Authentication for Space-Air-Ground Integrated VANETs
Authors: Luo Gege , Shi Mingxian , Zhao Caidan , Shi Zhiyuan
Published: June 2020

With the increasing demand for intelligent traffic management and road network intelligent information services, the vehicular ad hoc networks (VANETs) combined with information of air, space and ground have outstanding advantages in coverage, reliable transmission, and resource richness. Due to the characteristics of heterogeneous, numerous nodes, and frequent cross-network flow, the space–air–ground integrated network (SAGIN) puts forward higher requirements for security. This paper proposes a cross-regional node identity management architecture based on the hash chain, combined with radio frequency (RF) fingerprint theory, to guarantee node identity security with a non-duplicated physical information identity authentication mechanism. At the same time, the blockchain consensus mechanism is simplified to achieve block recording and verification. OMNet ++, SUMO, and Veins co-simulation platforms are used to generate transactions for cross-regional traffic flow. Based on the Hyperledger–Fabric architecture, Kafka and PBFT consensus algorithms are simulated. The simulation results show that the average delay of a single transaction generated block is about 0.9 ms, which achieves efficient and low-latency authentication.
Image Processing Techniques for Analysis of Satellite Images for Historical Maps Classification—An Overview
Authors: Asokan Anju , Anitha J. , Ciobanu Monica , Gabor Andrei , Naaji Antoanela , Hemanth D. Jude
Published: June 2020

Historical maps classification has become an important application in today’s scenario of everchanging land boundaries. Historical map changes include the change in boundaries of cities/states, vegetation regions, water bodies and so forth. Change detection in these regions are mainly carried out via satellite images. Hence, an extensive knowledge on satellite image processing is necessary for historical map classification applications. An exhaustive analysis on the merits and demerits of many satellite image processing methods are discussed in this paper. Though several computational methods are available, different methods perform differently for the various satellite image processing applications. Wrong selection of methods will lead to inferior results for a specific application. This work highlights the methods and the suitable satellite imaging methods associated with these applications. Several comparative analyses are also performed in this work to show the suitability of several methods. This work will help support the selection of innovative solutions for the different problems associated with satellite image processing applications.
Biomechanical Study of Proximal Femur for Designing Stems for Total Hip Replacement
Authors: Solórzano William , Ojeda Carlos , Diaz Lantada Andres
Published: June 2020

Innovative hip implants should be designed in accordance with biomechanical models of the proximal femur and take into account both body weight and muscle action in order to improve usability and biomimetic performance. This article proposes a finite element analysis of the proximal femur using both cortical and trabecular regions and employing transverse isotropic properties with standardized loads taken from active and young patients. Maximum principal stresses are plotted to show the mechanical behavior of the femur and grouped to evaluate stress shielding. Tsai–Wu and the maximum principal stress fields are useful for finding the areas more prone to failure and analyzing the influence of the stems on femoral mechanics. Other parameters, such as the stem material, absence of neck and osteotomy level, are explained. This paper is expected to provide a guide for designers and surgeons of femoral stems for assessing qualitatively and quantitatively the risks of stress shielding.
Using Low Salinity Waterflooding to Improve Oil Recovery in Naturally Fractured Reservoirs
Authors: Aljuboori Faisal Awad , Lee Jang Hyun , Elraies Khaled A. , Stephen Karl D.
Published: June 2020

Low salinity waterflooding is an effective technique to accelerate and boost oil recovery. The impact of this technique has been investigated widely in laboratories for various scales and rock typing, most of which have demonstrated a potential improvement in oil recovery. This improvement has been attributed to several chemical and physical interactions that led to a change in the wettability to become more water-wet, as well as a reduction in the residual oil saturation. Meanwhile, it is rare to find a discussion in the literature about the efficiency of low salinity flooding in naturally fractured reservoirs. Therefore, in this work, we investigate the potential advantages of this method in fractured reservoirs using numerical simulations. A new approach to estimate the weighting factor using a tracer model has been proposed to determine the brine salinity and, hence, its properties in the mixing region. We have also used the relative permeability curves as a proxy for any physical and chemical mechanisms which are not represented explicitly in the model. The simulation outcomes highlighted the advantage of low salinity waterflooding in fractured reservoirs. An increment in oil recovery by 10.7% to 13% of Stock Tank Oil Initially In Place (STOIIP) was obtained using the dual- and single-porosity model, respectively. Therefore, the low salinity waterflooding technique represents a promising low-cost, effective method in fractured reservoirs.
Estimating the Dynamic Behavior of Highway Steel Plate Girder Bridges Using Real-Time Strain Measurements
Authors: Kaloop Mosbeh R. , Elbeltagi Emad , Hu Jong Wan
Published: June 2020

Structural health monitoring (SHM) techniques are used to assess the behavior of structures during or after construction. The high cost of sensors is the main reason for the limited use of the SHM techniques. The present study investigates the dynamic behavior (dynamic acceleration, semi-static displacement, frequency and damping ratio) of highway steel plate girder bridges using strain measurements. The double filtration and polynomial prediction methods are used to estimate the dynamic behavior of the bridge using real-time strain measurements. To verify the accuracy of the developed method, the field monitoring measurements of the WonHyo bridge is used. The bridge behavior under different truck speeds and weights is observed and evaluated. The displacement and acceleration measurements are used to examine the results of the proposed method. The results of this study demonstrate that the strain measurements can be used to obtain an accurate semi-static displacement and dominant frequency content of the bridge. The accuracy of the developed model for the semi-static and dynamic behaviors is 99% and 69%, respectively.
Laboratory Evaluation of Gradation Improvement of Marginal Materials for Foamed Bitumen Stabilisation
Authors: White Greg , Espinosa Roberto
Published: June 2020

Foamed bitumen stabilisation is an attractive technology for increasing the use of marginal materials in pavement construction and rehabilitation. However, by their very nature, marginal materials do not meet the prescriptive requirements of many standard specifications. Consequently, performance-related evaluation is required. For foamed bitumen stabilised marginal materials, the cured and saturated moduli are common performance-related parameters that are also used for characterisation during structural pavement design. In this research, the indirect tensile moduli of three foamed bitumen stabilised marginal granular materials were compared to the modulus of a standard or premium material, in both cured and saturated conditions, after 3, 7 and 14 days of accelerated laboratory curing. The results indicated that the magnitude of granular material marginality was not related to the stabilised material modulus. Furthermore, the gradations of the two most marginal materials were improved by blending with another granular material and the improved marginal materials were also stabilised and tested. The gradation improvement had a variable effect on the stabilised material modulus, with the average modulus increasing by more than 20%. The modulus increase associated with the gradation improvement was related to the basis and magnitude of granular material marginality, with the saturated modulus of the most plastic marginal material increasing by the greater amount after improvement. It was concluded that foamed bitumen stabilisation is a particularly effective treatment for marginal granular materials. Furthermore, when used in combination with gradation improvement, the resulting foamed bitumen stabilised material can perform similarly to standard materials, based on cured and soaked modulus values. However, to allow the use of foamed bitumen stabilised marginal materials in pavement construction, specifications must be more performance-related and the current limits on plasticity and gradation must be relaxed.
Hybrid Scheme for Automated Classification of Pulmonary Nodules Using PET/CT Images and Patient Information
Authors: Yamada Ayumi , Teramoto Atsushi , Hoshi Masato , Toyama Hiroshi , Imaizumi Kazuyoshi , Saito Kuniaki , Fujita Hiroshi
Published: June 2020

The classification of pulmonary nodules using computed tomography (CT) and positron emission tomography (PET)/CT is often a hard task for physicians. To this end, in our previous study, we developed an automated classification method using PET/CT images. In actual clinical practice, in addition to images, patient information (e.g., laboratory test results) is available and may be useful for automated classification. Here, we developed a hybrid scheme for automated classification of pulmonary nodules using these images and patient information. We collected 36 conventional CT images and PET/CT images of patients who underwent lung biopsy following bronchoscopy. Patient information was also collected. For classification, 25 shape and functional features were first extracted from the images. Benign and malignant nodules were identified using machine learning algorithms along with the images’ features and 17 patient-information-related features. In the leave-one-out cross-validation of our hybrid scheme, 94.4% of malignant nodules were identified correctly, and 77.7% of benign nodules were diagnosed correctly. The hybrid scheme performed better than that of our previous method that used only image features. These results indicate that the proposed hybrid scheme may improve the accuracy of malignancy analysis.
Numerical Analysis of Multi-Phase Flow around Supercavitating Body at Various Cavitator Angle of Attack and Ventilation Mass Flux
Authors: Kim Dong-Hyun , Paramanantham SalaiSargunan S , Park Warn-Gyu
Published: June 2020

Cavitation flow is an important issue in many areas of mechanical engineering. In this study, the natural and ventilated cavitation analyses were performed using the developed code for the cavitation flow analysis. The governing equation is the Navier-Stokes equation based on a homogeneous mixture model. This model assumes that all fluids are in an equilibrium state of momentum. The momentum equations are solved using the homogeneous mixture phase, although the continuity equations are solved in the liquid, vapor, and gas phases, separately. Computational analysis was performed for the different injection conditions and inflow velocity conditions under the same conditions as the experiments. The comparison between the cavitation shape and the drag showed good agreement with the experiments. Based on this, this study predicted the change of cavitation shape according to the change of cavitator angle of attack.
Application of Monte Carlo Methods to Consider Probabilistic Effects in a Race Simulation for Circuit Motorsport
Authors: Heilmeier Alexander , Graf Michael , Betz Johannes , Lienkamp Markus
Published: June 2020

Applying an optimal race strategy is a decisive factor in achieving the best possible result in a motorsport race. This mainly implies timing the pit stops perfectly and choosing the optimal tire compounds. Strategy engineers use race simulations to assess the effects of different strategic decisions (e.g., early vs. late pit stop) on the race result before and during a race. However, in reality, races rarely run as planned and are often decided by random events, for example, accidents that cause safety car phases. Besides, the course of a race is affected by many smaller probabilistic influences, for example, variability in the lap times. Consequently, these events and influences should be modeled within the race simulation if real races are to be simulated, and a robust race strategy is to be determined. Therefore, this paper presents how state of the art and new approaches can be combined to modeling the most important probabilistic influences on motorsport races—accidents and failures, full course yellow and safety car phases, the drivers’ starting performance, and variability in lap times and pit stop durations. The modeling is done using customized probability distributions as well as a novel “ghost” car approach, which allows the realistic consideration of the effect of safety cars within the race simulation. The interaction of all influences is evaluated based on the Monte Carlo method. The results demonstrate the validity of the models and show how Monte Carlo simulation enables assessing the robustness of race strategies. Knowing the robustness improves the basis for a reasonable determination of race strategies by strategy engineers.
Formation of Multilayered Sporadic E under an Influence of Atmospheric Gravity Waves (AGWs)
Authors: Didebulidze Goderdzi G. , Dalakishvili Giorgi , Todua Maya
Published: June 2020

The formation of multilayered sporadic E by atmospheric gravity waves (AGWs), propagating in the mid-latitude lower thermosphere, is shown theoretically and numerically. AGWs with a vertical wavelength smaller than the width of the lower thermosphere lead to the appearance of vertical drift velocity nodes (regions where the ions’ vertical drift velocity, caused by these waves, is zero) of heavy metallic ions (Fe+). The distance between the nearest nodes is close to the AGWs’ vertical wavelength. When the divergence of the ion vertical drift velocity at its nodes has a minimal negative value, then these charged particles can accumulate into Es-type thin layers and the formation of multilayered sporadic E is possible. We showed the importance of the ions’ ambipolar diffusion in the formation of Es layers and control of their densities. Oblique downward or upward propagation of AGWs causes downward or upward motion of the ion vertical drift velocity nodes by the vertical propagation phase velocity of these waves. In this case, the formed Es layers also descend or move upward with the same phase velocity. The condition, when the horizontal component of AGWs’ intrinsic phase velocity (phase velocity relative to the wind) and background wind velocity have same magnitudes but opposite directions, is favorable for the formation of the multilayered sporadic E at fixed heights of the sublayers. When the AGWs are absent, then horizontal homogeneous wind causes the formation of sporadic E but with a single peak. In the framework of the suggested theory, it is shown that, in the lower thermosphere, the wind direction, magnitude, and shear determine the development of the processes of ion/electron convergence into the Es-type layer, as well as their density divergence. Consideration of arbitrary height profiles of the meridional and zonal components of the horizontal wind velocity, in case of AGW propagation, should be important for the investigation of the distribution and behavior of heavy metallic ions on regional and global scales.
The Optical Properties of Aerosols at the Summit of Mount Tai in May and June and the Retrieval of the Complex Refractive Index
Authors: Zhao Dapeng , Yin Yan , Zhang Min , Wang Honglei , Lu Chunsong , Yuan Liang , Shi Shuangshuang
Published: June 2020

To study the optical properties of background atmospheric aerosols in East China, we carried out observations of the physical, chemical and optical properties of atmospheric aerosols at the summit of Mount Tai (Mt. Tai, 1533.7 m above sea level) from 13 May to 25 June 2017. The results show that the average scattering coefficient ( σ sca , 550 ) at 550 nm of the aerosols at the summit of Mt. Tai is 40.3 Mm−1, and the average absorption coefficient ( σ abs , 550 ) at 550 nm is 16.0 Mm−1. The complex refractive index of aerosols is a key parameter for aerosol retrieval and modeling. There are few studies on the equivalent complex refractive index of aerosol in the Taishan area. We calculated the aerosol equivalent complex refractive index using the observed aerosol scattering coefficients, absorption coefficients and particle size distribution data, providing more data support for future modeling in this region. The real part (n) of the complex refractive index at 550 nm of aerosol ranges from 1.31 to 1.98 (mostly under 1.50), with an average value of 1.38, while the imaginary part (k) ranges from 0.014 to 0.251 (less than 0.10 for over 95% samples), with an average value of 0.040. The analysis of the n and k of the aerosol average complex refractive index shows that the scattering properties of the aerosols at the summit of Mt. Tai are relatively weak and the absorption properties are relatively strong when compared with those of other kinds of aerosols. The k of the aerosol complex refractive index at the summit of Mt. Tai has strong correlations with the wind speed, temperature, as revealed by the correlation analysis.
Elevation Effects on Air Temperature in a Topographically Complex Mountain Valley in the Spanish Pyrenees
Authors: Navarro-Serrano Francisco , López-Moreno Juan Ignacio , Azorin-Molina Cesar , Alonso-González Esteban , Aznarez-Balta Marina , Buisán Samuel T. , Revuelto Jesús
Published: June 2020

Air temperature changes as a function of elevation were analyzed in a valley of the Spanish Pyrenees. We analyzed insolation, topography and meteorological conditions in order to understand how complex topoclimatic environments develop. Clustering techniques were used to define vertical patterns of air temperature covering more than 1000 m of vertical elevation change. Ten locations from the bottom of the valley to the summits were monitored from September 2016 to June 2019. The results show that (i) night-time lapse rates were between −4 and −2 °C km−1, while in the daytime they were from −6 to −4 °C km−1, due to temperature inversions and topography. Daily maximum temperature lapse rates were steeper from March to July, and daily minimum temperatures were weaker from June to August, and in December. (ii) Different insolation exposure within and between the two analyzed slopes strongly influenced diurnal air temperatures, creating deviations from the general lapse rates. (iii) Usually, two cluster patterns were found (i.e., weak and steep), which were associated with stable and unstable weather conditions, respectively, in addition to high-low atmospheric pressure and low-high relative humidity. The results will have direct applications in disciplines that depend on air temperature estimations (e.g., snow studies, water resources and sky tourism, among others).
Improvement of the Numerical Tropical Cyclone Prediction System at the Central Weather Bureau of Taiwan: TWRF (Typhoon WRF)
Authors: Hsiao Ling-Feng , Chen Der-Song , Hong Jing-Shan , Yeh Tien-Chiang , Fong Chin-Tzu
Published: June 2020

Typhoon WRF (TWRF) based on the Advanced Research Weather Research and Forecasting Model (ARW WRF) was operational at the Central Weather Bureau (CWB) for tropical cyclone (TC) predictions since 2010 (named TWRF V1). CWB has committed to improve this regional model, aiming to increase the model predictability toward typhoons over East Asia. In 2016, an upgraded version designed to replace TWRF V1 became operational (named TWRF V2). Compared with V1, which has triple-nested meshes with coarser resolution (45/15/5 km), V2 increased the model resolution to 15/3 km. Since V1 and V2 were maintained in parallel from 2016 to 2018, this study utilized the real-time forecasts to investigate the impact of model resolution on TC prediction. Statistical measures pointed out the superiority of the high-resolution model on TC prediction. The forecast performance was also found competitive with that of two leading global models. The case study further pointed out, with the higher resolution, the model not only advanced the prediction on the TC track and inner core structure but also improved the representativeness of the complex terrain. Overall, the high-resolution model can better handle the so-called terrain phase-lock effect and, therefore, improve the TC quantitative precipitation forecast over the complex Taiwanese terrain.
Evolution Characteristics during Initial Stage of Triggered Lightning Based on Directly Measured Current
Authors: Chen Zefang , Zhang Yang , Fan Yanfeng , Wang Jingxuan , Zheng Dong , Fan Xiangpeng , Xu Liangtao , Lyu Weitao , Zhang Yijun
Published: June 2020

The initiation of a leader is an important lightning discharge process, but how an upward positive leader (UPL) initiates is still not fully understood. The evolution characteristics of a UPL during its initial stage was systematically studied based on directly measured current data of 14 triggered lightning events in 2019. It was found that the initial stage of triggered lightning can be divided into two types: a single initial process form and a multiple initial process form, with percentages of 64.29% and 35.71%, respectively. Compared with the former, the latter usually lasts longer, and the corresponding lightning is often triggered under a lower ground-level quasi-static electric field. In each initial process, precursor current pulses (PCPs), PCP clusters and initial precursor current pulse (IPCPs) are typical current waveforms, and the pulse durations and transferred charges of PCPs increase linearly with time. However, in the multiple initial process form, the pulse durations and transferred charges of PCPs will reduce significantly after each previous initial process and then continue to increase in the following initial process. In each initial process, when the pulse duration and transferred charge of a PCP increase to a certain extent, PCP clusters and IPCPs begin to appear. For the emergence of PCP clusters, the average values of the threshold are 3.48 μs and 19.53 μC, respectively. For the occurrence of IPCPs, the corresponding values are 4.69 μs and 27.23 μC, respectively. The average values of pulse durations and transferred charges of IPCPs are larger than those of PCP clusters. Compared with adjacent PCP clusters, IPCPs contain more pulses, with a critical range of 6–7. IPCPs also last longer, and have a critical range of 138–198 μs.
Nitrogen-Doped Flower-Like Hybrid Structure Based on Three-Dimensional Graphene
Authors: Dasgupta Kinshuk , Khosravifar Mahnoosh , Sawant Shrilekha , Adusei Paa Kwasi , Kanakaraj Sathya Narayan , Kasik Jacob , Shanov Vesselin
Published: June 2020

A new flower-like hybrid structure consisting of nitrogen-doped 3-dimensional (3D) graphene and vertically aligned graphene has been synthesized using a combination of low-pressure chemical vapor deposition (LPCVD) and plasma-enhanced chemical vapor deposition (PECVD) techniques. Active nitrogen (N) species were found to be essential for the growth of the flower-like morphology. N-doping was responsible for enhanced electrical conductivity and wettability of the obtained nano-carbon hybrid structure. Based on the conducted studies a growth mechanism has been proposed. The high specific surface area, low resistance to charge transfer and enhanced specific capacitance of this nitrogen-doped hybrid structure, makes it an excellent candidate material for supercapacitors.