bluuebunny/crossref_metadata_2025 huggingface dataset:
Biochar Integration with Legume Crops in Summer Gape Synergizes Nitrogen Use Efficiency and Enhance Maize Yield
Authors: Jalal Fazal , Arif Muhammad , Akhtar Kashif , Khan Aziz , Naz Misbah , Said Fazal , Zaheer Sajjad , Hussain Syed , Imtiaz Muhammad , Khan Muhammad Ali , Ali Muhammad , Wei Fan
Published: January 2020

Besides carbon (C) sequestration, biochar (BC) is recently believed to deliver multiple eco-friendly benefits to the soil for enhancing crop productivity. Use of mineral fertilizers coupled with BC been suggested a promising sustainable strategy for increasing crops yield. However, imperative study is needed to investigate (1) BC integration with multiple legumes crop adjusted in summer gape for pooling more organic carbon and nitrogen, and (2) subsequently looking into its synergism with mineral N in the following crop. Therefore, two years’ field experiments were conducted on maize under cereal based cropping pattern with the adjustment of legumes (i.e., mungbean, cowpea, and Sesbania) with a fallow in summer. In legumes, treatments consist of (0 and 50 t ha−1) BC application. However, N rates of 0, 90, 120, 150 kg ha−1 were added to the subsequent maize crop. Preceding legumes plots with the use of 50 t ha−1 biochar enhanced maize grain yield, above ground biomass, stover N, grain N, soil C, and N content after maize harvest and N use efficiency as compared to non-legumes with BC and legumes without BC plots. N application increased grain yield, above-ground biomass, stover N, grain N, and soil N but reduced N use efficiency with higher rates. Conclusively, the integration of biochar and legumes is a promising option for increasing the entire farm production of cereal-based cropping systems. This increment in yield was associated with supplying a viable input of N and C to soil and increased yields from this supplementary ‘summer gap’ crop.
Effects of Straw Return Mode on Soil Aggregates and Associated Carbon in the North China Plain
Authors: Ma Shoutian , Kan Zhengrong , Qi Jianying , Zhang Hailin
Published: January 2020

Crop straw is widely used to manage soil organic carbon (SOC) sequestration as an environmentally friendly practice in the North China Plain. However, little is known about the effects of straw returning modes on SOC sequestration in this region. Thus, a field experiment was conducted to study SOC accumulation and mineralization as well as aggregate stability and aggregate-associated SOC for the following three straw returning modes: no straw returning (NSR), only wheat straw returning (WR), and both wheat and maize straw returning (WR-MR). SOC concentration and storage were higher for WR and WR-MR than for NSR in the 0–20 cm soil layer, respectively (p < 0.05). Although WR and WR-MR resulted in higher mineralization per unit of soil than NSR, no significant difference in mineralization per unit of soil carbon was observed among straw returning modes in the upper soil layer. The mean weight diameters of aggregates at 0–5 cm were higher under treatments with crop retention than under NSR. At this soil depth, the aggregate-associated C concentration and stock for each soil size were significantly decreased by NSR. These findings suggest that WR-MR and WR are effective residue management practices. In particular, WR is the optimal strategy to enhance SOC sequestration, considering other applications of straw (e.g., forage, fuel, or biomass).
AquaCrop-Simulated Response of Sorghum Biomass and Grain Yield to Biochar Amendment in South Sudan
Authors: Starr Mike , Deng Biar , Helenius Juha
Published: January 2020

The dependency on rainfed agriculture and weak adaptability of the agricultural sector to climate change threaten food security in Sub-Saharan Africa (SSA). Biochar has widely been touted as a relatively easy means of increasing the soil water storage capacity of soils and thereby improving or maintaining crop yields. In this study we simulated the effect of biochar amendment on sorghum aboveground biomass and grain yield at a site in South Sudan. We used the model AquaCrop parameterized using site, soil, and cropping management data from a field experiment carried out at the site in 2011 and 2012, which were both wet years. Changes in soil hydraulic properties due to biochar were based on a published meta-analysis study. In order to investigate whether the response to biochar differed in dry years, simulations were also carried out for 1990, which was the driest year during the period 1979–2014. Measured and modelled biomass and yields with and without biochar for 2011 and 2012 were compared. Simulated and measured yields depended on growing season rainfall and distribution. The simulations showed that biochar amendment had an effect on rooting zone soil water content and sorghum biomass and grain yield in 1990, but not in 2011 and 2012. In view of expected climate change, the results have important implications for sorghum production and the potential use of biochar in SSA. Given the limited response of grain yield to biochar shown in our simulations, careful selection of sorghum variety and cultivar and consideration of planting date may be a more effective means of improving yields than applying biochar.
Commercial Local Pharmacotherapeutics and Adjunctive Agents for Nonsurgical Treatment of Periodontitis: A Contemporary Review of Clinical Efficacies and Challenges
Authors: Tan Oi Leng , Safii Syarida Hasnur , Razali Masfueh
Published: January 2020

Periodontal infections tend to be site-specific, mostly confined to the periodontal pocket. With the surge of antibiotic-resistant bacteria, the trend is shifting towards other therapeutic modalities, especially locally delivered approaches that include other pharmacotherapeutic drugs and medical devices. This narrative review aimed to provide insights into the clinical efficacy of local drug delivery and adjunctive agents used in nonsurgical management of periodontitis. Electronic (PubMed/MEDLINE, CENTRAL, and EMBASE) and bibliographic searches of past systematic reviews were carried out to identify previous publications on the topic. Only relevant literature and randomized controlled trials published in English were selected. In addition, a literature review was developed based on the selected articles. Experimental drugs or agents were excluded. This review highlights the clinically proven and commercially available therapeutic agents related to the management of periodontal disease with comparisons of their clinical efficacies and challenges. A vast array of commercial local pharmacotherapeutic agents had been clinically tested, but the methodologies and clinical results varied within and between each agent used, causing difficulty in drawing conclusions and providing support to the superiority of one agent over another. Considering the benefit–cost ratio with the modest clinical results, the long-term usefulness of these agents remains debatable.
Phenolic Compounds and the Anti-Atherogenic Effect of Bee Bread in High-Fat Diet-Induced Obese Rats
Authors: Othman Zaidatul Akmal , Wan Ghazali Wan Syaheedah , Noordin Liza , Mohd. Yusof Nurul Aiman , Mohamed Mahaneem
Published: January 2020

This study was undertaken to determine the phenolic compounds and the anti-atherogenic effect of bee bread in high-fat diet (HFD)-induced obese rats. The presence of phenolic compounds in bee bread was determined by liquid chromatography–mass spectrometry. Thirty-two male Sprague Dawley rats were divided into four groups, (n = 8/group); i.e., Normal (N), HFD (high-fat diet), HFD + BB (high-fat diet and 0.5 g/kg/day bee bread), and HFD + O (high-fat diet and 10 mg/kg/day orlistat) groups. After 6 weeks of the experiment, rats were sacrificed. Five phenolic compounds were identified in bee bread; namely, caffeic acid, ferulic acid, kaempferol, apigenin, and isorhamnetin. Bee bread significantly reduced Lee obesity index and levels of total cholesterol (TC), low-density lipoprotein (LDL), fatty acid synthase (FAS) activity, atherogenic index, oxidised-LDL (oxLDL), and malondialdehyde (MDA), and significantly increased aortic antioxidant activities, such as those of superoxide dismutase (SOD) and glutathione peroxidase (GPx). Adipocyte sizes were found to be smaller in the HFD + BB group compared to the N group, and en face aortas showed an absence of atherosclerotic plaque in rats supplemented with bee bread. These changes might suggest an anti-atherogenic effect of bee bread in HFD-induced obese rats via its antioxidant and hypocholesterolaemic properties.
The Implicit Keller Box Scheme for Combined Heat and Mass Transfer of Brinkman-Type Micropolar Nanofluid with Brownian Motion and Thermophoretic Effect Over an Inclined Surface
Authors: Rafique Khuram , Anwar Muhammad Imran , Misiran Masnita , Khan Ilyas , Sherif El-Sayed M.
Published: January 2020

The main purpose of the present analysis is to report the numerical solution of the thermal radiations and magnetohydrodynamic (MHD) effect on the flow of micropolar nanofluid. Further, the effect of Brownian motion and thermophoresis on the flow field are also elucidated. The combined phenomenon of heat and mass transfer is considered. Compatible similarities are implemented for the conversion of nonlinear ordinary differential equations from nonlinear partial differential equations. The numerical solution of the governing differential equations is obtained via the implicit Keller box technique. This is an efficient scheme based on the finite difference method. Findings demonstrate that the heat and mass exchange reduce with growth of the Brinkman parameter, whereas the wall shear stress enhances with improving the magnitude of the Brinkman factor. The temperature contour enhances when the radiation parameter reaches its peak, which is useful for industrial processes. The heat and mass flow rates decrease against higher magnitudes of inclination.
Prediction of Radiation Frost Using Support Vector Machines Based on Micrometeorological Data
Authors: Lu Yongzong , Hu Yongguang , Li Pingping , Paw U Kyaw Tha , Snyder Richard L.
Published: January 2020

Radiation frost happens frequently in the Yangtze River Delta region, which causes high economic loss in agriculture industry. It occurs because of heat losses from the atmosphere, plant and soil in the form of radiant energy, which is strongly associated with the micrometeorological characteristics. Multidimensional and nonlinear micrometeorological data enhances the difficulty in predicting the radiation frost. Support vector machines (SVMs), a type of algorithms, can be supervised learning which widely be employed for classification or regression problems in research of precision agriculture. This paper is the first attempt of using SVMs to build prediction models for radiation frost. Thirty-two kinds of micrometeorological parameters, such as daily mean temperature at six heights (Tmean0.5, Tmean1.5, Tmean2.0, Tmean3.0, Tmean4.5 and Tmean6.0), daily maximum and minimum temperatures at six heights (Tmax0.5, Tmax1.5, Tmax2.0, Tmax3.0, Tmax4.5 and Tmax6.0, and Tmin0.5, Tmin1.5, Tmin2.0, Tmin3.0, Tmin4.5 and Tmin6.0), daily mean relative humidity at six heights (RH0.5, RH1.5, RH2.0, RH3.0, RH4.5 and RH6.0), net radiation (Rn), downward short-wave radiation (Rsd), downward long-wave radiation (Rld), upward long-wave radiation (Rlu), upward short-wave radiation (Rsu), soil temperature (Tsoil) and soil heat flux (G) and daily average wind speed (u) were collected from November 2016 to July 2018. Six combinations inputs were used as the basis dataset for testing and training. Three types of kernel functions, such as linear kernel, radial basis function kernel and polynomial kernel function were used to develop the SVMs models. Five-fold cross validation was conducted for model fitting on training dataset to alleviate over-fitting and make prediction results more reliable. The results showed that an SVM with the radial basis function kernel (SVM-BRF) model with all the 32 micrometeorological data obtained high prediction accuracy in training and testing sets. When the single type of data (temperature, humidity and radiation data) was used for the SVM without any functions, prediction accuracy was better than that with functions. The SVM-BRF model had the best prediction accuracy when using the multidimensional and nonlinear micrometeorological data. Considering the complexity level of the model and the accuracy of prediction, micrometeorological data at the canopy height with the SVM-BRF model has been recommended for radiation frost prediction in Yangtze River Delta and probably could be applied in elsewhere with the similar terrains and micro-climates.
Similarity Analysis for Time Series-Based 2D Temperature Measurement of Engine Exhaust Gas in TDLAT
Authors: Jang Hyeonae , Choi Doowon
Published: January 2020

As regulations on the emission of pollutants from combustion systems are further tightened, it is necessary to reduce pollutant species and improve combustion efficiency to completely understand the process in the combustion field. Tunable diode laser absorption tomography (TDLAT) is a powerful tool that can analyze two-dimensional (2D) temperature and species concentration with fast-response and non-contact. In this study, stabilized spectra were implemented using the mean periodic signal technique to enable real-time 2D temperature measurement in harsh conditions. A time series statistical-based verification algorithm was introduced to select an optimal spectral cycle to track 2D reconstruction temperature. The statistical-based verification is based on the Two-sample t test, root mean square error, and time-based Mahalanobis distance, which is a technique for similarity analysis between thermocouple and reconstruction temperature of 18 candidate cycles. As a result, it was observed that the statistical-based TDLAT contribute to improving the accuracy of time series-based 2D temperature measurements.
Preparation of Hybrid Molybdenum Disulfide/Single Wall Carbon Nanotube–n-Type Silicon Solar Cells
Authors: Almalki Samira , Yu LePing , Grace Tom , Bati Abdulaziz S. R. , Shapter Joseph G.
Published: January 2020

Carbon nanotube/silicon (CNT/Si) heterojunction solar cells represent one new architecture for photovoltaic devices. The addition of MoS2 to the devices is shown to increase the efficiency of the devices. Two structures are explored. In one case, the single wall carbon nanotubes (SWCNTs) and MoS2 flakes are mixed to make a hybrid, which is then used to make a film, while in the other case, a two layer system is used with the MoS2 deposited first followed by the SWCNTs. In all cases, the solar cell efficiency is improved largely due to significant increases in the fill factor. The rise in fill factor is due to the semiconducting nature of the MoS2, which helps with the separation of charge carriers.
Experimental and Numerical Investigation of Striker Shape Influence on the Destruction Image in Multilayered Composite after Low Velocity Impact
Authors: Sławski Sebastian , Szymiczek Małgorzata , Kaczmarczyk Jarosław , Domin Jarosław , Duda Sławomir
Published: January 2020

The paper presents results obtained by experimental and numerical research focusing on the influence of the strikers’ geometry at the images of the destruction created in hybrid composite panels after applying impact load. In the research, the authors used four strikers with different geometry. The geometries were designed to keep the same weight for each of them. The composite panels used in the experiment were reinforced with aramid and carbon fabrics. An epoxy resin was used as a matrix. The experiments were carried with an impact kinetic energy of 23.5 J. The performed microscopy tests allowed for determination of destruction mechanisms of the panels depending on the geometry of the striker. The numerical calculations were performed using the finite element method. Each reinforcement layer of the composite was modeled as a different part. The bonded connection between the reinforcement layers was modeled using bilateral constraints. That approach enabled engineers to observe the delamination process during the impact. The results obtained from experimental and numerical investigations were compared. The authors present the impact of the striker geometry on damage formed in a composite panel. Formed damage was discussed. On the basis of the results from numerical research, energy absorption of the composite during impact depending on the striker geometry was discussed. It was noted that the size of the delamination area depends on the striker geometry. It was also noted that the diameter of the delamination area is related to the amount of damage in the reinforcing layers.
Therapeutic Potential of Polymer-Coated Mesoporous Silica Nanoparticles
Authors: Bansal Kuldeep K. , Mishra Deepak K. , Rosling Ari , Rosenholm Jessica M.
Published: January 2020

Mesoporous silica nanoparticles (MSNs) find tremendous applications in drug delivery due to several advantages such as their easy fabrication process, high drug loading, biodegradability, biocompatibility, and so forth. Nevertheless, despite several advantages, the use of this striking drug delivery carrier is restricted due to premature drug release owing to the porous structure. Coating of the pores using polymers has emerged as a great solution to this problem. Polymer coatings, which act as gatekeepers, avoid the premature release of loaded content from MSNs and offers the opportunity for controlled and targeted drug delivery. Therefore, in this review, we have compiled the polymer-based coating approaches used in recent years for improving the drug delivery capability of MSNs. This manuscript provides an insight into the research about the potential of polymer-coated MSNs, allowing the selection of right polymer for coating purposes according to the desired application.
Comparative Study on the Corrosion Inhibitive Effect of 2-Mecraptobenzothiazole and Na2HPO4 on Industrial Conveying API 5L X42 Pipeline Steel
Authors: Kartsonakis Ioannis A. , Stamatogianni Panagiota , Karaxi Evangelia K. , Charitidis Costas A.
Published: January 2020

Mild or low-carbon steel has an increasing utilization and is widely used for building construction, machinery parts, and pipelines, because it can be machined easily and has enhanced weldability as well as a low price. In any case, the corrosion resistance of mild steel under the conditions in industrial applications or in atmosphere is a thoughtful concern. This study inquires into the application of 2-mecraptobenzothiazole (MBT) and Na2HPO4 as corrosion inhibitors for the protection of API 5L X42 pipeline steel in 3.5 wt % NaCl as well as in water from the Athens city supply system. The electrochemical/morphological characterizations of the aforementioned mild steel proved that the corrosion protection mechanisms can be assigned to the protective layers created onto the metal surface because of the presence of the inhibitors, which prevent chloride’s penetration. The synergistic effect of the MBT and Na2HPO4 corrosion inhibition behavior, in a molar ratio of 1:1, revealed that the additives performed effectively with corrosion inhibition efficiency above 90%.
Printability of 3D Printed Hydrogel Scaffolds: Influence of Hydrogel Composition and Printing Parameters
Authors: Naghieh Saman , Sarker MD , Sharma N. K. , Barhoumi Zohra , Chen Xiongbiao
Published: January 2020

Extrusion-based bioprinting of hydrogel scaffolds is challenging due to printing-related issues, such as the lack of capability to precisely print or deposit hydrogels onto three-dimensional (3D) scaffolds as designed. Printability is an index to measure the difference between the designed and fabricated scaffold in the printing process, which, however, is still under-explored. While studies have been reported on printing hydrogel scaffolds from one or more hydrogels, there is limited knowledge on the printability of hydrogels and their printing processes. This paper presented our study on the printability of 3D printed hydrogel scaffolds, with a focus on identifying the influence of hydrogel composition and printing parameters/conditions on printability. Using the hydrogels synthesized from pure alginate or alginate with gelatin and methyl-cellulose, we examined their flow behavior and mechanical properties, as well as their influence on printability. To characterize the printability, we examined the pore size, strand diameter, and other dimensions of the printed scaffolds. We then evaluated the printability in terms of pore/strand/angular/printability and irregularity. Our results revealed that the printability could be affected by a number of factors and among them, the most important were those related to the hydrogel composition and printing parameters. This study also presented a framework to evaluate alginate hydrogel printability in a systematic manner, which can be adopted and used in the studies of other hydrogels for bioprinting.
Adsorption and Desorption of Nitrogen, Phosphorus, Potassium, and Soil Buffering Capacity Following Application of Chicken Litter Biochar to an Acid Soil
Authors: Palanivell Perumal , Ahmed Osumanu Haruna , Latifah Omar , Abdul Majid Nik Muhamad
Published: January 2020

Adsorption and desorption of nitrogen (N), phosphorus (P), and potassium (K) soils are controlled by pH, pH buffering capacity, organic matter, and cation exchange capacity (CEC). These factors optimized to improve timely availability of N, P, and K crop use using organic amendments such as chicken litter biochar (CLB). The objective of this study was to determine the effects of CLB on N, P, K sorption and pH buffering capacity of an acid soil. Different rates of CLB were mixed with an acid soil for N, P, and K sorption and pH buffering capacity determination. The CLB increased soil pH and pH buffering capacity, but unlike P and K adsorption, the different rates of CLB significantly increased N adsorption, suggesting that this soil amendment has high affinity for N than P and K. Also, because CLB reduced N, P, and K desorption, it suggests that N in particular will be slowly released with time. The reduced N desorption but higher N adsorption further indicates that N can be temporary fixed by CLB. This work has revealed CLB is more effective controlling soil N availability for timely crop use to avoid losses.
Finite Element Method and Cut Bar Method-Based Comparison Under 150°, 175° and 310 °C for an Aluminium Bar
Authors: Gonzalez Duran José Eli Eduardo , González-Rodríguez Oscar J. , Zamora-Antuñano Marco Antonio , Rodríguez-Reséndiz Juvenal , Méndez-Lozano Néstor , Gómez Meléndez Domingo José , García García Raul
Published: January 2020

Analyses were developed using a finite element method of the experimental measurement system for thermal conductivity of solid materials, used by the Centro Nacional de Metrología (CENAM), which operates under a condition of permanent heat flow. The CENAM implemented a thermal conductivity measurement system for solid materials limited in its operating intervals to measurements of maximum 300 ° C for solid conductive materials. However, the development of new materials should be characterised and studied to know their thermophysical properties and ensure their applications to any temperature conditions. These task demand improvements in the measurement system, which are proposed in the present work. Improvements are sought to achieve high-temperature measurements in metallic materials and conductive solids, and this system may also cover not only metallic materials. Simulations were performed to compare the distribution of temperatures developed in the measurement system as well as the radial heat leaks, which affect the measurement parameters for an aluminium bar, and uses copper bars as reference material. The simulations were made for measurements of an aluminium bar at a temperature of 150 ° C, in the plane and 3D, another at 175 ° C and one more known maximum temperature reached by a sample of the aluminium bar with a new heater acquired at 310 ° C.
A Feasibility Study of Privacy Ensuring Emergency Vehicle Approaching Warning System
Authors: Petrov Tibor , Pocta Peter , Roman Ján , Buzna Ľuboš , Dado Milan
Published: January 2020

With the deployment of Vehicular Ad hoc Networks (VANETs), new transport safety and efficiency applications are emerging. One of the fields where the adoption of information and communication technologies (ICT) is expected to bring great benefits, is emergency systems. A properly designed emergency vehicle warning system should provide car drivers with adequate reaction times and additional information, complementing the currently used lights and sirens. The objective is to increase road safety and to create conditions for a fast and reliable movement of emergency vehicles (EVs). The available literature addressing privacy issues in VANET-based emergency vehicle warning systems is strongly limited. In this paper, the privacy ensuring emergency vehicle approaching warning system (PEEV-WS) is proposed based on a requirements analysis. Privacy is ensured by avoiding transmissions of sensitive information (e.g., expected EV route) over the wireless channel. This is achieved by assigning the decision-making responsibility to an EV and determining which vehicles can potentially interfere with the EV in the near future, and to notify those vehicles only by unicasting vehicle-customized information. The performance of the system is evaluated by federated telco-traffic simulations in terms of end-to-end delay and message delivery probability for three commonly used ad hoc routing protocols—Ad hoc On-Demand Distance Vector (AODV), Greedy Perimeter Stateless Routing (GPSR), and Dynamic MANET On-demand (DYMO), as well as in terms of reaction time, which the system provides to the drivers. Despite low applicability of the ad hoc routing protocols for vehicular communication, especially for low-latency and high-frequency applications, the simulations of the communication network demonstrate that the AODV protocol, with the modified configuration, can support the emergency vehicle warning system. The traffic simulations confirm that the system has the potential to provide drivers with sufficient reaction time.
Optimal Placement of Multiple Feeder Terminal Units Using Intelligent Algorithms
Authors: Lin Dan , Liu Qianjin , Li Fusheng , Wang Ziyao , Zeng Guangxuan , Chen Yixuan , Yu Tao
Published: January 2020

In order to solve the placement problem of three kinds of feeder terminal units (FTU) in the distribution network, this paper proposes a novel mathematical model. The model considers economic cost and electricity supply reliability from the perspective of life cycle cost. The reliability algorithm in this model is established for the distribution network configured with centralized feeder automation. Different evaluation indices of reliability and the importance of several kinds of customers are also considered in this model. Aiming at the reliability evaluation in this model, this paper puts forward the reliability analysis method for the distribution network with three kinds of FTUs. In view of the difficulty to express the reliability of distribution network in a formula with decision variables, and the non-deterministic polynomial hard (NP-hard) nature of this model, a variety of intelligent algorithms are applied to solve the model. The feasibility and effectiveness of the model and methods for FTUs placement optimization problem are verified by a case study of the Roy Billinton test system (RBTS) Bus 5 system.
On the Use of LoRaWAN for the Monitoring and Control of Distributed Energy Resources in a Smart Campus
Authors: Pasetti Marco , Ferrari Paolo , Silva Diego Rodrigo Cabral , Silva Ivanovitch , Sisinni Emiliano
Published: January 2020

The application of the most recent advances of the Internet-of-Things (IoT) technology to the automation of buildings is emerging as a promising solution to achieve greater efficiencies in energy consumption, and to allow the realization of sustainable models. The application of IoT has been demonstrated as effective in many fields, such as confirmed, for instance, by the Industry 4.0 concepts, which are revolutionizing modern production chains. By following this approach, the use of distributed control architectures and of IoT technologies (both wired and wireless) would result in effective solutions for the management of smart environments composed of groups of buildings, such as campuses. In this case, heterogeneous IoT solutions are typically adopted to satisfy the requirements of the very diverse possible scenarios (e.g., indoor versus outdoor coverage, mobile versus fixed nodes, just to mention a few), making their large-scale integration cumbersome. To cope with this issue, this paper presents an IoT architecture able to transparently manage different communication protocols in smart environments, and investigates its possible application for the monitoring and control of distributed energy resources in a smart campus. In particular, a use–case focused on the integration of the Long Range Wide Area Network (LoRaWAN) technology is considered to cope with heterogeneous indoor and outdoor communication scenarios. The feasibility analysis of the proposed solution is carried out by computing the scalability limits of the approach, based on the proposed smart campus data model. The results of the study showed that the proposed solution would be able to manage more than 10,000 nodes. An experimental validation of the LoRaWAN technology confirms its suitability in terms of coverage and latency, with a minimum LoRaWAN cell coverage range of 250 m, and a communication latency of about 400 ms. Finally, the advantages of the proposed solution in the supervision and management of a PV system are highlighted in a real-world scenario.
Augmented and Virtual Reality Evolution and Future Tendency
Authors: Muñoz-Saavedra Luis , Miró-Amarante Lourdes , Domínguez-Morales Manuel
Published: January 2020

Augmented reality and virtual reality technologies are increasing in popularity. Augmented reality has thrived to date mainly on mobile applications, with games like Pokémon Go or the new Google Maps utility as some of its ambassadors. On the other hand, virtual reality has been popularized mainly thanks to the videogame industry and cheaper devices. However, what was initially a failure in the industrial field is resurfacing in recent years thanks to the technological improvements in devices and processing hardware. In this work, an in-depth study of the different fields in which augmented and virtual reality have been used has been carried out. This study focuses on conducting a thorough scoping review focused on these new technologies, where the evolution of each of them during the last years in the most important categories and in the countries most involved in these technologies will be analyzed. Finally, we will analyze the future trend of these technologies and the areas in which it is necessary to investigate to further integrate these technologies into society.
In Vitro Effect of Putty Calcium Silicate Materials on Human Periodontal Ligament Stem Cells
Authors: Rodríguez-Lozano Francisco Javier , López-García Sergio , García-Bernal David , Pecci-Lloret Miguel R. , Guerrero-Gironés Julia , Pecci-Lloret María P. , Lozano Adrián , Llena Carmen , Spagnuolo Gianrico , Forner Leopoldo
Published: January 2020

New bioactive materials have been developed for retrograde root filling. These materials come into contact with vital tissues and facilitate biomineralization and apical repair. The objective of this study was to evaluate the cytocompatibility and bioactivity of two bioactive cements, Bio-C Repair (Angelus, Londrina, Pr, Brazil) and TotalFill BC RRM putty (FGK, Dentaire SA, La-Chaux-de-fonds, Switzerland). The biological properties in human periodontal ligament stem cells (hPDLSCs) that were exposed to Bio-C Repair and TotalFill BC RRM putty were studied. Cell viability, migration, and cell adhesion were analyzed. Moreover, qPCR and mineralization assay were performed to evaluate the bioactivity potential of these cements. The results were statistically analyzed using ANOVA and the Tukey test (p < 0.05). It was observed that cell viability and cell migration in Bio-C Repair and TotalFill BC RRM putty were similar to the control without statistically significant differences, except at 72 h when TotalFill BC RRM putty was slightly lower (p < 0.05). Excellent cell adhesion and morphology were observed with both Bio-C Repair and TotalFill BC RRM putty. Both cements promoted the osteo- and cementogenic differentiation of hPDLSCs. These results suggest that Bio-C Repair and TotalFill BC RRM putty are biologically appropriate materials to be used as retrograde obturation material.
Idiopathic Sudden Sensorineural Hearing Loss: Should Otoacoustic Emissions Be Added to the Monitoring Protocol? A Systematic Review
Authors: Babich Kaley , Dunckley Kathleen T.
Published: January 2020

Idiopathic sudden sensorineural hearing loss (ISSNHL) refers to a loss of hearing, most commonly unilateral, that occurs suddenly (≤72 h) with no identifiable cause or etiology. To date, there is no standard protocol to predict prognosis (hearing recovery) for patients with ISSNHL. However, studies have shown that changes in otoacoustic emissions (OAEs) often occur prior to changes in audiometric hearing thresholds. OAEs originate from the electrochemical motility of the outer hair cells (OHC) and reflect the integrity of the inner ear, specifically the cochlear amplifier. Therefore, OAEs may be useful as a prognostic predictive factor in patients with ISSNHL from the initial onset of symptoms through recovery. A systematic review of the literature was undertaken to assess the relationship between pure tone thresholds, OAEs, and subjective hearing improvement and/or recovery. Fourteen studies were identified for inclusion, and they overwhelmingly support the inclusion of OAEs in the protocol to monitor ISSNHL recovery. This finding supports the development of a standard diagnostic protocol that includes OAEs to predict patient hearing outcomes.
Modeling Palletized Products: The Case of Semi-Filled Bottles under Top-Load Conditions
Authors: Pavlovic Ana , Fragassa Cristiano , Vegliò Luca , de Camargo Felipe Vannucchi , Minak Giangiacomo
Published: January 2020

An investigation on numerical methods able to simplify the mechanical behavior of PET bottles, partially filled with liquid, under compression loadings is presented here. Compressive stress conditions on bottles are very common during their transportation and can be accompanied by large deformations and instabilities that can compromise the integrity of the pack, with the risk of significant damages. The present paper proposes two approaches, both based on finite elements, and with elastic-plastic material models properly defined with the scope of investigating the complex phenomena that take place during these loading conditions. Although not perfect in terms of accuracy, these numerical methods have been proven to be capable to predicti the transport-related integrity risks, showing results that agree with experimental data, especially during the initial phases of load compression.
Seismic Behavior of Triple Tunnel Complex in Soft Soil Subjected to Transverse Shaking
Authors: Naseem Ahsan , Kashif Muhammad , Iqbal Nouman , Schotte Ken , De Backer Hans
Published: January 2020

Combining multiple tunnels into a single tunnel complex while keeping the surrounding area compact is a complicated procedure. The condition becomes more complex when soft soil is present and the area is prone to seismic activity. Seismic vibrations produce sudden ground shaking, which causes a sharp decrease in the shear strength and bearing capacity of the soil. This results in larger ground displacements and deformation of structures located at the surface and within the soil mass. The deformations are more pronounced at shallower depths and near the ground surface. Tunnels located in that area are also affected and can undergo excessive distortions and uplift. The condition becomes worse if the tunnel area is larger, and, thus, the respective tunnel complex needs to be properly evaluated. In this research, a novel triple tunnel complex formed by combining three closely spaced tunnels is numerically analyzed using Plaxis 2D software under variable dynamic loadings. The effect of variations in lining thickness, the inner supporting structure, embedment depth on the produced ground displacements, tunnel deformations, resisting bending moments, and the developed thrusts are studied in detail. The triple tunnel complex is also compared with the rectangular and equivalent horizontal twin tunnel complexes in terms of generated thrusts and resisted seismic-induced bending moments. From the results, it is concluded that increased thickness of the lining, inner structure, and greater embedment depth results in decreased ground displacements, tunnel deformations, and increased resistance to seismic-induced bending moments. The comparison of shapes revealed that the triple tunnel complex has better resistance against moments with the least amount of thrust and surface heave produced.
Analysis and Verification on Energy Consumption of the Quadruped Robot with Passive Compliant Hydraulic Servo Actuator
Authors: Hua Zisen , Rong Xuewen , Li Yibin , Chai Hui , Li Bin , Zhang Shuaishuai
Published: January 2020

The hydraulic servo actuator with passive compliance (HPCA) is designed for hydraulically-driven quadruped robots. It is characterized by an accumulator that connects to the piston chamber of the hydraulic cylinder to buffer impact forces between a robot’s feet and the ground. This paper studies the energy efficiency of this actuator in the dynamic locomotion of a quadruped robot. Different from the traditional methods of storing potentially recyclable energy using accumulators, the energy-saving principle of HPCA is to utilize the pressure-transition characteristics of the asymmetric hydraulic cylinder with control of the symmetrical valve. The accumulator can store and release oil during the switching of the transition point in each gait cycle of the robot, thereby improving the energy efficiency of the actuator. The influence of the initial inflation pressure and working volume of the accumulator on the energy efficiency of the HPCA is studied by simulation and physical experiments. The results show that the HPCA has a higher energy efficiency that is independent of the physical parameters of the accumulator.
Mechanical and Heterogeneous Properties of Coal and Rock Quantified and Mapped at the Microscale
Authors: Sun Changlun , Li Guichen , Zhang Suhui , Xu Jiahui , Yang Houqiang
Published: January 2020

Due to the impossibility of obtaining intact standard experimental samples, it is difficult to test the mechanical properties of soft and broken coal and rock obtained from deep coal mines. So, an advanced experimental technology based on a small sample volume, nanoindentation technology, was introduced and used to measure the mechanical parameters of them. By using the averaging method, the hardness of shale, mudstone and coal are 1191.90 MPa, 674.95 MPa and 424.30 MPa, respectively; their elastic moduli are 20.39 GPa, 11.72 GPa and 5.47 GPa; and their fracture toughness were 1.66 MPa·m0.5, 1.28 MPa·m0.5 and 0.77 MPa·m0.5. These three mechanical parameters were used to quantify and map the heterogeneous properties of coal and rock for convenience and accuracy. For example, the inter quartile range (IQR) of the hardness of shale, mudstone, and coal are 1502.10 MPa, 1016.20 MPa and 54.64 MPa, respectively, meaning that coal has the best homogeneity among them. Nanoindentation technology provides researchers with a convenient method to conduct mechanical experiments at the microscale.
An Ensemble Learning and RUL Prediction Method Based on Bearings Degradation Indicator Construction
Authors: Tian Qiaoping , Wang Honglei
Published: January 2020

The prediction of the remaining life of a bearing plays a vital role in reducing the accident-related maintenance costs of machinery and in improving the reliability of machinery and equipment. To predict bearing remaining useful life (RUL), the abilities of statistical characteristics to reflect the bearing degradation state differ, and the single prediction model has low generalization ability and a poor prediction effect. An ensemble robust prediction method is proposed here to predict bearing RUL based on the construction of a bearing degradation indicator set: the initial bearing degradation indicator subsets were constructed using the Fast Correlation-Based Filter with Approximate Markov Blankets (FCBF-AMB) and Maximal Information Coefficient (MIC) selection methods. Through the cross-operation of the obtained subsets, we obtained a set of robust degradation indicators. These selected degradation indicators were fed into the long short-term memory (LSTM) neural network prediction model enhanced by the AdaBoost algorithm. We found through calculation that the average prediction accuracy of the proposed method is 91.40%, 92.04%, and 93.25% at 2100, 2250, and 2400 rpm, respectively. Compared with other methods, the proposed method improves the prediction accuracy by 1.8% to 14.87% at most. Therefore, the method proposed in this paper is more accurate than the other methods in terms of RUL prediction.
Towards Portability of Models for Predicting Students’ Final Performance in University Courses Starting from Moodle Logs
Authors: López-Zambrano Javier , Lara Juan A. , Romero Cristóbal
Published: January 2020

Predicting students’ academic performance is one of the older challenges faced by the educational scientific community. However, most of the research carried out in this area has focused on obtaining the best accuracy models for their specific single courses and only a few works have tried to discover under which circumstances a prediction model built on a source course can be used in other different but similar courses. Our motivation in this work is to study the portability of models obtained directly from Moodle logs of 24 university courses. The proposed method intends to check if grouping similar courses by the degree or the similar level of usage of activities provided by the Moodle logs, and if the use of numerical or categorical attributes affect in the portability of the prediction models. We have carried out two experiments by executing the well-known classification algorithm over all the datasets of the courses in order to obtain decision tree models and to test their portability to the other courses by comparing the obtained accuracy and loss of accuracy evaluation measures. The results obtained show that it is only feasible to directly transfer predictive models or apply them to different courses with an acceptable accuracy and without losing portability under some circumstances.
Comparative Study on the Energetic and Ecologic Parameters of Dual Fuels (Diesel–NG and HVO–Biogas) and Conventional Diesel Fuel in a CI Engine
Authors: Rimkus Alfredas , Stravinskas Saulius , Matijošius Jonas
Published: January 2020

The Article presents the results of the experimental research and numerical analysis of a compression ignition (CI) engine adapted for running on dual fuels of different composition (diesel and natural gas, diesel and biogas, biodiesel and natural gas, and biodiesel and biogas). The main goal was to find out the impact of different dual fuels on energy performance and emissions depending on the start of injection (SOI) of diesel and the crank angle degree (CAD). Pure conventional diesel fuel and second generation hydrotreated vegetable oil (HVO) (Neste) was used in the research. Natural gas contained 97 vol. % of methane. Biogas (biomethane) was simulated using a methane and carbon dioxide blend consisting of 60 vol. % of methane and 40 vol. % of carbon dioxide. Dual (liquid and gaseous) fuels were used in the tests, with the energy share of liquid fuels accounting for 40% and gas for 60%. The research results have shown that having replaced conventional diesel fuel with dual fuel, engine’s BTE declined by 11.9–16.5%. The use of methane in the dual fuel blend reduced CO2 volumetric fraction in the exhaust gases by 17–20%, while biomethane increased CO2 volumetric fraction by 10–14%. Dual fuel significantly increased CO and HC emissions, but NOx volumetric fraction decreased by 67–82% and smoke by 23–39%. The numerical analysis of the combustion process revealed changes in the ROHR (Rate of Heat Release) that affected engine efficiency and exhaust emissions was done by AVL (Anstalt für Verbrennungskraftmaschinen List) BOOST program.
Effects of Colored Light on Growth and Nutritional Composition of Tilapia, and Biofloc as a Food Source
Authors: Lopez-Betancur Daniela , Moreno Ivan , Guerrero-Mendez Carlos , Gómez-Meléndez Domingo , Macias P. Manuel de J. , Olvera-Olvera Carlos
Published: January 2020

Light stimulation and biofloc technology can be combined to improve the efficiency and sustainability of tilapia production. A 73-day pilot experiment was conducted to investigate the effect of colored light on growth rates and nutritional composition of the Nile tilapia fingerlings (Oreochromis niloticus) in biofloc systems. The effect of colored light on the nutritional composition of bioflocs as a food source for fish was measured. Three groups were illuminated in addition to natural sunlight with colored light using RGB light emitting diodes (LEDs) with peak wavelengths (λ) of 627.27 nm for red (R), 513.33 nm for green (G), and 451.67 nm for blue (B) light. LED light intensity was constant (0.832 mW / cm 2 ), and had an 18-h photoperiod of light per day throughout the study. The control group was illuminated only with natural sunlight (natural). Tilapia had an average initial weight of 0.242 g. There was a significant effect of colored light on tilapia growth and composition. The R group showed the best growth rate, highest survival, and highest lipid content. The B group showed homogeneous growth with the lowest growth rate and lipid content, but the highest protein level. On the other hand, the biofloc composition was influenced by the green light in the highest content of lipids, protein, and nitrogen-free extract.
AI-Based Modeling and Monitoring Techniques for Future Intelligent Elastic Optical Networks
Authors: Liu Xiaomin , Lun Huazhi , Fu Mengfan , Fan Yunyun , Yi Lilin , Hu Weisheng , Zhuge Qunbi
Published: January 2020

With the development of 5G technology, high definition video and internet of things, the capacity demand for optical networks has been increasing dramatically. To fulfill the capacity demand, low-margin optical network is attracting attentions. Therefore, planning tools with higher accuracy are needed and accurate models for quality of transmission (QoT) and impairments are the key elements to achieve this. Moreover, since the margin is low, maintaining the reliability of the optical network is also essential and optical performance monitoring (OPM) is desired. With OPM, controllers can adapt the configuration of the physical layer and detect anomalies. However, considering the heterogeneity of the modern optical network, it is difficult to build such accurate modeling and monitoring tools using traditional analytical methods. Fortunately, data-driven artificial intelligence (AI) provides a promising path. In this paper, we firstly discuss the requirements for adopting AI approaches in optical networks. Then, we review various recent progress of AI-based QoT/impairments modeling and monitoring schemes. We categorize these proposed methods by their functions and summarize advantages and challenges of adopting AI methods for these tasks. We discuss the problems remained for deploying AI-based methods to a practical system and present some possible directions for future investigation.