bluuebunny/crossref_metadata_2025 huggingface dataset:
Influences of Water Content in Feedstock Oil on Burning Characteristics of Fatty Acid Methyl Esters
Authors: Lin Cherng-Yuan , Ma Lei
Published: September 2020

Strong alkaline-catalyst transesterification with short-chain alcohol is generally used for biodiesel production due to its dominant advantages of shorter reaction time and higher conversion rate over other reactions. The existence of excess water content in the feedstock oil might retard the transesterification rate and in turn deteriorate the fuel characteristics of the fatty acid methyl esters. Hence, optimum water content in the raw oil, aimed towards both lower production cost and superior fuel properties, becomes significant for biodiesel research and industrial practices. Previous studies only concerned the influences of water contents on the yield or conversion rate of fatty acid methyl esters through transesterification of triglycerides. The effects of added water in the reactant mixture on burning characteristics of fatty acid methyl esters are thus first investigated in this study. Raw palm oil was added with preset water content before being transesterified. The experimental results show that the biodiesel produced from the raw palm oil containing a 0.05 wt.% added water content had the highest content of saturated fatty acids and total fatty acid methyl esters (FAME), while that containing 0.11 wt.% water content had the lowest content of total FAME and fatty acids of longer carbon chains than C16 among the biodiesel products. Regarding burning characteristics, palm-oil biodiesel made from raw oil with a 0.05 wt.% added water content among those biodiesels was found to have the highest distillation temperatures, flash point, and ignition point, which implies higher safety extents during handling and storage of the fuel. The added water content 0.05 wt.% in raw oil was considered the optimum to produce palm-oil biodiesel with superior fuel structure of fatty acids and burning characteristics. Higher or lower water content than 0.05 wt.% would cause slower nucleophilic substitution reaction and thus a lower conversion rate from raw oil and deteriorated burning characteristics in turn.
Design and Experimental Study on a New Closed-Cycle Desalination System Based On Ambient Temperature
Authors: Liu Jun , Sun Yong , Yv Sanjiang , Wang Jiaquan , Hu Kaixuan
Published: September 2020

The use of seawater desalination technology to solve water shortages in energy- and resource-scarce regions has attracted widespread attention worldwide. In this paper, the performance of a closed-cycle humidification–dehumidification desalination system with a heat pump was experimentally investigated. The system is a closed-cycle system, which includes humidifiers, a heat pump, dehumidifiers, and an air heat exchanger. The heat pump is used by the system to carry energy. The effects of different parameters on the system performance were studied. Scale and economic analyses of the system were conducted to explore the application prospects of the system. The maximum gained output ratio of the system was 4.82. The maximum freshwater production was 960 kg/h, and the cost per kilogram of freshwater was USD 0.03, which are more considerable compared with other systems. This system provides an effective way to save energy in remote areas with energy shortages and freshwater resource shortages.
Soybean Oil Epoxidation: Kinetics of the Epoxide Ring Opening Reactions
Authors: Santacesaria Elio , Turco Rosa , Russo Vincenzo , Tesser Riccardo , Di Serio Martino
Published: September 2020

The epoxide ring opening reaction (ROR) can be considered as the most important side reaction occurring in the epoxidation of soybean oil reaction network. This reaction consistently reduces the selectivity to epoxidized soybean oil (ESBO). The reaction is also important for producing polyols and lubricants. In this work, the reaction was studied in different operative conditions to evaluate the effect on ROR rate respectively: (i) The Bronsted acidity of the mineral acid (H2SO4 or H3PO4), used as catalyst for promoting the oxidation with hydrogen peroxide of formic to performic acid, that is, the reactant in the epoxide formation; (ii) the concentration of the nucleophilic agents, normally present during the ESBO synthesis like HCOOH, HCOOOH, H2O, H2O2; (iii) the stirring rate that changes the oil–water interface area and affects the mass transfer rate; (iv) the adopted temperature. Many different kinetic runs were made in different operative conditions, starting from an already epoxidized soybean oil. On the basis of these runs two different reaction mechanisms were hypothesized, one promoted by the Bronsted acidity mainly occurring at the oil–water interface and one promoted by the nucleophilic agents, in particular by formic acid. As it will be seen, the kinetic laws corresponding to the two mentioned mechanisms are quite different and this explain the divergent data reported in the literature on this subject. All the kinetic runs were correctly interpreted with a new developed biphasic kinetic model.
Novel Application of Pretreatment and Diagnostic Method Using Dynamic Pressure Fluctuations to Resolve and Detect Issues Related to Biogenic Residue Ash in Chemical Looping Gasification
Authors: Di Giuliano Andrea , Funcia Ibai , Pérez-Vega Raúl , Gil Javier , Gallucci Katia
Published: September 2020

Biogenic residues are a promising feedstock to produce liquid biofuels via chemical looping gasification (CLG), but they form ashes with a high inorganic matter content, thus causing agglomeration and deposition in CLG-fluidized beds made of oxygen carriers (OC). The aim of this work is to develop pretreatments for residual biomasses to prevent this issue. Raw forest pine (as a reference material) and wheat straw residues were considered. The latter were pretreated by torrefaction at 250, 260, or 270 °C and through the washing of torrefied biomasses. Torrefaction encouraged a de-chlorinating effect, while washing allowed the removal of 30–40% of S, 60–70% of K, and 40–50% of P. The analysis of pressure fluctuation signals (standard deviations and dominant frequencies) was utilized to verify the improvement of the performance of treated biomass in fluidized beds: three OCs were, respectively, coupled with ashes from all biomasses, then fluidized from 700 to 1000 °C at two and three times the minimum fluidization velocity. The diagnostic method used to analyze pressure fluctuations was shown to be effective for detecting the incipient fading of bubbling fluidization. This phenomenon was related to the agglomeration or the severe fragmentation of OC particles mixed with ashes, thanks to scanning electron microscopy and particle-size measurements. These characterizations and pressure fluctuations analyses confirmed the general improvement of wheat straw performances after pretreatments.
Multivariate General Compound Point Processes in Limit Order Books
Authors: Guo Qi , Remillard Bruno , Swishchuk Anatoliy
Published: September 2020

In this paper, we focus on a new generalization of multivariate general compound Hawkes process (MGCHP), which we referred to as the multivariate general compound point process (MGCPP). Namely, we applied a multivariate point process to model the order flow instead of the Hawkes process. The law of large numbers (LLN) and two functional central limit theorems (FCLTs) for the MGCPP were proved in this work. Applications of the MGCPP in the limit order market were also considered. We provided numerical simulations and comparisons for the MGCPP and MGCHP by applying Google, Apple, Microsoft, Amazon, and Intel trading data.
Spatial Agreement among Vegetation Disturbance Maps in Tropical Domains Using Landsat Time Series
Authors: Bueno Inacio T. , McDermid Greg J. , Silveira Eduarda M. O. , Hird Jennifer N. , Domingos Breno I. , Acerbi Júnior Fausto W.
Published: September 2020

Detecting disturbances in native vegetation is a crucial component of many environmental management strategies, and remote sensing-based methods are the most efficient way to collect multi-temporal disturbance data over large areas. Given that there is a large range of datasets for monitoring, analyzing, and detecting disturbances, many methods have been well-studied and successfully implemented. However, factors such as the vegetation type, input data, and change detection method can significantly alter the outcomes of a disturbance-detection study. We evaluated the spatial agreement of disturbance maps provided by the Breaks For Additive Season and Trend (BFAST) algorithm, evaluating seven spectral indices in three distinct vegetation domains in Brazil: Atlantic forest, savanna, and semi-arid woodland, by assessing levels of agreement between the outputs. We computed individual map accuracies based on a reference dataset, then ranked their performance, while also observing their relationships with specific vegetation domains. Our results indicated a low rate of spatial agreement among index-based disturbance maps, which itself was minimally influenced by vegetation domain. Wetness indices produced greater detection accuracies in comparison to greenness-related indices free of saturation. The normalized difference moisture index performed best in the Atlantic forest domains, yet performed poorest in semi-arid woodland, reflecting its specific sensitivity to vegetation and its water content. The normalized difference vegetation index led to high disturbance detection accuracies in the savanna and semi-arid woodland domains. This study offered novel insight into vegetation disturbance maps, their relationship to different ecosystem types, and corresponding accuracies. Distinct input data can produce non-spatially correlated disturbance maps and reflect site-specific sensitivity. Future research should explore algorithm limitations presented in this study, as well as the expansion to other techniques and vegetation domains across the globe.
Doppler Aerosol WiNd (DAWN) Lidar during CPEX 2017: Instrument Performance and Data Utility
Authors: Greco Steven , Emmitt George D. , Garstang Michael , Kavaya Michael
Published: September 2020

During 25 May–24 June 2017, NASA’s Doppler Aerosol WiNd (DAWN) lidar was flown on board a NASA DC-8 aircraft as part of the Convective Processes EXperiment (CPEX) airborne campaign based out of Ft. Lauderdale, FL. Central to DAWN’s deployment was the goal of obtaining high time and spatial resolution wind velocity measurements, particularly with respect to the convective life cycle. We describe the processes involved in deriving wind profiles from DAWN observations and evaluate the performance of DAWN in terms of data coverage, resolution and frequency. Comparisons with dropsonde wind measurements show an overall low bias of <0.20 m/s with a RMSD of ~1.6 and R2 > 0.92 for both u and v components for the data set as a whole (over 160 comparisons). From this CPEX experience, we find that the DAWN wind profiles are of high precision, ~30 m vertical resolution and with horizontal spacing as fine as 3–7 km, and rival dropsondes for horizontal wind coverage (aerosols and clouds permitting). Case studies illustrate the benefit of using the DAWN to investigate and characterize the dynamics of the tropical atmosphere over open ocean waters in conditions ranging from undisturbed to active convection.
Hyperspectral Image Classification Using Feature Relations Map Learning
Authors: Dou Peng , Zeng Chao
Published: September 2020

Recently, deep learning has been reported to be an effective method for improving hyperspectral image classification and convolutional neural networks (CNNs) are, in particular, gaining more and more attention in this field. CNNs provide automatic approaches that can learn more abstract features of hyperspectral images from spectral, spatial, or spectral-spatial domains. However, CNN applications are focused on learning features directly from image data—while the intrinsic relations between original features, which may provide more information for classification, are not fully considered. In order to make full use of the relations between hyperspectral features and to explore more objective features for improving classification accuracy, we proposed feature relations map learning (FRML) in this paper. FRML can automatically enhance the separability of different objects in an image, using a segmented feature relations map (SFRM) that reflects the relations between spectral features through a normalized difference index (NDI), and it can then learn new features from SFRM using a CNN-based feature extractor. Finally, based on these features, a classifier was designed for the classification. With FRML, our experimental results from four popular hyperspectral datasets indicate that the proposed method can achieve more representative and objective features to improve classification accuracy, outperforming classifications using the comparative methods.
Automated Assessment in Programming Courses: A Case Study during the COVID-19 Era
Authors: Barra Enrique , López-Pernas Sonsoles , Alonso Álvaro , Sánchez-Rada Juan Fernando , Gordillo Aldo , Quemada Juan
Published: September 2020

The COVID-19 pandemic imposed in many countries, in the short term, the interruption of face-to-face teaching activities and, in the medium term, the existence of a ‘new normal’, in which teaching methods should be able to switch from face-to-face to remote overnight. However, this flexibility can pose a great difficulty, especially in the assessment of practical courses with a high student–teacher ratio, in which the assessment tools or methods used in face-to-face learning are not ready to be adopted within a fully online environment. This article presents a case study describing the transformation of the assessment method of a programming course in higher education to a fully online format during the COVID-19 pandemic, by means of an automated student-centered assessment tool. To evaluate the new assessment method, we studied students’ interactions with the tool, as well as students’ perceptions, which were measured with two different surveys: one for the programming assignments and one for the final exam. The results show that the students’ perceptions of the assessment tool were highly positive: if using the tool had been optional, the majority of them would have chosen to use it without a doubt, and they would like other courses to involve a tool like the one presented in this article. A discussion about the use of this tool in subsequent years in the same and related courses is also presented, analyzing the sustainability of this new assessment method.
Partial Grazing Exclusion as Strategy to Reduce Land Degradation in the Traditional Brazilian Faxinal System: Field Data and Farmers’ Perceptions
Authors: Antoneli Valdemir , Pulido Fernández Manuel , de Oliveira Taís , Lozano-Parra Javier , Bednarz João Anésio , Vrahnakis Michael , García-Marín Ramón
Published: September 2020

Land degradation is becoming a serious concern for the sustainability of traditional agrosilvopastoral systems such as the Brazilian faxinal. The IAP (Environmental Institute of the Federal State of Paraná) is favoring the partial exclusion to grazing for 10 years as strategy both to recover degraded lands and to reduce negative effects. Nevertheless, this strategy is being followed by a reduced number of owners (faxinalenses) and little is known about the effectiveness of these measures due to either lack of field data and knowledge on faxinalenses’ perceptions. We have identified one out of few farms that have followed this official strategy and, within the same farm, we have compared values of some soil properties (bulk density, porosity, water holding capacity, penetration resistance, soil organic matter and root density) from an excluded area to grazing for 10 years, with some areas that represent a gradient of grazing intensity (natural forest, secondary forest, degraded forest, grassland and a degraded area by pigs). In addition, we have interviewed some faxinalenses (one faxinal farm is owned by several farmers) in order to better understand how the risk of land degradation is perceived by them and their opinions about the usefulness of partial grazing exclusion as a strategy to improve the management of their farms. The results have shown that soil quality increases considerably as a consequence of grazing exclusion, in spite of land has been used for cropping yerba mate during the exclusion time, but faxinalenses are not mindful of these benefits and they are no longer interested in excluding other areas of their farms. They think this strategy is simply an obligation imposed by the environmental authority.
Urban Sustainability Evaluation Based on the DPSIR Dynamic Model: A Case Study in Shaanxi Province, China
Authors: Liu Shidong , Ding Peiyi , Xue Binrui , Zhu Hongbing , Gao Jun
Published: September 2020

The sustainability of urban cities has been the focus of significant academic research in recent years and is emphasized in Goal 11 of the Sustainable Development Goals (SDGs). In this study, we adopted the Drive-Pressure-State-Impact-Response model (DPSIR) to promote a conceptual study of sustainable development index (SDI) to compare the different urban sustainable development status and try to find the factors that affect the urban sustainable development. The framework of indicators we used is mainly based on Goal 11 of the SDGs’ targets and indicators. We chose six cities in the Shaanxi Province of China and studied them from 2008 to 2018. The results show that: (1) the sustainable development of urban cities is greatly influenced by China’s national economic development plans and urban development strategies; (2) the economic growth and management level of authorities can significantly promote urban sustainability; (3) the urban sustainability of the six cities in Shaanxi Province showed a significant imbalance and this imbalance affected the overall development of the region; (4) compared with Guanzhong urban agglomeration, Shannan urban agglomeration is subject to the policy needs of environmental protection in the Qinling mountain area and its economic development is restricted; therefore, its urban sustainability is relatively low. Theoretical contributions are presented to assist in addressing these challenges and to support policies and initiatives that move these cities in China towards achieving SDG 11.
A Novel Nitrogen Removal Technology Pre-Treating Chicken Manure, Prior to Anaerobic Digestion
Authors: Kirby Marie E. , Mirza Muhammad W. , Davies James , Ward Shane , Theodorou Michael K.
Published: September 2020

Chicken manure is an agricultural by-product that is a problematic feedstock for anaerobic digestion due to its high nitrogen content inhibiting methane yields. This research examines a novel pilot-scale method of ammonia stripping, the nitrogen recovery process (NRP) developed by Alchemy Utilities Ltd. The NRP was designed to remove and recover nitrogen from chicken manure and two different operating conditions were examined. Both operating conditions demonstrated successful nitrogen removal and recovery. The biochemical methane potential assays were used to compare the digestibility of the NRP-treated chicken manures to that of a fresh chicken manure control. Overall, the biochemical methane potential assays demonstrated that some NRP-treated chicken manure treatments produced significantly more methane compared to untreated manure, with no inhibition occurring in relation to ammonium. However, some of the NRP-treated chicken manures produced similar or lower methane yields compared to fresh chicken manure. The NRP requires further development to improve the efficiency of the pilot-scale unit for commercial-scale operation and longer-term continuous anaerobic digestion trials are required to determine longer-term methane yield and ammonium inhibition effects. However, these initial results clearly demonstrate the technology’s potential and novel application for decentralised, on-farm nitrogen recovery and subsequent anaerobic digestion of chicken manure.
Energy Retrofit in European Building Portfolios: A Review of Five Key Aspects
Authors: Ruggeri Aurora Greta , Gabrielli Laura , Scarpa Massimiliano
Published: September 2020

The research about energy efficiency in buildings has exponentially increased during the last few years. Nevertheless, both research and practice still cannot rely on complete methodologies tailored for building portfolios as a whole, because the attention has always been drawn to individual premises. Yet, energy efficiency analyses need to go beyond the single building perspective and incorporate strategic district approaches to optimize the retrofit investment. For this purpose, several aspects should be considered simultaneously, and new methodologies should also be promoted. Therefore, this paper aims to discuss energy retrofit campaigns in building portfolios, drawing an exhaustive and updated review about the challenge of jumping from the single-building perspective to a stock-based analysis. This research discusses the publications available on the topic from five key aspects that are all essential steps in achieving a complete and reliable study of energy efficiency at a portfolio level. They are energy modelling and assessment, energy retrofit design, decision-making criteria assessment, optimal allocation of (financial) resources and risk valuation. This review, therefore, advocates for joint consideration of the problem as a basis on which to structure further disciplinary developments. Research gaps are highlighted, and new directions for future research are suggested.
Capabilities of Corporate Volunteering in Strengthening Social Capital
Authors: Glińska-Neweś Aldona , Górka Joanna
Published: September 2020

Corporate volunteering is becoming increasingly popular among the ways that companies manifest their social responsibility. Its popularity is due to the variety of benefits it brings to all parties. Among other things, it is capable of strengthening social capital, although specific phenomena and processes related to this remain largely unexplored. The aim of the paper is to identify how the frequency and intensity of contacts between volunteers and beneficiaries affect social capital building. The empirical study was based on a qualitative research approach and conducted in the form of individual semi-structured interviews with employees responsible for corporate volunteering in their companies. The results of the study suggest that corporate volunteering strengthens social capital regardless of the extent to which volunteers have contact with the beneficiaries of their volunteering work. However, the frequency and intensity of this contact may affect specific dimensions of social capital, leading to the strengthening of bonding social capital and/or bridging social capital.
Energy- and Environment-Biased Technological Progress Induced by Different Types of Environmental Regulations in China
Authors: Zhou Xiaoxiao , Xia Ming , Zhang Teng , Du Juntao
Published: September 2020

With the increasing pressure of energy exhaustion and environmental degradation, environmental regulation is considered as a strategy to achieve sustainable development. This paper specifically analyzes the mechanism of multi-dimensional environmental regulations on energy- and environment-biased technological progress, and empirically detects the differentiated impacts using China’s panel data from the period 2000–2016, employing the generalized method of moments (GMM) and a dynamic threshold model. The results reveal that: (1) command-and-control regulation (CCR) promotes energy-saving and pollution abatement technological progress. Market-based regulation (MBR) stimulates energy-saving technological progress, while informal regulation (IR) only accelerates environment conservation technological progress. (2) There are threshold effects on the relationship of environmental regulations and biased technological progress. With economic developments, CCR and MBR have positive effects on energy- and environment-related technological progress, whilst IR fails to promote backstop and pollution abatement technological progress. The clear diversity in the impacts of different environment regulations on biased technological progress provides new insights for the optimal future policy design.
Quantifying the Effect of Crown Vertical Position on Individual Tree Competition: Total Overlap Index and Its Application in Sustainable Forest Management
Authors: Wang Boheng , Bu Yuankun , Tao Guanhu , Yan Chenran , Zhou Xiaolu , Li Weizhong , Zhao Pengxiang , Yang Yanzheng , Gou Ruikun
Published: September 2020

Competition is an essential driving factor that influences forest community sustainability, yet measuring it poses several challenges. To date, the Competition Index (CI) has generally been the tool of choice for quantifying actual competition. In this study, we proposed using the Total Overlap Index (TOI), a CI in which the Area Overlap (AO) index has been adapted and modified to consider the “shading” and “crowding” effects in the vertical dimension. Next, based on six mixed forest plots in Xiaolong Mountain, Gansu, China, we assessed the results to determine the TOI’s evaluation capability. Individual-tree simulation results showed that compared to the modified Area Overlap index (AOM), the TOI has superior quantification capability in the vertical direction. The results of the basal area increment (BAI) model showed that the TOI offers the best evaluation capability among the four considered CIs in mixed forest (with Akaike Information Criterion (AIC) of 1041.60 and log-likelihood (LL) of −511.80 in the model fitting test, mean relative error of −28.67%, mean absolute percent error of 117.11%, and root mean square error of 0.7993 in cross-validation). Finally, the TOI was applied in the Kaplan–Meier survival analysis and Cox proportional-hazards analysis. The Kaplan–Meier survival analysis showed a significant difference between the low- (consisting of trees with the TOI lower than 1) and high-competition (consisting of trees with the TOI higher than 1) groups’ survival and hazard curves. Moreover, the results of the Cox proportional-hazards analysis exhibited that the trees in the low-competition group only suffered 34.29% of the hazard risk that trees in the high-competition group suffered. Overall, the TOI expresses more dimensional information than other CIs and appears to be an effective competition index for evaluating individual tree competition. Thus, the competition status quantified using this method may provide new information to guide policy- and decision-makers in sustainable forest management planning projects.
Social Learning and Transdisciplinary Co-Production: A Social Practice Approach
Authors: Slater Kimberley , Robinson John
Published: September 2020

To address the challenge of achieving social learning in support of transformative change to sustainability, this paper develops an analytical framework that applies a social practice theory (SPT) lens to illuminate the constituent elements and dynamics of social learning in the context of transdisciplinary coproduction for sustainability transitions. Adopting an SPT approach affords a means of interpreting concrete practices at the local scale and exploring the potential for scaling them up. This framework is then applied to a real-world case at the urban neighbourhood scale in order to illustrate how social learning unfolded in a grassroots transdisciplinary coproduction process focused on climate action. We find that a social practice perspective illuminates the material and nonmaterial dimensions of the relationship between social learning and transdisciplinary coproduction. In decoupling these properties from individual human agency, the SPT perspective affords a means of tracing their emergence among social actors, generating a deeper understanding of how social learning arises and effects change, and sustainability can be reinforced.
Some New Newton’s Type Integral Inequalities for Co-Ordinated Convex Functions in Quantum Calculus
Authors: Vivas-Cortez Miguel , Aamir Ali Muhammad , Kashuri Artion , Bashir Sial Ifra , Zhang Zhiyue
Published: September 2020

Some recent results have been found treating the famous Simpson’s rule in connection with the convexity property of functions and those called generalized convex. The purpose of this article is to address Newton-type integral inequalities by associating with them certain criteria of quantum calculus and the convexity of the functions of various variables. In this article, by using the concept of recently defined q1q2 -derivatives and integrals, some of Newton’s type inequalities for co-ordinated convex functions are revealed. We also employ the limits of q1,q2→1− in new results, and attain some new inequalities of Newton’s type for co-ordinated convex functions through ordinary integral. Finally, we provide a thorough application of the newly obtained key outcomes, these new consequences can be useful in the integral approximation study for symmetrical functions, or with some kind of symmetry.
LISA Sensitivity to Gravitational Waves from Sound Waves
Authors: Schmitz Kai
Published: September 2020

Gravitational waves (GWs) produced by sound waves in the primordial plasma during a strong first-order phase transition in the early Universe are going to be a main target of the upcoming Laser Interferometer Space Antenna (LISA) experiment. In this short note, I draw a global picture of LISA’s expected sensitivity to this type of GW signal, based on the concept of peak-integrated sensitivity curves (PISCs) recently introduced in two previous papers. In particular, I use LISA’s PISC to perform a systematic comparison of several thousands of benchmark points in ten different particle physics models in a compact fashion. The presented analysis (i) retains the complete information on the optimal signal-to-noise ratio, (ii) allows for different power-law indices describing the spectral shape of the signal, (iii) accounts for galactic confusion noise from compact binaries, and (iv) exhibits the dependence of the expected sensitivity on the collected amount of data. An important outcome of this analysis is that, for the considered set of models, galactic confusion noise typically reduces the number of observable scenarios by roughly a factor of two, more or less independent of the observing time. The numerical results presented in this paper are also available in the online repository Zenodo.
Conformal Invariance of Characteristic Lines in a Class of Hydrodynamic Models
Authors: Wacławczyk Marta , Grebenev Vladimir N. , Oberlack Martin
Published: September 2020

This paper addresses the problem of the existence of conformal invariance in a class of hydrodynamic models. For this we analyse an underlying transport equation for the one-point probability density function, subject to zero-scalar constraint. We account for the presence of non-zero viscosity and large-scale friction. It is shown analytically, that zero-scalar characteristics of this equation are invariant under conformal transformations in the presence of large-scale friction. However, the non-zero molecular diffusivity breaks the conformal group (CG). This connects our study with previous observations where CG invariance of zero-vorticity isolines of the 2D Navier–Stokes equation was analysed numerically and confirmed only for large scales in the inverse energy cascade. In this paper, an example of CG is analysed and possible interpretations of the analytical results are discussed.
Multi Body Dynamic Equations of Belt Conveyor and the Reasonable Starting Mode
Authors: Guo Yongbo , Wang Fansheng
Published: September 2020

Based on the rigid finite element method and multibody dynamics, a discrete model of a flexible conveyor belt considering the material viscoelasticity is established. RFE (rigid finite element) and SDE (spring damping element) are used to describe the rigidity and flexibility of a conveyor belt. The dynamic differential equations of the RFE are derived by using Lagrange’s equation of the second kind of the non-conservative system. The generalized elastic potential capacity and generalized dissipation force of the SDE are considered. The forward recursive formula is used to construct the conveyor belt model. The validity of dynamic equations of conveyor belt is verified by field test. The starting mode of the conveyor is simulated by the model.
The Effect of Using New Synbiotics on the Turkey Performance, the Intestinal Microbiota and the Fecal Enzymes Activity in Turkeys Fed Ochratoxin A Contaminated Feed
Authors: Śliżewska Katarzyna , Markowiak-Kopeć Paulina , Sip Anna , Lipiński Krzysztof , Mazur-Kuśnirek Magdalena
Published: September 2020

The feed supplementation of probiotic microorganisms is a promising method for detoxification of ochratoxin A (OTA) in poultry. The aim of the study was to investigate the effect of newly elaborated synbiotics on the turkey performance, the intestinal microbiota and its enzymatic activity in turkeys (0–15 weeks) fed OTA contaminated feed (198.6–462.0 µg/kg) compared to control group (OTA-free feed). The studies determined the composition of intestinal microorganisms by the culture method and the activity of fecal enzymes by spectrophotometry. It was found that OTA had an adverse effect on the body weight, the intestinal microbiota and the fecal enzymes activity in turkeys. On the other hand, synbiotics resulted in an increase in the count of beneficial bacteria while reducing the number of potential pathogens in the digestive tract. Moreover, synbiotics caused an increase in the activity of α-glucosidase and α-galactosidase, while decreasing the activity of potentially harmful fecal enzymes (β-glucosidase, β-galactosidase, β-glucuronidase) in the turkey’s excreta. Results indicate a beneficial effect of elaborated synbiotics on the health of turkeys and a reduction of the negative impact of OTA contaminated feed. These synbiotics can be successfully used as feed additives for turkeys.
Staphylococcal Enterotoxin C—An Update on SEC Variants, Their Structure and Properties, and Their Role in Foodborne Intoxications
Authors: Etter Danai , Schelin Jenny , Schuppler Markus , Johler Sophia
Published: September 2020

Staphylococcal enterotoxins are the most common cause of foodborne intoxications (staphylococcal food poisoning) and cause a wide range of diseases. With at least six variants staphylococcal enterotoxin C (SEC) stands out as particularly diverse amongst the 25 known staphylococcal enterotoxins. Some variants present unique and even host-specific features. Here, we review the role of SEC in human and animal health with a particular focus on its role as a causative agent for foodborne intoxications. We highlight structural features unique to SEC and its variants, particularly, the emetic and superantigen activity, as well as the roles of SEC in mastitis and in dairy products. Information about the genetic organization as well as regulatory mechanisms including the accessory gene regulator and food-related stressors are provided.
Evaluation of Glycosylated FlpA and SodB as Subunit Vaccines Against Campylobacter jejuni Colonisation in Chickens
Authors: Vohra Prerna , Chintoan-Uta Cosmin , Terra Vanessa S. , Bremner Abi , Cuccui Jon , Wren Brendan W. , Vervelde Lonneke , Stevens Mark P.
Published: September 2020

Campylobacter jejuni is the leading bacterial cause of human gastroenteritis worldwide and the handling or consumption of contaminated poultry meat is the key source of infection. C. jejuni proteins FlpA and SodB and glycoconjugates containing the C. jejuni N-glycan have been separately reported to be partially protective vaccines in chickens. In this study, two novel glycoproteins generated by protein glycan coupling technology—G-FlpA and G-SodB (with two and three N-glycosylation sites, respectively)—were evaluated for efficacy against intestinal colonisation of chickens by C. jejuni strain M1 relative to their unglycosylated variants. Two independent trials of the same design were performed with either a high challenge dose of 107 colony-forming units (CFU) or a minimum challenge dose of 102 CFU of C. jejuni M1. While antigen-specific serum IgY was detected in both trials, no reduction in caecal colonisation by C. jejuni M1 was observed and glycosylation of vaccine antigens had no effect on the outcome. Our data highlight inconsistencies in the outcome of C. jejuni vaccination trials that may reflect antigen-, challenge strain-, vaccine administration-, adjuvant- and chicken line-specific differences from previously published studies. Refinement of glycoconjugate vaccines by increasing glycosylation levels or using highly immunogenic protein carriers could improve their efficacy.
Drag Force Modeling of Surface Wave Dissipation by a Vegetation Field
Authors: Yang Tze-Yi , Chan I-Chi
Published: September 2020

In this paper, we explore the use of coastal vegetation as a natural barrier to defend our shoreline from hazards caused by large wind waves, storm surges, and tsunamis. A numerical model based on XBeach is employed to evaluate the wave damping by vegetation. An explicit formula for the required drag coefficient used to help describe the additional force imposed by the vegetation is developed through a series of numerical experiments. Overall, our predictions agree reasonably with available laboratory data in the literature for various incident wave conditions and vegetation configurations. Our analysis suggests that a small unvegetated open space in the middle of a vegetation strip does not have a significant impact on the amount of wave height attenuation at the exit of the vegetated bed.
CFD Modelling of the Transport of Soluble Pollutants from Sewer Networks to Surface Flows during Urban Flood Events
Authors: Beg Md , Rubinato Matteo , Carvalho Rita , Shucksmith James
Published: September 2020

Surcharging urban drainage systems are a potential source of pathogenic contamination of floodwater. While a number of previous studies have investigated net sewer to surface hydraulic flow rates through manholes and gullies during flood events, an understanding of how pollutants move from sewer networks to surface flood water is currently lacking. This paper presents a 3D CFD model to quantify flow and solute mass exchange through hydraulic structures featuring complex interacting pipe and surface flows commonly associated with urban flood events. The model is compared against experimental datasets from a large-scale physical model designed to study pipe/surface interactions during flood simulations. Results show that the CFD model accurately describes pipe to surface flow partition and solute transport processes through the manhole in the experimental setup. After validation, the model is used to elucidate key timescales which describe mass flow rates entering surface flows from pipe networks. Numerical experiments show that following arrival of a well-mixed solute at the exchange structure, solute mass exchange to the surface grows asymptotically to a value equivalent to the ratio of flow partition, with associated timescales a function of the flow conditions and diffusive transport inside the manhole.
Mechanistic Study of Pb2+ Removal from Aqueous Solutions Using Eggshells
Authors: Hamouda Mohamed A. , Sweidan Haliemeh , Maraqa Munjed A. , El-Hassan Hilal
Published: September 2020

This study investigates the impact of eggshell particle size and solid-to-water (s/w) ratio on lead (Pb2+) removal from aqueous solution. Collected raw eggshells were washed, crushed, and sieved into two particle sizes (<150 and 150–500 µm). Batch Pb2+ removal experiments were conducted at different s/w ratios with initial Pb2+ concentrations of up to 70 mg/L. The contribution of precipitation to Pb2+ removal was simulated by quantifying removal using eggshell water, whereas sorbed Pb2+ was quantified by acid digestion. Results indicated that eggshell particle sizes did not affect Pb2+ removal. High removal (up to 99%) of Pb2+ was achieved for low initial Pb2+ concentrations (<30 mg/L) across all s/w ratios studied. However, higher removal capacity was observed at lower s/w ratios. In addition, results confirmed that precipitation played a major role in the removal of Pb2+ by eggshells. Yet, this role decreased as the s/w ratio and initial concentration of Pb2+ increased. A predictive relationship that relates the normalized removal capacity of eggshells to the s/w ratio was developed to potentially facilitate the design of the reactor.
The Prediction of Oceanic Mesoscale Eddy Properties and Propagation Trajectories Based on Machine Learning
Authors: Wang Xin , Wang Huizan , Liu Donghan , Wang Wenke
Published: September 2020

Mesoscale eddies play an important role in ocean circulation, material energy exchange and variation of ocean environments. Machine learning methods can efficiently process massive amounts of data and automatically learn the implicit features, thus providing a new approach to eddy prediction research. Using the mesoscale eddy trajectory data derived from multimission satellite altimetry, we propose relevant machine learning models based on long short-term memory network (LSTM) and the extra trees (ET) algorithm for the prediction of eddy properties and propagation trajectories. Characteristic factors, including attribute features and past eddy displacements, were exploited to construct prediction models with high effectiveness and few predictors. To study their effects at different forecasting times, we separately trained the models by rebuilding the corresponding relationship between eddy samples and labels. In addition, the variation characteristics and the predictability of eddy properties and propagation trajectories were discussed from the prediction results. Cross-validation shows that at different prediction times, our method is superior to previous methods in terms of the mean absolute error (MAE) of eddy properties and the root mean square error (RMSE) of propagation. The stable variation in eddy properties makes the prediction more dependent on the historical time series than that of a propagation forecast. The short-term propagation prediction of eddies contained more noise than long-term predictions, and the long-term predictions revealed a more significant trend. Finally, we discuss the effect of eddy properties on the prediction ability of the eddy propagation trajectory.
Applicability of Kinematic Wave Model for Flood Routing under Unsteady Inflow
Authors: Zheng Hanwu , Huang Er , Luo Ming
Published: September 2020

This study implemented kinematic wave and dynamic wave approximation of flood routing for a prismatic rectangular channel. The results of the two methods were compared by differences in maximum flow depth, and the applicability of kinematic wave equation was discussed. The influences of hydraulic and geometrical factors on the applicability of kinematic wave equation were considered. It was found that a portion of the numerical results violated existing criteria used to indicate the applicability of kinematic wave equation, particularly when geometrical and hydraulic factors were considered together. This is because the characteristics of upstream inflow were rarely or incompletely considered in these criteria. Therefore, the present study proposed a new criterion. The theoretical influence of all factors was considered using three parameters, namely, KF02, ηts/T0′ and Qbottom/Qpeak (K, F0, ηts, T0′, Qbottom, and Qpeak represent the kinematic wave number, Froude number, the time span of discharge exceeding 90% of maximum discharge in hydrograph, wave travel time in the channel, base flow discharge, and peak discharge, respectively, while the subscript 0 represent the value of reference discharge). The influences of these three parameters were illustrated by the momentum equation of one-dimensional Saint-Venant equation. The numerical results showed that the value of ηts/T0′ (KF02)D could be used to determine the relative error ξh of kinematic wave equation. In addition, for each Qbottom/Qpeak the value of ηts/T0′ (KF02)D used to depict the same relative error ξh was different. This new criterion was validated using two real case studies, and it showed a good performance.
Comparison of Surface Roughness and Transport Processes of Sawed, Split and Natural Sandstone Fractures
Authors: Frank Sascha , Heinze Thomas , Wohnlich Stefan
Published: September 2020

In single fractures, dispersion is often linked to the roughness of the fracture surfaces and the resulting local aperture distribution. To experimentally investigate the effects of diverse fracture types and surface morphologies in sandstones, three fractures were considered: those generated by sawing and splitting, and a natural sedimentary fracture. The fracture surface morphologies were digitally analyzed and the hydraulic and transport parameters of the fractures were determined from Darcy and the tracer tests using a fit of a continuous time random walk (CTRW) and a classical advection–dispersion equation (ADE). While the sawed specimen with the smoothest surface had the smallest dispersivity, the natural fracture has the largest dispersivity due to strong anisotropy and non-matching fracture surfaces, although its surface roughness is comparable to the split specimen. The parameterization of the CTRW and of the ADE agree well for β > 4 of the truncated power law. For smaller values of β, non-Fickian transport processes are dominant. Channeling effects are observable in the tracer breakthrough curves. The transport behavior in the fractures is controlled by multiple constraints such as several surface roughness parameters and the equivalent hydraulic aperture.
Treatment of Bio-Treated Coking Wastewater by Catalytic Ozonation with Semi-Batch and Continuous Flow Reactors
Authors: He Can , Wang Jianbing , Xu Heng , Ji Xiangyu , Wang Weiyi , Xu Xieyang
Published: September 2020

In this work, the treatment of bio-treated coking wastewater (BCW) by catalytic ozonation was conducted in semi-batch and continuous flow reactors. The kinetics of chemical oxygen demand (COD) removal were analyzed using BCWs from five coking plants. An integral reactor with catalytic ozonation stacked by ozone absorption (IR) was developed, and its efficiency was studied. The catalyst of MnxCe1-xO2/γ-Al2O3 was efficient in the catalytic ozonation process for the treatment of various BCWs. The chemical oxygen demand (COD) removal efficiencies after 120 min reaction were 64–74%. The overall apparent reaction rate constants were 0.0101–0.0117 min−1, which has no obvious relationship with the initial COD of BCW and pre-treatment biological process. The IR demonstrated the highest efficiency due to the enhancement of mass transfer and the utilization efficiency of ozone. Bypass internal circulation can further improve the reactor efficiency. The optimal results were obtained with the ozone absorption section accounting for 19% of the valid water depth in the reactor and 250% of circulation flow ratio. The long-term and full-scale application of the novel reactor in a continuous mode indicated stable removal of COD and polycyclic aromatic hydrocarbons (PAHs). The results showed that the system of IR is a promising reactor type for tertiary treatment of coking wastewater by catalytic ozonation.