bluuebunny/crossref_metadata_2025 huggingface dataset:
The Activity of Natural Radionuclides Th-232, Ra-226, K-40, and Na-22, and Anthropogenic Cs-137, in the Water, Sediment, and Common Carp Produced in Purified Wastewater from a Slaughterhouse
Authors: Pelić Miloš , Mihaljev Željko , Živkov Baloš Milica , Popov Nenad , Gavrilović Ana , Jug-Dujaković Jurica , Ljubojević Pelić Dragana
Published: August 2023

In the immediate vicinity of a slaughterhouse, a fishpond was built that uses treated wastewater from the slaughterhouse, and in this way integrates a new value chain in the form of purification and use of slaughterhouse wastewater in an aquaculture production system. The negative aspect of such integrated production systems is the concern related to the safety of fish meat produced in these systems. The aim of this research was to determine the activity level of Cs-137, K-40, Ra-226, Th-232, and Na-22 in water, sediment, and carp harvested from a pond that received purified water from a slaughterhouse. All samples were collected in spring and in autumn. The activity concentrations of selected radionuclides were determined by gamma spectrometry (HPG-e detector). The activity of K-40 in water samples ranged from 8.4 to 15.6 Bq L−1. The specific activity concentrations of the Ra-226 in water samples ranged between 1.02 ± 0.11 and 2.76 ± 0.49 Bq kg−1. The results of the activity of natural radionuclides (Bq kg−1) in the sediment samples were in the following ranges: 440–629 for K-40, 10.7–15 for Th-232, 20.2–44.4 for Ra-226, and 1.08–2.04 for Na-22, with average values of 531.75, 12.3, 32.97, and 1.75, for K-40, Th-232, Ra-226, and Na-22, respectively. The average content of Th-232 (12.3 Bq kg−1) did not exceed the world UNSCEAR average value of 45, while the average content of Ra-226 (32.97 Bq kg−1) slightly exceeded the UNSCEAR value of 32 Bq kg−1. The K-40 concentration activity of 531.75 Bq kg−1 was much higher than the UNSCEAR weighted average value of 420 Bq kg−1. In the fish samples, natural radionuclide Na-22 was detected only in autumn (2.74 ± 0.32 Bq kg−1). Results of Cs-137 and Th-232 concentrations were below the method detection limit in all samples, ˂0.5 Bq kg−1 and ˂2 Bq kg−1, respectively. The activity of K-40 was in the range from 121 to 160 Bq kg−1. The activity concentrations of the Ra-226 in carp samples ranged between 9.5 and 54.4 Bq kg−1. The results indicate that consumption of fish meat obtained from this integrated system does not pose a significant health concern in the case of the usual consumption rate that is typical for the population of Serbia. Almost no statistically significant seasonal variations were observed.
Research on Carbon Emission Structure and Model in Low-Carbon Rural Areas: Bibliometric Analysis
Authors: Yu Zejun , Wang Yao , Zhao Bin , Li Zhixin , Hao Qingli
Published: August 2023

As the energy crisis and environmental problems are exacerbated, rural carbon emissions have gradually attracted increasing attention. Meanwhile, rural areas have the important function of ecological carbon sequestration, so the research field of carbon emissions has gradually expanded from urban to rural areas in recent years. To systematically sort out the research progress regarding low-carbon rural areas, a total of 583 papers published during 2013–2023 were acquired through the bibliometric analysis method from the “professional field of science of building technology” in the core database of Web of Science. Then, the research stage, author cooperation, institutional cooperation, national distribution, and keyword co-occurrence of “low-carbon rural areas” were analyzed via data visualization analysis software VOSviewer, and the current hot issues, such as carbon emission calculation list and elements, carbon emission measurement method/model, and energy saving and emission reduction paths, were further summarized and reviewed. The statistical analysis results show that: (1) in most of the current research on rural carbon emissions, geographical characteristics and rural carbon emissions have been rarely analyzed; (2) there is a lack of interdisciplinary research, e.g., less cooperation with geographic information or other disciplines; (3) the differences and characteristics of rural carbon emission factors in different economies and regions have rarely been analyzed. Based on the analysis, this research pointed out that future research can be comprehensively carried out in formulating rural carbon emission inventory, establishing a multi-scale and multi-regional statistical method and so on. This research also provides a comprehensive analysis and summary of the existing research on the structure and model of carbon emissions in low-carbon rural areas and also presents the problems that need to be paid attention to in the future research, pointing out the research direction for relevant scholars.
Financial Analysis and Survival Research of the Visegrad Countries’ Health Industries
Authors: Vitéz-Durgula Judit , Dunay Anna , Thalmeiner Gergő , Vajai Balázs , Pataki László
Published: August 2023

Our study examined the financial situation of small and medium-sized enterprises (SMEs) in the health industry of the Visegrad Four (V4: Czech Republic, Poland, Slovakia, Hungary) in the period 2008–2021. The basis of the analysis was the reports available in the Crefoport database. During the analysis, we took into account four key financial indicators (liquidity, profitability (ROA), efficiency, capital structure) and used the Kaplan–Meier survival estimator to examine the viability of enterprises. In our study, we draw attention to the national economic importance of healthcare SMEs in the CEE region, and within that, in the V4 countries during the period of Industry 4.0 and the COVID-19 pandemic. Our research goal is to examine the life expectancy of healthcare enterprises operating in Hungary at the time of their establishment, in relation to the SMEs of the other three countries. The health industry SMEs of the V4 countries showed positive growth (+18%) in the period under review compared to the average of the 3 years before the COVID-19 pandemic, in the average of the first 3 years of the COVID-19 pandemic. The study paid particular attention to the life expectancy of businesses at the time of establishment. According to our results, the life expectancy of healthcare enterprises operating in Hungary at the time of establishment is high, but it does not differ significantly from that of the other examined countries. Our study highlights that the health industry SMEs of the examined countries do not need financial support; they are standing on a stable footing, which provides them with an excellent opportunity to either expand abroad or introduce innovations.
Design of an Optimum Compact EGR Cooler in a Heavy-Duty Diesel Engine towards Meeting Euro 7 Emission Regulations
Authors: Gumus Emrah , Otkur Murat
Published: August 2023

Exhaust gas recirculation (EGR) has been an efficient emission treatment strategy employed in internal combustion engines (ICEs) to cope with NOx emission limits since the introduction of Euro 4 regulations for heavy-duty commercial vehicles. A portion of the exhaust gas is fed back into the intake port, replacing O2 in the fresh air with inert CO2 from the exhaust gas, resulting in a reduction in the combustion temperature and, hence, a reduction in NOx emissions. Considering the high exhaust temperature, this process increases the charge mixture temperature and degrades the volumetric efficiency of the engine. EGR coolers have been introduced as vital parts of EGR exhaust treatment systems with the aim of reducing the intake port temperature to increase volumetric efficiency and further reduce combustion temperatures. EGR coolers are heat exchangers (HXs) that generally employ engine coolant to reduce the EGR temperature with effectiveness values around 0.7~0.85 and downgrade with engine usage owing to soot deposition. Increasing the effectiveness of the EGR cooler has a positive effect on engine volumetric efficiency and reduces NOx, particulate matter (PM), and fuel consumption. The current study involved the design of a microchannel HX for a 500 PS heavy-duty Euro 6 diesel engine EGR cooler. The mechanical and thermal-hydraulic design calculations of the proposed HX were performed using Mathematica software. The optimum HX dimensions for the required boundary conditions were determined, and the performance of the EGR cooler was analyzed for the current and proposed options. Furthermore, Diesel-RK software was used to model the engine performance with NOx, PM, CO2 emissions, and fuel consumption predictions. The results show that the newly proposed microchannel HX design improves NOx, PM, and specific fuel consumption by 6.75%, 11.30%, and 0.65%, respectively.
Externalities of Pesticides and Their Internalization in the Wheat–Maize Cropping System—A Case Study in China’s Northern Plains
Authors: Li Qiang , Si Ruotong , Guo Sen , Waqas Muhammad Ahmed , Zhang Baogui
Published: August 2023

When the production or use of a product imposes a cost or benefit on a third party, this is referred to as an externality. Externalities of pesticides are associated with social and environmental costs. However, there is still a lack of a systematic method for evaluating and internalizing the externalities of pesticides. This study utilizes the pesticide’s environmental impact quotient and environmental accounting methods to assess the external costs associated with pesticide usage in the winter-wheat–summer-maize cropping system in China’s northern plains, with a specific focus on the pesticide use in Botou City during the year 2020 as a case study. Additionally, we introduce the concept of the net external value of pesticides and propose a methodology for its internalization, aiming to quantify the external costs induced by pesticide usage and explore the possibility of integrating them into market transactions. The results showed that the total external costs of pesticide use are 423.9 USD ha−1, with a positive external value of 171.9 USD ha−1 and a net external value of −252.0 USD ha−1. The negative external costs associated with pesticide use outweigh the positive external values. External costs varied significantly according to environmental receptors, after retaining two significant figures: applicators accounted for 45% of the total external costs, followed by pickers (32%), consumers (11%), groundwater (4.5%), fish (3.9%), beneficial insects (1.7%), birds (1.3%), and bees (1.1%). The external costs of maize cultivation were 33% higher than those of wheat cultivation. The application of herbicides resulted in the highest external costs compared with fungicides and insecticides. Based on the internalization of the results, imposing an ecological tax on pesticide users is recommended, with rates of 3.29% for wheat and 6.76% for maize. This research contributes to sustainable agricultural development by providing valuable insights for farmers in selecting environmentally friendly pesticides and informing the implementation of ecological taxes on pesticide usage.
New Three Wave and Periodic Solutions for the Nonlinear (2+1)-Dimensional Burgers Equations
Authors: Razzaq Waseem , Zafar Asim , Alsharidi Abdulaziz Khalid , Alomair Mohammed Ahmed
Published: August 2023

This research paper is about the new three wave, periodic wave and other analytical wave solutions of (2+1)-Dimensional Burgers equations by utilizing Hirota bilinear and extended sinh-Gordon equation expansion (EShGEE) schemes. Achieved solutions are verified and demonstrated by different plots with the use of Mathematica 11.01 software. Some of the achieved solutions are also described graphically by two-dimensional, three-dimensional and contour plots. The gained solutions are helpful for the future study of concerned models. Finally, these two schemes are simple, fruitful and reliable to handle the nonlinear PDEs.
A Class of Discrete Memristor Chaotic Maps Based on the Internal Perturbation
Authors: Yihyis Worke Adugna , He Shaobo , Tang Zhouqing , Wang Huihai
Published: August 2023

Further exploration into the influence of a memristor on the behavior of chaotic systems deserves attention. When constructing memristor chaotic systems, it is commonly believed that increasing the number of memristors will lead to better system performance. This paper proposes a class of chaotic maps with different discrete memristors, achieved through internal perturbation based on the Sine map. The I-V curve of the discrete memristor has a symmetrical structure. The dynamic characteristics of the designed system are analyzed using the chaotic attractor phase diagram, Lyapunov exponent (LE) spectrum, and bifurcation diagram. Numerical simulations demonstrate that internal perturbations of discrete memristors enhance the Sine map’s chaotic characteristics, expand the chaos range, and improve the ergodicity and LE value. Moreover, the type of discrete memristors has a significant impact on the dynamic characteristics of the system, while the number of discrete memristors has little influence. Therefore, in this paper, a direction for the design of a discrete memristor chaotic system is provided. Finally, a discrete memristor chaotic map with a simple structure and better performance is selected. Based on this, a pseudo-random sequence generator is designed, and the generated sequence passes the National Institute of Standards and Technology (NIST) test.
Symmetry in a Fractional-Order Multi-Scroll Chaotic System Using the Extended Caputo Operator
Authors: Matouk A. E. , Almutairi D. K. , Herzallah M. A. E. , Abdelkawy M. A. , Abdelhameed T. N.
Published: August 2023

In this work, complex dynamics are found in a fractional-order multi-scroll chaotic system based on the extended Gamma function. Firstly, the extended left and right Caputo fractional differential operators are introduced. Then, the basic features of the extended left Caputo fractional differential operator are outlined. The proposed operator is shown to have a new fractional parameter (higher degree of freedom) that increases the system’s ability to display more varieties of complex dynamics than the corresponding case of the Caputo fractional differential operator. Numerical results are performed to show the effectiveness of the proposed fractional operators. Then, rich complex dynamics are obtained such as coexisting one-scroll chaotic attractors, coexisting two-scroll chaotic attractors, or approximate periodic cycles, which are shown to persist in a shorter range as compared with the corresponding states of the integer-order counterpart of the multi-scroll system. The bifurcation diagrams, basin sets of attractions, and Lyapunov spectra are used to confirm the existence of the various scenarios of complex dynamics in the proposed systems.
Ulam–Hyers Stability of Pantograph Hadamard Fractional Stochastic Differential Equations
Authors: Kahouli Omar , Albadran Saleh , Aloui Ali , Ben Makhlouf Abdellatif
Published: August 2023

In this article, we investigate the existence and uniqueness Theorem of Pantograph Hadamard fractional stochastic differential equations (PHFSDE) using the fixed-point Theorem of Banach (BFPT). According to the generalized Gronwall inequalities, we prove the stability in the sense of Ulam–Hyers (UHS) of PHFSDE. We give some examples to show the effectiveness of our results.
An Option Game Model of Supplier R&D Co-Competition under Uncertainty
Authors: Song Yinghua , Sang Xiaoyan , Wang Zhe , Xu Hongqian
Published: August 2023

In order to improve the market competitiveness of suppliers and their resilience to emergencies, it is of great significance to discuss the investment decision making of suppliers in developing new products under uncertain and competitive environments. In this paper, with the background of knowledge spillover, absorptive capacity, initial R&D investment, and innovation efficiency asymmetry, the uncertainty of price, sales, and cost are incorporated into the evaluation system as three important risk factors. On the basis of the existing real option investment evaluation model, a real option game model of R&D investment of supplier enterprises based on multiple random variables is established. The sensitivity analysis of parameters is carried out with an example of one enterprise’s monitor R&D project. The results depict that the probability of R&D success has a great impact on the value of enterprise options, which depends on the R&D investment, innovation efficiency, and R&D performance of enterprises. Secondly, the drift rate of price, sales, and cost also has a significant impact on improvement in enterprise option value.
A Revision of the Chrysis leachii Group from Cyprus, with a Description of an Outstanding Species and a New Synonymy (Hymenoptera, Chrysididae)
Authors: Rosa Paolo , Makris Christodoulos
Published: August 2023

A new species in the Chrysis leachii group from Cyprus, Chrysis kalliroi Rosa & Makris, sp. Nov., is described. Distribution, illustrations, and a key to the Cypriot members of this species group are provided. Chrysis lanceolata Linsenmaier, 1959 is recorded from Cyprus for the first time. Chrysis pumilio Balthasar, 1953 stat. nov. is raised to species rank. Chrysis cypruscula Linsenmaier, 1959 (repl. Name for Chrysis leachii cypriana Linsenmaier, 1951 nec Enslin, 1950) is synonymised with Chrysis pumilio Balthasar, 1953.
Image Denoising Using Hybrid Deep Learning Approach and Self-Improved Orca Predation Algorithm
Authors: Jebur Rusul Sabah , Zabil Mohd Hazli Bin Mohamed , Hammood Dalal Abdulmohsin , Cheng Lim Kok , Al-Naji Ali
Published: August 2023

Image denoising is a critical task in computer vision aimed at removing unwanted noise from images, which can degrade image quality and affect visual details. This study proposes a novel approach that combines deep hybrid learning with the Self-Improved Orca Predation Algorithm (SI-OPA) for image denoising. Leveraging Bidirectional Long Short-Term Memory (Bi-LSTM) and optimized Convolutional Neural Networks (CNN), the hybrid model aims to enhance denoising performance. The CNN’s weights are optimized using SI-OPA, resulting in improved denoising accuracy. Extensive comparisons against state-of-the-art denoising methods, including traditional algorithms and deep learning-based techniques, are conducted, focusing on denoising effectiveness, computational efficiency, and preservation of image details. The proposed approach demonstrates superior performance in all aspects, highlighting its potential as a promising solution for image-denoising tasks. Implemented in Python, the hybrid model showcases the benefits of combining Bi-LSTM, optimized CNN, and SI-OPA for advanced image-denoising applications.
Modeling the Chlorine Series from the Treatment Plant of Drinking Water in Constanta, Romania
Authors: Bărbulescu Alina , Barbeș Lucica
Published: August 2023

Ensuring good drinking water quality, which does not damage the population’s health, should be a priority of decision factors. Therefore, water treatment must be carried out to remove the contaminants. Chlorination is one of the most used treatment procedures. Modeling the free chlorine residual concentration series in the water distribution network provides the water supply managers with a tool for predicting residual chlorine concentration in the networks. With regard to this idea, this article proposes alternative models for the monthly free chlorine residual concentration series collected at the Palas Constanta Water Treatment Plant, in Romania, from January 2013 to December 2018. The forecasts based on the determined models are provided, and the best results are highlighted.
Modulation of Autophagy and Cell Death by Bacterial Outer-Membrane Vesicles
Authors: Pin Camille , David Laure , Oswald Eric
Published: August 2023

Bacteria, akin to eukaryotic cells, possess the ability to release extracellular vesicles, lipidic nanostructures that serve diverse functions in host–pathogen interactions during infections. In particular, Gram-negative bacteria produce specific vesicles with a single lipidic layer called OMVs (Outer Membrane Vesicles). These vesicles exhibit remarkable capabilities, such as disseminating throughout the entire organism, transporting toxins, and being internalized by eukaryotic cells. Notably, the cytosolic detection of lipopolysaccharides (LPSs) present at their surface initiates an immune response characterized by non-canonical inflammasome activation, resulting in pyroptotic cell death and the release of pro-inflammatory cytokines. However, the influence of these vesicles extends beyond their well-established roles, as they also profoundly impact host cell viability by directly interfering with essential cellular machinery. This comprehensive review highlights the disruptive effects of these vesicles, particularly on autophagy and associated cell death, and explores their implications for pathogen virulence during infections, as well as their potential in shaping novel therapeutic approaches.
A Novel Therapeutic Formulation for the Improved Treatment of Indian Red Scorpion (Mesobuthus tamulus) Venom-Induced Toxicity-Tested in Caenorhabditis elegans and Rodent Models
Authors: Das Bhabana , Madhubala Dev , Mahanta Saurov , Patra Aparup , Puzari Upasana , Khan Mojibur R. , Mukherjee Ashis K.
Published: August 2023

Indian Red Scorpion (Mesobuthus tamulus) stings are a neglected public health problem in tropical and sub-tropical countries, including India. The drawbacks of conventional therapies using commercial anti-scorpion antivenom (ASA) and α1-adrenoreceptor antagonists (AAA) have prompted us to search for an adequate formulation to improve treatment against M. tamulus stings. Novel therapeutic drug formulations (TDF) of low doses of commercial ASA, AAA, and ascorbic acid have remarkably improved in neutralising the in vivo toxic effects of M. tamulus venom (MTV) tested in Caenorhabditis elegans and Wistar strain albino rats in vivo models. The neutralisation of MTV-induced production of free radicals, alteration of the mitochondrial transmembrane potential, and upregulated expression of genes involved in apoptosis, detoxification, and stress response in C. elegans by TDF surpassed the same effect shown by individual components of the TDF. Further, TDF efficiently neutralized the MTV-induced increase in blood glucose level within 30 to 60 min post-treatment, organ tissue damage, necrosis, and pulmonary oedema in Wistar rats, indicating its clinical application for effecting treating M. tamulus envenomation. This study demonstrates for the first time that C. elegans can be a model organism for screening the neutralization potency of the drug molecules against a neurotoxic scorpion venom.
Attitudes towards HPV Vaccination Policy Strategies to Improve Adolescent Vaccination Coverage among Pediatric Providers in New York State
Authors: Shaw Jana , Hanley Samantha , Sitnik Elana , Berry Winter , Blatt Steven , Seserman Michael , Formica Margaret K.
Published: August 2023

Pediatric providers’ stances on HPV vaccination-related policies are largely unknown. To gain insight into pediatric providers’ perspectives and potential recommendations for directed policy, we conducted a cross-sectional survey of the American Academy of Pediatrics members in New York. Almost all providers expressed confidence in discussing the HPV vaccine with patients (98.6%, n = 72). Among common barriers to vaccination, providers listed parental safety concerns (n = 60, 82.2%), vaccination not being required for school entry (n = 59, 80.8%), and moral opposition to vaccination (n = 48, 65.8%). Among all respondents, 29 (39.7%), 13 (17.8%), and 2 (2.7%) agreed the vaccine should be required for middle, high, and tertiary school entry, respectively. Support for pharmacist-provision of the vaccine varied, with 31 (42.5%) providers expressing support. Most providers supported adolescent self-consent to vaccination, (n = 67, 91.8%). Providers continued to encounter barriers to HPV vaccination and indicated support of HPV vaccination mandates for school entry, pharmacist provision of the vaccine, and adolescent self-consent to vaccination.
Effect of Penthorum Chinense Pursh Compound on AFB1-Induced Immune Imbalance via JAK/STAT Signaling Pathway in Spleen of Broiler Chicken
Authors: Lu Qin , Hu Yu , Nabi Fazul , Li Zhenzhen , Janyaro Habibullah , Zhu Wenyan , Liu Juan
Published: August 2023

Aflatoxin B1(AFB1) is the main secondary metabolite produced by Aspergillus flavus, which is highly toxic, carcinogenic, mutagenic and teratogenic. It can induce immune imbalance in animals or humans. Penthorum chinense Pursh (PCP) is a traditional herbal plant that has been used as a hepatoprotective drug with a long history in China. Based on the theory of traditional Chinese Medicine, we prepared Penthorum chinense Pursh Compound (PCPC) by combining four herbal medicines: 5 g Penthorum chinense Pursh, 5 g Radix bupleuri, 1 g Artemisia capillaris Thunb and 1 g Radix glycyrrhizae. The role of the Penthorum chinense Pursh Compound (PCPC) in preventing AFB1-induced immune imbalance in broiler chickens was studied. A total of 180 broiler chickens were equally distributed in six groups: controls, AFB1, YCHD and high-, medium- and low-dose PCPC treatment groups. After 28 days, broilers were anesthetized, and serum spleen and thymus samples were collected for analysis. Results show that AFB1 significantly increased and decreased the relative organ weight of the spleen and thymus, respectively. Pathological section of hematoxylin/eosin (H&E) stained spleen sections showed that AFB1 resulted in splenic tissue damage. Both the serum levels of Immunoglobulin A (IgA) and Immunoglobulin G (IgG) were suppressed in the AFB1 group. IL-6 was elevated in the AFB1 group. The balance between pro-inflammatory cytokines (IFN-γ and IL-2) and anti-inflammatory cytokine (IL-4) was disturbed by AFB1. The apoptosis-related protein and JAK/STAT pathway-related gene expression indicated that AFB1-induced apoptosis via JAK/STAT pathway. PCPC has proven its immunoprotective effects by preventing AFB1-induced immune imbalance. PCPC can be applied as a novel immune-modulating medicine in broiler chickens. It can be applied as a novel immune modulator in veterinary clinical practice.
Comparative Analysis of the Pre-Parturition and Post-Parturition Genital Tract Microbiota in Plateau Bangor Sewa Sheep
Authors: Ma Hongcai , Zhao Wangsheng , Song Tianzeng , Baijiu Zhaxi , Zhang Zhenzhen
Published: August 2023

(1) Background: Bangor Sewa sheep are an economically significant livestock species on the plateau. The roles of microbiota in reproduction are complex and critical for animal health. But little is known currently about the microbiome of plateau Bangor Sewa sheep. The purpose of this study was to discover the changes in the genital tract microbiota of pre- and post-partum Bangor Sewa sheep. (2) Methods: Samples from the birth canal were obtained for 16S rRNA sequencing, three days before and after delivery, respectively. (3) Results: The results showed that there was a noticeable difference in three phyla and 74 genera between the pre- and post-parturition groups in the microbiota of Bangor Sewa sheep. The changes included a decrease in the abundance of genera related to health (unclassified_Cellulomonadaceae, Cellulomonas, Fibrobacti, Flavobacterium, Eubacterium_ventriosum_group, Acetitomaculum, Aeromicrobium, Dietzia, Romboutsia, Ruminococcus, etc.) and an increased abundance of negatively related genera (Nocardioides, unclassified_Clostridia, Sphingobacteriaceae, unclassified_Ruminococcaceae, Prevotellaceae_UCG_004, Micromonospora, Streptococcus, Facklamia, Bosea, etc.) spp. (4) Conclusions: Microbes can serve as indicators of the physical state of Bangor Sewa sheep. These findings laid the foundation for deciphering the effects of microbial changes during birth on the reproductive health of plateau Bangor Sewa sheep.
Technological and Economic Optimization of Wheat Straw Black Liquor Decolorization by Activated Carbon
Authors: Suditu Gabriel Dan , Drăgoi Elena Niculina , Puițel Adrian Cătălin , Nechita Mircea Teodor
Published: August 2023

Wheat straws are a globally abundant agro-waste that may play a critical role in the global transition from single-use plastics to green materials as an inexpensive and renewable raw material. Vast amounts of wastewater are produced during the technological process of wheat straw-cellulose/hemicellulose conversion. In this context, this work focuses on wastewater decolorization via activated carbon adsorption. A set of carefully planned experiments enabled the identification of a model that described the relationship between the system’s outputs and parameters. While process optimization is frequently connected with identifying process parameters that improve efficiency, this work employed a multi-objective optimization approach from both a technological and economic aspect. Nondominated sorting genetic algorithm versions II and III—NSGA-II and NSGA-III algorithms—were applied. As objectives, maximum efficiency and minimum cost per experiment were followed in different scenarios using pseudoweights and trade-off metrics. When optimizing only the efficiency, the results indicated a 95.54% decolorization yield, costing 0.1228 Euro/experiment, and when considering both the efficiency and cost, different solutions were obtained. The lowest cost was 0.0619, with a 74.42% decolorization. These findings indicate that incorporating an economic perspective into the optimization procedure can improve cost estimation and facilitate managerial decision-making.
Application of Chitosan and Its Derivatives as Bioflocculants for Iron and Turbidity Removal from Filter Backwash Water
Authors: Maćczak Piotr , Kaczmarek Halina , Ziegler-Borowska Marta
Published: August 2023

The present study aimed to investigate the potential application of chitosan (CS) and its two derivatives, dialdehyde chitosan (DCT) and carboxymethyl chitosan (CMC), as new flocculants in the purification of filter backwash water. The main objective of the work was to remove the disadvantages and inconveniences associated with using synthetic flocculants, mainly based on polyacrylamide, by using biodegradable and non-toxic biopolymer flocculants. The chitosan derivatives were obtained in the process of the chemical modification of this polysaccharide. CS was oxidated with periodate in acetic acid solution to obtain DCT with a degree of substitution (DS) of 44.29%. For the CMC synthesis, after the alkaline activation of chitosan, the solution was treated with monochloroacetic acid (MCA) at 60 °C for 3 h, leading to carboxymethylated chitosan formation with a DS of 49.55%. Characterizations of the flocculants using Fourier transform infrared (FT-IR) spectroscopy, 13C nuclear magnetic resonance (13C NMR) spectroscopy, and an elementary analysis confirmed the successful modification of the chitosan. The morphology and thermal stability of the samples were investigated using scanning electron microscopy (SEM) and a thermogravimetric analysis (TGA), respectively. Moreover, the biopolymer materials were studied in a series of flocculation jar tests for filter backwash water samples collected at a water treatment plant (WTP) in Kutno, Poland. CMC turned out to be a particularly effective agent in an optimal amount of 0.2 mg/L, achieving nearly 99% iron removal and 98.26% turbidity removal efficiency rates, which indicates that chitosan–based materials can be ecological alternatives for polyacrylamide flocculants, effectively removing the impurities of iron ions.
Experimental Study of the Hydrodynamics of an Open Channel with Algae Attached to the Side Wall
Authors: Pan Li , Zhao Lianjun , Zhang Mingwu , Lai Zhiqiang
Published: August 2023

The construction of large-scale water diversion projects has effectively alleviated the current situation of the uneven distribution of water resources in China. However, due to the siltation of very fine sediment and organic matter on the side wall of an open channel, and the slow velocity of the side wall flow field, it is easy for epipelic algae to be produced, which affects water quality. Because prototype observation cannot be used to predict the series of flow in real time, and the calculation of the mathematical model is affected by parameter limitations, these two methods often cannot truly reflect the hydrodynamic characteristics of an open channel with epipelic algae. Therefore, by referring to the design parameters of the water diversion project channel, this study took the epipelic algae growing on the side wall of an open channel as the research object and used the scale of 1:30 to carry out a generalized flume experiment. Through the analysis of the physical characteristics of the prototype sample, and the simulation of the cohesive force between the oblique side wall and the epipelic algae, multi-group and multi-series hydrodynamic tests were carried out. The velocity distribution law and flow field distribution law were analyzed. The research results show that the presence of epipelic algae has a certain hindering effect on the flow velocity and significantly reduces the range of the peak velocity of the channel along the water depth. The position of the maximum velocity on the vertical line of the channel flow appears at the relative water depth of 0.6. In the case of small flow, the epipelic algae group only reduces the average flow rate of the channel by 5~6%; in the case of large flow, the effect of epipelic algae on the channel flow rate is minimal. This paper includes important scientific guiding significance and practical value for the regulation of water quantity and water quality safety, as well as the protection of long-distance projects.
Characteristics of the Sediment Transport Process in Vegetation Hillslopes under Different Flow Rates
Authors: Luo Mingjie , Pan Chengzhong , Peng Jun , Wang Li
Published: August 2023

Vegetation filter strips (VFSs) have always been an important measure to control agricultural soil erosion, especially in mountainous and hilly areas with more sloping farmland. To investigate the mechanism of the sediment-trapping process by VFSs, a series of tests were conducted with four gradients of flow rate, 7.5–45 L min−1 m−1, and two different sediment concentrations of 40 and 120 g L−1. The whole process of overland flow was monitored, and sediment and particle size samples from the inflow and outflow were collected and measured. The results showed that the changes in sediment concentration did not significantly affect the corresponding coefficients in the power function relationship between overland flow rate and velocity. Using the Reynolds number alone cannot effectively indicate the flow pattern of overland flow on vegetation hillslopes. The peak particle size and linear function were effective in describing the relationship between sediment particle composition and delivery rate during the sediment-trapping process by VFSs. During the sediment-trapping process, the sediment-trapping capacity of VFSs continued to decrease. The increase in sediment discharge was accompanied by a higher proportion of coarse particles. Under the same flow rate conditions, when the sediment concentration was higher, the coarse particles and their proportion also increased faster. Therefore, using only a certain particle size threshold to distinguish suspended and transported sediment may lead to inaccurate estimation of the sediment-trapping performance of VFSs. This study deepened the understanding of the mechanism of water–sediment processes on vegetation hillslopes and promoted the widespread and efficient application of VFSs management technology.
A Survey Method for Drift Ice Characteristics of the Yellow River Based on Shore-Based Oblique Images
Authors: Li Chunjiang , Li Zhijun , Zhang Baosen , Deng Yu , Zhang Han , Wu Shuai
Published: August 2023

Acquisition of continuous drift ice characteristic parameters such as ice size, shape, concentration, and drift velocity are of great importance for understanding river freezing and thawing processes. This study acquired hourly oblique images captured by a shore-based camera in the winter of 2021–2022 on the Yellow River, China. The pixel point scale method for correcting oblique images is provided. The 61 lines were measured at the calibration site and the absolute error between the measured value and the calculated value was in the range of 0.009–0.850 m, with a mean error of 0.236 m. After the correction of oblique images, the true equivalent diameter of drift ice during the freezing period ranged from 0.52–13.10 m with a mean size of 3.36 m, which was larger than that of 2.30 m during the thawing period which ranged from 0.20–12.54 m. It was found that the size of drift ice increased with time during the freezing period and decreased with time during the thawing period. The fractal dimension and roundness were used to represent drift ice shape. The fractal dimension ranged from 1.0–1.3 and the roundness ranged from 0.1–1.0. A Gaussian distribution was used to estimate drift ice size and shape distributions. There is a nonlinear relationship between ice concentration and drift velocity, which can be well expressed by the logistic function. In the future, drift ice parameters for more years and hydrometeorological data for the same time need to be accumulated, which helps to analyze the freezing and thawing patterns of river ice.
Sequestration of Toxic Metal Ions from Industrial Effluent Using the Novel Chelating Resin Tamarind Triazine Amino Propanoic Acid (TTAPA)
Authors: Mandal Kalpa , Abomuti May Abdullah , Al-Harbi Sami A. , Tejasvi Sarika , Park Sangeun , Raigar Madhu Bala , Oh Seungdae
Published: August 2023

Due to higher levels of industrial activity, the concentrations of toxic substances in natural water bodies are increasing. One of the most dangerous groups of toxic compounds is heavy metals, with even trace amounts of most heavy metals being harmful to aquatic life. This is why purifying water has become an urgent priority. In this context, ion-exchange resins have become more widely used in water treatment processes. However, to reduce the costs and improve the sustainability of this strategy, natural resins are favored over synthetic versions. Therefore, in the present study, a natural tamarind-based chelating resin was developed. The tamarind triazine amino propanoic acid (TTAPA) resin was synthesized and characterized using Fourier-transform infrared spectroscopy, thermogravimetry analysis, scanning electron microscopy, elemental analysis, and physicochemical analysis of the moisture content, total ion-exchange capacity, bulk volume, bulk density, and percentage nitrogen content. The biological oxygen demand and chemical oxygen demand of the industrial effluent before and after treatment were also analyzed. The batch analysis was used to determine the distribution coefficient and percentage removal of the metal ions Fe(II), Zn(II), Pb(II), Cu(II), and Cd(II). The removal efficiency of the prepared TTAPA resin was highest for Fe(II), followed by Cu(II), Zn(II), Pb(II), and Cd(II) in order. The chelating ion-exchange resin also had a metal ion recovery of more than 95%, thus demonstrating great promise for the sequestration of heavy metal ions from industrial wastewater. The proposed TTAPA resin is biodegradable, non-toxic, cost-effective, reproducible, and eco-friendly.
Applicability of the Modified Green-Ampt Model Based on Suction Head Calculation in Water-Repellent Soil
Authors: Sun Yixiang , Yang Yalong , Zhang Bei , Zhang Xing , Xu Yangyang , Xiang Youzhen , Chen Junying
Published: August 2023

Water repellency has a great influence on water infiltration into soil. Currently, there is no modified correlation model that is applicable to the water infiltration of water-repellent soils (WRS). In order to better construct a model suitable for water infiltration in water-repellent soil, our objectives are to validate the effect of a modified Green-Ampt model. We modified the model by assuming that the saturated and unsaturated zones had the same thickness and by combining three formulas of the suction head (Sf VG, Sf BC, Sf GP) and the average saturated hydraulic conductivity. Therefore, we obtained three modified models: the Green-Ampt-VG, Green-Ampt-BC, and Green-Ampt-GP models. Indoor one-dimensional water infiltration experiments were conducted to simulate the cumulative infiltration (CI), the distance of the wetting front (Zf), and the infiltration rate of a hydrophilic treatment and repellent treatments. The results showed that as the degree of repellency increased, the soil suction head decreased, and the relationship between the value of the soil suction head and the degree of WRS was exponential. In addition, the simulated values of the modified CI formula highly fit the measured values of all treatments in the three models (RMSE: 1.696, 1.812, and 0.694). The modified Green-Ampt-VG model had the best simulation effect on the infiltration rate (RMSE: 0.036) and Zf (RMSE: 3.976). The results indicated that the suction head values obtained from the parameters of the VG model were closest to the actual values compared the other models. These results can provide a reference for the solution of problems involving the suction head and water infiltration into WRS in the future.
Assessing the Effects of Miedzyodrze Area Revitalization on Estuarine Flows in the Odra River
Authors: Mańko Robert
Published: August 2023

The estuarine section of the Odra River network is influenced by various phenomena that shape its hydrological regime. The Lower Odra region includes “Miedzyodrze,” an area between the main branches of the Odra River that was previously used for agriculture. However, due to a lack of maintenance in the 20th century, Miedzyodrze’s infrastructure suffered significant damage, resulting in blockages and channel shallowing. Previous models of the lower Odra River network overlooked Miedzyodrze’s hydrodynamic impact on flow. To address this, a study aimed to assess Miedzyodrze’s influence on flows within the network. Three computational scenarios were developed: one treating Miedzyodrze as an uncontrolled floodplain, another excluding it from the flow like past models, and a third incorporating the hydraulic capacity of selected Miedzyodrze channels with hypothetical restoration. The construction of the models involved extensive field research, including bathymetric surveys and an inventory of channels and structures. Challenges arose from legal and technical constraints during the research. The hydraulic network model was developed using Hec-Ras software and underwent calibration and verification processes for accuracy and reliability. The study focused on analyzing changes in water distribution, flow reduction along the East Odra, flow ratios at specific points, and downstream flow alterations based on different scenarios and the aperture extent of the Widuchowa weir. The conducted analyses and deductions validate the thesis proposed in this study that the potential process of channel dredging and renovation of the hydraulic infrastructure in Miedzyodrze will significantly influence the flow distribution within the lower Odra River network. The significant impact of the Międzyodrze area on water distribution in the lower course of the Odra River has been successfully demonstrated. Under specific hydrological scenarios, a potential increase in flow through the Międzyodrze area from approximately 10–100 m3/s to a range of 60–420 m3/s has been identified. This dynamic alteration of river flow exerts a pronounced influence on further water distribution within the entire river network. For the purpose of addressing the matter at hand within this study, the following procedures were undertaken: → analysis of characteristic flow regimes and states, → bathymetric measurements, → flow measurements at selected cross-sections, → construction of a numerical model of the river network, → model calibration, → formulation of a set of boundary conditions, → modeling, → results analysis.
Characterization of the Erosion Basin Shaped by the Jet Flow of Sky-Jump Spillways
Authors: Pellegrino Raffaella , Toledo Miguel Á.
Published: August 2023

The sky-jump spillway is an economical solution to return water to rivers, but an unsuitable flip bucket design might jeopardize the spillway, the dam, or other appurtenant works. Characterizing in advance, during the design phase, the position, size, and shape of the erosion basin would be useful to ensure that water flow is returned to the river in a safe way. Also, it would be useful for the safety assessment throughout the exploitation phase when erosion has not yet reached its maximum extension. Here, based on experimental laboratory work, the location, size, and shape of the erosion basin are analyzed, and a procedure is given for its characterization according to the design of the sky-jump spillway.
Photocatalytic Degradation of Humic Acid Using Bentonite@Fe3O4@ZnO Magnetic Nanocomposite: An Investigation of the Characterization of the Photocatalyst, Degradation Pathway, and Modeling by Solver Plugin
Authors: Hossein Panahi Ayat , Al-Musawi Tariq J. , Masihpour Mahdieh , Fard Seyedeh Fatemeh Tabatabaei , Nasseh Negin
Published: August 2023

Humic acid (HA), the most highly prevalent type of natural organic matter (NOM), plays an effective role in the generation of disinfectant byproducts such as trihalomethanes and haloacetic acid, which are well known to be definitive carcinogens. Therefore, the proactive elimination of HA from water and wastewater is a crucial means of preventing this pollutant from reacting with the chlorine incorporated during the disinfection process. This study investigated the UV light photocatalytic elimination of HA, employing a bentonite@Fe3O4@ZnO (BNTN@Fe3O4@ZnO) magnetic nanocomposite. The most significant variables pertinent to the photocatalytic degradation process examined in this work included the pH (3–11), nanocomposite dose (0.005–0.1 g/L), reaction time (5–180 min), and HA concentration (2–15 mg/L). The synthesized materials were characterized via field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), energy-dispersive X-ray spectroscopy (EDX), and vibrating-sample magnetometer (VSM) techniques, all of which revealed outstanding catalytic properties for the BNTN@Fe3O4@ZnO. The conditions under which greater efficiency was achieved included a pH of 3, a nanocomposite dose of 0.01 g/L, and an HA concentration of 10 mg/L. Under these conditions, in just 90 min of photocatalytic reaction, an HA degradation efficiency of 100% was achieved. From the modeling study of the kinetic data, the Langmuir–Hinshelwood model showed good compliance (R2 = 0.97) with the empirical data and predicted values. Thus, it can be concluded that the BNTN@Fe3O4@ZnO catalyst acts very efficiently in the HA removal process under a variety of treatment conditions.
Problems of yield of a hotel enterprise and ways to solve them
Authors:   Federal State Budgetary Educational Institution of Higher Education Russian University of Economics G. V. Plekhanov, Moscow, Steinke A. Yu.
Published: August 2023

Income management of hotel enterprises and the development of recommendations for their improvement is an important and relevant topic of the article, because due to the unstable political and economic situation, the decrease in the flow of foreign tourists to Russia and the economic consequences of the coronavirus pandemic, hotel enterprises need to apply income management methods in order to remain profitable and competitive.
Individual guest service as a tool to increase competitiveness in the hotel business
Authors:   Graduate School of Management Russian Economic Universit G. V. Plekhanov, Moscow, Ivanov A. A.
Published: August 2023

The quality of service is an important component of the hotel’s image. Many stories of creating global hotel brands are connected with the formation of a unique service. The article analyzes the experience of Moscow hotels and makes recommendations for improving the level of service in them.