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Aluminum-Free Steelmaking: Desulfurization and Nonmetallic Inclusion Evolution of Si-Killed Steel in Contact with CaO-SiO2-CaF2-MgO Slag
Stephano P. T. Piva, Petrus Christiaan Pistorius
February 23, 2023 (v1)
Keywords: clean steel, kinetics, ladle treatment, nonmetallic inclusions, slag, steelmaking
In some applications, deep desulfurization and deoxidation of steels without the use of aluminum are required, using Si as a deoxidant instead, with double-saturated slags in the CaO-SiO2-CaF2-MgO system. This work studied the desulfurization and nonmetallic inclusion evolution for the system using an induction furnace and compared the results with FactSage kinetic simulations. Steel samples were taken from the steel melt and analyzed with ICP-MS and combustion analysis for chemistry, and SEM/EDS for nonmetallic inclusion quantity, size, and composition. The results indicate that the steel was deeply desulfurized, with a final sulfur partition coefficient of 580; MgO was reduced from the slag, yielding dissolved [Mg] that transformed liquid Mn−silicate inclusions into forsterite and MgO. Intentional reoxidation of the melt with oxidized electrolytic iron demonstrated a significant concentration of dissolved [Mg] in the steel, by the formation of additional forsterite and MgO upon reoxi... [more]
Effect of Pulse Type and Substitution Level on Dough Rheology and Bread Quality of Whole Wheat-Based Composite Flours
Yiqin Zhang, Ruijia Hu, Michael Tilley, Kaliramesh Siliveru, Yonghui Li
February 23, 2023 (v1)
Subject: Materials
Keywords: bread texture, chickpea, dough rheology, green pea, lentil, Mixolab, pulse, whole grain bread, yellow pea
Pulse flours are commonly added to food products to improve the functional properties, nutritional profiles, product quality and health benefits. This study aimed at assessing the effects of the partial replacement (0−25%) of whole wheat flour with diversified whole pulse flours (yellow pea, green pea, red lentil, and chickpea) on dough properties and bread quality. The pulse flours had higher protein contents and ash, but lower moisture content and larger average particle size, compared to whole wheat flour. Increasing the substitution level of pulse flours decreased dough viscosity, stability, development time and bread volume, and accelerated bread retrogradation. The incorporation of 5% yellow pea flour led to a similar bread quality as that with only whole wheat flour. Among all the tested pulse flours, the composite flour containing yellow pea flour or chickpea flour had overall better potential for bread making by providing good dough handling properties and product quality. Thi... [more]
A Numerical Procedure for Multivariate Calibration Using Heteroscedastic Principal Components Regression
Alessandra da Rocha Duailibe Monteiro, Thiago de Sá Feital, José Carlos Pinto
February 23, 2023 (v1)
Subject: Materials
Keywords: heteroscedastic principal components regression (H-PCR), measurement error, multivariate analysis, near infrared spectroscopy (NIRS), numerical procedure
Many methods have been developed to allow for consideration of measurement errors during multivariate data analyses. The incorporation of the error structure into the analytical framework, usually described in terms of the covariance matrix of measurement errors, can provide better model estimation and prediction. However, little effort has been made to evaluate the effects of heteroscedastic measurement uncertainties on multivariate analyses when the covariance matrix of measurement errors changes with the measurement conditions. For this reason, the present work describes a new numerical procedure for analyses of heteroscedastic systems (heteroscedastic principal component regression or H-PCR) that takes into consideration the variations of the covariance matrix of measurement fluctuations. In order to illustrate the proposed approach, near infrared (NIR) spectra of xylene and toluene mixtures were measured at different temperatures and stirring velocities and the obtained data were... [more]
Review on the Battery Model and SOC Estimation Method
Wenlu Zhou, Yanping Zheng, Zhengjun Pan, Qiang Lu
February 23, 2023 (v1)
Keywords: battery model, power battery, research review, SOC estimation method
The accuracy of the power battery model and SOC estimation directly affects the vehicle energy management control strategy and the performance of the electric vehicle, which is of great significance to the efficient management of the battery and the improvement of the reliability of the vehicle. Based on the research of domestic and foreign battery models and the previous results of SOC estimation, this paper classifies power battery models into electrochemical mechanism models, equivalent circuit models and data-driven models. This paper analyzes the advantages and disadvantages of various battery models and current research progress. According to the choice of battery model, the previous research results of the power battery SOC estimation method are divided into three categories: the direct measurement method not based on battery model, the estimation method using black box battery model, and the battery model SOC estimation method based on state space. This paper will summarize and... [more]
Reactive Chromatography Applied to Ethyl Levulinate Synthesis: A Proof of Concept
Carmelina Rossano, Claudio Luigi Pizzo, Riccardo Tesser, Martino Di Serio, Vincenzo Russo
February 23, 2023 (v1)
Subject: Materials
Keywords: Dowex 50WX-8, ethyl levulinate, ion-exchange resin, levulinic acid, reactive chromatography
Levulinic acid (LA) has been highlighted as one of the most promising platform chemicals, providing a wide range of possible derivatizations to value-added chemicals as the ethyl levulinate obtained through an acid catalyzed esterification reaction with ethanol that has found application in the bio-fuel market. Being a reversible reaction, the main drawback is the production of water that does not allow full conversion of levulinic acid. The aim of this work was to prove that the chromatographic reactor technology, in which the solid material of the packed bed acts both as stationary phase and catalyst, is surely a valid option to overcome such an issue by overcoming the thermodynamic equilibrium. The experiments were conducted in a fixed-bed chromatographic reactor, packed with Dowex 50WX-8 as ion exchange resin. Different operational conditions were varied (e.g., temperature and flow rate), pulsing levulinic acid to the ethanol stream, to investigate the main effects on the final con... [more]
Numerical Study on Flow and Release Characteristics of Gas Extinguishing Agent under Different Filling Pressure and Amount Conditions
Quanwei Li, Hui Ge, Renming Pan, Zhaojun Zhang, Ruiyu Chen
February 23, 2023 (v1)
Keywords: airplane weight reduction, gas fire-extinguishing system, gas–liquid two-phase pipeline flow, gasification ratio, mass flow rate, release time
The fire-extinguishing system is an indispensable fire-protection facility on the aircraft. In order to guide weight reduction of the aircraft’s fixed gas fire-extinguishing system by improving its release efficiency, so as to improve fuel economy and reduce carbon emissions, the influence of filling pressures and filling amounts on the release efficiency of gas extinguishing agent along pipelines were studied based on numerical simulations. The release process of the fire-extinguishing system was analyzed. The effects of the filling pressure and filling amount of Halon 1301 agent on the release characteristics, such as release time, mass flow rate, and gasification ratio, were studied. Results show that the release process can be divided into three major phases, which are firstly the initial rapid filling of the pipeline, secondly the concentrated release of the liquid extinguishing agent, and thirdly the gas ejection along the pipeline. The second phase can also be subdivided into tw... [more]
Investigation on the Interactive Effects between Temperature and Chemical Composition of Organic Wastes on Anaerobic Co-Digestion Performance
Siqi Zhang, Ying Wang, Jinghui Song, Chenjing Sheng, Zezhou Shang, Rui Wang, Xiaojiao Wang, Gaihe Yang, Yongzhong Feng, Guangxin Ren
February 23, 2023 (v1)
Subject: Biosystems
Keywords: anaerobic co-digestion, composition, methane production, microbial community, temperature
Synergistic effects among different chemical components under the anaerobic co-digestion (AcoD) process played an important role in improving its performance, which might be affected by the digesting temperature. The results showed that the actual methane production (AMP) and gasification rate (GR) of 50% lipid content were the highest, and the carbohydrate and protein content should be adjusted according to the temperature. Under mesophilic conditions, the M1 reactor with high protein content (carbohydrate−lipid−protein ratio, CLP = 20:50:30) had the highest AMP of 552.02 mL/g VS and GR of 74.72%. However, as the temperature increased, the high protein content produced high levels of ammonia nitrogen (AN) and free ammonia (FA), which formed a certain degree of ammonia inhibition, resulting in lower AMP and GR. Under thermophilic conditions, the low protein T2 reactor (CLP = 40:50:10) had the highest AMP and GR at 485.45 mL/g VS and 67.18%. In addition, the M1 and T2 reactors had the h... [more]
Optimization of Cascade Cooling System Based on Lithium Bromide Refrigeration in the Polysilicon Industry
Shutong Yang, Youlei Wang, Yufei Wang
February 23, 2023 (v1)
Subject: Optimization
Keywords: cascade cooling system, heat load distribution, LiBr-H2O absorption refrigeration, temperature breakpoints, waste heat recovery
Cascade cooling systems containing different cooling methods (e.g., air cooling, water cooling, refrigerating) are used to satisfy the cooling process of hot streams with large temperature spans. An effective cooling system can significantly save energy and costs. In a cascade cooling system, the heat load distribution between different cooling methods has great impacts on the capital cost and operation cost of the system, but the relative optimization method is not well established. In this work, a cascade cooling system containing waste heat recovery, air cooling, water cooling, absorption refrigeration, and compression refrigeration is proposed. The objective is to find the optimal heat load distribution between different cooling methods with the minimum total annual cost. Aspen Plus and MATLAB were combined to solve the established mathematical optimization model, and the genetic algorithm (GA) in MATLAB was adopted to solve the model. A case study in a polysilicon enterprise was u... [more]
Health Benefits and Pharmacological Properties of Hinokitiol
Naoufal El Hachlafi, Fatima Lakhdar, Aya Khouchlaa, Saad Bakrim, Nasreddine El Omari, Abdelaali Balahbib, Mohammad Ali Shariati, Gokhan Zengin, Kawtar Fikri-Benbrahim, Giustino Orlando, Claudio Ferrante, Luigi Meninghi, Abdelhakim Bouyahya
February 23, 2023 (v1)
Subject: Biosystems
Keywords: cancer, hinokitiol, NF-κB, pharmacological action, signaling pathways
Hinokitiol is a natural bioactive compound found in several aromatic and medicinal plants. It is a terpenoid synthetized and secreted by different species as secondary metabolites. This volatile compound was tested and explored for its different biological properties. In this review, we report the pharmacological properties of hinokitiol by focusing mainly on its anticancer mechanisms. Indeed, it can block cell transformation at different levels by its action on the cell cycle, apoptosis, autophagy via inhibiting gene expression and dysregulating cellular signaling pathways. Moreover, hinokitiol also exhibits other pharmacological properties, including antidiabetic, anti-inflammatory, and antimicrobial effects. It showed multiple and several effects through its inhibition, interaction and/or activation of the main cellular targets inducing these pathologies.
Imbalance Modelling for Defect Detection in Ceramic Substrate by Using Convolutional Neural Network
Yo-Ping Huang, Chun-Ming Su, Haobijam Basanta, Yau-Liang Tsai
February 23, 2023 (v1)
Keywords: convolutional neural network, deep learning, defect detection, imbalance dataset
The complexity of defect detection in a ceramic substrate causes interclass and intraclass imbalance problems. Identifying flaws in ceramic substrates has traditionally relied on aberrant material occurrences and characteristic quantities. However, defect substrates in ceramic are typically small and have a wide variety of defect distributions, thereby making defect detection more challenging and difficult. Thus, we propose a method for defect detection based on unsupervised learning and deep learning. First, the proposed method conducts K-means clustering for grouping instances according to their inherent complex characteristics. Second, the distribution of rarely occurring instances is balanced by using augmentation filters. Finally, a convolutional neural network is trained by using the balanced dataset. The effectiveness of the proposed method was validated by comparing the results with those of other methods. Experimental results show that the proposed method outperforms other met... [more]
A Comparative Study of Improvement of Phycoremediation Using a Consortium of Microalgae in Municipal Wastewater Treatment Pond Systems as an Alternative Solution to Africa’s Sanitation Challenges
Paul J. Oberholster, Maronel Steyn, Anna-Maria Botha
February 23, 2023 (v1)
Subject: Environment
Keywords: Africa, consortia of microalgae, domestic wastewater, phycoremediation, pond treatment systems, sustainable development goals
The reuse of wastewater has been observed as a viable option to cope with increasing water stress in Africa. The present case studies evaluated the optimization of the process of phycoremediation as an alternative low-cost green treatment technology in two municipality wastewater treatment pond systems that make up the largest number of domestic sewage treatment systems on the African continent. A consortium of specific microalgae (Chlorella vulgaris and Chlorella protothecoides) was used to improve the treatment capacity of domestic wastewater at two operational municipality wastewater pond systems under different environmental conditions in South Africa. Pre- and post-phycoremediation optimization through mass inoculation of a consortium of microalgae, over a period of one year under different environmental conditions, were compared. It was evident that the higher reduction of total phosphates (74.4%) in the effluent, after treatment with a consortium of microalgae at the Motetema po... [more]
Research on Feedback-Linearized Sliding Mode Control of Direct-Drive Volume Control Electro-Hydraulic Servo System
Gexin Chen, Pengshuo Jia, Guishan Yan, Huilong Liu, Wenbin Chen, Chunyu Jia, Chao Ai
February 23, 2023 (v1)
Keywords: direct-drive volumetric control, electro-hydraulic servo system, feedback linearization theory, pressure control, sliding mode variable structure theory
In this paper, a control strategy combining the feedback linearization theory and sliding mode variable structure theory is proposed to solve various nonlinear factors, uncertainty of external disturbance and high-precision pressure control problems in the Direct-Drive Volume Control (DDVC) electro-hydraulic servo system. The nonlinear mathematical model of the DDVC electro-hydraulic servo system is established, and the nonlinear factors in the system are accurately linearized by the feedback linearization theory. The uncertainty of external disturbance in the system is compensated by the sliding mode control variable structure theory. The feedback-linearized sliding mode control algorithm proposed in this paper is verified using the DDVC electro-hydraulic servo system experimental platform. The experimental results show that, compared with the classical PID control, the proposed control algorithm can effectively improve the pressure output precision, as well as the dynamic response ch... [more]
Extraction Processes Affect the Composition and Bioavailability of Flavones from Lamiaceae Plants: A Comprehensive Review
Manuel Adrian Picos-Salas, José Basilio Heredia, Nayely Leyva-López, Dulce Libna Ambriz-Pérez, Erick Paul Gutiérrez-Grijalva
February 23, 2023 (v1)
Keywords: antioxidants, apigenin, bioaccessibility, bioavailability, flavones, Lamiaceae, luteolin, Ocimum, Origanum, Thymus
Lamiaceae plants are a widespread family of herbaceous plants with around 245 plant genera and nearly 22,576 species distributed in the world. Some of the most representative and widely studied Lamiaceae plants belong to the Ocimum, Origanum, Salvia, and Thymus genera. These plants are a rich source of bioactive molecules such as terpenes, flavonoids, and phenolic acids. In this sense, there is a subgroup of flavonoids classified as flavones. Flavones have antioxidant, anti-inflammatory, anti-cancer, and anti-diabetic potential; thus, efficient extraction techniques from their original plant matrixes have been developed. Currently, conventional extraction methods involving organic solvents are no longer recommended due to their environmental consequences, and new environmentally friendly techniques have been developed. Moreover, once extracted, the bioactivity of flavones is highly linked to their bioavailability, which is often neglected. This review aims to comprehensively gather rec... [more]
Modelling and Control of Corticotropin Permeation from Hydrogels across a Natural Membrane in the Presence of Albumin
Wioletta Siemiradzka, Barbara Dolińska, Florian Ryszka
February 23, 2023 (v1)
Subject: Materials
Keywords: albumin, corticotropin, release/permeation process, rheological stability, spectrophotometric determination, transdermal dosage form
(1) Background: Skin is a difficult barrier to overcome, especially for molecules with masses greater than 500 Da. It has been suggested that albumin may contribute to more effective penetration of many therapeutic substances. In this study, an attempt was made to use albumin in semi-solid formulations to increase the skin penetration of another peptide—corticotropin (ACTH). (2) Methods: Hydrogels were prepared at two concentrations: 15 mg/g and 20 mg/g corticotropin, then albumin was added to them in different stoichiometric ratios. The degree of ACTH release from hydrogels, both with and without albumin addition, was investigated. For selected hydrogels the process of corticotropin permeation through a model membrane, i.e., pig skin, was examined. (3) Results: The study of corticotropin release showed that the addition of albumin, depending on its amount, may delay or increase the release process. Similarly, a study of ACTH permeation through porcine skin showed that albumin can dela... [more]
A Numerical Analysis of the Effect of Impeller Rounding on Centrifugal Pump as Turbine
Hualin Yang, Lingli Zhu, Hao Xue, Junyong Duan, Fang Deng
February 23, 2023 (v1)
Keywords: hydraulic optimization, numerical analysis, pump as turbine, rounded blades
Pump as turbine (PAT) is one of the micro-hydro system components. It can be used alone as a generator in remote areas without power supply, and in hydraulic networks instead of pressure-reducing valves. However, its hydraulic optimization still remains an open research problem. One of the optimization techniques is the rounding of the sharp edges at the blade periphery. Existing studies are mostly based on prototype experiments to obtain the optimization effect. In order to more intuitively analyze the influence of this structural optimization on the internal flow of PAT, this paper uses the CFD method to study the influence of the leading edge of the centrifugal pump blade and the fillet of the impeller on the turbine performance. By simulating the PAT performance at different flow rates and speeds, the internal hydraulic performance changes caused by the inverted circular blade are analyzed. Simulation results show that, under various operating conditions, the impeller inverted circ... [more]
The Quality of Horsemeat and Selected Methods of Improving the Properties of This Raw Material
Renata Stanisławczyk, Mariusz Rudy, Stanisław Rudy
February 23, 2023 (v1)
Subject: Materials
Keywords: freezing, glycolysis, horsemeat, marinating, quality
Horsemeat has a strictly defined group of consumers whose demand varies depending on the country or region. There is no tradition of consuming horsemeat in Poland. From a technological point of view, this raw material is as good as other types of meat. In the opinion of the consumer, compared to other species of animals, horsemeat is characterized by an intense red-brown colour and greater cohesiveness resulting from the type of muscle fibres. This meat has a sweetish taste due to the high carbohydrate content. The management of horsemeat often involves the use of modern freezing methods. Freezing horsemeat with the use of liquefied carbon dioxide is a method that increases its suitability for consumption as well as for export purposes in comparison with the traditional air-cooling method. To eliminate the unfavourable quality features of horsemeat, there are substances used to improve the functional and sensory properties of this meat. This paper discusses the research and development... [more]
Grape (Vitis vinifera L. cv. País) Juices Obtained by Steam Extraction
Walther Ide, Constanza Sabando, Johanna Castaño, Natalia Pettinelli, Richard Bustos, Ana Linares, Leandro Mora, Niels Müller, Guillermo Pascual, Saddys Rodríguez-Llamazares
February 23, 2023 (v1)
Keywords: antioxidant capacity, juice, país grape, phenolic compounds, steam extraction
L. cv. País is an ancestral Chilean grape undervalued due to its undesirable oenological characteristics. In this study, steam extraction for the production of grape juice, a new product, according to our knowledge, is proposed as an alternative for the valorization of this fruit. The effect of the extraction time on the composition and antioxidant capacity of País grape juice obtained was evaluated, as well as the change in the phenolic profile during storage. The soluble solid values and total polyphenol and total anthocyanin content increased with the extraction time. However, a residence time of the juice in the extraction device higher than 10 min led to thermal degradation of anthocyanins and flavonols. The most abundant phenolic compound identified and quantified by HPLC-DAD in the País grape juice was cinnamic acid. The storage of juices had a greater effect on anthocyanin and flavonol losses than the residence time of the juice in the extraction device. The antioxidant capacit... [more]
Metagenomic Analysis of Suansun, a Traditional Chinese Unsalted Fermented Food
Yaping Hu, Xiaodong Chen, Jie Zhou, Wenxuan Jing, Qirong Guo
February 23, 2023 (v1)
Keywords: functional gene, KEGG pathway, metagenomic, microbial diversity, suansun
Suansun, made from fresh bamboo shoots fermented without salt, is a traditional food in China’s southern region and is popular for its nutritious and unique flavor. To comprehensively understand the microbial species and characteristics of suansun, Illumina HiSeq metagenomic sequencing technology was used to sequence suansun’s fermentation broth obtained from six traditional producing areas in southern China, and the microbial community structure, diversity, and functional genes were analyzed. A total of 8 phyla, 16 classes, 30 orders, 63 families, 92 genera, and 156 species of microorganisms were identified in the suansun samples, with Lactiplantibacillus predominating, accounting for up to 81% of the species, among which 12 species, including Lactiplantibacillus plantarum, were the main species. A total of 12,751 unigenes were annotated to 385 metabolic pathway classes, of which 2927 unigenes were involved in carbohydrate metabolism. Lactiplantibacillus fermentum, Lactiplantibacillus... [more]
The Effect of Inclination on Natural Convective Heat Transfer from a Slender Cuboid
Abdulrahim Kalendar, Yousuf Alhendal, Shafqat Hussain, Patrick Oosthuizen
February 23, 2023 (v1)
Keywords: constant heat flux, constant temperature, edge effects, inclined, laminar, natural convection, numerical simulations, slender cuboid
A numerical study was undertaken of the naturally occurring laminar convective heat transfer from a slender cuboid with a relatively narrow cross-section (square) and an exposed top surface. The cuboid was perpendicularly placed on an adiabatic flat base plate and two types of surface boundary conditions were considered. The slender cuboid was inclined relative to the vertical axis at angles ranging from 0 to 180 degrees. The flow was considered symmetrical along the vertical axis of the slender cuboid. The equations governing the system were numerically solved in terms of dimensionless variables using FLUENT software. From the results obtained, mean Nusselt numbers over the slender cuboid were calculated using parameters such as: the Rayleigh number for heat flux, Ra*; the Rayleigh number, Ra; the slender cuboid dimensionless width, i.e., the ratio of the width to the height of the heated slender cuboid, W = w/h; and the position of the slender cuboid relative to the vertical, φ. Simu... [more]
Bidirectional Resonant Converter for DC Microgrid Applications
Bor-Ren Lin
February 23, 2023 (v1)
Keywords: bidirectional power operation, DC microgrid, resonant converter
A bidirectional resonant converter is presented and verified in this paper for an electric vehicle battery charger/discharger system. The presented circuit can achieve forward and backward power operation, low switching losses on active devices, and wide output voltage operation. The circuit structure of the presented converter includes two resonant circuits on the primary and secondary sides of an isolated transformer. The frequency modulation approach is adopted to control the studied circuit. Owing to the resonant circuit characteristic, active devices for both forward (battery charge) and backward (battery discharge) power operation can be turned on at zero voltage switching. In order to implement a universal battery charger for different kinds of electric vehicle applications, the DC converter is demanded to have a wide output voltage range capability. The topology morphing between a full bridge resonant circuit and half bridge resonant circuit is selected to obtain high- and low-... [more]
Biomolecular Modifications Linked to Oxidative Stress in Amyotrophic Lateral Sclerosis: Determining Promising Biomarkers Related to Oxidative Stress
Takashi Hosaka, Hiroshi Tsuji, Akira Tamaoka
February 23, 2023 (v1)
Subject: Biosystems
Keywords: amyotrophic lateral sclerosis (ALS), biomarker, oxidative DNA damage, oxidative protein modification, oxidative RNA damage, oxidative stress
Reduction−oxidation reactions are essential to cellular homeostasis. Oxidative stress transcends physiological antioxidative system damage to biomolecules, including nucleic acids and proteins, and modifies their structures. Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease. The cells present in the central nervous system, including motor neurons, are vulnerable to oxidative stress. Neurodegeneration has been demonstrated to be caused by oxidative biomolecular modifications. Oxidative stress has been suggested to be involved in the pathogenesis of ALS. Recent progress in research on the underlying mechanisms of oxidative stress in ALS has led to the development of disease-modifying therapies, including edaravone. However, the clinical effects of edaravone remain limited, and ALS is a heretofore incurable disease. The reason for the lack of reliable biomarkers and the precise underlying mechanisms between oxidative stress and ALS remain unclear. As... [more]
Application of Green Surfactants in the Remediation of Soils Contaminated by Hydrocarbons
Israel Gonçalves Sales da Silva, Fabíola Carolina Gomes de Almeida, Nathália Maria Padilha da Rocha e Silva, Joaquim Teodoro Romão de Oliveira, Attilio Converti, Leonie Asfora Sarubbo
February 23, 2023 (v1)
Subject: Environment
Keywords: biobased surfactant, biodegradation, bioremediation, biosurfactant, green surfactant, Petroleum, Starmerella bombicola
Among the innovative technologies utilized for the treatment of contaminated soils, the use of green surfactants appears to be a biocompatible, efficient, and attractive alternative, since the cleaning processes that normally use synthetic surfactants as additives cause other problems due to toxicity and the accumulation of by-products. Three green surfactants, i.e., two biobased (biobased 1 and biobased 2) surfactants produced by chemical synthesis and a microbial surfactant produced from the yeast Starmerella bombicola ATCC 22214, were used as soil remediation agents and compared to a synthetic surfactant (Tween 80). The three surfactants were tested for their ability to emulsify, disperse, and remove different hydrophobic contaminants. The biosurfactant, which was able to reduce the water surface tension to 32.30 mN/m at a critical micelle concentration of 0.65 g/L, was then used to prepare a commercial formulation that showed lower toxicity to the tested environmental bioindicators... [more]
In Situ Fenton Triggered PDA Coating Copper Mesh with Underwater Superoleophobic Property for Oily Wastewater Pretreatment
Ying Xu, Wei Wang, Zhigao Zhu, Bin Xu
February 23, 2023 (v1)
Subject: Environment
Keywords: in situ Fenton, oily wastewater pretreatment, polydopamine, underwater superoleophobic
The issue of oily wastewater treatment has become a worldwide challenge due to increasing industrial oily wastewater and frequent oil spill accidents. As an integral part of practical sewage treatment, pretreatment is conducted to remove inorganic particles, floating oil, and some emulsified oil, and to pave the way for post-treatment. Here, we report a facile fabricated, hydrostable, and rapid underwater-formed superoleophobic copper mesh with polydopamine (PDA) coating for efficient oily wastewater pre-treatment. Unlike with traditional technologies, using the interface phenomenon to solve the problem of oil/water mixture separation provided a new approach for the low energy input pretreatment process. The PDA coating formed by the in situ Fenton method not only rapidly constructs a protection layer for the etched hierarchical micro-size particles on mesh and results in enhanced hydrophilicity, but also exhibits high uniformity and enhanced stability in acid/alkali medium. Benefiting... [more]
Kinetics of Cometabolic Transformation of 4-chlorophenol and Phenol Degradation by Pseudomonas putida Cells in Batch and Biofilm Reactors
Yen-Hui Lin
February 23, 2023 (v1)
Subject: Biosystems
Keywords: batch tests, biofilm reactor, cometabolic transformation, degradation, kinetics
The biodegradation kinetics of 4-chlorophenol (4-CP) and phenol and microbial growth of Pseudomonas putida (P. putida) cells were estimated in batch and biofilm reactors. The kinetic parameters of cells on phenol were determined using the Haldane formula. The maximum specific growth rate of P. putida on phenol, the half-saturation constant of phenol and the self-inhibition constant of phenol were 0.512 h−1, 78.38 mg/L and 228.5 mg/L, respectively. The yield growth of cells on phenol (YP) was 0.618 mg phenol/mg cell. The batch experimental results for the specific transformation rate of 4-CP by resting P. putida cells were fitted with Haldane kinetics to evaluate the maximum specific utilization rate of 4-CP, half-saturation constant of 4-CP, and self-inhibition constant of 4-CP, which were 0.246 h−1, 1.048 mg/L and 53.40 mg/L, respectively. The negative specific growth rates of cells on 4-CP obtained were fitted using a kinetic equation to investigate the true transformation capacity a... [more]
Roles of Drying, Size Reduction, and Blanching in Sustainable Extraction of Phenolics from Olive Leaves
Fereshteh Safarzadeh Markhali
February 23, 2023 (v1)
Subject: Biosystems
Keywords: blanching, by-products, drying, grinding, olive leaves, phenolics, preprocessing, size reduction, sustainable extraction
It is now known that olive leaves contain a sizable portion of polyphenols and there is much research highlighting that these natural ingredients favorably exhibit bio-functional activities. In this regard, many studies have focused on the exploration of optimum conditions involved directly in the extraction process. These investigations, while being highly valuable, may somewhat cast a shadow over other contributing factors such as those involved in the preprocessing of leaves, including size reduction, drying, and blanching. The use of these unit operations under appropriate conditions, together with other benefits, potentially exert improved surface area, homogeneity, and diffusion/mass transfer which may help develop the liberation of target bio-compounds. The research work in this area, particularly size reduction, is relatively limited. Although in various experiments they are incorporated, not many studies have focused on them as the main predictor variables. The performance of... [more]
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