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Improving Computer Vision-Based Wildfire Smoke Detection by Combining SE-ResNet with SVM
Xin Wang, Jinxin Wang, Linlin Chen, Yinan Zhang.
June 5, 2024 (v1)
Keywords: computer vision, deep learning, smoke detection, support vector machine, wildfire early warning.
Wildfire is one of the most critical natural disasters that poses a serious threat to human lives as well as ecosystems. One issue hindering a high accuracy of computer vision-based wildfire detection is the potential for water mists and clouds to be marked as wildfire smoke due to the similar appearance in images, leading to an unacceptable high false alarm rate in real-world wildfire early warning cases. This paper proposes a novel hybrid wildfire smoke detection approach by combining the multi-layer ResNet architecture with SVM to extract the smoke image dynamic and static characteristics, respectively. The ResNet model is improved via the SE attention mechanism and fully convolutional network as SE-ResNet. A fusion decision procedure is proposed for wildfire early warning. The proposed detection method was tested on open datasets and achieved an accuracy of 98.99%. The comparisons with AlexNet, VGG-16, GoogleNet, SE-ResNet-50 and SVM further illustrate the improvements.
Long-Term Ampacity Prediction Method for Cable Intermediate Joints Based on the Prophet Model
Zhiqiang Zhang, Wenping Liu, Lingcheng Zeng, Song He, Heng Zhou, Jiangjun Ruan.
June 5, 2024 (v1)
Subject: Environment
Keywords: cable intermediate joint, dynamic ampacity, temperature inversion, time series.
The development of power grids is hindered by the limited transmission capacity of cable equipment, necessitating the accurate prediction of dynamic ampacity for cable expansion. This study focuses on the 110 kV cable intermediate joint, employing radial and axial inversion techniques for real-time conductor temperature inversion. Utilizing the Prophet time series model, we predict environmental changes and propose a dynamic ampacity evaluation method for cable intermediate joints. Experimental validation confirms the model’s accuracy, with prediction errors under 10 K, demonstrating its potential for enhancing cable system reliability and power grid development.
Pyrene-Modified Cyclic Peptides Detect Cu2+ Ions by Fluorescence in Water
Yuhi Maekawa, Sora Sakura, Yuji Furutani, Rento Fujihara, Hisashi Sugime, Takashi Ohtsuki, Mizuki Kitamatsu.
June 5, 2024 (v1)
Subject: Biosystems
Keywords: fluorescence, metal ion, peptide, pyrene.
The detection of metal ions is an option for maintaining water quality and diagnosing metal ion-related diseases. In this study, we successfully detected metal ions using fluorescent peptides in water. First, we prepared seven linear (L1−L7) and seven cyclic (C1−C7) peptides containing two pyrenyl (Pyr) units and assessed the response to various metal ions by fluorescence. The results indicated that C1, which contains a hexameric cyclic peptide moiety consisting of Pyr and Gly units, did not show a fluorescent response to metal ions, while the linear L1 corresponding to C1 showed a response to Cu2+, but its selectivity was found to be poor through a competition assay for each metal ion. We then assessed C2−C7 and L2−L7, in which Gly was replaced by His units at various positions in the same manner. The results showed that C2−C7 responded to Cu2+ in a manner dependent on the His position. Additionally, superior selectivity was observed in C7 through a competition assay. These results de... [more]
Modification of Copper Benzene-1,3,5-tricarboxy Late (Cu-BTC) Composites with Multiwalled Carbon Nanotubes and Amino Groups for Enhanced CO2/CH4 Selective Adsorption Performance and Water Stability
Weiwei Jian, Qiuyan Hai, Adili Youlidaxi, Tianqiang Liu, Danzhu Ma, Fengrui Jia.
June 5, 2024 (v1)
Subject: Materials
Keywords: CNT-NH2-Cu-BTC, CO2/CH4separation, water stability.
CNT-NH2-Cu-BTC was prepared via hydrothermal synthesis for the adsorption and separation of CO2/CH4 mixtures with 2, 6, and 10% multiwalled carbon nanotube (MWCNT) additions. NH2-BTC composites were synthesized by changing the organic ligand and adding NH2-BDC (15, 25, 35, and 45%) to improve the adsorption capacity. MWCNTS were loaded to enhance the water stability of the material. The structure, surface morphology, and pore size distribution of the composites were characterized using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and specific surface area and pore structure measurements. The CO2/CH4 selective adsorption performance was studied via breakthrough experiments using a self-made adsorption device. The CO2 adsorption capacity of Cu-BTC increased due to the addition of NH2-BDC, with 35%NH2-Cu-BTC exhibiting the best CO2 adsorption property, i.e., a CO2 adsorption capacity of 1.82 mmol/g and a CO2/CH4 sepa... [more]
Numerical Study of the Thermal and Hydraulic Characteristics of Plate-Fin Heat Sinks
Olga V. Soloveva, Sergei A. Solovev, Rozalina Z. Shakurova.
June 5, 2024 (v1)
Keywords: Computational Fluid Dynamics, heat exchanger, heat transfer, hydrodynamics, microelectronic cooling, numerical modeling.
One of the main trends in the development of the modern electronics industry is the miniaturization of electronic devices and components. Miniature electronic devices require compact cooling systems that can dissipate large amounts of heat in a small space. Researchers are exploring ways to improve the design of the heat sink of the cooling system in such a way that it increases the heat flow while at the same time reducing the size of the heat sink. Researchers have previously proposed different designs for heat sinks with altered fin shapes, perforations, and configurations. However, this approach to optimizing the design of the heat sink results in an increase in the labor intensity of its production. Our goal is to optimize the heat sink design to reduce its size, reduce metal consumption, and increase heat flow. This goal is achieved by changing the number of fins and the distance between them. In this case, there is no significant difference in the geometry of a conventional plat... [more]
Energy Storage Capacity Configuration Planning Considering Dual Scenarios of Peak Shaving and Emergency Frequency Regulation
Xiaozheng Chen, Dongliang Nan, Xiaofu Xiong, Hongzhou Chen, Wenqing Ma.
June 5, 2024 (v1)
Keywords: bi-level programming, emergency frequency regulation, energy storage configuration, frequency constraint, peak shaving.
New energy storage methods based on electrochemistry can not only participate in peak shaving of the power grid but also provide inertia and emergency power support. It is necessary to analyze the planning problem of energy storage from multiple application scenarios, such as peak shaving and emergency frequency regulation. This article proposes an energy storage capacity configuration planning method that considers both peak shaving and emergency frequency regulation scenarios. A frequency response model based on emergency frequency regulation combined with low-frequency load shedding is established, taking into account the frequency safety constraints of the system and the principle of idle time reuse, to establish a bi-level programming model. In the upper-level model, the optimization objective is to minimize the annual operating cost of the system during the planning period, combined with the constraints of power grid operation to plan the energy storage capacity. The lower-level... [more]
Green Extraction of Phytochemicals from Fresh Vegetable Waste and Their Potential Application as Cosmeceuticals for Skin Health
Harichandana Valisakkagari, Chandrika Chaturvedi, H. P. Vasantha Rupasinghe.
June 5, 2024 (v1)
Keywords: bioactives, extraction techniques, food waste, green processes, phytochemicals, skin health, vegetables.
The utilization of bioactive compounds from fresh produce waste, which is gaining attention in the agri-food and cosmetics industries, focuses on employing green extraction over conventional extraction methods. This emerging field addresses environmental concerns about food waste and the uses of bioactive phytochemicals for skin health. Modern green extraction methods aim to minimize the energy-intensive process and the use of harmful solvents. These techniques include ultrasound, microwave, and supercritical fluid extraction, pulsed electric field extraction, pressurized liquid extraction, and subcritical water extraction methods, which provide high efficacy in recovering bioactive phytochemicals from vegetable and root crops. The phytochemicals, such as carotenoids, polyphenols, glucosinolates, and betalains of fresh produce waste, exhibit various therapeutic properties for applications in skin health. These dietary antioxidants help to neutralize free radicals generated by UV radiat... [more]
Analysis of Thermoacoustic Instabilities Using the Helmholtz Method in a Swirled Premixed Combustor
Zhijian Yu, Yongqing Xu.
June 5, 2024 (v1)
Keywords: acoustic mode shape, flame describing function, Helmholtz method, swirled premixed combustor, thermoacoustic instability.
The Helmholtz method is developed to predict the self-excited thermoacoustic instabilities in a gas turbine combustor, combining flame describing functions, the measured damping rates under the firing condition, and the non-uniform spatial distributions of the physical parameters. The impact of the hydrodynamic and geometrical parameters on the thermoacoustic instabilities is investigated. The measured damping rates show lower values under a hot condition compared with those in a cold state. The experimental results indicate that the relative errors of the predicted eigenfrequencies and the velocity fluctuation levels are below 10%. The pressure amplitude decreases and the phase increases in the axial direction, indicating a typical 1/4-wavelengh mode. At a higher equivalence ratio, the mode shape in the axial direction becomes steeper due to the elevated fluctuation amplitude at the pressure antinode after enhancing the thermal power. When the air flow rate increases, the discrepancie... [more]
Use of MTM, RAV and ZAK Methods in Determining Working Methods and Time Norms in Technological Operations of Sewing Clothes
Snježana Kirin, Anica Hursa Šajatović, Snježana Firšt Rogale.
June 5, 2024 (v1)
Keywords: clothing production, MTM method, RAV method, sewing process, time norms, working method, ZAK method.
The paper presents the application of MTM, RAV and ZAK methods in the determination of working methods and time norms for the technological process of sewing. The technological operation of sewing the back sleeve seam on a men’s jacket is used for the study. The paper presents the designed workplace in a real production process. In addition, the appropriate working method and the time norm are determined using the MTM (Method Time Measurement), RAV (determination of sewing time for straight seams) and ZAK (determination of sewing time for curved seams) methods. The aim of the study was to combine the methods for determining different types of time (manual, machine-hand and machine) for performing technological operations and precisely calculate the time norms. For the described methods of determining the production time, computer programs were developed that speed up the calculation of the time norm. If the working method is defined in advance and the characteristics of the sewing mach... [more]
Well Shut-In Pressure Determination Method for Deepwater Drilling Considering Fluid-Solid-Heat Coupling
Yongqian Ma, Yang Ke, Huangang Zhu, Peng Zhao, Xueqi Liu, Xiaohui Sun, Zhiyuan Wang.
June 5, 2024 (v1)
Keywords: deepwater drilling, heat-fluid-solid coupling, shut-in well pressure, well control.
Blowout is one of the most serious safety threats in deepwater drilling. Considering the characteristics of gas invasion in complex formations, gas migration and distribution, and dynamic changes in temperature inside a wellbore, a deepwater well-closing pressure determination method considering thermal-fluid-solid coupling was proposed. The model was verified using actual data, and the average error in the increase in casing pressure during the closing process was found to be 5.42%. The shut-in pressure of oil and gas wells under a transient shut-in process was analyzed. The results showed that the fluid thermal expansion caused by temperature recovery had a significant impact on the change in wellhead backpressure after well closure. Furthermore, the time required for the wellbore pressure to recover to the formation pressure varies nonlinearly with factors such as geothermal gradients, pit gains, bottom-hole pressure, and gas production indices. A pressure calculation chart was deve... [more]
Optimized Bentonite Clay Adsorbents for Methylene Blue Removal
Hamad Noori Hamad, Syazwani Idrus, Badronnisa Yusuf, Nur Syakina Jamali, Amimul Ahsan, Sri Suhartini, Abdul Malek Abdul Wahab.
June 5, 2024 (v1)
Subject: Materials
Keywords: Adsorption, bentonite clay, cationic dyes, drinking water, isotherm, low-cost adsorbents, methylene blue removal.
This study addresses the urgent need for effective water treatment methods by synthesizing and characterizing activated bentonite clay (ABC) adsorbents to remove methylene blue (MB) from aqueous solutions efficiently. Conventional adsorbents often exhibit limitations in efficiency and regeneration capabilities, necessitating novel approaches to water treatment. The primary objective is synthesizing and characterizing high-quality ABC adsorbents capable of effectively removing MB. The activation process was optimized, and adsorbent performance was evaluated regarding MB removal efficiency and regeneration potential. Various activation dos-ages were investigated, and comprehensive physicochemical characterization was performed using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), BET (Brunauer−Emmett−Teller) analysis, X-ray fluorescence (XRF), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The synthesized adsorbents demonstrated excepti... [more]
Parametric Energy Efficiency Impact Analysis for Industrial Process Heating Furnaces Using the Manufacturing Energy Assessment Software for Utility Reduction
Prakash Singh Bisht, Bhaskaran Gopalakrishnan, Rupesh Dahal, Hailin Li, Zhichao Liu.
June 5, 2024 (v1)
Keywords: emission reduction, energy assessment, Energy Efficiency, industrial furnace, Sustainability, utility reduction.
Industrial process heating furnace operations consume considerable energy in the U.S. manufacturing sector, making it crucial to identify energy efficient strategies due to the growing need to minimize energy usage and emissions. It is important to identify the potential impact of these factors to enable process engineers to operate process heating systems at the maximum possible efficiency. This study examines and identifies the key impact factors that influence the efficiency of process heating systems using MEASUR (v1.4.0), the DOE software tools such as the insulation effectiveness, the burner stoichiometry, cooling medium, thermal storage, and atmospheric gases. Data from a two-fuel-fired heat treatment furnace and an electric arc furnace (EAF) for steelmaking were employed to establish the baseline heat balance models in MEASUR. The fractional factorial design experiment was developed with two-level parameter values and energy efficiency strategies for the heat input into industr... [more]
Study on the Preparation and Aging Performance of Temperature-Indicating Patch Used for Thermal Defect Detection of Transformer Bushing Cylinder Head
Mingqin Wang, Xiaobin Wu, Nan Jiang, Chenghua Liu, Richang Xian, Wentao Jia.
June 5, 2024 (v1)
Subject: Materials
Keywords: color-changing properties, temperature-indicating patch, thermal aging, transformer bushing cylinder head.
Elevated temperatures at the transformer bushing cylinder head can precipitate failures, leading to significant power outages. In response, this study introduces a reversible temperature-indicating patch for the nuanced detection of thermal anomalies in the transformer bushing’s cylinder head. The patch, crafted through a melting process, utilizes a reversible discoloration material and is developed in two variants via an adsorption substrate method. Comprehensive evaluations of the patches’ color-changing characteristics, alongside their electrical and hydrophobic properties, were conducted using an automatic contact angle measuring instrument and an AC flashover test platform. The findings reveal that the temperature-indicating patch exhibits a discernible color transition within the range of 49~55 °C, with a color reversion temperature span of 45~55 °C, denoting marked sensitivity and robust reversibility. Additionally, it was observed that prolonged thermal aging correlates with a... [more]
Adhesion Behavior of Underground Coal Dust with Fused Silica: Effects of Relative Humidity and Particle Size
Shujun Zhou, Yue Yang, Hongfei Shang.
June 5, 2024 (v1)
Keywords: adhesion behavior, coal dust, fused silica, humidity dependence.
Coal dust particles adhering to a camera lens reduce its light transmittance, which deteriorates the performance of the camera and may lead to serious problems with mining equipment that requires visual ability. Aiming at improving coal dust removal and cleaning technologies, the adhesion behavior of coal dust with fused silica is studied here. Experiments were conducted from microscopic and statistical points of view. The adhesion force between a single coal dust particle and fused silica is tested using atomic force microscopy (AFM), and the number and size distribution of large amounts of coal dust particles on fused silica are tested using a home-made adhesion experimental platform and image processing method. The results show that the adhesion force increases at high relative humidity (RH); it is dominated by van der Waals forces at low RH and capillary forces at high RH. The fused silica glass surface is predominantly covered by small-sized coal dust particles, and the total numb... [more]
Application of Pure and Modified Polyvinylidene Fluoride Materials for Wastewater Treatment Using UASB Reactor Technologies: A Review
Mmontshi Lebohang Sikosana, Keneiloe Khoabane Sikhwivhilu, Richard Moutloali, Daniel Madyira.
June 5, 2024 (v1)
Subject: Materials
Keywords: anaerobic membrane bioreactor, chemical organic demand, municipal wastewater treatment, polyvinylidene fluoride, upflow anaerobic sludge blanket.
Wastewater treatment is now required because of the problems caused by water constraints. Wastewater is anaerobically digested to produce biogas, which can be used as a source of energy for things like lighting and heating. The upflow anaerobic sludge blanket (UASB) reactor has been recognized as an important wastewater treatment technology among anaerobic treatment methods. Although their treated effluent typically does not meet most discharge criteria, UASB reactors are generally stated to have a chemical oxygen demand (COD) reduction ranging from 60 to 90% for most types of wastewater. In comparison to traditional anaerobic procedures, anaerobic municipal wastewater treatment using membranes can produce higher effluent quality in terms of COD, suspended solids (SSs) and pathogen counts, as well as a steady treatment performance to fulfill strict discharge regulations. The objective of this review was to perform a literature review on parameters to consider when selecting a membrane... [more]
Research on Numerical Simulation Methods for Reservoirs of Loose Sandstone Considering the Equilibrium Time of Vertical Seepage Flow
Shuozhen Wang, Qing You, Ruichao Zhang, Chunlei Yu, Shuoliang Wang, Congcong Li, Xiao Zhuo.
June 5, 2024 (v1)
Keywords: loose sandstone reservoir, numerical simulation, vertical seepage flow equilibrium time.
Due to their high porosity and permeability characteristics, reservoirs of loose sandstone have great development potential. Under weak dynamic conditions, the vertical migration and mass exchange of oil−water two-phase fluids in loose sandstone reservoirs occur very easily. The phenomenon of vertical seepage flow equilibrium has a significant impact on the distribution of oil−water two-phase fluids in the reservoir. However, existing mainstream numerical simulators cannot accurately describe the phenomenon of vertical migration of oil−water two-phase fluids under weak dynamic conditions. In this study, using 3D printing technology, multiple transparent rock core holders were constructed to conduct experiments on the vertical seepage flow equilibrium time of different viscosities and contents of crude oil under different permeabilities of rock cores. Through the analysis and regression of experimental results, a predictive formula for the vertical seepage flow equilibrium time of loose... [more]
Impact of Blade Modifications on the Performance of a Darrieus Wind Turbine
M. Özgün Korukçu.
June 5, 2024 (v1)
Keywords: Darrieus, dimple, pitch angle, vertical axis wind turbine.
Vertical axis wind turbines (VAWTs) are gaining increasing significance in the realm of renewable energy. One notable advantage they possess is their ability to operate efficiently in diverse wind conditions, including low-speed and turbulent winds, which are often prevalent in urban areas. In this study, dimples and pitch angles into the rotor blades are used to enhance the aerodynamic performance of a straight-bladed Darrieus turbine. To simulate the turbine’s rotation under transient conditions, computational fluid dynamics calculations are conducted in a two-dimensional setting. The unsteady Navier−Stokes equations are solved, and the k-ω SST turbulence model is employed to represent turbulent flow. The results of the simulation demonstrate that the application of a circular dimple on the pressure side of the blades, positioned at 0.25 of the chord length with a diameter of 0.08 chord length, leads to a 5.18% increase in the power coefficient at λ = 2.7, in comparison to a turbine... [more]
MALDI-TOF Mass Spectrometry-Based Identification of Aerobic Mesophilic Bacteria in Raw Unpreserved and Preserved Milk
Nataša Mikulec, Jasminka Špoljarić, Dijana Plavljanić, Nina Lovrić, Fabijan Oštarić, Jasenka Gajdoš Kljusurić, Khan Mohd. Sarim, Nevijo Zdolec, Snježana Kazazić.
June 5, 2024 (v1)
Keywords: aerobic mesophilic bacteria, MALDI-TOF mass spectrometry, preserved milk, raw unpreserved milk, sodium azide (NaN3).
The number of aerobic mesophilic bacteria in milk is one of the indicators of the hygienic quality of milk. The aim of this work was to determine such aerobic mesophilic bacteria and their number in raw unpreserved milk and milk preserved with sodium azide. In 40 collected samples, the total number of aerobic mesophilic bacteria was determined using the classical method of counting colonies on a nutrient medium according to the international standard HRN EN ISO 4833-1:2013. The results showed a trend of decreasing the number of grown colonies in milk preserved with sodium azide. MALDI-TOF mass spectrometry also successfully identified 392 bacterial colonies in raw unpreserved milk samples and 330 colonies in preserved milk samples. Of these, 30 genera and 54 bacterial species were identified in the raw unpreserved milk samples, while 27 genera and 41 bacterial species were identified in the preserved samples. By using a collective approach, the present study provided a more detailed in... [more]
Quantitative Evaluation of Pre-Drilling Safety by Combining Analytic Hierarchy Process with Alternating Condition Expectation
Kunkun Fan, Shankai Sun, Haiyang Yu, Wenbin Sun, Hai Lin, Chunguang Wang, Shugang Hou, Huanfu Du, Dong Chen, Jia He.
June 5, 2024 (v1)
Keywords: alternating condition expectation, analytic hierarchy process, drilling engineering, quantitative analysis, safety evaluation.
In order to avoid potential personnel and financial losses, the evaluation of pre-drilling safety is of great importance in oil and gas exploration and development. This paper presents a method of evaluating pre-drilling safety through combining the Analytic Hierarchy Process (AHP) with the Alternating Condition Expectation (ACE) method. An indicator system with a 9-3-1 structure was established, incorporating various unrestricted variables to describe the technical factor. Additionally, nine membership functions and weights were determined in order to build the AHP model by connecting the independent variables in the basic layer to dependent variables in the middle layer. Four transformed functions were also formulated to construct the ACE model by linking the middle variables to the pre-drilling safety value in the final layer. A total of 28 sets of on-site drilling data from three oilfields were collected for the establishment and verification of the AHP-ACE model. Average absolute... [more]
Bi-Level Inverse Robust Optimization Dispatch of Wind Power and Pumped Storage Hydropower Complementary Systems
Xiuyan Jing, Liantao Ji, Huan Xie.
June 5, 2024 (v1)
Subject: Optimization
Keywords: economic dispatch, pumped storage hydropower, wind power.
This paper presents a bi-level inverse robust economic dispatch optimization model consisting of wind turbines and pumped storage hydropower (PSH). The inner level model aims to minimize the total generation cost, while the outer level introduces the optimal inverse robust index (OIRI) for wind power output based on the ideal perturbation constraints of the objective function. The OIRI represents the maximum distance by which decision variables in the non-dominated frontier can be perturbed. Compared to traditional methods for quantifying the worst-case sensitivity region using polygons and ellipses, the OIRI can more accurately quantify parameter uncertainty. We integrate the grid multi-objective bacterial colony chemotaxis algorithm and the bisection method to solve the proposed model. The former is adopted to solve the inner level problem, while the latter is used to calculate the OIRI. The proposed approach establishes the relationship between the maximum forecast deviation and the... [more]
Estimating the Influencing Factors of Gas−Water Relative Permeability in Condensate Gas Reservoirs under High-Temperature and High-Pressure Conditions
Shuheng Cui, Qilin Wu, Zixuan Wang.
June 5, 2024 (v1)
Keywords: condensate gas reservoir, gas–water relative permeability, high pressure, high temperature, influencing factors.
The gas−water relative permeability curve plays a crucial role in reservoir simulation and development for condensate gas reservoirs. This paper conducted a series of high-temperature and high-pressure analysis experiments on real gas cores from Wells A and B in Block L of the Yinggehai Basin to investigate the effects of temperature, pressure, and different types of gas media on gas−water seepage. The gas−water relative permeability was simulated in this experiment through variations in temperature, pressure, and gas composition. Temperature has a significant impact on both gas and water relative permeability, particularly on gas relative permeability. As temperature increases, gas relative permeability shows a substantial increase, while water relative permeability remains relatively unchanged. Under the same effective stress, increasing pressure causes downward shifts in both the gas and water relative permeability curves; however, there is a more pronounced decrease in gas relative... [more]
Improving the Functionality of Yogurt after Fortification with a Synbiotic Combination of a Potential Probiotic and Bacteriocin-Producing Bacteria and Hydnora abyssinica Phytosomes
Ghoson Daba, Waill Elkhateeb, Tarek Nour Soliman, Asmaa Negm El-Dein, Takeshi Zendo.
June 5, 2024 (v1)
Keywords: antimicrobial, bacteriocin, functional yogurt, Hydnora abyssinica, Lactiplantibacillus plantarum, phytosomes, probiotics.
Functional dairy products are attracting consumers’ attention, as they simultaneously have nutritional and health benefits. Hence, we aimed in this study to fortify a dairy product (yogurt) with phytosomes of extract from Hydnora abyssinica (a holoparasitic plant that has ethnobotanical value) and a potential bacteriocin-producing probiotic lactic acid bacterium (LAB). Goat cheese was screened for LAB with promising antimicrobial activity, and the safety and probiotic potential of the selected isolate were studied. As a result, strain GA5 was selected due to its wide antimicrobial activity that was suggested to be caused by bacteriocin production. Moreover, this strain showed promising stress tolerance, in vitro antioxidant activity (95 ± 2.8%), and hydrophobic potential (87.18 ± 3.43%). Strain GA5 was molecularly identified as Lactiplantibacillus plantarum GA5. On the other hand, a hydromethanolic extract was prepared from H. abyssinica flowers, and its prebiotic potential and polyphe... [more]
Research on Multi-Physical Field Characteristics of Deep Coal Seam Mining Based on the Rock-Coal-Rock Model
Feng Du, Yi Zhang, Linchao Dai, Weilong Cui, Bo Wang, Jiazhi Sun.
June 5, 2024 (v1)
Subject: Materials
Keywords: damage failure, deep coal seams, mining disturbance, multiple physical fields, numerical simulation.
In order to disclose the multi-physical field characteristics of the deep coal seam mining process and their dynamic evolution legislation, based on the “rock-coal-rock” model, during the mining process, the stress field, displacement field, energy field, and plastic zone evolution process are all simulated using FLAC3D6.0. The findings show that stress in the original rock is redistributed as a result of coal seam mining, creating a pressure relief zone in the middle of the goaf and advanced support pressure in the front part of the working face. The roof falls following the termination of coal seam mining. The collapsed blocks fill the middle of the goaf, playing a supporting role. The floor bulges as a new supporting pressure zone forms and builds up high elasticity. The stress reduction zone shifts from a rectangular to an inner circular distribution and an outer square as the working face’s mining distance increases and the range of the fracture field expands accordingly. In addit... [more]
Studies on Reactive Extraction of Itaconic Acid from Fermentation Broths
Alexandra Cristina Blaga, Lenuta Kloetzer, Dan Cascaval, Anca-Irina Galaction, Alexandra Tucaliuc.
June 5, 2024 (v1)
Subject: Biosystems
Keywords: Aspergillus terreus, fermentation broths, itaconic acid, reactive extraction, tri-n-octylamine.
Itaconic acid is a high-value organic acid that serves as a platform molecule in different industries. This research focuses on the separation of itaconic acid using reactive extraction as a sustainable and efficient method for acid recovery from fermentation broth. Itaconic acid was produced through fungal fermentation processes involving Aspergillus terreus ATCC® 32588™, obtaining a concentration of 47 g/L in the final broths. For the reactive extraction system, the organic phase included tri-n-octylamine as an extractant dissolved in dichloromethane or n-heptane and 1-octanol as a phase modifier. The effect of the main influencing factors (pH of the aqueous phase, extractant concentrations in the organic phase, and the addition of 1-octanol) on extraction efficiency was investigated. The highest extraction degree (97%) was achieved using an organic phase with tri-n-octylamine dissolved in dichloromethane and with 20% 1-octanol. Conversely, in the reactive extraction system with tri-... [more]
A Novel Slickwater System with Strong-Polarity Fibers for High-Efficiency Proppant Flowback Mitigation
Yang Xu, Ping Chen, Kun Wang, Suoliang Wang, Qingcong Meng, Mingqi Li, Yingxian Ma, Jie Zeng.
June 5, 2024 (v1)
Subject: Materials
Keywords: fiber fracturing fluid, proppant carrying capacity, proppant flowback mitigation, strong-polarity fiber.
To avoid or mitigate proppant flowback after a massive hydraulic fracturing of tight formations and to reduce its impairment to well productivity, this study developed a new type of fiber material with strong polarity based on polyester fiber. This fiber material is modified by introducing a strong-polar functional monomer into the molecular structure and adopting the means of surface grafting. On the basis of this fiber material, a fiber slip-water system with excellent dispersion performance can be established to prevent proppant backflow. Laboratory experiments were performed to analyze the specific function of the fibers with strong polarity and its working mechanisms. The results indicate that strong-polarity fibers have excellent dispersion performance. The fibers and resistance-reducing agents form an interwoven structure that can carry proppants, resulting in the enhancement of the sand-carrying capacity of the fracturing fluid system and the overall strength of the sand bank.... [more]
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