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Showing records 38142 to 38166 of 43292. [First] Page: 1 1523 1524 1525 1526 1527 1528 1529 1530 1531 Last
Deep Reinforcement Learning for Traffic Light Timing Optimization
Bin Wang, Zhengkun He, Jinfang Sheng, Yu Chen
February 21, 2023 (v1)
Subject: Optimization
Keywords: deep reinforcement learning, traffic light control
Existing inflexible and ineffective traffic light control at a key intersection can often lead to traffic congestion due to the complexity of traffic dynamics, how to find the optimal traffic light timing strategy is a significant challenge. This paper proposes a traffic light timing optimization method based on double dueling deep Q-network, MaxPressure, and Self-organizing traffic lights (SOTL), namely EP-D3QN, which controls traffic flows by dynamically adjusting the duration of traffic lights in a cycle, whether the phase is switched based on the rules we set in advance and the pressure of the lane. In EP-D3QN, each intersection corresponds to an agent, and the road entering the intersection is divided into grids, each grid stores the speed and position of a car, thus forming the vehicle information matrix, and as the state of the agent. The action of the agent is a set of traffic light phase in a signal cycle, which has four values. The effective duration of the traffic lights is... [more]
Numerical Study on Pile Group Effect and Carrying Capacity of Four-Barreled Suction Pile Foundation under V-H-M Combined Loading Conditions
Zhen Qi, Tongzhong Wei, Changtao Wang, Fengyun Wang, Yin Wang, Jianghong Wang, Juan Li
February 21, 2023 (v1)
Keywords: combined carrying capacity, finite element analysis, four-barreled suction pile foundation, group effect, undrained shear strength
Multi-barreled composite foundations are generally used in offshore oil platform structure. However, there is still a lack of theoretical analyses and experimental research. This paper presents the results of a three-dimensional finite element analysis of a four-barreled suction pile foundation in heterogeneous clay foundation. The pile group effect and carrying capacity are numerically simulated. The effects of different pile embedment depths, pile spacings and non-uniformity coefficients of clay on the pile group effect are studied. Considering the changes in the foundation carrying capacity under vertical, horizontal and bending moment coupling loads, the foundation carrying capacity envelopes under horizontal and moment (H-M) and vertical, horizontal and moment (V-H-M) loading modes are drawn. The results show that pile spacing and embedment depth have great influence on the pile group effect. The bearing capacity envelope of foundations under V-H-M loading mode is greatly affected... [more]
Enhancing the Surface Quality of FDM Processed Flapping Wing Micro Mechanism Assembly through RSM−TOPSIS Hybrid Approach
Devaraj Rajamani, Esakki Balasubramanian, Lung-Jieh Yang
February 21, 2023 (v1)
Keywords: additive manufacturing, analysis of variance, fused deposition modeling, micro mechanism, Optimization, surface quality
Improving surface quality attributes is a critical task in the production of micro-sized near-net-shaped components for end-use applications using additive manufacturing techniques. In the present study, we investigated the effect of fused deposition modeling (FDM) process parameters such as layer thickness, part orientation, raster width and raster angle on the surface quality characteristics of as-fabricated test specimens in order to develop the assembly of a flapping wing micro mechanism. Through a Box−Behnken design, a suitable experimental strategy was developed, and test specimens were manufactured. The performance of the experiments was statistically assessed using multi-response analysis of variance (ANOVA). The microstructures of the test specimens produced with various processing parameters were examined using a scanning electron microscope to identify micro surface flaws under various processing conditions. Furthermore, the optimal FDM parameters for improved surface qualit... [more]
Preparation and Application of Coal-Liquefaction-Residue-Based Carbon Material
Liang Xu, Yizhe Lu, Nuerbiya Yalikun, Congchao Shi, Haoyang Wang, Yueyuan Xu, Jie Liu
February 21, 2023 (v1)
Subject: Materials
Keywords: activation, carbon material, coal liquefaction residue, electrochemical sensor, p-nitrophenol
P-Nitrophenol (4-NP) is a high toxicity material and has harmful effects on the environment. Thus, the analysis of 4-NP is an important topic at present. In this work, the fabrication of a novel electrochemical sensor based on coal-liquefaction-residue (CLR)-derived porous carbon (PC) materials. CLR-based porous carbon material was prepared by the high-temperature carbonization method and the morphology and structure of the materials were characterized by scanning electron microscopy and other characterization methods. Subsequently, the electrochemical properties of the modified electrodes were studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements. The results showed that under optimal conditions, the sensor had a good electrochemical performance for environmental pollutant 4-NP. In particular, the linear range of the sensor was 10−200 μmol·L-1 and the detection limit was 1.169 μmol·L−1 on the basis of the signal-to-noise ratio S/N = 3. The electrode... [more]
Cartilage Tissue in Forensic Science—State of the Art and Future Research Directions
Marcin Tomsia, Julia Cieśla, Joanna Pilch-Kowalczyk, Przemysław Banaszek, Elżbieta Chełmecka
February 21, 2023 (v1)
Keywords: age estimation, computed tomography, costal cartilage, forensic genetics, forensic toxicology, postmortem interval
Cartilage tissue performs many functions in the human body. The diseases and injuries affecting it are prevalent due to its slow regeneration rate. However, cartilage tissue is exceptionally important for its auspicious use in forensic medicine due to its slow postmortem degradation rate. The presented review summarizes the latest research on cartilage tissues and their current and potential applications in forensic science. It also describes the most important studies on using cartilage and its microscopic and macroscopic analyses to estimate the deceased age and determine postmortem interval (PMI) values and the crime weapon. Additionally, the review describes attempts to isolate DNA from cartilage tissue for individual identification. The review also mentions recent, less abundant studies on the cartilage in forensic toxicology and genetics. It points out further directions and prospects for research development on cartilage tissue and its promising use in forensic medicine
Model Forecasting Development for Dengue Fever Incidence in Surabaya City Using Time Series Analysis
Mahmod Othman, Rachmah Indawati, Ahmad Abubakar Suleiman, Mochammad Bagus Qomaruddin, Rajalingam Sokkalingam
February 21, 2023 (v1)
Keywords: ARIMA model, dengue fever, forecasting, SARIMA model, time-series analysis
Dengue hemorrhagic fever (DHF) is one of the most widespread and deadly diseases in several parts of Indonesia. An accurate forecast-based model is required to reduce the incidence rate of this disease. Time-series methods such as autoregressive integrated moving average (ARIMA) models are used in epidemiology as statistical tools to study and forecast DHF and other infectious diseases. The present study attempted to forecast the monthly confirmed DHF cases via a time-series approach. The ARIMA, seasonal ARIMA (SARIMA), and long short-term memory (LSTM) models were compared to select the most accurate forecasting method for the deadly disease. The data were obtained from the Surabaya Health Office covering January 2014 to December 2016. The data were partitioned into the training and testing sets. The best forecasting model was selected based on the lowest values of accuracy metrics such as the root mean square error (RMSE), mean absolute error (MAE), and mean absolute percentage error... [more]
Physical Environment Study of Traditional Village Patterns in Jinxi County, Jiangxi Province Based on CFD Simulation
Zhiyi Zhou, Jun Deng, Pengfei Wang, Chunlei Zhou, Yuxuan Xu, Wanping Jiang, Kai Ma
February 21, 2023 (v1)
Subject: Environment
Keywords: Computational Fluid Dynamics, numerical simulation, physical environment, site selection model, traditional village, vernacular architecture
As a theory in ancient China, Feng Shui is used in terrain exploring to find ideal living environments. In this study, 62 traditional villages documented on China’s and Jiangxi’s protection lists in Jinxi County, Jiangxi Province were divided into four categories according to their landscape patterns and were simulated by CFD (computational fluid dynamics) with PHOENICS and quantitatively analyzed based on their wind and thermal environments. The results showed that hills greatly improve the wind environment of villages when they are in the windward direction. Concerning thermal environments, water and vegetation effectively reduced the summer temperatures in villages, while hills kept villages warm in winter. This paper verified the positive effect of elements such as mountains, water and forests on the improvement of wind and thermal environments of villages and the rationality of the site election principle of Bei Shan Mian Shui, also known as back mountain facing water, which is up... [more]
Modification of Flux Oxygen Behaviour via Co-Cr-Al Unconstrained Metal Powder Additions in Submerged Arc Welding: Gas Phase Thermodynamics and 3D Slag SEM Evidence
Theresa Coetsee, Frederik De Bruin
February 21, 2023 (v1)
Keywords: aluminium, chromium, cobalt, oxygen control, powder, pyrometallurgy, welding
Aluminium metal is avoided as main reactant in submerged arc welding (SAW) because it is easily oxidised in this process. Aluminium is an effective de-oxidiser and can be used to prevent Cr and Co loss to the slag by preventing oxidation of these metals. In our novel application of aluminium metal powder in SAW we demonstrate the modification of flux oxygen behaviour. The Co-Cr-Al-alloyed weld metal total oxygen content is decreased to 180 ppm O, compared to 499 ppm O in the weld metal from the original flux, welded without metal powder additions. The flux oxygen behaviour is modified by the added aluminium powder through the lowering of the original flux-induced partial oxygen pressure in the arc cavity and at the molten flux-weld pool interface. Carbon steel was alloyed to 5.9% Co, 6.3 % Cr and 5.1% Al at 81% Co yield, 87% Cr yield and 70% Al yield. Gas-slag-alloy thermochemical equilibrium calculations confirm the partial oxygen-pressure-lowering effect of aluminium. BSE (backscatte... [more]
Sunflower Oil Flavored by Spearmint through Conventional and Ultrasound-Assisted Maceration: Differences in Oxidative Stability, Microbial Contamination and Sensory Properties
Xinjian Lu, Haoduo Yang, Yudong Meng, Dongying Wang
February 21, 2023 (v1)
Subject: Biosystems
Keywords: flavored sunflower oil, microbial survival, oxidative stability, sensory attributes, ultrasound-assisted maceration
The preparation of flavored vegetable oils using spice and herb plants is considered to be an indispensable opportunity for the application of these plants. In the present exploration, sunflower oil (SFO) samples flavored by Mentha spicata L. (spearmint) were prepared using the maceration method (MM) and ultrasound-assisted maceration (UM). The antioxidant effects, sensory evaluation and the oxidative stability during accelerated storage; the physicochemical properties including the levels for acid value (AV), peroxide value (PV) and p-anisidine value (AnV); and the specific extinction values at 232 nm (K232) and 268 nm (K268) of the SFO samples were measured. The contents of beneficial ingredients including chlorophylls, carotenoids, polyphenols and tocopherols, and the micro-organism colonies for yeasts, molds, Listeria monocytogenes and Enterobacteriaceae bacteria were determined. The results show that the physicochemical properties, beneficial ingredients, antioxidant effects, sens... [more]
Special Issue: Properties and Processing Process of Flour Products
Tonna Ashim Anyasi, Afam Israel Obiefuna Jideani
February 21, 2023 (v1)
The development of flour from established native sources to alternative and sustainable sources is increasing as demands for flour products rise due to recent global conflicts [...]
Investigation of the Vertical Propagation Pattern of the 3D Hydraulic Fracture under the Influence of Interlayer Heterogeneity
Bingqian Wan, Yancheng Liu, Bo Zhang, Shuai Luo, Leipeng Wei, Litao Li, Jiang He
February 21, 2023 (v1)
Keywords: finite element method, HF vertical propagation, hydraulic fracturing, interlayer heterogeneity, thin interlayers
The low permeability and thinly interbedded reservoirs have poor physical properties and strong interbedded heterogeneity, and it is difficult to control the hydraulic fracture (HF) height and width during hydraulic fracturing, which affects the effect of HF penetration and sand addition. In this work, a three-dimensional fluid−solid fully coupled HF propagation model is established to simulate the influence of interlayer heterogeneity on vertical HF height and HF width, and the relationship between HF length and HF width under different treatment parameters is further studied. The results show that, in thin interbedded strata, the high interlayer stress contrast, high tensile strength, and low Young’s modulus will inhibit the vertical propagation of HFs. The interlayer heterogeneity results in the vertical wavy distribution of HF width. Under the high interlayer stress contrast, Young’s modulus, and tensile strength, the HF width profile becomes narrow and the variation amplitude decr... [more]
The Mechanism Research of Low-Frequency Pressure Oscillation in the Feeding Pipe of Cryogenic Rocket Propulsion System
Chengfeng Zhu, Yanzhong Li, Fushou Xie, Lei Wang, Yuan Ma
February 21, 2023 (v1)
Keywords: curvature estimation, heat transfer, low-frequency oscillation, mass transfer, oxygen jet condensation
In the propulsion system of cryogenic liquid rockets, low-frequency pressure oscillation is a long-standing issue occurring in its feeding pipe, and is not conducive to the normal operation of the rocket. Its mechanism and excitation process are not very clear due to the limitation of the existing numerical method and the difficulty of the real dynamic experiment. Inspired by the periodic suck-back flow phenomenon of steam condensation, the fluctuation of the two-phase interface might be the crucial factor to initiate the low-frequency pressure oscillation. To simulate this interfacial characteristic of cryogenic propellant, a novel numerical model is proposed to predict the mass transfer rate weighted by the interfacial curvature. Aiming at the oxygen jet condensation simulation, the low-frequency pressure oscillation phenomenon is obtained successfully with the excitation frequency of 10.6 Hz, consistent with the natural frequency of the engine test run. It is conducted so the low-fr... [more]
Optimization of Anti-Plugging Working Parameters for Alternating Injection Wells of Carbon Dioxide and Water
Kemin Li, Guangsheng Cao, Gaojun Shan, Ning Zhang, Xincheng Liu, Shengbo Zhai, Yujie Bai
February 21, 2023 (v1)
Subject: Optimization
Keywords: alternate injection of CO2 and water, hydrate freeze plugging, limit shut-in time
In the process of oilfield development, the use of CO2 can improve the degree of reservoir production. Usually, CO2 is injected alternately with water to expand the spread range of CO2, and CO2 presents a supercritical state in the formation conditions. In the process of alternating CO2 and water injection, wellbore freezing and plugging frequently occur. In order to determine the cause of freezing and plugging of injection wells, the supercritical CO2 flooding test area of YSL Oilfield in China is taken as an example to analyze the situation of freezing and plugging wells in the test area. The reasons for hydrate freezing and plugging are obtained, the distribution characteristics and sources of hydrate near the well are clarified, and a coupling model is established to calculate the limit injection velocity and limit shut-in time of CO2 and water alternate injection wells. The results show that the main reasons for freezing and plugging of supercritical CO2 water alternate injection... [more]
The Mixture of Probability Distribution Functions for Wind and Photovoltaic Power Systems Using a Metaheuristic Method
Amr Khaled Khamees, Almoataz Y. Abdelaziz, Makram R. Eskaros, Mahmoud A. Attia, Ahmed O. Badr
February 21, 2023 (v1)
Keywords: Mayfly algorithm, metaheuristic optimization methods, mixture probability distribution functions, probability distribution functions, statistical error
The rising use of renewable energy sources, particularly those that are weather-dependent like wind and solar energy, has increased the uncertainty of supply in these power systems. In order to obtain considerably more accurate results in the analysis of power systems, such as in the planning and operation, it is necessary to tackle the stochastic nature of these sources. Operators require adequate techniques and procedures to mitigate the negative consequences of the stochastic behavior of renewable energy generators. Thus, this paper presents a modification of the original probability distribution functions (PDFs) where the original PDFs are insufficient for wind speed and solar irradiance modeling because they have a significant error between the real data frequency distribution and the estimated distribution curve. This modification is using a mixture of probability distributions, which can improve the fitting of data and reduce this error. The main aim of this paper is to model wi... [more]
Prediction of Reservoir Fracture Parameters Based on the Multi-Layer Perceptron Machine-Learning Method: A Case Study of Ordovician and Cambrian Carbonate Rocks in Nanpu Sag, Bohai Bay Basin, China
Jianya Pei, Yunfeng Zhang
February 21, 2023 (v1)
Keywords: Cambrian carbonate, fracture parameter prediction, MLP machine learning method, Ordovician carbonate
Developing a model that can accurately predict internal fractured reservoirs in the context of the ultra-low physical properties of carbonate rocks by only employing conventional mathematical methods can be very challenging. This process is challenging because the relationship between basic fracture parameters and the logging response in carbonate reservoirs has not been studied, and the traditional method lacks adaptability due to the complex relationship between basic fracture parameters and the logging response. However, data-driven approaches supplemented by machine learning algorithms based on multi-layer perceptrons (MLP) provide a more reliable solution to this challenge. In this paper, a classical fracture parameter evaluation data set is established using fracture porosity, fracture density, fracture length, and fracture width data that can be identified by resistivity and acoustic imaging logging. Another data set can be composed of different types of logs, and it can be used... [more]
Implementation of Industrial Traceability Systems: A Case Study of a Luxury Metal Pieces Manufacturing Company
Guilherme Fortuna, Pedro Dinis Gaspar
February 21, 2023 (v1)
Keywords: AIDC technologies, barcode, business technology development, Industry 4.0, Kaizen, RFID, traceability
Technological advances have shown an accentuated growth trend, which is directly proportional to the quality of life in today’s society. As a result, the business market is becoming increasingly competitive and customers are becoming more demanding, forcing companies to look for new tools and adopt new work methodologies to improve their flexibility, effectiveness and efficiency, ensuring a better response to market needs. In this context, the tools for tracking objects, totally or partially automatic, are considered essential technologies to all kinds of analysis and the treatment of business data, providing several benefits to companies, including waste reduction, identification of bottlenecks, cost reduction, improvement of product quality and the entire flow of business information. A case study of an industrial company specializing in machining, polishing and galvanoplasty of metallic alloys, small size pieces to be incorporated in luxury fashion accessories, is presented. Derived... [more]
Analogues of Oxamate, Pyruvate, and Lactate as Potential Inhibitors of Plasmodium knowlesi Lactate Dehydrogenase Identified Using Virtual Screening and Verified via Inhibition Assays
Fazia Adyani Ahmad Fuad, Nurhainis Ogu Salim
February 21, 2023 (v1)
Keywords: inhibition assay, lactate dehydrogenase, malaria, Plasmodium knowlesi, virtual screening
Malaria management remains a challenge, due to the resistance of malaria parasites to current antimalarial agents. This resistance consequently delays the global elimination of malaria throughout the world. Hence, the demand is increasing for new and effective antimalarial drugs. The identification of potential drugs that target Pk-LDH can be obtained through virtual screening analyses, as this has been previously applied to discover Pf-LDH inhibitors. In this study, the selected candidates from our virtual screening analyses were subsequently tested against purified Pk-LDH, and verified through an inhibition of Pk-LDH via enzymatic activity assays. Virtual screening analysis from this study showed that 3,3-Difluoropyrrolidine hydrochloride and 3-hydroxytetrahydrofuran exhibited binding affinity values of −3.25 kcal/mol and −3.74, respectively. These compounds were selected for evaluation towards inhibitory activity against Pk-LDH assays, including two compounds from a previous study w... [more]
Effect of Inclusion of Date Press Cake on Texture, Color, Sensory, Microstructure, and Functional Properties of Date Jam
Nashi K. Alqahtani, Tareq M. Alnemr, Abdelrahman R. Ahmed, Salim Ali
February 21, 2023 (v1)
Subject: Materials
Keywords: antioxidants, by-product upgrading, date press cake, jam, microstructure, sensorial properties
Date press cake (DPC) is a by-product of the date syrup industry with a high content of dietary fibers, minerals, and antioxidant compounds. Accordingly, the present study aimed to evaluate the inclusion of DPC on the color parameters, texture profile, sensory evaluation, microstructure properties, total phenolics, and antioxidant capacity of date jam. The DPC was included in the preparation of date jam in an increasing level of 0, 3, 6, 9, and 12% (w/w). The results revealed that increasing DPC levels significantly increased the hardness, cohesiveness, adhesiveness, and chewiness properties of date jam. The increase in DPC inclusion levels significantly decreased the L* values and increased the a*, b*, and ΔE values of the jam. The DPC addition significantly increased the phenolics content and antioxidant capacity in a dose-dependent manner and the highest value reported in the jam contained 12% DPC by 40.02 and 11.50% compared to the control, respectively. The scanning electron micro... [more]
COD Reduction of Aeration Effluent by Utilizing Optimum Quantities of UV/H2O2/O3 in a Small-Scale Reactor
Mehdi Rafiee, Morteza Sabeti, Farshid Torabi, Aria Rahimbakhsh
February 21, 2023 (v1)
Keywords: advanced oxidation processes (AOPs), aeration contaminants, COD reduction, H2O2, ozone, UV
Extensive research has been carried out to figure out safe means of disposing various industrial effluents. Industrial wastewaters from the aeration industry such as heavy metals and oily substances contain a high degree of contamination. The advanced oxidation process is one of the most effective and rapid methods of removing contaminations, which can lead to a high chemical oxygen demand (COD). The aim of the present study is to reduce the COD of an aeration effluent with the initial COD of 13,004 mg/L. About 20 sets of experimental tests were conducted to identify the contribution of H2O2, O3, and UV to the treatment process. The influence of the quantities of additives and the dose of the UV irradiance were, too, among the subjects of the study. These factors were altered throughout the experiments and their mutual effects were measured. To design the experiments, Minitab software 16 was utilized. The experimental conditions were set at the standard values of 25 °C and 1 bar to min... [more]
Facile Preparation and Characterization of Silica Nanoparticles from South Africa Fly Ash Using a Sol−Gel Hydrothermal Method
Patrick Ehi Imoisili, Emeka Charles Nwanna, Tien-Chien Jen
February 21, 2023 (v1)
Subject: Materials
Keywords: fly ash, hydrothermal, nanoparticles, silica, sol–gel
Silica nanoparticles (SNPs) consist of several applications which include lightweight aggregates, energy storage, and drug delivery. Nevertheless, the silica reagents used in SNP synthesis are both costly and hazardous. As a result, it is critical to look for other sources of silica. For this research, a simple sol−gel hydrothermal approach is used to make SNPs from South African fly ash (SAFA). SAFA is classified as fly ash class F according to X-ray fluorescence (XRF) analysis. The wide-angle X-ray diffraction (XRD) pattern reveals the structural composition of SAFA and the amorphous phase of extracted SNPs, while Fourier transform infrared (FTIR) examination reveals the presence of silanol and siloxane groups. Basic SNPs were generally spherical with diameters of about 60 nm, according to scanning electron microscopy (SEM) and transition electron microscope (TEM) studies. The presence of SiO2 is confirmed by energy-dispersive X-ray spectroscopy (EDX) spectrum analysis. Particle size... [more]
A Review on the Applications of Coffee Waste Derived from Primary Processing: Strategies for Revalorization
Johanna Andrea Serna-Jiménez, José A. Siles, María de los Ángeles Martín, Arturo F. Chica
February 21, 2023 (v1)
Subject: Environment
Keywords: biocomposite, biofuel, biorefinery, circular economy, coffee waste
Coffee is an extremely popular beverage worldwide. To obtain it, the berry must be depulped, fermented, washed, dried, and roasted, producing residues: pulp and husk, mucilage, and parchment. Recently there has been an interest in generating high-value products. In this article, advances in the valorization process are critically reviewed, including an overview of the composition of residues derived from primary processing, uses in food, biocomposite, and biofuel production (thermochemical conversion). With an increasing production of coffee projected in the coming years, there is an urgent need to balance it with the appropriate use and industrial application of coffee wastes and by-products, which are renewable resources rich in carbohydrates, proteins, pectin, and bioactive compounds (polyphenols). The applications described above, together with those that will undoubtedly be developed in the future, represent promising opportunities to take advantage of agro-industrial residues der... [more]
A Review on the Hydrothermal Treatment of Food Waste: Processing and Applications
Chuanbin Wang, Zhi Wang, Xutong Wang, Ning Li, Junyu Tao, Wandong Zheng, Beibei Yan, Xiaoqiang Cui, Zhanjun Cheng, Guanyi Chen
February 21, 2023 (v1)
Keywords: applications, food waste, hydrothermal treatment, influence condition
The amount of food waste is increasing with the development of society and the increase in population; the rough treatment of food waste could result in a serious environmental crisis and waste of resources. Hydrothermal treatment is a promising scheme to achieve the harmless treatment and utilization of food waste. Although there are many studies on the hydrothermal treatment of food waste, there is still a lack of systematic summary and comprehensive analysis of the relevant literature. In this review, we provide an in-depth analysis of the specific impact mechanisms of hydrothermal conditions on the gaseous, solid, and liquid products. Meanwhile, the hydrothermal conversion mechanisms of food waste components are systematically sorted out. The review also discusses the potential application areas for the derived products from the hydrothermal treatment of food waste. Finally, the main challenges and future research directions are proposed to improve the development of the hydrotherm... [more]
The Effect of Water, Nanoparticulate Silica and Dry Water on the Flow Properties of Cohesionless Sand
Leigh Duncan Hamilton, Harald Zetzener, Arno Kwade
February 21, 2023 (v1)
Subject: Materials
Keywords: cohesion, dry water, flowability, fumed silica, granular materials, liquid bridges, Mixing, water storage
Cement hydration within particle bed concrete 3D printing processes can be benefited by storing water in the otherwise dry aggregate bulk material. Additional water also has the advantage of acting as a source of passive cooling. However, even small amounts of liquid lead to detrimental effects on bulk properties, such as the flowability. For that reason, this study proposes implementing dry water (DW) in order to store large amounts of water in a bulk material of non-absorbent, coarse sand whilst maintaining its initial bulk properties. DW is essentially created by mixing water and hydrophobic fumed silica in a high shear process, leading to water droplets surrounded by a protective silica shell. Herein, several DW variants, distinguished by their deionised water to hydrophobic silica ratio, were mixed with non-absorbent, coarse sand particles. In addition, mixtures were produced to contain a specific overall water content of up to wH2O = 5% within the bulk material. It was shown that... [more]
Limited Phosphorous Supply Improved Lipid Content of Chlorella vulgaris That Increased Phenol and 2-Chlorophenol Adsorption from Contaminated Water with Acid Treatment
Sidra Javed, Cyrus Raza Mirza, Aqib Hassan Ali Khan, Walid Khalifa, Belkacem Achour, Rocio Barros, Sohail Yousaf, Tayyab Ashfaq Butt, Mazhar Iqbal
February 21, 2023 (v1)
Subject: Environment
Keywords: acidification, algal biomass, phenol adsorption, phosphorus limitation, phycoremediation
Phenolic compounds are toxic and ominously present in industrial effluents, which can end up in water bodies, causing potential damage to living organisms. This study employed the dried biomass of freshwater green microalgae Chlorella vulgaris to remove phenol and 2-chlorophenol from an aqueous environment. C. vulgaris was grown under different phosphorus- (P) starved conditions, and biomass was treated with sulfuric acid. It was observed that reducing the P level enhanced the lipid content by 7.8 times while decreasing protein by 7.2 times. P-starved C. vulgaris dried biomass removed phenol and 2-chlorophenol by 69 and 57%, respectively, after 180 min from the contaminated water. Acid-treated P-starved C. vulgaris dried biomass removed phenol and 2-chlorophenol by 77 and 75%, respectively, after 180 min. Thus, an economical and eco-friendly P-starved and acid treated C. vulgaris biomass has better potential to remove phenol and 2-chlorophenol from contaminated ground water and industr... [more]
Purity Control Based on a Type-II Fuzzy Controller for a Simulated Moving Bed
Chao-Fan Xie, Rey-Chue Hwang
February 21, 2023 (v1)
Keywords: PID controller, simulated moving bed, type-II fuzzy controller
The control of a simulated moving bed (SMB) is always a challenging chemical control topic due to its complexity and nonlinearity. Its mathematical model must undergo an affine transformation and digitization before it can be controlled. Basically, there are three aspects that need to be considered in the nonlinear control of an SMB. First, the nonlinear characteristics are more complicated due to the switching time parameters of discrete events. Second, the control objective is not to minimize the control output error, but to make the separated concentrations between the components of the substance reach a certain ratio. Finally, the control variables are highly coupled. So far, the vast majority of the industry still uses relatively simple PLC controls; a few use specific controllers based on materials to be separated such as model predictive controls and PID controllers. Therefore, there is no unified intelligent processing mode. In this paper, a type-II fuzzy controller is presente... [more]
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