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Improvement of Refrigeration Efficiency by Combining Reinforcement Learning with a Coarse Model
Dapeng Zhang, Zhiwei Gao
January 19, 2020 (v1)
Keywords: coarse model, data-driven methods, refrigeration, reinforcement learning
It is paramount to improve operational conversion efficiency in air-conditioning refrigeration. It is noticed that control efficiency for model-based methods highly relies on the accuracy of the mechanism model, and data-driven methods would face challenges using the limited collected data to identify the information beyond. In this study, a hybrid novel approach is presented, which is to integrate a data-driven method with a coarse model. Specifically, reinforcement learning is used to exploit/explore the conversion efficiency of the refrigeration, and a coarse model is utilized to evaluate the reward, by which the requirement of the model accuracy is reduced and the model information is better used. The proposed approach is implemented based on a hierarchical control strategy which is divided into a process level and a loop level. The simulation of a test bed shows the proposed approach can achieve better conversion efficiency of refrigeration than the conventional methods.
Characterizing a Newly Designed Steel-Wool-Based Household Filter for Safe Drinking Water Provision: Hydraulic Conductivity and Efficiency for Pathogen Removal
Raoul Tepong-Tsindé, Arnaud Igor Ndé-Tchoupé, Chicgoua Noubactep, Achille Nassi, Hans Ruppert
January 19, 2020 (v1)
Keywords: biosand filter, household filter, pathogen removal, permeability loss, zero-valent iron
This study characterizes the decrease of the hydraulic conductivity (permeability loss) of a metallic iron-based household water filter (Fe0 filter) for a duration of 12 months. A commercial steel wool (SW) is used as Fe0 source. The Fe0 unit containing 300 g of SW was sandwiched between two conventional biological sand filters (BSFs). The working solution was slightly turbid natural well water polluted with pathogens (total coliform = 1950 UFC mL−1) and contaminated with nitrate ([NO3−] = 24.0 mg L−1). The system was monitored twice per month for pH value, removal of nitrate, coliforms, and turbidity, the iron concentration, as well as the permeability loss. Results revealed a quantitative removal of coliform (>99%), nitrate (>99%) and turbidity (>96%). The whole column effluent depicted drinking water quality. The permeability loss after one year of operation was about 40%, and the filter was still producing 200 L of drinking water per day at a flow velocity of 12.5 L h−1. A progress... [more]
Plant and Biomass Extraction and Valorisation under Hydrodynamic Cavitation
Zhilin Wu, Daniele F. Ferreira, Daniele Crudo, Valentina Bosco, Livio Stevanato, Annalisa Costale, Giancarlo Cravotto
January 19, 2020 (v1)
Keywords: biomass treatment, hydrodynamic cavitation, plant extraction, Process Intensification, rotor/stator hydrodynamic rector
Hydrodynamic cavitation (HC) is a green technology that has been successfully used to intensify a number of process. The cavitation phenomenon is responsible for many effects, including improvements in mass transfer rates and effective cell-wall rupture, leading to matrix disintegration. HC is a promising strategy for extraction processes and provides the fast and efficient recovery of valuable compounds from plants and biomass with high quality. It is a simple method with high energy efficiency that shows great potential for large-scale operations. This review presents a general discussion of the mechanisms of HC, its advantages, different reactor configurations, its applications in the extraction of bioactive compounds from plants, lipids from algal biomass and delignification of lignocellulosic biomass, and a case study in which the HC extraction of basil leftovers is compared with that of other extraction methods.
An Analysis of Antimicrobial Resistance of Clinical Pathogens from Historical Samples for Six Countries
Karen Li, Joanna Zheng, Thomas Deng, James Peng, Dagmar Daniel, Qian Jia, Zuyi Huang
January 19, 2020 (v1)
Subject: Biosystems
Keywords: antimicrobial resistance, clinical pathogens, data analysis, hierarchical clustering, principal component analysis
The spread of antimicrobial resistance pathogens in humans has increasingly become an issue that threatens public health. While the NCBI Pathogen Detection Isolates Browser (NPDIB) database has been collecting clinical isolate samples over time for various countries, few studies have been done to identify genes and pathogens responsible for the antimicrobial resistance in clinical settings. This study conducted the first multivariate statistical analysis of the high-dimensional historical data from the NPDIB database for six different countries from majorly inhabited landmasses, including Australia, Brazil, China, South Africa, the UK, and the US. The similarities among different countries in terms of genes and pathogens were investigated to understand the potential avenues for antimicrobial-resistance gene spreading. The genes and pathogens that were closely involved in antimicrobial resistance were further studied temporally by plotting time profiles of their frequency to evaluate th... [more]
Baicalein-Enriched Fraction Extracted from Oroxylum indicum (L.) Benth. ex Kurz Leaves Exerts Antioxidant and Inhibitory Effects Against Glioblastoma Multiforme
In Nee Kang, Nik Nur Hakimah Nik Salleh, Wan Jie Chung, Chong Yew Lee, Suat Cheng Tan
January 19, 2020 (v1)
Subject: Biosystems
Keywords: baicalein, complementary medicine for brain cancer, glioblastoma multiforme, natural product, Oroxylum indicum (L.) Benth. ex Kurz
Glioblastoma multiforme (GBM) is the most malignant subtype of primary brain cancer. To date, standard clinical treatment for GBM is limited in effectiveness and could impose additional side effects. Recently, numerous bioactive compounds isolated from natural plants appear to have beneficial anti-cancer properties. Here, the GBM inhibitory effect of baicalein, a bioactive flavonoid extracted from Oroxylum indicum (L.) Benth. ex Kurz, was evaluated. Firstly, three solvents were used to extract the baicalein. We found that the binary extraction system, using a combination of petroleum ether and methanol (PM), yielded the highest amount of baicalein (15%) compared to the mono extraction system using methanol (13%) or aqueous (0.04%) only. In order to further enhance the baicalein yield in PM crude extract, it was subjected to an enrichment fractionation procedure, which successfully increased the baicalein by nearly two-fold from the initial crude extract (15%) to the enriched fraction 5... [more]
Multi-Time-Scale Rolling Optimal Dispatch for Grid-Connected AC/DC Hybrid Microgrids
Zhao Luo, Zhendong Zhu, Zhiyuan Zhang, Jinghui Qin, Hao Wang, Zeyong Gao, Zhichao Yang
January 19, 2020 (v1)
Keywords: AC/DC hybrid, energy management, microgrids, multi-time-scale, rolling optimization
In order to reduce the impact of the randomness and volatility of renewable energy on the economic operation of AC/DC hybrid microgrids, a multi-time-scale rolling optimization strategy is proposed for the grid-connected AC/DC hybrid microgrids. It considers the source-load uncertainty declined with time scale reduction, and the scheduling cooperation problem of different units on different time scales. In this paper, we propose a three-time-scale optimal strategy of the day-ahead, intraday and real-time dispatching stage and a two-level rolling optimal strategy of the intraday and real-time stage, aiming at minimizing the operating cost. We added the power penalty cost in the rolling optimization model to limit the energy state of the energy storage system in the constraint, and improve the power correction and tracking effect of the rolling optimization. A typical-structure AC/DC hybrid microgrid is analyzed in this paper and the simulation results are shown to demonstrate the feasib... [more]
Process Modeling, Optimization, and Heat Integration of Ethanol Reforming Process for Syngas Production with High H2/CO Ratio
Dong Xiang, Peng Li, Xiaoyou Yuan
January 19, 2020 (v1)
Keywords: ethanol reforming, heat integration, hydrogen production, system optimization
The process modeling, parameter optimization, and heat integration of reforming ethanol to hydrogen is conducted in this paper. Modeling results show that the optimum reaction pressure for ethanol steam reforming is 1 bar. When the 7.4:1 is selected as a moderate water/ethanol ratio, the optimum reaction temperature is about 755 °C. As for heat integration, the composite curve and optimum heat-exchange network are given out by pinch technology, of which adding a heat exchanger can reduce 10,833 kW of heating duty and 10,833 kW of cooling duty and make the energy saving reach about 57.4%. Another two heat-integration plans are proposed for the ethanol steam-reforming process, to further decrease the high-level heat duty. Finally, similar heat integration was also carried out for the oxidative steam reforming, and the system is autothermal when the oxygen/ethanol is about 0.5:1 on the basis of above steam-reforming process, while the hydrogen molar purity is decreased from 69% to 66%.
Investigating the In-Flow Characteristics of Multi-Operation Conditions of Cross-Flow Fan in Air Conditioning Systems
Weijie Zhang, Jianping Yuan, Qiaorui Si, Yanxia Fu
January 19, 2020 (v1)
Keywords: cross-flow fan, internal flow, multi-operating condition, pressure fluctuation, the aerodynamic noise
Cross-flow fans are widely used in numerous applications such as low-pressure ventilation, household appliances, laser instruments, and air-conditioning equipment. Cross-flow fans have superior characteristics, including simple structure, small size, stable airflow, high dynamic pressure coefficient, and low noise. In the present study, numerical simulation and experimental research were carried out to study the unique secondary flow and eccentric vortex flow characteristics of the internal flow field in multi-operating conditions. To this end the vorticity and the circumferential pressure distribution in the air duct are obtained based on the performed experiments and the correlation between spectral characteristics of multiple operating conditions and the inflow state is established. The obtained results show that when the area of the airflow passage decreases while the area of the eccentric vortex area gradually increases, then the airflow of the cross-flow fan decreases, the outlet... [more]
Data Augmentation Applied to Machine Learning-Based Monitoring of a Pulp and Paper Process
Andréa Pereira Parente, Maurício Bezerra de Souza Jr., Andrea Valdman, Rossana Odette Mattos Folly
January 19, 2020 (v1)
Keywords: data-driven, FDD, Machine Learning, Monte Carlo technique, neural networks, pulp and paper industry, study case
Industrial archived process data represent a convenient source of information for data-driven models, such as artificial neural network (ANN), that can be used for safety and efficiency improvement like early or even predictive fault detection and diagnosis (FDD). Nonetheless, most of the data used for model generation are representative of the process nominal states and therefore are not enough for classification problems intended to determine abnormal process conditions. This work proposes the use of techniques to augment the original real data standards, dismissing the need for experiments that could jeopardize process safety. It uses the Monte Carlo technique to artificially increase the number of model inputs coupled to the nearest neighbor search (NNS) by geometric distances to consistently classify the generated patterns in normal or faulty statuses. Finally, a radial basis function neural network is trained with the augmented data. The methodology was validated by a study case... [more]
Numerical Study of Periodic Magnetic Field Effect on 3D Natural Convection of MWCNT-Water/Nanofluid with Consideration of Aggregation
Lioua Kolsi, Hakan F. Oztop, Kaouther Ghachem, Mohammed A. Almeshaal, Hussein A. Mohammed, Houman Babazadeh, Nidal Abu-Hamdeh
January 19, 2020 (v1)
Keywords: 3D natural convection, aggregation, MWCNT-nanofluid, periodic magnetic field
In this paper, a numerical study is performed to investigate the effect of a periodic magnetic field on three-dimensional free convection of MWCNT (Mutli-Walled Carbone Nanotubes)-water/nanofluid. Time-dependent governing equations are solved using the finite volume method under unsteady magnetic field oriented in the x-direction for various Hartmann numbers, oscillation periods, and nanoparticle volume fractions. The aggregation effect is considered in the evaluation of the MWCNT-water/nanofluid thermophysical properties. It is found that oscillation period, the magnitude of the magnetic field, and adding nanoparticles have an important effect on heat transfer, temperature field, and flow structure.
Exploitation of Wheat Straw Biorefinery Side Streams as Sustainable Substrates for Microorganisms: A Feasibility Study
Stefan Beisl, Julian Quehenberger, Donya Kamravamanesh, Oliver Spadiut, Anton Friedl
January 19, 2020 (v1)
Subject: Biosystems
Keywords: acetic acid, biorefinery, carbohydrates, lignocellulose, lipids, liquid hot water, polyhydroxybutyrate, side streams, tetraether
Lignocellulosic agricultural side products, like wheat straw, are widely seen as an important contribution to a future sustainable economy. However, optimization of biorefinery processes and exploitation of all side streams are crucial for an economically viable biorefinery. Pretreatment of lignocellulosic raw material, which is necessary for further processing steps, can generate low-value side streams. In this feasibility study, side streams from a liquid hot water (LHW) pretreatment of wheat straw were utilized for the production of polyhydroxybutyrate (PHB) and highly valuable tetraether lipids (TELs). Additional value created by these products can benefit the biorefinery’s economic operation. The utilized wheat straw was pretreated at 120 °C and 170 °C for up to two hours in laboratory and lab scale. The resulting side stream consists mainly of carbohydrates from hemicelluloses and fermentation inhibitors such as acetic acid. In order to achieve a successful production of both pro... [more]
Optimal Siting and Sizing of Distributed Generation Based on Improved Nondominated Sorting Genetic Algorithm II
Wei Liu, Fengming Luo, Yuanhong Liu, Wei Ding
January 19, 2020 (v1)
Keywords: distributed generation (DG), INSGA-II, multi-objective optimization, potential crowding distance, static and dynamic planning
With the development of distributed generation technology, the problem of distributed generation (DG) planning become one of the important subjects. This paper proposes an Improved non-dominated sorting genetic algorithm-II (INSGA-II) for solving the optimal siting and sizing of DG units. Firstly, the multi-objective optimization model is established by considering the energy-saving benefit, line loss, and voltage deviation values. In addition, relay protection constraints are introduced on the basis of node voltage, branch current, and capacity constraints. Secondly, the violation constrained index and improved mutation operator are proposed to increase the population diversity of non-dominated sorting genetic algorithm-II (NSGA-II), and the uniformity of the solution set of the potential crowding distance improvement algorithm is introduced. In order to verify the performance of the proposed INSGA-II algorithm, NSGA-II and multiple objective particle swarm optimization algorithms are... [more]
The Copper(II) Ions Solvent Extraction with a New Compound: 2,6-Bis(4-Methoxybenzoyl)-Diaminopyridine
Daria Bożejewicz, Katarzyna Witt, Małgorzata A. Kaczorowska, Borys Ośmiałowski
January 19, 2020 (v1)
Subject: Materials
Keywords: 2,6-bis(4-methoxybenzoyl)-diaminopyridine, dissociation constant, mass spectrometry, solvent extraction, stability constant
A new compound 2,6-bis(4-methoxybenzoyl)-diaminopyridine (L) was used as an extractant for copper(II) ion recovery in a solvent extraction conducted at a temperature of 25 °C. The best results (99% recovery of copper(II) ions) were obtained when the aqueous phase contained 0.001 mol/dm3 Cu(II) and 0.2 mol/dm3 NH3 (pH~5.8), while the organic phase was a 0.001 mol/dm3 chloroform solution of 2,6-bis(4-methoxybenzoyl)-diaminopyridine. Spectrophotometry studies were used to determine the dissociation constant of the tested compound and determine the stability constant of the complex of subjected compound with copper(II) ions. The high-resolution mass spectrometry (HRMS) and higher energy collisional dissociation tandem mass spectrometry (HCD MS/MS) methods have been applied for the confirmation of the structure of 2,6-bis(4-methoxybenzoyl)-diaminopyridine and to determine its complexation with Cu(II) in solution.
Review of Anaerobic Digestion Modeling and Optimization Using Nature-Inspired Techniques
Anjali Ramachandran, Rabee Rustum, Adebayo J. Adeloye
January 19, 2020 (v1)
Subject: Biosystems
Keywords: anaerobic digestion, ant colony optimization, artificial neural network, firefly algorithm, Genetic Algorithm, nature-inspired techniques, Particle Swarm Optimization
Although it is a well-researched topic, the complexity, time for process stabilization, and economic factors related to anaerobic digestion call for simulation of the process offline with the help of computer models. Nature-inspired techniques are a recently developed branch of artificial intelligence wherein knowledge is transferred from natural systems to engineered systems. For soft computing applications, nature-inspired techniques have several advantages, including scope for parallel computing, dynamic behavior, and self-organization. This paper presents a comprehensive review of such techniques and their application in anaerobic digestion modeling. We compiled and synthetized the literature on the applications of nature-inspired techniques applied to anaerobic digestion. These techniques provide a balance between diversity and speed of arrival at the optimal solution, which has stimulated their use in anaerobic digestion modeling.
Research on the Dynamic Behaviors of the Jet System of Adaptive Fire-Fighting Monitors
Xiaoming Yuan, Xuan Zhu, Chu Wang, Lijie Zhang, Yong Zhu
January 19, 2020 (v1)
Keywords: adaptive control, duffing equation, dynamics, fire-fighting monitor, flow control, jet system
Based on the principles of nonlinear dynamics, a dynamic model of the jet system for adaptive fire-fighting monitors was established. The influence of nonlinear fluid spring force on the dynamic model was described by the Duffing equation. Results of numerical calculation indicate that the nonlinear action of the fluid spring force leads to the nonlinear dynamic behavior of the jet system and fluid gas content, fluid pressure, excitation frequency, and excitation amplitude are the key factors affecting the dynamics of the jet system. When the excitation frequency is close to the natural frequency of the corresponding linear dynamic system, a sudden change in vibration amplitude occurs. The designed adaptive fire-fighting monitor had no multi-cycle, bifurcation, or chaos in the range of design parameters, which was consistent with the stroboscopic sampling results in the dynamic experiment of jet system. This research can provide a basis for the dynamic design and optimization of the ad... [more]
Vapor Liquid Equilibrium Measurements of Two Promising Tertiary Amines for CO2 Capture
Diego D. D. Pinto, Znar Zahraee, Vanja Buvik, Ardi Hartono, Hanna K. Knuutila
January 19, 2020 (v1)
Subject: Materials
Keywords: 12-HEPP, amine, Carbon Dioxide Capture, DEA-12-PD, VLE
Post combustion CO2 capture is still a rather energy intense, and therefore expensive, process. Much of the current research for reducing the process energy requirements is focused on the regeneration section. A good description of the vapor liquid equilibrium of the solvent is necessary for the accurate representation of the process. 3-(Diethylamino)-1,2-propanediol (DEA-12-PD) and 1-(2-hydroxyethyl)piperidine (12-HEPP) have been proposed as potential components in solvent blends for the membrane contactor. However, there are few available experimental data for these two tertiary amines making difficult to accurate simulate such process. In this work, we provide experimental data on the pure component saturation pressure (383 to 443 K) and on VLE of aqueous solutions of these amines (313 to 373 K) in order to fill part of the data gap. The data were used to estimate model parameters used to represent the data. The saturation pressure was modeled using the Antoine equation and the devi... [more]
A Comprehensive Review and Technical Guideline for Optimal Design and Operations of Fuel Cell-Based Cogeneration Systems
Farah Ramadhani, Mohd Azlan Hussain, Hazlie Mokhlis
January 19, 2020 (v1)
Keywords: cogeneration, fuel cell, guidelines, optimal design, review
The need for energy is increasing from year to year and has to be fulfilled by developing innovations in energy generation systems. Cogeneration is one of the matured technologies in energy generation, which has been implemented since the last decade. Cogeneration is defined as energy generation unit that simultaneously produced electricity and heat from a single primary fuel source. Currently, the implementation of this system has been spread over the world for stationary and mobile power generation in residential, industrial and transportation uses. On the other hand, fuel cells as an emerging energy conversion device are potential prime movers for this cogeneration system due to its high heat production and flexibility in its fuel usage. Even though the fuel cell-based cogeneration system has been popularly implemented in research and commercialization sectors, the review regarding this technology is still limited. Focusing on the optimal design of the fuel cell-based cogeneration s... [more]
Numerical and Experimental Investigation of External Characteristics and Pressure Fluctuation of a Submersible Tubular Pumping System
Yan Jin, Xiaoke He, Ye Zhang, Shanshan Zhou, Hongcheng Chen, Chao Liu
January 19, 2020 (v1)
Keywords: external characteristics, measurement, numerical simulation, pressure fluctuation, submersible tubular pumping system
This paper presents an investigation of external flow characteristics and pressure fluctuation of a submersible tubular pumping system by using a combination of numerical simulation and experimental methods. The steady numerical simulation is used to predicted the hydraulic performance of the pumping system, and the unsteady calculation is adopted to simulate the pressure fluctuation in different components of a submersible tubular pumping system. A test bench for a model test and pressure pulsation measurement is built to validate the numerical simulation. The results show that the performance curves of the calculation and experiment are in agreement with each other, especially in the high efficiency area, and the deviation is minor under small discharge and large discharge conditions. The pressure pulsation distributions of different flow components, such as the impeller outlet, middle of the guide vane, and guide vane outlet and bulb unit, are basically the same as the measurement d... [more]
Characterization of Poly(Ethylene Oxide) Nanofibers—Mutual Relations between Mean Diameter of Electrospun Nanofibers and Solution Characteristics
Petr Filip, Petra Peer
January 19, 2020 (v1)
Subject: Materials
Keywords: concentration, electrospinning, molecular weight, nanofiber diameter, poly(ethylene oxide)
The quality of electrospun poly(ethylene oxide) (PEO) nanofibrous mats are subject to a variety of input parameters. In this study, three parameters were chosen: molecular weight of PEO (100, 300, 600, and 1000 kg/mol), PEO concentration (in distilled water), and shear viscosity of PEO solution. Two relations free of any adjustable parameters were derived. The first, describing the initial stage of an electrospinning process expressing shear viscosity using PEO molecular weight and concentration. The second, expressing mean nanofiber diameter using concentration and PEO molecular weight. Based on these simple mathematical relations, it is possible to control the mean nanofiber diameter during an electrospinning process.
Diffusion in Binary Aqueous Solutions of Alcohols by Molecular Simulation
Alexander Klinov, Ivan Anashkin
January 19, 2020 (v1)
Keywords: alcohols, diffusion coefficient, intermolecular interaction, molecular dynamics, Water
Based on the molecular dynamics method, the calculations for diffusion coefficients were carried out in binary aqueous solutions of three alcohols: ethanol, isopropanol, and tert-butanol. The intermolecular potential TIP4P/2005 was used for water; and five force fields were analyzed for the alcohols. The force fields providing the best accuracy of calculation were identified based on a comparison of the calculated self-diffusion coefficients of pure alcohols with the experimental data for internal (Einstein) diffusion coefficients of alcohols in solutions. The temperature and concentration dependences of the interdiffusion coefficients were determined using Darken’s Equation. Transport (Fickian) diffusion coefficients were calculated using a thermodynamic factor determined by the non-random two-liquid (NRTL) and Willson models. It was demonstrated that for adequate reproduction of the experimental data when calculating the transport diffusion coefficients, the thermodynamic factor has... [more]
Comparative Analysis of Combustion Stability of Diesel/Ethanol Utilization by Blend and Dual Fuel
Wojciech Tutak, Arkadiusz Jamrozik
January 19, 2020 (v1)
Keywords: combustion duration, combustion stability, diesel fuel, dual fuel engine, Ethanol, ignition delay, rate of heat release
The aim of the work is a comparison of two combustion systems of fuels with different reactivity. The first is combustion of the fuel mixture and the second is combustion in a dual-fuel engine. Diesel fuel was burned with pure ethanol. Both methods of co-firing fuels have both advantages and disadvantages. Attention was paid to the combustion stability aspect determined by COVIMEP as well as the probability density function of IMEP. It was analyzed also the spread of the maximum pressure value, the angle of the position of maximum pressure. The influence of ethanol on ignition delay time spread and end of combustion process was evaluated. The experimental investigation was conducted on 1-cylinder air cooled compression ignition engine. The test engine operated with constant rpm equal to 1500 rpm and constant angle of start of diesel fuel injection. The engine was operated with ethanol up to 50% of its energy fraction.
Numerical Simulation of a Wall-Flow Particulate Filter Made of Biomorphic Silicon Carbide Able to Fit Different Fuel/Biofuel Inputs
M. Pilar Orihuela, Onoufrios Haralampous, Ricardo Chacartegui, Miguel Torres García, Julián Martínez-Fernández
January 19, 2020 (v1)
Keywords: biodiesel, biomorphic silicon carbide, diesel particulate filter, internal combustion engine, particulate matter emissions, vegetal waste
To meet the increasingly strict emission limits imposed by regulations, internal combustion engines for transport applications require the urgent development of novel emission abatement systems. The introduction of biodiesel or other biofuels in the engine operation is considered to reduce greenhouse gas emissions. However, these alternative fuels can affect the performance of the post-combustion systems due to the variability they introduce in the exhaust particle distribution and their particular physical properties. Bioceramic materials made from vegetal waste are characterized by having an orthotropic hierarchical microstructure, which can be tailored in some way to optimize the filtration mechanisms as a function of the particle distribution of the combustion gases. Consequently, they can be good candidates to cope with the variability that new biofuel blends introduce in the engine operation. The objective of this work is to predict the filtration performance of a wall-flow parti... [more]
Empirical Bayes Prediction in a Sequential Sampling Plan Based on Loss Functions
Khanittha Tinochai, Katechan Jampachaisri, Yupaporn Areepong, Saowanit Sukparungsee
January 19, 2020 (v1)
Keywords: empirical Bayes prediction, precautionary loss function, sequential sampling plan, squared error loss function
The application of empirical Bayes for lot inspection in sequential sampling plans is usually conducted to estimate the proportion of defective items in the lot rather than for hypothesis testing of the variables’ process mean. In this paper, we propose the use of empirical Bayes in a sequential sampling plan variables’ process mean testing under a squared error loss function and precautionary loss function, for which the prediction is performed to estimate a sequence of the mean when the data are normally distributed in the case of a known mean and unknown variance. The proposed plans are compared with the sequential sampling plan. The proposed techniques yielded smaller average sample number (ASN) and provided higher probability of acceptance (Pa) than the sequential sampling plan.
Fault Diagnosis of the Blocking Diesel Particulate Filter Based on Spectral Analysis
Shuang-xi Liu, Ming Lü
January 19, 2020 (v1)
Keywords: blockage, DPF, exhaust pressure, fault diagnosis, spectral analysis
Diesel particulate filter is one of the most effective after-treatment techniques to reduce Particulate Matters (PM) emissions from a diesel engine, but the blocking Diesel Particulate Filter (DPF) will seriously affect the engine performance, so it is necessary to study the fault diagnosis of blocking DPF. In this paper, a simulation model of an R425DOHC diesel engine with wall-flow ceramic DPF was established, and then the model was verified with experimental data. On this basis, the fault diagnosis of the blocking DPF was studied by using spectral analysis on instantaneous exhaust pressure. The results showed that both the pre-DPF mean exhaust pressure and the characteristic frequency amplitude of instantaneous exhaust pressure can be used as characteristic parameters of monitoring the blockage fault of DPF, but it is difficult to monitor DPF blockage directly by instantaneous exhaust pressure. In terms of sensitivity, the characteristic frequency amplitude of instantaneous exhaust... [more]
Colloids at Fluid Interfaces
Armando Maestro, Eduardo Guzmán
January 19, 2020 (v1)
Subject: Materials
Keywords: colloids, contact angle, dynamics, interfaces, particles, rheology, surface tension
Over the last two decades, understanding of the attachment of colloids to fluid interfaces has attracted the interest of researchers from different fields. This is explained by considering the ubiquity of colloidal and interfacial systems in nature and technology. However, to date, the control and tuning of the assembly of colloids at fluid interfaces remain a challenge. This review discusses some of the most fundamental aspects governing the organization of colloidal objects at fluid interfaces, paying special attention to spherical particles. This requires a description of different physicochemical aspects, from the driving force involved in the assembly to its thermodynamic description, and from the interactions involved in the assembly to the dynamics and rheological behavior of particle-laden interfaces.
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