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Records Added in November 2019
Records added in November 2019
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Showing records 26 to 50 of 115. [First] Page: 1 2 3 4 5 Last
Proposal of a Learning Health System to Transform the National Health System of Spain
Rafael Carnicero, David Rojas, Ignacio Elicegui, Javier Carnicero
November 24, 2019 (v1)
Keywords: Big Data applied to clinical research, Big Data applied to healthcare, Big Data applied to National Health System of Spain, data protection, learning health system, patient’s phenotyping
This article identifies the main challenges of the National Health Service of Spain and proposes its transformation into a Learning Health System. For this purpose, the main indicators and reports published by the Spanish Ministries of Health and Finance, Organization for Economic Co-operation and Development (OECD) and World Health Organization (WHO) were reviewed. The Learning Health System proposal is based on some sections of an unpublished report, written by two of the authors under request of the Ministry of Health of Spain on Big Data for the National Health System. The main challenges identified are the rising old age dependency ratio; health expenditure pressures and the likely increase of out-of-pocket expenditure; drug expenditures, both retail and consumed in hospitals; waiting lists for surgery; potentially preventable hospital admissions; and the use of electronic health record (EHR) data to fulfil national health information and research objectives. To improve its effica... [more]
The Removal of Silicate(IV) by Adsorption onto Hydrocalumite from the Sodium Hydroxide Leaching Solution of Black Dross
Thi Thuy Nhi Nguyen, Man Seung Lee
November 24, 2019 (v1)
Subject: Materials
Keywords: Adsorption, alumina, black dross, hydrocalumite, silicate
Alkaline leaching of mechanically activated black dross resulted in an aluminate(III) solution with a small amount of silicate(IV). To obtain pure aluminate(III) solution, the removal of silicate(IV) from the alkaline leaching solution was investigated by adsorption with hydrocalumite (Ca2Al(OH)6Cl·2H2O). The hydrocalumite was synthesized by the coprecipitation method. The characterization of the synthesized hydrocalumite was analyzed via X-ray diffraction (XRD), scanning electron microscopy (SEM) images and Fourier-transform infrared spectroscopy (FTIR). In our experimental conditions, silicate(IV) was selectively adsorbed onto hydrocalumite over aluminate(III). The reaction time greatly affected the removal percentage of aluminate(III) owing to mass action effect. When the reaction time was longer than 2 h, no aluminate(III) was adsorbed onto hydrocalumite and thus it was possible to selectively remove silicate(IV). When the dosage of hydrocalumite was in excess, the removal percenta... [more]
Review and Modeling of Crystal Growth of Atropisomers from Solutions
Lotfi Derdour, Eric J. Chan, Dimitri Skliar
November 24, 2019 (v1)
Keywords: conformer, growth inhibition, habit, Modelling, step propagation
In this paper, theories on anisotropic crystal growth and crystallization of atropisomers are reviewed and a model for anisotropic crystal growth from solution containing slow inter-converting conformers is presented. The model applies to systems with growth-dominated crystallization from solutions and assumes that only one conformation participates in the solute integration step and is present in the crystal lattice. Other conformers, defined as the wrong conformers, must convert to the right conformer before they can assemble to the crystal lattice. The model presents a simple implicit method for evaluating the growth inhibition effect by the wrong conformers. The crystal growth model applies to anisotropic growth in two main directions, namely a slow-growing face and a fast-growing face and requires the knowledge of solute crystal face integration coefficients in both directions. A parameter estimation algorithm was derived to extract those coefficients from data about temporal conc... [more]
Handling Constraints and Raw Material Variability in Rotomolding through Data-Driven Model Predictive Control
Abhinav Garg, Hassan A. Abdulhussain, Prashant Mhaskar, Michael R. Thompson
November 24, 2019 (v1)
Keywords: batch process modeling and control, Model Predictive Control, polymer processing, rotational molding, subspace identification
This work addresses the problems of uniquely specifying and robustly achieving user-specified product quality in a complex industrial batch process, which has been demonstrated using a lab-scale uni-axial rotational molding process. In particular, a data-driven modeling and control framework is developed that is able to reject raw material variation and achieve product quality which is specified through constraints on quality variables. To this end, a subspace state-space model of the rotational molding process is first identified from historical data generated in the lab. This dynamic model predicts the evolution of the internal mold temperature for a given set of input move trajectory (heater and compressed air profiles). Further, this dynamic model is augmented with a linear least-squares based quality model, which relates its terminal (states) prediction with key quality variables. For the lab-scale process, the chosen quality variables are sinkhole area, ultrasonic spectra amplitu... [more]
Energetic and Exergetic Investigations of Hybrid Configurations in an Absorption Refrigeration Chiller by Aspen Plus
Xiao Zhang, Liang Cai, Tao Chen
November 24, 2019 (v1)
Keywords: absorption refrigeration, Aspen Plus, exergetic analysis, hybrid cycles, simulation model
In the present study, a steady-state simulation model was built and validated by Aspen Plus to assess the performance of an absorption refrigeration chiller according to the open literature. Given the complex heat transfer happening in the absorbers and the generator, several assumptions were proposed to simplify the model, for which a new parameter ε l i q was introduced to describe the ratio of possible heat that could be recovered from the absorption and heat-transferring process in the solution cooling absorber. The energetic and the exergetic investigations of a basic cycle and hybrid cycles were conducted, in which the following parameters were analyzed: coefficient of performance (COP), exergetic efficiency, exergy destruction, and irreversibility. According to the results, the basic cycle exhibited major irreversibility in the absorbers and the generator. Subsequently, two proposed novel configurations were adopted to enhance its performance; the first (configuratio... [more]
The Biomass Potential and GHG (Greenhouse Gas) Emissions Mitigation of Straw-Based Biomass Power Plant: A Case Study in Anhui Province, China
Hui Li, Xue Min, Mingwei Dai, Xinju Dong
November 24, 2019 (v1)
Subject: Energy Policy
Keywords: Anhui, biomass resource, GHG emission mitigation, power plant
Anhui Province (AHP), a typical agriculture-based province in China, has a significant amount of biomass resources for the development of biomass power plants. By the end of 2016, 23 straw based biomass power plants were established in AHP, aggregating to 6560 MW capacity, which is now ranked second in China. This paper presents the current development status and GHG (Greenhouse Gas) mitigation effect of the straw based biomass power plants in Anhui Province. Total biomass production in 2016 was calculated as 41.84 million tons. Although there is huge biomass potential in AHP, the distribution is heterogeneous with a gradually decreasing trend from north to south. Furthermore, the installed capacity of power generation is also unmatched with the biomass resources. Based on a calculation made in 2016, approximately 3.44 million tons of CO2-eq were mitigated from the biomass power plants in AHP. The large-scale development of biomass power plants remains a challenge for the future, espec... [more]
An All-Factors Analysis Approach on Energy Consumption for the Blast Furnace Iron Making Process in Iron and Steel industry
Biao Lu, Suojin Wang, Kai Tang, Demin Chen
November 24, 2019 (v1)
Subject: Other
Keywords: all-factors analysis approach, BFIMP, energy flows, material flows, operation parameters
The blast furnace iron making process (BFIMP) is the key of the integrated steel enterprise for energy saving due to its largest energy consumption proportion. In this paper, an all-factors analysis approach on energy consumption was proposed in BFIMP. Firstly, the BFIMP composition and production data should be collected. Secondly, the material flows and energy flows analysis models could be established based on material balance and the thermal equilibrium. Then, the all influence factors (mainly including material flows, energy flows and operation parameters) on energy consumption were obtained. Thirdly, the main influence factors, which influenced the coke ratio (CR) and the pulverized coal injection ratio (PCIR), were obtained by using the partial correlation analysis (PCA) method, because CR and PCIR were the key energy consumption performance in BFIMP. Furthermore, anall-factors analysis result could be achieved by a multivariate linear model (MLR), which was established through... [more]
Study of the Lamellar and Micellar Phases of Pluronic F127: A Molecular Dynamics Approach
Juan M. R. Albano, Damian Grillo, Julio C. Facelli, Marta B. Ferraro, Mónica Pickholz
November 24, 2019 (v1)
Subject: Materials
Keywords: lamellar, micellar, molecular dynamics, Pluronic F127, poloxamer
In this work, we analyzed the behavior of Pluronic F127 through molecular dynamics simulations at the coarse-grain level, focusing on the micellar and lamellar phases. To this aim, two initial polymer conformations were considered, S-shape and U-shape, for both simulated phases. Through the simulations, we were able to examine the structural and mechanical properties that are difficult to access through experiments. Since no transition between S and U shapes was observed in our simulations, we inferred that all single co-polymers had memory of their initial configuration. Nevertheless, most copolymers had a more complex amorphous structure, where hydrophilic beads were part of the lamellar-like core. Finally, an overall comparison of the micellar a lamellar phases showed that the lamellar thickness was in the same order of magnitude as the micelle diameter (approx. 30 nm). Therefore, high micelle concentration could lead to lamellar formation. With this new information, we could unders... [more]
Numerical Simulation and Performance Prediction of Centrifugal Pump’s Full Flow Field Based on OpenFOAM
Si Huang, Yifeng Wei, Chenguang Guo, Wenming Kang
November 24, 2019 (v1)
Keywords: centrifugal pump, numerical simulation, OpenFOAM, performance prediction
The open-source software OpenFOAM 5.0 was used as a platform to perform steady-state and transient numerical simulation for full flow field of a pipeline centrifugal pump (specific speed ns = 65) in a wide operating capacity range of 0.3Qd~1.4Qd. The standard k-ε and k-ω SST (Shear-Stress Transport) turbulence models were selected in the flow governing equations. The simpleFoam and pimpleDyMFoam solvers were used for the steady-state and transient calculations, respectively. ParaView, the postprocessor in OpenFOAM, was used to display the calculated flow velocity, pressure and streamline distributions, and to analyze the relationship between the vortex and the hydraulic loss in the pump. The external performance parameters of the pump such as head, input power and efficiency were also calculated based on the simulated flow fields. The predicted pump performances by OpenFOAM and Ansys-Fluent are compared with the test results under the same calculation model, grids and boundary conditio... [more]
Task Scheduling Model of Double-Deep Multi-Tier Shuttle System
Yanyan Wang, Rongxu Zhang, Hui Liu, Xiaoqing Zhang, Ziwei Liu
November 24, 2019 (v1)
Keywords: double-deep multi-tier shuttle system, modified Simulated Annealing Algorithms, part-to-picker storage system, task scheduling problem
As a new type of part-to-picker storage system, the double-deep multi-tier shuttle system has been developed rapidly in the e-commerce industry because of its high flexibility, large storage capacity, and robustness. The system consists of a multi-tier shuttle sub-system that controls horizontal movement and a lift sub-system that manages vertical movement. The combination of shuttles and lifts, instead of a stacker crane in conventional automated storage and retrieval system, undertakes inbound/outbound tasks. Because of the complex structure and numerous equipment of the system, task scheduling has become a major difficulty in the outbound operation of the double-deep multi-tier shuttle system. Figuring out methods to improve the overall efficiency of task scheduling operations is the focus of current system application enterprises. This paper introduces the task scheduling problem for the shuttle system. Inspired from workshop production scheduling problems, we minimize the total ti... [more]
Numerical Investigation of Solid-Fueled Chemical Looping Combustion Process Utilizing Char for Carbon Capture
Xiaojia Wang, Xianli Liu, Yong Zhang, Bo Zhang, Baosheng Jin
November 24, 2019 (v1)
Keywords: bubbling fluidized bed, char, chemical looping combustion, fuel reactor, numerical simulation
The in-depth understanding of the gas−solid flow and reaction behaviors, and their coupling characteristics during the chemical looping combustion (CLC) process has the guiding significance for the operation and optimization of a chemical looping combustor. A three-dimensional numerical model is applied to investigate the char-fueled CLC characteristics in a fuel reactor for efficient CO2 separation and capture. Simulations are carried out in a bubbling fluidized bed fuel reactor with a height of 2.0 m and a diameter of 0.22 m. The initial bed height is 1.1 m, and hence the height−diameter ratio of the slumped bed is five. The oxygen carrier is prepared with 14 wt% of CuO on 86 wt% of inert Al2O3. In the process of mathematical modeling, a Eulerian-Eulerian two-fluid model is adopted for both of the gas and solid phases. Gas turbulence is modeled on the basis of a k−ε turbulent model. The reaction kinetics parameters are addressed based upon previous experimental investigations from li... [more]
An Approach for Feedforward Model Predictive Control of Continuous Pulp Digesters
Moksadur Rahman, Anders Avelin, Konstantinos Kyprianidis
November 24, 2019 (v1)
Keywords: feedforward, Kappa number, Modelling, predictive control, pulp and paper, pulp digester
Kappa number variability at the continuous digester outlet is a major concern for pulp and paper mills. It is evident that the aforementioned variability is strongly linked to the feedstock wood properties, particularly lignin content. Online measurement of lignin content utilizing near-infrared spectroscopy at the inlet of the digester is paving the way for tighter control of the blow-line Kappa number. In this paper, an innovative approach of feedforwarding the lignin content to a model predictive controller was investigated with the help of modeling and simulation studies. For this purpose, a physics-based modeling library for continuous pulp digesters was developed and validated. Finally, model predictive control approaches with and without feedforwarding the lignin measurement were evaluated against current industrial control and proportional-integral-derivative (PID) schemes.
Intelligent Control Strategy for Transient Response of a Variable Geometry Turbocharger System Based on Deep Reinforcement Learning
Bo Hu, Jie Yang, Jiaxi Li, Shuang Li, Haitao Bai
November 24, 2019 (v1)
Keywords: deep deterministic policy gradient, deep reinforcement learning, self-learning, transient response, variable geometry turbocharger
Deep reinforcement learning (DRL) is an area of machine learning that combines a deep learning approach and reinforcement learning (RL). However, there seem to be few studies that analyze the latest DRL algorithms on real-world powertrain control problems. Meanwhile, the boost control of a variable geometry turbocharger (VGT)-equipped diesel engine is difficult mainly due to its strong coupling with an exhaust gas recirculation (EGR) system and large lag, resulting from time delay and hysteresis between the input and output dynamics of the engine’s gas exchange system. In this context, one of the latest model-free DRL algorithms, the deep deterministic policy gradient (DDPG) algorithm, was built in this paper to develop and finally form a strategy to track the target boost pressure under transient driving cycles. Using a fine-tuned proportion integration differentiation (PID) controller as a benchmark, the results show that the control performance based on the proposed DDPG algorithm c... [more]
Performance and Kinetic Model of a Single-Stage Anaerobic Digestion System Operated at Different Successive Operating Stages for the Treatment of Food Waste
Sagor Kumar Pramanik, Fatihah Binti Suja, Mojtaba Porhemmat, Biplob Kumar Pramanik
November 24, 2019 (v1)
Keywords: anaerobic biofilm reactor, biogas, food waste, hydraulic retention time, kinetic model, kinetic study, process stability and performance
A large quantity of food waste (FW) is generated annually across the world and results in environmental pollution and degradation. This study investigated the performance of a 160 L anaerobic biofilm single-stage reactor in treating FW. The reactor was operated at different hydraulic retention times (HRTs) of 124, 62, and 35 days under mesophilic conditions. The maximum biogas and methane yield achieved was 0.934 L/g VSadded and 0.607 L CH4/g VSadded, respectively, at an HRT of 124 days. When HRT decreased to 62 days, the volatile fatty acid (VFA) and ammonia accumulation increased rapidly whereas pH, methane yield, and biogas yield decreased continuously. The decline in biogas production was likely due to shock loading, which resulted in scum accumulation in the reactor. A negative correlation between biogas yield and volatile solid (VS) removal efficiency was also observed, owing to the floating scum carrying and urging the sludge toward the upper portion of the reactor. The highest... [more]
Adsorption of Arsenic and Lead onto Stone Powder and Chitosan-Coated Stone Powder
Kyungho Jung, Sanghwa Oh, Hun Bak, Gun-Ho Song, Hong-Tae Kim
November 24, 2019 (v1)
Subject: Materials
Keywords: Adsorption, arsenic, chitosan-coated stone powder, lead, stone powder
Stone powder (SP) produced from masonry mills has been treated as a specific waste and rarely used for environmental purposes. In this study, we tested its potential as an adsorbent to remove arsenic (As) and lead (Pb) from water. The single-solute sorption isotherms for As(V) and Pb(II) onto SP and chitosan-coated SP (CSP) were investigated. Several sorption models, such as the Langmuir, Freundlich, and Dubinin−Radushkevich (DR) models, were used to analyze the adsorption features. The results demonstrated that As and Pb were successfully adsorbed onto SP and CSP, indicating that SP and CSP had potential as adsorbents of As and Pb. The maximum adsorption capacities of SP and CSP for Pb were 22.8 and 54.5 times higher than those for As, respectively. Chitosan coating increased the adsorption potential in Pb adsorption by 5% but decreased it in As adsorption. The adsorption potential also depended on the pH and temperature. The adsorption amount of As increased with pH but that of Pb de... [more]
Insights into Kinetics of Methane Hydrate Formation in the Presence of Surfactants
Jyoti Shanker Pandey, Yousef Jouljamal Daas, Nicolas von Solms
November 24, 2019 (v1)
Keywords: gas uptake, induction time, methane hydrate, rocking cell, sodium dodecyl sulfate
Sodium dodecyl sulfate (SDS) is a well-known surfactant, which can accelerate methane hydrate formation. In this work, methane hydrate formation kinetics were studied in the presence of SDS using a rocking cell apparatus in both temperature-ramping and isothermal modes. Ramping and isothermal experiments together suggest that SDS concentration plays a vital role in the formation kinetics of methane hydrate, both in terms of induction time and of final gas uptake. There is a trade-off between growth rate and gas uptake for the optimum SDS concentration, such that an increase in SDS concentration decreases the induction time but also decreases the gas storage capacity for a given volume. The experiments also confirm the potential use of the rocking cell for investigating hydrate promoters. It allows multiple systems to run in parallel at similar experimental temperature and pressure conditions, thus shortening the total experimentation time. Understanding methane hydrate formation and st... [more]
The Performance and Exhaust Emissions of a Diesel Engine Fuelled with Calophyllum inophyllum—Palm Biodiesel
Natalina Damanik, Hwai Chyuan Ong, M. Mofijur, Chong Wen Tong, Arridina Susan Silitonga, Abd Halim Shamsuddin, Abdi Hanra Sebayang, Teuku Meurah Indra Mahlia, Chin-Tsan Wang, Jer-Huan Jang
November 24, 2019 (v1)
Subject: Biosystems
Keywords: alternative fuel, Calophyllum inophyllum biodiesel, engine performance, exhaust emissions, palm biodiesel, transesterification
Nowadays, increased interest among the scientific community to explore the Calophyllum inophyllum as alternative fuels for diesel engines is observed. This research is about using mixed Calophyllum inophyllum-palm oil biodiesel production and evaluation that biodiesel in a diesel engine. The Calophyllum inophyllum−palm oil methyl ester (CPME) is processed using the following procedure: (1) the crude Calophyllum inophyllum and palm oils are mixed at the same ratio of 50:50 volume %, (2) degumming, (3) acid-catalysed esterification, (4) purification, and (5) alkaline-catalysed transesterification. The results are indeed encouraging which satisfy the international standards, CPME shows the high heating value (37.9 MJ/kg) but lower kinematic viscosity (4.50 mm2/s) due to change the fatty acid methyl ester (FAME) composition compared to Calophyllum inophyllum methyl ester (CIME). The average results show that the blended fuels have higher Brake Specific Fuel Consumption (BSFC) and NOx emiss... [more]
Show Me the Money! Process Modeling in Pharma from the Investor’s Point of View
Christos Varsakelis, Sandrine Dessoy, Moritz von Stosch, Alexander Pysik
November 24, 2019 (v1)
Keywords: diffusion of innovation, process modeling, return on investment
Process modeling in pharma is gradually gaining momentum in process development but budget restrictions are growing. We first examine whether and how current practices rationalize within a decision process framework with a fictitious investor facing a decision problem subject to incomplete information. We then develop an algorithmic procedure for investment evaluation on both monetary and diffusion-of-innovation fronts. Our methodology builds upon discounted cash flow analysis and Bayesian inference and utilizes the Rogers diffusion of innovation paradigm for computing lower expected returns. We also introduce a set of intangible metrics for quantifying the level of diffusion of process modeling within an organization.
Global Supervisory Structure for Decentralized Systems of Flexible Manufacturing Systems Using Petri Nets
Muhammad Bashir, Liang Hong
November 24, 2019 (v1)
Keywords: decentralized system, flexible manufacturing system, global controller, Petri nets, working zone
Decentralized supervisory structure has drawn much attention in recent years to address the computational complexity in designing supervisory structures for large Petri net model. Many studies are reported in the paradigm of automata while few can be found in the Petri net paradigm. The decentralized supervisory structure can address the computational complexity, but it adds the structural complexity of supervisory structure. This paper proposed a new method of designing a global controller for decentralized systems of a large Petri net model for flexible manufacturing systems. The proposed method can both reduce the computational complexity by decomposition of large Petri net models into several subnets and structural complexity by designing a global supervisory structure that can greatly reduce the cost at the implementation stage. Two efficient algorithms are developed in the proposed method. Algorithm 1 is used to compute decentralized working zones from the given Petri net model f... [more]
Simulation Study on Gas Holdup of Large and Small Bubbles in a High Pressure Gas−Liquid Bubble Column
Fangfang Tao, Shanglei Ning, Bo Zhang, Haibo Jin, Guangxiang He
November 24, 2019 (v1)
Keywords: high pressure bubble column, the critical bubble diameter, the gas holdup, the large bubbles, the small bubbles
The computational fluid dynamics-population balance model (CFD-PBM) has been presented and used to evaluate the bubble behavior in a large-scale high pressure bubble column with an inner diameter of 300 mm and a height of 6600 mm. In the heterogeneous flow regime, bubbles can be divided into “large bubbles” and “small bubbles” by a critical bubble diameter dc. In this study, large and small bubbles were classified according to different slopes in the experiment only by the method of dynamic gas disengagement, the critical bubble diameter was determined to be 7 mm by the experimental results and the simulation values. In addition, the effects of superficial gas velocity, operating pressure, surface tension and viscosity on gas holdup of large and small bubbles in gas−liquid two-phase flow were investigated using a CFD-PBM coupling model. The results show that the gas holdup of small and large bubbles increases rapidly with the increase of superficial gas velocity. With the increase of p... [more]
Rapid Processing of Abandoned Oil Palm Trunks into Sugars and Organic Acids by Sub-Critical Water
Hazwani Ishak, Hiroyuki Yoshida, Noor Azura Muda, Mohd Halim Shah Ismail, Shamsul Izhar
November 24, 2019 (v1)
Subject: Biosystems
Keywords: hydrolysis, oil palm trunk (OPT), organic acid, subcritical water (sub-CW), sugar
Abandoned oil palm trunk (OPT) is among the most abundant left-over biomass in Malaysia and is allowed to decompose naturally in the field. However, the recycling of OPT is less considered although OPT is a bioresource that has a high potential for conversion into value-added products. In this study, waste OPT was rapidly converted by hydrolysis using subcritical water (sub-CW). This work is the first attempt to explore the utilization of waste OPT based on the differences in moisture, cellulose and hemicellulose contents in the top and bottom segments, and from various ages of the waste OPT. 21- and 35-year-old OPTs were divided into top and bottom sections. The OPTs was subjected to sub-CW at a heating rate of 3.8 °C/s at various temperatures and times. The 21-year-old OPT was superior to the 35-year-old OPT for conversion into sugar and organic acid. The yield of the total sugar was between 0.41 and 0.77 kg/kg-OPT in the bottom and top sections. The excellent correlation between the... [more]
Highly Selective CO2 Capture on Waste Polyurethane Foam-Based Activated Carbon
Chao Ge, Dandan Lian, Shaopeng Cui, Jie Gao, Jianjun Lu
November 24, 2019 (v1)
Subject: Materials
Keywords: Carbon Dioxide Capture, high selectivity, physical activation, ultra-micropore, waste polyurethane foam
Low-cost activated carbons were prepared from waste polyurethane foam by physical activation with CO2 for the first time and chemical activation with Ca(OH)2, NaOH, or KOH. The activation conditions were optimized to produce microporous carbons with high CO2 adsorption capacity and CO2/N2 selectivity. The sample prepared by physical activation showed CO2/N2 selectivity of up to 24, much higher than that of chemical activation. This is mainly due to the narrower microporosity and the rich N content produced during the physical activation process. However, physical activation samples showed inferior textural properties compared to chemical activation samples and led to a lower CO2 uptake of 3.37 mmol·g−1 at 273 K. Porous carbons obtained by chemical activation showed a high CO2 uptake of 5.85 mmol·g−1 at 273 K, comparable to the optimum activated carbon materials prepared from other wastes. This is mainly attributed to large volumes of ultra-micropores (<1 nm) up to 0.212 cm3·g−1 and... [more]
Pelletization of Sunflower Seed Husks: Evaluating and Optimizing Energy Consumption and Physical Properties by Response Surface Methodology (RSM)
Xuyang Cui, Junhong Yang, Xinyu Shi, Wanning Lei, Tao Huang, Chao Bai
November 24, 2019 (v1)
Subject: Optimization
Keywords: energy consumption, pelletization, performance evaluation, RSM optimization, sunflower seed husk
Pelletization is a significant approach for the efficient utilization of biomass energy. Sunflower seed husk is a common solid waste in the process of oil production. The novelty of this study was to determine the parameters during production of a novel pellet made from sunflower seed husk. The energy consumption (W) and physical properties (bulk density (BD) and mechanical durability (DU)) of the novel pellet were evaluated and optimized at the laboratory by using a pelletizer and response surface methodology (RSM) under a controlled moisture content (4%−14%), compression pressure (100−200 MPa), and die temperature (70−170 °C). The results show that the variables of temperature, pressure, and moisture content of raw material are positively correlated with BD and DU. Increasing the temperature and moisture content of raw materials can effectively reduce W, while increasing the pressure has an adverse effect on W. The optimum conditions of temperature (150 °C), pressure (180 MPa), and m... [more]
Synthetic Effect of EDTA and Ni2+ on Methane Production and Microbial Communities in Anaerobic Digestion Process of Kitchen Wastes
Tingting Zhong, Yali Liu, Xiaorong Kang
November 24, 2019 (v1)
Subject: Biosystems
Keywords: EDTA, kitchen waste, methane, microbial community, Ni2+
Batch tests were carried out to study the effect of simultaneous addition of ethylenediaminetetraacetic acid and Ni2+ (EDTA-Ni) on anaerobic digestion (AD) performances of kitchen wastes (KWs). The results indicated that the cumulative biogas yield and methane content were enhanced to 563.82 mL/gVS and 63.7% by adding EDTA-Ni, respectively, which were almost 1.15 and 1.07-fold of that in the R2 with Ni2+ addition alone. At the same time, an obvious decrease of propionic acid was observed after EDTA-Ni addition. The speciation analysis of Ni showed that the percentages of water-soluble and exchangeable Ni were increased to 38.8% and 36.3% due to EDTA-Ni addition, respectively. Also, the high-throughput sequencing analysis revealed that the EDTA-Ni promoted the growth and metabolism of Methanosarcina and Methanobacterium, which might be the major reason for propionic acid degradation and methane production.
Fault Diagnosis Method for Hydraulic Directional Valves Integrating PCA and XGBoost
Yafei Lei, Wanlu Jiang, Anqi Jiang, Yong Zhu, Hongjie Niu, Sheng Zhang
November 24, 2019 (v1)
Keywords: extreme gradient boosting (XGBoost), fault diagnosis, HUAWEI Cloud machine learning service (MLS), hydraulic valve, principal component analysis (PCA)
A novel fault diagnosis method is proposed, depending on a cloud service, for the typical faults in the hydraulic directional valve. The method, based on the Machine Learning Service (MLS) HUAWEI CLOUD, achieves accurate diagnosis of hydraulic valve faults by combining both the advantages of Principal Component Analysis (PCA) in dimensionality reduction and the eXtreme Gradient Boosting (XGBoost) algorithm. First, to obtain the principal component feature set of the pressure signal, PCA was utilized to reduce the dimension of the measured inlet and outlet pressure signals of the hydraulic directional valve. Second, a machine learning sample was constructed by replacing the original fault set with the principal component feature set. Third, the MLS was employed to create an XGBoost model to diagnose valve faults. Lastly, based on model evaluation indicators such as precision, the recall rate, and the F1 score, a test set was used to compare the XGBoost model with the Classification And... [more]
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