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Showing records 1 to 25 of 1931. [First] Page: 1 2 3 4 5 Last
Study on Wear Properties of the Flow Parts in a Centrifugal Pump Based on EDEM−Fluent Coupling
Si Huang, Jiaxing Huang, Jiawei Guo, Yushi Mo
September 13, 2019 (v1)
Keywords: centrifugal pump, EDEM–Fluent coupling, numerical simulation, solid–liquid two-phase flow, wear
By using EDEM−Fluent codes and coupling the continuous fluid medium with a solid particle discrete element, the solid−liquid two-phase flow field in a centrifugal pump was simulated under the same inlet conditions of the particle volume fraction and three flow conditions of 0.7Qd, 1.0Qd and 1.3Qd. By introducing the Archard wear model, the wear was calculated, and the wear law was obtained for the pump flow parts such as the leading edge of the impeller blade, blade tip, blade pressure side, blade suction side, impeller shroud, hub and volute. The results demonstrate that the wear of volute is about 70% of the total wear of pump. The wear in the impeller mainly occurs in the blade leading edge, the junction of the hub and the trailing part of the blade pressure side, and the junction of the shroud and the rear part of the blade suction side. Under lower flow conditions, the wear in the impeller shroud is relatively considerable. As the flow rate increases, the wear in the blade pressur... [more]
Optimized Energy Management Strategies for Campus Hybrid PV−Diesel Systems during Utility Load Shedding Events
Jacques Maritz
September 13, 2019 (v1)
Keywords: digital resource management, energy management, hybrid PV–diesel generator systems
The unique situation of utility power curtailment unveils opportunities in the fields of energy management and digital resource management. During utility load shedding events, campuses are typically driven as Photo Voltaic (PV)−diesel generator hybrid systems, of which the main fossil resource driver is diesel. With the appropriate Supervisory Control and Data Acquisition (SCADA) systems, discrete departmental energy policies along with control, forecasting and Internet of Things (IoT) infrastructure, the campus hybrid system could be optimized on a short timescale during the shedding event. In this paper the optimization methodology, required technology infrastructure, possible forecasting algorithms and potential implementation will be discussed.
Performance Improvement and Energy Cost Reduction under Different Scenarios for a Parabolic Trough Solar Power Plant in the Middle-East Region
Mujeeb Iqbal Soomro, Abdullah Mengal, Qadir Nawaz Shafiq, Syed Aziz Ur Rehman, Shakir Ali Soomro, Khanji Harijan
September 13, 2019 (v1)
Keywords: Abu Dhabi, concentrated solar power, levelized cost of energy, performance improvement, System Advisor Model
Concentrated solar power (CSP) is a leading renewable energy technology, and the parabolic trough (PT) is one of the most used configurations of CSP. In the present study, the performance improvement and energy cost reduction of a 50 MWe PT plant for Abu Dhabi, United Arab Emirates (UAE) is presented. The simulations were carried out using the System Advisor Model software. The analyses of a PT plant with different technologies/parameters are undertaken in the first instance for seven cases. These cases include solar multiple, solar collectors, receivers, heat transfer fluid, cooling system (evaporative and air-cooled), thermal energy storage system (4−12 h), and fossil dispatch mode (0.25 to 1.0). Based on these analysis, the eighth case, which is found to be the best-case scenario in this study, was considered by taking into account the best of preceding case results and was determined to be the most suitable both in terms of performance and cost reduction. It is, therefore, conclude... [more]
Modelling Hydration Swelling and Weakening of Montmorillonite Particles in Mudstone
Changlun Sun, Guichen Li, Yuantian Sun, Jintao He, Haoyu Rong
September 13, 2019 (v1)
Subject: Materials
Keywords: hydration, montmorillonite, mudstone, particle, swelling and weakening
It is of paramount importance to understand the hydration swelling and weakening properties of clay minerals, such as montmorillonite, to determine their mechanical responses during deep underground argillaceous engineering. In this study, the mineral components and microscopic structure of mudstone were characterised using X-ray powder diffraction and field-emission scanning electron microscopy. Experimental schemes were devised to determine the properties of mudstone under the influence of underground water and stress; these involved compacting montmorillonite particles with various water contents and conducting uniaxial compression tests. Experimental results demonstrated that compaction stress changes the microscopic structure of the montmorillonite matrix and affects its properties, and stress independency was found at particular water and stress conditions. Two equations were then obtained to describe the swelling and weakening properties of the montmorillonite matrix based on th... [more]
Effects of Operating Parameters on the Cut Size of Turbo Air Classifier for Particle Size Classification of SAC305 Lead-Free Solder Powder
Nipon Denmud, Kradsanai Baite, Thawatchai Plookphol, Somjai Janudom
September 13, 2019 (v1)
Keywords: cut size, DOE, powder classification, SAC305, turbo air classifier
In the present study, the effects of operating parameters, namely, rotor speed, feed rate, and inlet air velocity, on the cut diameter of a cage-type separator were studied. The design of experiments (DOE) method was used to investigate the relationship between the operating parameters and the cut size. The experimental results were statistically analyzed using MINITAB 16 software. Both the rotor speed and air inlet velocity had significant main effects on the cut size. The feed rate was also significant but had a weak effect with respect to the rotor speed and inlet air velocity effects. The cut size decreased with an increase in rotor speed and increased with an increase in air inlet velocity. However, the cut size slightly decreased with an increase in feed rate. An empirical multiple-variable linear model for predicting the cut size of the classification was created and presented. The results derived from the statistical analysis were in good agreement with those from the experimen... [more]
Optimization of the Production Technology of Oxidized Cyclodextrin Bisulfite
Yana-Ya Kostyro, Anastasiya Soldatenko, Alexey Levchuk
September 13, 2019 (v1)
Keywords: active pharmaceutical ingredient, cyclodextrin, oligosaccharides, oxidation of carbohydrates, production technology, sodium periodate
The A.E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences has developed an original active pharmaceutical ingredient based on an oxidized cyclodextrin oligosaccharide, which is a bisulfite derivative. Conducted pharmacological studies proved its antiviral activity in vitro and in vivo experiments against the influenza A (H1N1) virus. The aim of this work was to optimize the technology of obtaining the active pharmaceutical ingredient based on the bisulfite derivative of oxidized cyclodextrin to increase the efficiency and safety of the process. For this, a scaled method of oligosaccharide oxidation was tested on pilot plants in accordance with the requirements of green chemistry. As a result, the reaction time was reduced from three to five days (laboratory conditions) to 1.5 h, and the safety and environmental friendliness of process was ensured. The use of cross-flow filtration and the method of freeze-drying eliminated 96% of ethyl alcohol,... [more]
Utility Paths Combination in HEN for Energy Saving and CO2 Emission Reduction
Abdelbagi Osman, Mohanad Eltayeb, Fahd Rajab
September 13, 2019 (v1)
Keywords: CO2 emission, energy saving, HEN retrofit, path analysis, paths combination
Energy demand and flue gas emissions, namely carbon dioxide (CO2) associated with the industrial revolution have exhibited a continuous rise. Several approaches were introduced recently to mitigate energy consumption and CO2 emissions by either grass root design or retrofit of existing heat exchanger networks (HEN) in chemical process plants. In this work, a combinatorial approach of path combination is used to generate several options for heat recovery enhancement in HEN. The options are applied to successively shift heat load from HEN utilities using combined utility paths at different heat recovery approach temperature (HRAT) considering exchangers pressure drop. Industrial case study for HEN of the preheat train in crude oil distillation unit from the literature is used to demonstrate the approach. The obtained results have been studied economically using the cost targeting of Pinch Technology. As a result, both external energy usage and CO2 emissions have been reduced from a heate... [more]
Deep Learning-Based Pose Estimation of Apples for Inspection in Logistic Centers Using Single-Perspective Imaging
Lino Antoni Giefer, Juan Daniel Arango Castellanos, Mohammad Mohammadzadeh Babr, Michael Freitag
September 13, 2019 (v1)
Keywords: deep learning, lie algebra, logistic centers, pose estimation, quality inspection
Fruit packaging is a time-consuming task due to its low automation level. The gentle handling required by some kinds of fruits and their natural variations complicates the implementation of automated quality controls and tray positioning for final packaging. In this article, we propose a method for the automatic localization and pose estimation of apples captured by a Red-Green-Blue (RGB) camera using convolutional neural networks. Our pose estimation algorithm uses a cascaded structure composed of two independent convolutional neural networks: one for the localization of apples within the images and a second for the estimation of the three-dimensional rotation of the localized and cropped image area containing an apple. We used a single shot multi-box detector to find the bounding boxes of the apples in the images. Lie algebra is used for the regression of the rotation, which represents an innovation in this kind of application. We compare the performances of four different network ar... [more]
A Novel MPC with Actuator Dynamic Compensation for the Marine Steam Turbine Rotational Control with a Novel Energy Dynamic Model
Sheng Liu, Baoling Zhao, Ling Wu
September 13, 2019 (v1)
Keywords: actuator dynamic compensation, dynamic performance, energy dynamic model, Model Predictive Control, steam turbine rotational speed control
The conventional modeling method of the marine steam turbine rotational speed control system (MSTRSCS) is based on Newton’s second law, constructing the mechanical equations between the rotational acceleration and the resultant torque. The disadvantages of this are nonlinearity, a complex structure and an infinite point of discontinuity in the rotational acceleration when the rotational speed is close to 0. Taking the kinetic energy of MSTRSCS as the output variable by using the kinetic energy theorem in this paper, we convert the complex nonlinear model of MSTRSCS into a linear one, since kinetic energy and rotational speed are homeomorphic. Model predictive control (MPC) adopts a discrete-time model, whereas the real system is time-continuous. Hence, poor performance is obtained in the real system when the time-discrete control law is applied to the MSTRSCS through the actuator. In case of high requirements for system accuracy and control performance, conventional MPC (CMPC) cannot m... [more]
Recent Novel Hybrid Pd−Fe3O4 Nanoparticles as Catalysts for Various C−C Coupling Reactions
Sanha Jang, Shamim Ahmed Hira, Dicky Annas, Sehwan Song, Mohammad Yusuf, Ji Chan Park, Sungkyun Park, Kang Hyun Park
September 13, 2019 (v1)
Keywords: C–C coupling reaction, heterogeneous catalyst, hybrid catalyst, Pd–Fe3O4 nanoparticles
The use of nanostructure materials as heterogeneous catalysts in the synthesis of organic compounds have been receiving more attention in the rapid developing area of nanotechnology. In this review, we mainly focused on our own work on the synthesis of hybrid palladium−iron oxide nanoparticles. We discuss the synthesis of Pd−Fe3O4—both morphology-controlled synthesis of Pd−Fe3O4 and transition metal-loaded Pd−Fe3O4—as well as its application in various C−C coupling reactions. In the case of rose-like Pd−Fe3O4 hybrid nanoparticles, thermal decomposition can be used instead of oxidants or reductants, and morphology can be easily controlled. We have developed a method for the synthesis of nanoparticles that is facile and eco-friendly. The catalyst was recyclable for up to five continual cycles without significant loss of catalytic activity and may provide a great platform as a catalyst for other organic reactions in the near future.
A Computational Fluid Dynamics Approach for the Modeling of Gas Separation in Membrane Modules
Salman Qadir, Arshad Hussain, Muhammad Ahsan
September 13, 2019 (v1)
Keywords: Computational Fluid Dynamics, concentration polarization, gas separation, membrane module
Natural gas demand has increased rapidly across the globe in the last decade, and it is set to play an important role in meeting future energy requirements. Natural gas is mainly produced from fossil fuel and is a side product of crude oil produced beneath the earth’s crust. Materials hazardous to the environment, like CO2, H2S, and C2H4, are present in raw natural gas. Therefore, purification of the gaseous mixture is required for use in different industrial applications. A comprehensive computational fluid dynamics (CFD) model was proposed to perform the separation of natural gas from other gases using membrane modules. The CFD technique was utilized to estimate gas flow variations in membrane modules for gas separation. CFD was applied to different membrane modules to study gas transport through the membrane and flux, and to separate the binary gas mixtures. The different parameters of membrane modules, like feed and permeate pressure, module length, and membrane thickness, have bee... [more]
Finite Time Thermodynamic Optimization of an Irreversible Proton Exchange Membrane Fuel Cell for Vehicle Use
Changjie Li, Ye Liu, Bing Xu, Zheshu Ma
September 13, 2019 (v1)
Subject: Optimization
Keywords: finite time thermodynamic model, irreversibility, operating parameters, optimal performance, PEMFC
A finite time thermodynamic model of an irreversible proton exchange membrane fuel cell (PEMFC) for vehicle use was established considering the effects of polarization losses and leakage current. Effects of operating parameters, including operating temperature, operating pressure, proton exchange membrane water content, and proton exchange membrane thickness, on the optimal performance of the irreversible PEMFC are numerically studied in detail. When the operating temperature of the PEMFC increases, the optimal performances of PEMFC including output power density, output efficiency, ecological objective function, and ecological coefficient of performance, will be improved. Among them, the optimal ecological objective function increased by 81%. The proton film thickness has little effect on the output efficiency and the ecological of coefficient performance. The maximum output power density increased by 58% as the water content of the proton exchange membrane increased from 50% to the s... [more]
Innovative Effluent Capture and Evacuation Device that Increases COD Removal Efficiency in Subsurface Flow Wetlands
Pedro Cisterna-Osorio, Verónica Lazcano-Castro, Gisela Silva-Vasquez, Mauricio Llanos-Baeza, Ignacio Fuentes-Ortega
September 13, 2019 (v1)
Keywords: artificial wetlands, horizontal wetland, subsurface flow
The objective of this work is to evaluate the impact of innovative modifications made to conventional effluent capture and discharge devices used in subsurface flow wetlands (SSFW). The main modifications that have been developed extend the influence of the capture and discharge device in such a way that the SSFW width and height are fully covered. This improved innovative device was applied and evaluated in two subsurface flow wetlands, one on a pilot scale and one on a real scale. To evaluate the impact of the innovative device with respect to the conventional one in the operational functioning of subsurface flow wetlands, the elimination of chemical oxygen demand (COD) was measured and compared. The results show that for the innovative device, the COD removal was 10% higher than for the conventional device, confirming the validity and effectiveness of the modifications implemented in the effluent capture and discharge devices used in SSFW.
Curcumin Analogues with Aldose Reductase Inhibitory Activity: Synthesis, Biological Evaluation, and Molecular Docking
Dasharath Kondhare, Sushma Deshmukh, Harshad Lade
September 13, 2019 (v1)
Subject: Biosystems
Keywords: aldose reductase inhibitor, antidiabetic, Claisen–Schmidt condensation, curcumin analogues, molecular docking
Curcumin, a constituent of Curcuma longa, has shown numerous biological and pharmacological activities, including antidiabetic effects. Here, a novel series of curcumin analogues were synthesized and evaluated for in vitro inhibition of aldose reductase (AR), the first and rate-limiting enzyme of the polyol pathway, which plays a key role in the onset and progression of diabetic complications. Biological activity studies showed that all the curcuminoids exhibited moderate to good AR inhibitory (ARI) activities compared with that of the quercetin standard. Importantly, compounds 8d, 8h, 9c, 9e, and 10g demonstrated promising ARI activities, with the 50% inhibitory concentration (IC50) values of 5.73, 5.95, 5.11, 5.78, and 5.10 µM, respectively. Four other compounds exhibited IC50 values in the range of 6.04−6.18 µM. Methyl and methoxy derivatives showed a remarkable ARI potential compared with that of other substitutions on the aromatic ring. Molecular docking experiments demonstrated t... [more]
Natural Deep Eutectic Solvent-Assisted Pectin Extraction from Pomelo Peel Using Sonoreactor: Experimental Optimization Approach
Amal A. M. Elgharbawy, Adeeb Hayyan, Maan Hayyan, Mohamed E. S. Mirghani, Hamzah Mohd. Salleh, Shahidah Nusailah Rashid, Gek Cheng Ngoh, Shan Qin Liew, Mohd Roslan Mohd Nor, Mohd Yakub Zulkifli bin Mohd Yusoff, Yatimah Alias
September 13, 2019 (v1)
Subject: Biosystems
Keywords: Citrus grandis, definitive screening design, Extraction, natural deep eutectic solvent, pectin, pomelo
Background: Natural deep eutectic solvents (NADESs) can be used for extracting a wide range of biomaterials, such as pectin. This study introduces a new generation of natural solvents for pectin extraction which could replace the conventional solvents in the food industry. Methods: In this study, NADESs were used for pectin extraction from pomelo (Citrus grandis (L.) Osbeck) peels using a sonoreactor. Definitive screening design (DSD) was used to screen the influence of time, temperature, solid/liquid ratio, and NADES/water ratio on the pectin yield and degree of esterification (DE). Results: The primary screening revealed that the best choices for the extraction were choline chloride−malonic acid (ChCl-Mal) and choline chloride−glucose−water (ChCl:Glc:W). Both co-solvents yielded 94% pectin and 52% DE after optimization at 80 °C, with 60 min of sonication, pH < 3.0, and a NADES-to-water ratio of 1:4.5 (v/v). Morphological screening showed a smooth and compact surface of the pectin fro... [more]
Gain Scheduling of a Robust Setpoint Tracking Disturbance Rejection and Aggressiveness Controller for a Nonlinear Process
Veeramani Bagyaveereswaran, Pachiyappan Arulmozhivarman
September 13, 2019 (v1)
Keywords: controller, gain scheduling, Optimization, performance criteria, PID, regulatory, servo
In this paper, a robust setpoint tracking disturbance rejection and aggressiveness (RTD-A) controller is designed and developed to control the liquid level of a conical tank process. Meta-heuristic algorithms like grey wolf optimization and the genetic algorithm are used to tune the parameters of the RTD-A controller. Its performance is later compared with that of the conventional standard proportional integral derivative controller. The gain scheduled RTD-A controller is designed and implemented on a nonlinear conical tank process. Also, various performances attributes such as the integral square error, integral absolute error, integral time absolute error, rise time, and settling time are calculated for the first-order process and conical tank process. The servo responses with RTD-A are also compared against the responses recorded from the conventional control schemes.
Fabrication of Green Superhydrophobic/Superoleophilic Wood Flour for Efficient Oil Separation from Water
Xuefei Tan, Deli Zang, Haiqun Qi, Feng Liu, Guoliang Cao, Shih-Hsin Ho
September 13, 2019 (v1)
Subject: Biosystems
Keywords: oil adsorption, oil-water separation, superhydrophobic, superoleophilic, sustainable material, wood flour
The removal of oil from waste water is gaining increasing attention. In this study, a novel synthesis method of green superhydrophobic/superoleophilic wood flour is proposed using the deposition of nano−zinc oxide (nZnO) aggregated on the fiber surface and the subsequent hydrophobic modification of octadecanoic acid. The as-prepared wood flour displayed great superhydrophobicity and synchronous superoleophilicity properties with the water contact angle (WCA) of 156° and oil contact angle (OCA) of 0° for diesel oil. Furthermore, the as-prepared wood flour possessed an excellent stability, probably due to the strong adhesion of nZnO, which aggregates to the fiber surface of wood flour with the action of glutinous polystyrene. The maximum adsorption capacity of as-prepared wood flour was 20.81 g/g for engine oil, which showed that the as-prepared wood flour is a potential candidate as an efficient oil adsorbent in the field of water-oil separation. Moreover, it has good chemical steadines... [more]
Irregularity Molecular Descriptors of Hourglass, Jagged-Rectangle, and Triangular Benzenoid Systems
Zafar Hussain, Shazia Rafique, Mobeen Munir, Muhammad Athar, Maqbool Chaudhary, Haseeb Ahmad, Shin Min Kang
September 13, 2019 (v1)
Subject: Materials
Keywords: benzenoid systems, complexity of structure, hourglass benzenoid system, irregularity measures
Determining the degree of irregularity of a certain molecular structure or a network has been a key source of interest for molecular topologists, but it is also important as it provides an insight into the key features used to guess properties of the structures. In this article, we are interested in formulating closed forms of irregularity measures of some popular benzenoid systems, such as hourglass H (m, n), jagged-rectangular J (m, n), and triangular benzenoid T (m, n) systems. We also compared our results graphically and concluded which benzenoid system among the above listed is more irregular than the others.
Selective Cesium Adsorptive Removal on Using Crosslinked Tea Leaves
Dan Yu, Shintaro Morisada, Hidetaka Kawakita, Keisuke Ohto, Katsutoshi Inoue, Ximing Song, Guolin Zhang
September 13, 2019 (v1)
Keywords: adsorptive removal, biomass wastes, cesium selectivity, ion-exchange
To remove the radioactive cesium from the polluted environment, tea leaves were chosen as cheap, and abundantly available environment-friendly bio-adsorbents to investigate the alkali metals adsorption. Fresh and used tea leaves (FT and UT) were found to have high efficiency and selectivity for cesium adsorption, after the crosslinking with concentrated sulfuric acid. Calculation of the proton-exchanged amount suggested adsorption mechanism of three alkali metals on crosslinked tea leaves involve a cationic exchange with a proton from the hydroxyl groups of the crosslinked tea leaves, as well as coordination with ethereal oxygen atoms to form the chelation. Further, considering the practical application of the polluted water treatment, the competitive adsorption of Cs+ and Na+ ions was investigated by the batch-wise method and column chromatography separation. Unlike the conventional ion exchange and chelate resins with less selectivity for Cs+ coexisting cations, both crosslinked fres... [more]
Statistical Process Monitoring of the Tennessee Eastman Process Using Parallel Autoassociative Neural Networks and a Large Dataset
Seongmin Heo, Jay H. Lee
September 13, 2019 (v1)
Keywords: autoassociative neural network, Big Data, nonlinear principal component analysis, parallel neural networks, process monitoring
In this article, the statistical process monitoring problem of the Tennessee Eastman process is considered using deep learning techniques. This work is motivated by three limitations of the existing works for such problem. First, although deep learning has been used for process monitoring extensively, in the majority of the existing works, the neural networks were trained in a supervised manner assuming that the normal/fault labels were available. However, this is not always the case in real applications. Thus, in this work, autoassociative neural networks are used, which are trained in an unsupervised fashion. Another limitation is that the typical dataset used for the monitoring of the Tennessee Eastman process is comprised of just a small number of data samples, which can be highly limiting for deep learning. The dataset used in this work is 500-times larger than the typically-used dataset and is large enough for deep learning. Lastly, an alternative neural network architecture, whi... [more]
Improvement of 1,3-Butadiene Separation in 2,3-Butanediol Dehydration Using Extractive Distillation
Daesung Song, Young-Gak Yoon, Seung-Kwon Seo, Chul-Jin Lee
September 5, 2019 (v1)
Keywords: 1-butene, 1,3-butadiene, 2,3-butanediol dehydration, Distillation, economic feasibility, extractive distillation
This study was performed to investigate the extractive distillation for 1,3-butadiene (1,3-BD) purification as a part of the 2,3-butanediol (2,3-BDO) dehydration process. The separation of 1,3-BD from 1-butene produced as a 2,3-BDO dehydration by-product while using distillation is complicated due to the similar volatilities of the two compounds. Thus, an extractive distillation system is proposed for the effective recovery of 1,3-BD, and is compared with a conventional distillation system in terms of its performance and economic feasibility. A higher 1,3-BD recovery rate was achieved while using the proposed system and the relative profitabilities of both separation systems were analyzed according to the market price of 1,3-BD, which is a decisive variable for economic feasibility.
Process Simulation of the Separation of Aqueous Acetonitrile Solution by Pressure Swing Distillation
Jing Li, Keliang Wang, Minglei Lian, Zhi Li, Tingzhao Du
September 5, 2019 (v1)
Keywords: acetonitrile, full-heat integration, pressure swing distillation, Water
The separation of aqueous acetonitrile solution by pressure swing distillation (PSD) was simulated and optimized through Aspen Plus software. The distillation sequence of the low pressure column (LPC) and high pressure column (HPC) was determined with a phase diagram. The pressures of the two columns were set to 1 and 4 atm, respectively. Total annual cost (TAC) was considered as the objective function, and design variables, such as the tray number, the reflux ratio, and the feeding position, were optimized. The optimum process parameters were obtained. For the reduction of energy consumption, the PSD with full-heat integration was designed. The TAC of this method is lower by 32.39% of that of the PSD without heat integration. Therefore, it is more economical to separate acetonitrile and water mixture by PSD with full-heat integration, which provides technical support for the separation design of such azeotropes.
Spatial Variations of Bacterial Communities of an Anaerobic Lagoon-Type Biodigester Fed with Dairy Manure
Marleny García-Lozano, Inty Omar Hernández-De Lira, David H. Huber, Nagamani Balagurusamy
September 5, 2019 (v1)
Subject: Biosystems
Keywords: anaerobic digestion, bacterial communities, biodigester, PICRUSt, spatial variations
Anaerobic digestion technology is being widely employed for sustainable management of organic wastes generated in animal farms, industries, etc. Nevertheless, biodigester microbiome is still considered a “black box” because it is regulated by different physico-chemical and operational factors. In this study, the bacterial diversity and composition in different sites of a full-scale lagoon type biodigester (23,000 m3) fed with dairy manure, viz., the influent, beginning, middle, final and effluent were analyzed. The biodigester registered a total of 1445 OTUs, which demonstrated the complex microbial ecosystem in it. Of them, only six OTUs were shared among all the different sampling points. The most abundant phyla belonged to Firmicutes, Proteobacteria, Latescibacteria and Thermotogae. The Simpson and Shannon index showed that the highest microbial diversity was observed in the beginning point of the biodigester, meanwhile, the lowest diversity was recorded in the middle. Based on the... [more]
Control Strategy for Inverter Air Conditioners under Demand Response
Yanbo Che, Jianxiong Yang, Yuancheng Zhao, Siyuan Xue
September 5, 2019 (v1)
Keywords: demand response, inverter air conditioner, virtual energy storage, virtual state of charge
Air conditioning loads are important resources for demand response. With the help of thermal energy storage capacity, they can reduce peak load, improve the reliability of power grid operations, and enhance the emergency capacity of a power grid, without affecting the comfort of the users. In this paper, a virtual energy storage model for inverter air conditioning loads, which reflects their operating characteristics and is more conducive to practical application, is established. Two parts are involved in the virtual energy storage model: An electrical parameter part, based on the operating characteristics, and a thermal parameter part, based on the equivalent thermal parameter model. The control function and restrictive conditions of the virtual energy storage are analyzed and a control strategy, based on virtual state-of-charge ranking, is proposed. The strategy controls the inverter air conditioners through re-assigning indoor temperature set-points within the pre-agreed protocol in... [more]
Removal of Lead and Cadmium Ions from Aqueous Solution by Adsorption on a Low-Cost Phragmites Biomass
Abdulaziz N. Amro, Mohammad K. Abhary, Muhammad Mansoor Shaikh, Samah Ali
September 5, 2019 (v1)
Subject: Materials
Keywords: cadmium, Freundlich isotherm, kinetic study, Langmuir isotherm, lead, treated phragmites biomass
In recent years, the interest in waste water treatment increased to preserve the environment. The objective of this study is the removal of lead and cadmium ions from aqueous solution by treated Phragmites biomass (TPB). TPB was characterized by using Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray analysis (EDS) which indicates the presence of functional groups that may be responsible of metal adsorption such as hydroxyl, carbonyl, sulfonate and carboxylate. Characterization by scanning electron microscopy (SEM) and surface area analysis using the Brunauer−Emmett−Teller method (BET) illustrated that TPB is nonporous with a small surface area. The influences of various experimental factors were investigated; the proposed method recommended the extraction of Pb+2 and Cd+2 metal ions by TPB at pH 5.0. A contact time of 60 and 45 min was required for the adsorption 50 mL (50 ppm) Pb+2 and Cd+2 respectively to reach equilibrium when 0.10 g TPB was used. The optim... [more]
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