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High Pressure Injection of Chemicals in a Gravel Beach
Xiaolong Geng, Ali Abdollahi-Nasab, Chunjiang An, Zhi Chen, Kenneth Lee, Michel C. Boufadel
October 26, 2019 (v1)
Subject: Other
Keywords: bioremediation, Exxon Valdez oil spill, high pressure injection, tidal beach, tracer study
The remediation of beaches contaminated with oil includes the application of surfactants and/or the application of amendments to enhance oil biodegradation (i.e., bioremediation). This study focused on evaluating the practicability of the high pressure injection (HPI) of dissolved chemicals into the subsurface of a lentic Alaskan beach subjected to a 5 m tidal range. A conservative tracer, lithium, in a lithium bromide (LiBr) solution, was injected into the beach at 1.0 m depth near the mid-tide line. The flow rate was varied between 1.0 and 1.5 L/min, and the resulting injection pressure varied between 3 m and 6 m of water. The concentration of the injected tracer was measured from four surrounding monitoring wells at multiple depths. The HPI associated with a flow rate of 1.5 L/min resulted in a Darcy flux in the cross-shore direction at 1.15 × 10−5 m/s compared to that of 7.5 × 10−6 m/s under normal conditions. The HPI, thus, enhanced the hydraulic conveyance of the beach. The resul... [more]
On the Three-Dimensional Structure of the Flow through Deterministic Lateral Displacement Devices and Its Effects on Particle Separation
Valentina Biagioni, Alessandra Adrover, Stefano Cerbelli
October 26, 2019 (v1)
Subject: Other
Keywords: deterministic ratchets, label-free separation, three-dimensional effects
Experiments have shown that a suspension of particles of different dimensions pushed through a periodic lattice of micrometric obstacles can be sorted based on particle size. This label-free separation mechanism, referred to as Deterministic Lateral Displacement (DLD), has been explained hinging on the structure of the 2D solution of the Stokes flow through the patterned geometry, thus neglecting the influence of the no-slip conditions at the top and bottom walls of the channel hosting the obstacle lattice. We show that the no-slip conditions at these surfaces trigger the onset of off-plane velocity components, which impart full three-dimensional character to the flow. The impact of the 3D flow structure on particle transport is investigated by enforcing an excluded volume approach for modelling the interaction between the finite-sized particles and the solid surfaces. We find that the combined action of particle diffusion and of the off-plane velocity component causes the suspended pa... [more]
Retraction: Chen, J. et al. Computational Fluid Dynamics Modeling of the Catalytic Partial Oxidation of Methane in Microchannel Reactors for Synthesis Gas Production. Processes 2018, 6, 83
Processes Editorial Office
September 23, 2019 (v1)
Subject: Other
We have become aware that figures, tables, experimental data, and a whole paragraph in the results and discussion section of the published article [...]
Special Issue “Renewable Polymers: Processing and Chemical Modifications”
Tizazu Mekonnen, Marc A. Dubé
September 5, 2019 (v1)
Subject: Other
The use of renewable resources for polymer production is receiving substantial and ever-growing interest [...]
Computational Study of MHD Nanofluid Flow Possessing Micro-Rotational Inertia over a Curved Surface with Variable Thermophysical Properties
Zahid Ahmed, Ali Al-Qahtani, Sohail Nadeem, Salman Saleem
August 15, 2019 (v1)
Subject: Other
Keywords: carbon nanotubes, curved surface, MHD, nanofluids, variable viscosity
This work presents a numerical investigation of viscous nanofluid flow over a curved stretching surface. Single-walled carbon nanotubes were taken as a solid constituent of the nanofluids. Dynamic viscosity was assumed to be an inverse function of fluid temperature. The problem is modeled with the help of a generalized theory of Eringen Micropolar fluid in a curvilinear coordinates system. The governing systems of non-linear partial differential equations consist of mass flux equation, linear momentum equations, angular momentum equation, and energy equation. The transformed ordinary differential equations for linear and angular momentum along with energy were solved numerically with the help of the Keller box method. Numerical and graphical results were obtained to analyze the flow characteristic. It is perceived that by keeping the dynamic viscosity temperature dependent, the velocity of the fluid away from the surface rose in magnitude with the values of the magnetic parameter, whil... [more]
Separation Emulsion via Non-Ionic Surfactant: An Optimization
Murtada Mohammed Abdulredha, Siti Aslina Hussain, Luqman Chuah Abdullah
August 15, 2019 (v1)
Subject: Other
Keywords: demulsification, non-ionic surfactant, RSM, water-in-oil emulsion
Achieving emulsion stability in the petroleum industry is a major challenge due to several problems encountered in the oil refining process, such as corrosion in equipment, high-pressure drops in pipelines, and catalyst poisoning in upstream facilities. Thus, several methods are applied for emulsion treatment and chemical treatment using surface-active agents, a fundamental method in the petroleum industry. The present work investigated the performance of a non-ionic surfactant in separating water in a crude oil emulsion via the bottle test technique. Then, a Fractional Factorial Design (2K−1) was used to characterise the effect of significant variables. In particular, a Pareto chart was employed and factors such as demulsifier dosage, toluene concentration, pressure, sitting time, and temperature were investigated. Accordingly, the parameters applied were further analysed using a Central Composite Design (CCD) based on the Response Surface Method (RSM). The experimental results based... [more]
A Novel Technology for Separating Copper, Lead and Zinc in Flotation Concentrate by Oxidizing Roasting and Leaching
Qian Zhang, Qicheng Feng, Shuming Wen, Chuanfa Cui, Junbo Liu
August 15, 2019 (v1)
Subject: Other
Keywords: copper–lead–zinc of flotation concentrate, leaching, oxidizing roasting
In this work, oxidizing roasting was combined with leaching to separate copper, lead, and zinc from a concentrate obtained by bulk flotation of a low-grade ore sourced from the Jiama mining area of Tibet. The flotation concentrate contained 7.79% Cu, 22.00% Pb, 4.81% Zn, 8.24% S, and 12.15% CaO; copper sulfide accounted for 76.97% of the copper, lead sulfide for 25.55% of the lead, and zinc sulfide for 67.66% of the zinc. After oxidizing roasting of the flotation concentrate, the S content in the roasting slag decreased to 0.22%, indicating that most sulfide in the concentrate was transformed to oxide, which was beneficial to leaching. The calcine was subjected to sulfuric acid leaching for separation of copper, lead, and zinc; i.e., copper and zinc were leached, and lead was retained in the residue. The optimum parameters of the leaching process were: a leaching temperature of 55 °C; sulfuric acid added at 828 kg/t calcine; a liquid:solid ratio of 3:1; and a leaching time of 1.5 h. Un... [more]
Impact of Thermal Radiation on Magnetohydrodynamic Unsteady Thin Film Flow of Sisko Fluid over a Stretching Surface
Abdul Samad Khan, Yufeng Nie, Zahir Shah
August 14, 2019 (v1)
Subject: Other
Keywords: HAM and numerical method, MHD, Sisko fluid, thin films, unsteady stretching sheet
The current article discussed the heat transfer and thermal radioactive of the thin liquid flow of Sisko fluid on unsteady stretching sheet with constant magnetic field (MHD). Here the thin liquid fluid flow is assumed in two dimensions. The governing time-dependent equations of Sisko fluid are modeled and reduced to Ordinary differential equations (ODEs) by use of Similarity transformation with unsteadiness non-dimensionless parameter S t . To solve the model problem, we used analytical and numerical techniques. The convergence of the problem has been shown numerically and graphically using Homotopy Analysis Method (HAM). The obtained numerical result shows that the HAM estimates of the structures is closed with this result. The Comparison of these two methods (HAM and numerical) has been shown graphically and numerically. The impact of the thermal radiation R d and unsteadiness parameter S t over thin liquid flow is discovered analytically. Moreover, to know th... [more]
Systems Evaluation through New Grey Relational Analysis Approach: An Application on Thermal Conductivity—Petrophysical Parameters’ Relationships
Saad Ahmed Javed, Aqib Mashood Khan, Wenjie Dong, Adil Raza, Sifeng Liu
August 8, 2019 (v1)
Subject: Other
Keywords: absolute GRA, grey relational analysis, petrophysical parameters, second synthetic GRA, thermal conductivity
The current study introduces a new technique for the analysis of uncertain systems and uncertain processes in geothermics/earth sciences. The method is the second synthetic grey relational analysis (SSGRA) model, which incorporated the advantages of both Deng’s GRA model and the bidirectional absolute GRA model. The SSGRA model has been earlier successfully applied in project management and healthcare systems. The current study is a pioneer in demonstrating the feasibility of the SSGRA model in a geothermal environment. In the current study, the model was used to determine the associations between thermal conductivity and petrophysical parameters in an Algerian reservoir. The results revealed that thermal conductivity is most strongly associated with porosity followed by density and permeability. Their relationships are also discussed. The study concludes with valuable insights about the model and its application in engineering and natural sciences especially when the system contains u... [more]
Numerical Determination of RVE for Heterogeneous Geomaterials Based on Digital Image Processing Technology
Lanlan Yang, Weiya Xu, Qingxiang Meng, Wei-Chau Xie, Huanling Wang, Mengcheng Sun
August 8, 2019 (v1)
Subject: Other
Keywords: coefficient of variation, CV, digital image processing, DIP, heterogeneous geomaterials, mechanical properties, representative volume element, RVE
Representative volume element (RVE) is an important parameter in numerical tests of mechanical properties of heterogeneous geomaterials. For this study, a digital image processing (DIP) technology was proposed for estimating the RVE of heterogeneous geomaterials. A color image of soil and rock mixture (SRM) with size of 400 × 400 mm2 taken from a large landslide was used to illustrate the determination procedure of the SRM. Six sample sizes ranging from 40 × 40 mm2 to 240 × 240 mm2 were investigated, and twelve random samples were taken from the binarized image for each sample size. A connected-component labeling algorithm was introduced to identify the microstructure. After establishing the numerical finite difference models of the samples, a set of numerical triaxial tests under different confining pressures were carried out. Results show that the size of SRM sample affects the estimation of the mechanical properties, including compressive strength, cohesion, and internal friction an... [more]
Sweep Frequency Heating based on Injection Locked Magnetron
Fengming Yang, Wenwen Wang, Bo Yan, Tao Hong, Yang Yang, Huacheng Zhu, Li Wu, Kama Huang
August 7, 2019 (v1)
Subject: Other
Keywords: heating uniformity, injection-locking, microwave heating, sweep frequency
Conventional microwave heating has serious problems such as non-uniform heating and low efficiency. A novel magnetron microwave sweep frequency heating method is proposed to improve microwave heating uniformity. In this method, the frequency-sweeping signal is injected into the magnetron by the injection frequency-locking technique, and the microwave sweep frequency heating of the magnetron is realized. In this paper, a complicated injection frequency locking system is given and analyzed and a multiphysics calculation model based on the finite element method for electromagnetic waves and heat transfer is established. The calculation of microwave sweep frequency heating is realized by the combination of COMSOL and MATLAB. The results show that the sweep frequency heating has an obvious superiority. An experiment is carried out to verify the simulation results. The simulation results are in agreement with the experimental data. Moreover, the effect of sweep bandwidth and sweep interval o... [more]
In Situ Measurements and CFD Numerical Simulations of Thermal Environment in Blind Headings of Underground Mines
Wenhao Wang, Chengfa Zhang, Wenyu Yang, Hong Xu, Sasa Li, Chen Li, Hui Ma, Guansheng Qi
July 31, 2019 (v1)
Subject: Other
Keywords: auxiliary ventilation, duct position, numerical simulations, the heat dissipation of LHD, thermal environment, ventilation cooling
In order to gain a knowledge of the heat emitted from a variety of sources at the blind heading of an underground gold mine, the present study conducts an in situ measurement study in a blind heading within the load haul dumps (LHDs) that are operating. The measurements can provide a reliable data basis for the setting of numerical simulations. The results demonstrate that the distances between the forcing outlet and the mining face (denoted as Zm), as well as the heat generation from LHDs (denoted as QL), has brought significant impacts on the airflow velocity, relative humidity, and temperature distributions in the blind heading. Setting Zm to 5 m could achieve a relative optimal cooling performance, also indicating that when the LHD is fully operating in the mining face, employing the pure forcing system has a limited effect on the temperature decrease of the blind heading. According to the numerical simulations, a better cooling performance can be achieved based on the near-forcing... [more]
Internal R&D and Acquisition Performance of Chinese Pharmaceutical Firms: Moderation Effect of Acquisition Motive and Corporate Ownership
Qi Yue, Xing Hua, Jianyuan Li
July 31, 2019 (v1)
Subject: Other
Keywords: acquisition motives, acquisition performance, corporate ownership, D, internal R&, technical acquisition
Although corporate capability has been recognized as a key factor affecting corporate acquisition performance, the role of R&D capability in acquisition performance has not been fully explained. The aim of this paper was to research the impact of internal R&D on acquisition performance according to a sample of 215 acquisitions of Chinese listed pharmaceutical companies from 2012 to 2016. First, it was found that R&D has a significant negative effect on acquisition performance. Furthermore, it was confirmed that the acquisition motive and the ownership of the acquiring firm have a moderating effect on the relationship between R&D and acquisition performance. Compared to non-technical acquisitions, the negative effect of internal R&D on acquisition performance was reduced for technical acquisitions. Compared with non-state-owned-enterprise acquisition, the negative effect of internal R&D on the acquisition performance of state-owned enterprises was weakened. Our study enriches the resear... [more]
Simulation of the Gas Filling and Evacuation Processes in an Inertial Confinement Fusion (ICF) Hohlraum
Liangyu Wu, Hua Zhou, Cheng Yu, Feng Yao
July 30, 2019 (v1)
Subject: Other
Keywords: evacuation, filling, hohlraum, inertial confinement fusion, Knudsen regime, microcapillary tube
In indirect inertial confinement fusion (ICF), the prediction of gas pressures and mass flow rates in the hohlraum is critical for fielding the hohlraum film and the support tent. To this end, it is desirable to understand the gas filling and evacuation process through the microcapillary fill tube and the support tent. In this work, a unified flow simulation of the filling and evacuation processes through the microcapillary fill tube and the support tent in an ICF hohlraum was conducted to study the gas pressure and mass flow rate in the hohlraum. The effects of the support tent size and the microcapillary fill tube size on the critical pressure variation and pressure difference across the hole on the support tent are examined. The results indicate that an increase in the diameter of the hole and the hole number leads to a smaller pressure difference across the hole on the support tent. If the diameter of the hole on the support tent is larger than 0.06 mm, the critical pressure variat... [more]
Viscoelastic MHD Nanofluid Thin Film Flow over an Unsteady Vertical Stretching Sheet with Entropy Generation
Asad Ullah, Zahir Shah, Poom Kumam, Muhammad Ayaz, Saeed Islam, Muhammad Jameel
July 29, 2019 (v1)
Subject: Other
Keywords: entropy generation, HAM, liquid films, magnetic field, nanofluid, second-grade fluid, thin film, time depending stretching surface
The boundary-layer equations for mass and heat energy transfer with entropy generation are analyzed for the two-dimensional viscoelastic second-grade nanofluid thin film flow in the presence of a uniform magnetic field (MHD) over a vertical stretching sheet. Different factors, such as the thermophoresis effect, Brownian motion, and concentration gradients, are considered in the nanofluid model. The basic time-dependent equations of the nanofluid flow are modeled and transformed to the ordinary differential equations system by using similarity variables. Then the reduced system of equations is treated with the Homotopy Analysis Method to achieve the desire goal. The convergence of the method is prescribed by a numerical survey. The results obtained are more efficient than the available results for the boundary-layer equations, which is the beauty of the Homotopy Analysis Method, and shows the consistency, reliability, and accuracy of our obtained results. The effects of various paramete... [more]
Special Issue on “Membrane Materials, Performance and Processes”
João C. Diniz da Costa, Julius Motuzas
July 29, 2019 (v1)
Subject: Other
This Special Issue on “Membrane Materials, Performance and Processes” of Processes provides a collection of interdisciplinary work representative of the current development in the fields ofmembrane science and technology [...]
Effect of the Heterogeneity on Sorptivity in Sandstones with High and Low Permeability in Water Imbibition Process
Yang Wu, Yixin Zhao, Peng Li
July 29, 2019 (v1)
Subject: Other
Keywords: heterogeneity, neutron radiography, sorptivity, tortuosity fractal dimension
Capillary imbibition in unsaturated rocks is important for the exploitation of tight reservoirs, such as oil and gas reservoirs. However, the physical properties of natural rocks tend to be relatively uneven, mainly in the heterogeneity of material composition and pore space. Reservoir heterogeneity is an important factor affecting the exploitation of oil fields and other reservoirs, which can be evaluated by the pore structure tortuosity fractal dimension DT of rock. The greater the value of DT, the stronger the heterogeneity of sandstone. Two types of sandstone with high and low permeability were selected to study the effect of heterogeneity on the imbibition behavior by using high-resolution X-ray imaging and neutron radiography. Quantitative results of the wetting front position for each specimen were extracted from the neutron images. The wetting front advanced linearly with the power index of time t1/(2DT). Different values of DT were selected to estimate and discuss the effect o... [more]
The Effects of Water Friction Loss Calculation on the Thermal Field of the Canned Motor
Yiping Lu, Azeem Mustafa, Mirza Abdullah Rehan, Samia Razzaq, Shoukat Ali, Mughees Shahid, Ahmad Waleed Adnan
July 28, 2019 (v1)
Subject: Other
Keywords: canned motor, computational fluid dynamics (CFD), numerical simulation, three-dimensional temperature field, water friction loss
The thermal behavior of a canned motor also depends on the losses and the cooling capability, and these losses cause an increase in the temperature of the stator winding. This paper focuses on the modeling and simulation of the thermal fields of the large canned induction motor by different calculation methods of water friction loss. The values of water friction losses are set as heat sources in the corresponding clearance of water at different positions along the duct and are calculated by the analytical method, loss separation test method, and by assuming the values that may be larger than the experimental results and at zero. Based on Finite volume method (FVM), 3D turbulent flow and heat transfer equations of the canned motor are solve numerically to obtain the temperature distributions of different parts of the motor. The analysis results of water friction loss are compared with the measurements, obtained from the total losses using the loss separation method. The results show tha... [more]
Recent Advances in Fluid Flow in Fractured Porous Media
Richeng Liu, Sha Lou, Yujing Jiang
July 28, 2019 (v1)
Subject: Other
The fluid flows through both the fractures and pores in deep-seated rock masses, which is of special importance for the performance of underground facilities such as groundwater use and nuclear waste disposal [...]
Research on Identification of LVRT Characteristics of Photovoltaic Inverters Based on Data Testing and PSO Algorithm
Pingping Han, Guijun Fan, Weizhen Sun, Bolong Shi, Xiaoan Zhang
July 28, 2019 (v1)
Subject: Other
Keywords: LVRT, parameter identification, particle swarm optimization algorithm, PV inverter, real operation data
With the continuous increment of photovoltaic (PV) energy connection into a power grid, the accuracy of control parameters of PV power generation systems becomes the key to the stable operation of the power grid. At present, parameter identification based on an intelligent algorithm is a common means to obtain control parameters. However, most of the data used for identification are simulation data and the identified parameters are difficult to use in practical engineering. Therefore, aiming at the acquisition of low voltage ride through (LVRT) control parameters of PV unit, a method of identification of LVRT parameters of the PV unit is proposed, which combines sensitivity analysis with field measurement. In this paper, the test scheme of the required data is put forward through sensitivity analysis of the identified parameters, and the intelligent algorithm is used to identify the low voltage traverse parameters of the data. Finally, the optimal value is extracted from the identifica... [more]
A New Method for Simultaneous Determination of the TDC Offset and the Pressure Offset in Fired Cylinders of an Internal Combustion Engine
Urban Žvar Baškovič, Rok Vihar, Igor Mele, Tomaž Katrašnik
July 26, 2019 (v1)
Subject: Other
Keywords: internal combustion engine, offset correction algorithm, pressure offset, TDC offset, thermodynamic analysis
An innovative computationally efficient method for the simultaneous determination of top dead centre (TDC) offset and pressure offset is presented. It is based on characteristic deviations of the rate of heat release (ROHR) that are specific for both offsets in compression phase and expansion phase after the end of combustion. These characteristic deviations of the ROHR are derived from first principles and they were also confirmed through manual shifts of the pressure trace. The ROHR is calculated based on the first law of thermodynamics using an in-cylinder pressure trace, engine geometrical parameters and operating point specific parameters. The method can be applied in off-line analyses using an averaged pressure trace or in on-line analyses using a single pressure trace. In both application areas the method simultaneously determines the TDC position and the pressure offset within a single processing of the pressure trace, whereas a second refinement step can be performed for obtai... [more]
An Experimental Facility to Validate Ground Source Heat Pump Optimisation Models for the Australian Climate
Yuanshen Lu, Kamel Hooman, Aleks D. Atrens, Hugh Russell
July 26, 2019 (v1)
Subject: Other
Keywords: Australian GSHP, Gatton GSHP, ground source heat pump (GSHP), heat pump
Ground source heat pumps (GSHPs) are one of the most widespread forms of geothermal energy technology. They utilise the near-constant temperature of the ground below the frost line to achieve energy-efficiencies two or three times that of conventional air-conditioners, consequently allowing a significant offset in electricity demand for space heating and cooling. Relatively mature GSHP markets are established in Europe and North America. GSHP implementation in Australia, however, is limited, due to high capital price, uncertainties regarding optimum designs for the Australian climate, and limited consumer confidence in the technology. Existing GSHP design standards developed in the Northern Hemisphere are likely to lead to suboptimal performance in Australia where demand might be much more cooling-dominated. There is an urgent need to develop Australia’s own GSHP system optimisation principles on top of the industry standards to provide confidence to bring the GSHP market out of its in... [more]
Analysis of Dynamic Characteristic for Solar Arrays in Series and Global Maximum Power Point Tracking Based on Optimal Initial Value Incremental Conductance Strategy under Partially Shaded Conditions
Jian Zhao, Xuesong Zhou, Youjie Ma, Yiqi Liu
July 26, 2019 (v1)
Subject: Other
Keywords: dynamic characteristic, global maximum power point tracking (GMPPT), necessary condition, partial shading condition (PSC), photovoltaic (PV)
Partial shading (PS) is an unavoidable condition which significantly reduces the efficiency and stability of a photovoltaic (PV) system. With PS, the system usually exhibits multiple-peak output power characteristics, but single-peak is also possible under special PS conditions. In fact it is shown that the partial shading condition (PSC) is the necessary but not sufficient condition for multiple-peak. Based on circuit analysis, this paper shows that the number of peak points can be determined by short-circuit currents and maximum-power point currents of all the arrays in series. Then the principle is established based on which the number of the peak points is to be determined. Furthermore, based on the dynamic characteristic of solar array, this paper establishes the rule for determination of the relative position of the global maximum power point (GMPP). In order to track the GMPP within an appropriate period, a reliable technique and the corresponding computer algorithm are develope... [more]
Acknowledgement to Reviewers of Energies in 2016
Energies Editorial Office
July 26, 2019 (v1)
Subject: Other
The editors of Energies would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]
A Wavelet-Modified ESPRIT Hybrid Method for Assessment of Spectral Components from 0 to 150 kHz
Luisa Alfieri, Antonio Bracale, Guido Carpinelli, Anders Larsson
July 26, 2019 (v1)
Subject: Other
Keywords: high-frequency spectral components, modified estimation of signal parameters by rotational invariancetechnique (ESPRIT), power quality, waveform distortion, wavelet transform
Waveform distortions are an important issue in distribution systems. In particular, the assessment of very wide spectra, that include also components in the 2⁻150 kHz range, has recently become an issue of great interest. This is due to the increasing presence of high-spectral emission devices like end-user devices and distributed generation systems. This study proposed a new sliding-window wavelet-modified estimation of signal parameters by rotational invariance technique (ESPRIT) method, particularly suitable for the spectral analysis of waveforms that have very wide spectra. The method is very accurate and requires reduced computational effort. It can be applied successfully to detect spectral components in the range of 0⁻150 kHz introduced both by distributed power plants, such as wind and photovoltaic generation systems, and by end-user equipment connected to grids through static converters, such as fluorescent lamps.
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