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The degradation characteristics of oily sludge in the bioreactor were studied by using Euler-multiphase flow method, in which the gas-liquid two-phase and gas-liquid-solid three-phase flow field dynamics model was established. The working characteristics of the conventional bioreactor and the proposed new bioreactor were simulated via FLUENT software respectively, and the distribution of bubble diameter and the accumulation and dispersion phenomenon of the oily sludge particles were studied. The experimental results showed that compared with the conventional bioreactor, the proposed one can significantly improve the degradation efficiency of oily sludge and greatly reduce energy consumption.

The two-dimensional streamline curvature through-flow modeling of turbomachinery is still a key element for turbomachinery preliminary analysis. Basically, axisymmetric swirling flow field is solved numerically. The effects of blades are imposed as sources of swirl, work input/output and entropy generation. Although the topic is studied vastly in the literature for compressors and turbines, combined modeling of the transonic fan and the downstream splitter of turbofan engine configuration, to the authors’ best knowledge, is limited. In a prior study, the authors presented a new method for bypass fan modeling for inverse design calculations. Moreover, new set of practical empirical correlations are calibrated and validated. This paper is an extension of this study to rapid off-design analysis of transonic by-pass fan systems. The methodology is validated by two test cases: NASA 2-stage fan and GE-NASA bypass fan case. The proposed methodology is a simple extension for streamline curvature method and can be applied to existing compressor methodologies with minimum numerical effort.

With the steady growth in distributed generation, more and more attention is paid to low voltage distribution networks. Many of these studies neglected the fact that most of the consumers and small generating units are phase-neutral connected in a multipoint-grounded neutral system – at least in low voltage (LV) distribution systems that is common in Europe. If an equipment utilizes local regulation, it also detects this phase-to-neutral voltage. The effect of neutral can be substantial considering the narrow band of regulation and/or with equipment sensitive to neutral-earth voltage. Until now, the correct modelling of these kind of networks has been scarce; some of them face accuracy or convergence problems with these networks. This article presents an example for the problem and a new alternative calculation method to enable fast, simple-to-implement and accurate load flow calculation for unbalanced networks. Therefore, studies and control algorithms can rely on a more precise model.

The heavy-metal-free photocatalytic system, in which carbon nitride is coated on polylactic acid (PLA) as biodegradable plastic through a simple dip coating method, was used for dye decomposition under visible light irradiation. Solvent selection, solvent concentration, and the number of coatings for dip coating were investigated to optimize the conditions for loading carbon nitride on PLA. Carbon nitride cannot be coated on PLA in water, but it can be strongly coated by decomposing the surface of PLA with ethanol or chlorobenzene to promote physical adsorption and activate surface. The number of dip coatings also affected the photocatalytic decomposition ability. The photocatalytic system was able to decompose the dye continuously in the flow method, and dye (rhodamine B) was decomposed by about 50% at a residence time of 12 min (flow rate 0.350 mL/min) for 30 h.

A new, improved modified Newton Raphson (IMNR) load flow method is proposed for AC islanded microgrids. The absence of a strong slack bus and the droop control of distributed generation (DG) units pose challenges that can not be tackled by the conventional load flow techniques. The proposed load flow method extends the traditional Newton-Raphson technique to the islanded microgrid case with complex loads. The proposed load flow method has been tested on three different networks, and the performance of the proposed method has been compared with other methods. The IMNR method is fast and takes fewer iterations to converge. The proposed method is used to analyze the loadability of islanded microgrid, and the results are presented.

On-line activity measurement of fission products in a primary circuit water is often used for a fuel failure detection in research and power nuclear reactors. When gamma spectrometry is used for the activity measurement, high signal from 16N radionuclide and other activation products make the detection of fission products difficult. The detection of delayed neutrons emitted from several fission products is also used; however, if the detector is placed near the outlet coolant pipe, the signal from the delayed neutrons cannot be distinguished from the neutrons emitted due to 17N decay and deuterium photofission, with exception of a reactor scram condition. In this paper, a method of discontinuing the flow of primary circuit water is described. This method is based on the water flowing through a bypass on the outlet pipe to the sampling container and the flow is periodically temporarily interrupted, e.g., using 200 s + 200 s cycles. Neutrons located in the vicinity of the sampling container are continuously detected with a measuring sampling time of less than 2 s. The signal part, corresponding to the delayed neutrons, is evaluated by the signal decay analyzing during the flow interruption. The main sources of delayed neutrons suitable for this method are 137I, 87Br, and 88Br radionuclides with half-lives of 24.5 s, 55.7 s, and 16.5 s, respectively. The method was theoretically analyzed and experimentally verified in the LVR-15 research reactor.

In this paper, a modified backward/forward sweep (BFS) load flow algorithm is proposed to solve power flow for islanded droop-controlled ac microgrids. The proposed method has been formulated such that the system frequency is one of the system’s unknown variables which is typical for an islanded network justifying further the absence of a slack bus. As a result, new equations have been systematically developed and incorporated with the conventional BFS method. The modified BFS method has been applied to the 33-bus test system and the results obtained are compared with simulation results from the direct BFS method as well as PSCAD/EMTDC. In comparison to the conventional methods, the proposed method is accurate, simple, and easy to implement thus serving as a useful tool for microgrid analysis and planning.

The critical temperatures (Tc) and critical pressures (pc) of five binary mixtures (DEC + hexane, DEC + heptane, DEC + octane, DEC + cyclohexane, DEC + ethanol) and a ternary mixture (DEC + ethanol + heptane) were determined over the whole range of concentration using an accurate experimental apparatus based on flow method. The combined standard uncertainty of temperature is 0.2 K while that of pressure is 5.2 kPa. The critical temperatures of DEC + octane and DEC + cyclohexane mixtures present a non-ideal behavior. The maximum average absolute deviations of Redlich–Kister equations for Tc and pc of five binary mixtures are 0.08% and 0.41%, respectively. Cibulka's equations and Singh−Sharma's equations were used to correlate the critical parameters of ternary mixture. The critical surfaces of ternary mixture were plot using Cibulka's equations.

In this work, frost formation on wavy plates with −5 to 2 °C air temperatures, 85% air relative humidity, 0.31–0.92 m/s air velocities and −20 to −5 °C cooling surface temperatures was experimentally and numerically investigated. In the experiments, the frost layer growth process was recorded with frost thickness and weight measured. The experimental results show that the frost thickness increases with time and the frost layer grows faster with higher phase change driving force and higher water vapor mass flux. In the simulations, a frosting model was implemented as the source term in the Euler multi-phase flow method to simulate frosting process. The simulation results of frost layer growth show that densest frost appears at the leading edge of the plate. The frost density on the peaks of the plate is larger than that on the bottom of the valley. The simulations show that the air velocity increases with the frost layer growing. The simulated frost profile, frost weight and frost thickness agree well with the experimental results, which means the frosting model can be used to predict frost formation on wavy plates.

Through-flow method is still widely applied in the revolution of the design of a turbomachinery, which can provide not merely the performance characteristic but also the flow field. In this study, a program based on the through-flow method was proposed, which had been verified by many other numerical examples. So as to improve the accuracy of the calculation, abundant loss and deviation models dependent on the real geometry of engine were put into use, such as: viscous losses, overflow in gaps, leakage from a flow path through seals. By means of this program, the aerodynamic performance of a certain high through-flow commercial fan/booster was investigated. On account of the radial distributions of the relevant parameters, flow deterioration in this machine was speculated. To confirm this surmise, 3-D numerical simulation was carried out with the help of the NUMECA software. Through detailed analysis, the speculation above was demonstrated, which provide sufficient evidence for the conclusion that the through-flow method is an essential and effective method for the performance prediction of the fan/booster.

Fast and accurate optical flow estimation is a challenging problem in computer vision. In this paper, we present a novel model to solve the optical flow problem by combining the strengths of the Split Bregman method with the advantages of an efficient variational framework. It allows us to employ different regularization tensors for the Split Bregman regularizer to preserve motion discontinuities. Simultaneously, a novel nonlocal Split Bregman method with adaptive support weights is also developed for the smoothness regularization to preserve motion details, repel outliers, enhance contrast, and reduce motion blurring and staircase effect. The proposed algorithm shows significant improvements in preserving sharp flow edges and important motion details. Most of all, it requires only a few iterations to achieve fast convergence and runs faster than the classic TV-L1 flow method. Our method significantly outperforms the current state-of-the-art methods on the challenging MPI-Sintel dataset and shows good performance on the Kitti flow 2015 and Middlebury datasets.

This study analyzes the distribution of the flow field in a foundation trench under different sand deposit arrangements based on the assumption of uniform sand-water mixed flow. Based on the influence of the sand deposit boundaries, this study investigated sand deposit arrangement and construction optimization. Results show the density of the sand deposit in parallel and alternative sand deposit arrangements. Sand deposits should be arranged symmetrically to simplify the sand deposit boundaries during construction to guarantee the overlapping of sand deposits in a large area and to prevent a sharp boundary from being produced. During sand deposit construction, regional linkage with the external water flow and symmetrical construction should be maintained to reduce sharp intersections between haped sand deposits. The sand-filling sequence for a large section of immersed tube tunnel with multirow sand deposits should be middle first, followed by each side.

The scale effect holds true for both the strength and permeability of a rock mass, especially for a jointed rock mass. Thus, the size of a rock mass structure must be considered during design, and the rock mass permeability obtained in laboratory must be modified against the scale effect before being applied in engineering practice. Based on the progressive failure process analysis and the fluid–solid coupled theory, this paper reproduces variations of macroscopic permeability of jointed rock masses with various sizes using numerical methods. The relationship between the observation scale and the seepage directionality or randomicity is presented, and the sensitivity of the scale effects of rock mass strength and permeability is compared. The results from this study reveal that for jointed rock masses with randomly distributed orthogonal joints, as the observation scale increases, the macroscopic permeability increases following a negative exponential equation. The variation of permeability along different directions gradually attenuates, and the rock mass permeability tends to be isotropic at the macroscopic level. When the observation scale approaches the characteristic size, the macroscopic permeability becomes stable and isotropic. Moreover, it is found that the rock mass strength is more sensitive to the scale effect than the permeability, and the characteristic size corresponding to strength is smaller than that for permeability. Furthermore, the rock mass permeability suddenly increases as the rock mass fails under compression, which is caused by coalescence of the seepage channels. In this case, the scale effect becomes less important. Thus, during the design of rock structures, it is necessary to comprehensively consider the scale effects of both rock mass strength and permeability, and the parameters shall be calibrated according to the laboratory test results.

The aero-thermal–coupled phenomenon is significant in modern cooled turbines, and an aero-thermal coupled through-flow method has previously been developed by the authors for considering the influence of heat transfer and coolant mixing in through-flow design. However, the original cooling model is not capable of calculating the distribution of the coolant mass flow rate and pressure loss in complex cooling structures. Therefore, in this paper, a one-dimensional flow calculation for the internal coolant is introduced into the heat transfer calculation to further improve the through-flow cooling model. Based on various empirical correlations, the cooling model can be used to simulate different cooling structures, such as ribbed channels and cooling holes. Three operating conditions were selected for verification of the NASA-C3X vane, which has 10 internal radial cooling channels. The calculated Nusselt number of internal cooling channels strongly agrees with the experimental data, and the predicted blade surface pressure and temperature distributions at mid span are also in good agreement with the experimental data. The convergence history of the meridional velocity and blade surface temperature demonstrates effective convergence properties. Therefore, the aero-thermal–coupled through-flow method with the new cooling model can provide a reliable tool for cooled turbine through-flow design and analysis.

Purpose The purpose of this paper is to understand how the Wyoming Quit Tobacco Program (WQTP) is used by its subscribers and to better understand how WQTP might be connected to WQTP outcomes. Design/methodology/approach Provider intake and program use data corresponding to the May 2010 to March 2012 enrollment period (n=6,168) were used. All program flows were constructed using frequencies and crosstabs, based on an initial theoretical model prepared by the program provider. Data were adjusted based on analysis that explored all possible uses beyond those specified by the provider’s theoretical model. Findings Although the authors could replicate the structure – the theoretical model constructed by the provider – the authors were not able to replicate all relationships between program components. The authors also found that most individuals signed up and used web-based services. Only a few individuals finished their treatment regimens in the way they were designed to be used by the program. Originality/value This is the first case study to use a program flow method to investigate an entire comprehensive tobacco cessation program structure and delivery.

In this work, the isobaric molar heat capacities of methyl caprate, methyl laurate and their mixtures at temperatures from 313 K to 335 K and at pressures up to 16.2 MPa were measured using a flow calorimeter. The isobaric molar heat capacities of these mixtures were observed to increase as the temperature and the concentration of methyl laurate rise, while they increase as the pressure falls. The excess molar heat capacities were calculated using the experimental heat capacity data, which are positive and very small compared to the isobaric molar heat capacities. A correlation was proposed for the isobaric molar heat capacities of the methyl caprate and methyl laurate mixtures with the maximum deviation of 1.8%.

A measurement study was conducted for the effective drainage radius of borehole along coal seam #9 of the Kaiyuan Coal Mine using the gas pressure method and gas flow method. The measurement results show that the effective drainage radius of borehole along coal seam #9 was 0.75 m, 27 days after drainage, and 1.5 m, 92 days after drainage. Experimental schemes were designed for the entire evolution of the stress in the coal mass around the borehole, and an experimental study on methane seepage in the coal mass around borehole was conducted. Fitting functions for the permeability of the coal sample and its vertical stress were obtained by fitting the experimental data. Based on the vertical stress–permeability functional relationship of coal masses around borehole, a numerical calculation model for methane seepage from coal masses around borehole was established, and the influences of drainage time, initial gas pressure, borehole diameter, and drainage negative pressure on the effective drainage radius of borehole were investigated. The numerical simulation results show that with the increase in initial gas pressure and borehole diameter, the effective drainage radius of borehole increases continuously but its increase amplitude decreases constantly. With the increase in drainage negative pressure, the effective drainage radius of borehole increases linearly but the increase amplitude is relatively small. The layout parameters of borehole along coal seam #9 of the Kaiyuan Coal Mine were optimized based on the numerical calculation results, and the reasonable drainage time, reasonable borehole diameter, and reasonable drainage negative pressure are 180 days, 120 mm, and 15 kPa, respectively, for the borehole along coal seam #9.

Modern power distribution systems are installed with a number of distributed power generation. Increased integration of distributed power generation makes the distribution system vulnerable to unbalanced operating conditions. This would then require the support of Flexible AC Transmission System (FACTS) devices for a smooth operation of the distribution system. Unbalanced power system operation requires an unbalanced load flow analysis in order to assess true system feasibility. This paper presents an innovative unbalance load flow analysis method with the presence of unbalanced operation of SVCs (Static Var Compensators) and STATCOMs (STATic synchronous COMpensators). Unlike the existing methods, the proposed method applies reduced steps in the calculation, and the parameter limits of FACTS devices are dynamically determined in an iterative process. Case studies demonstrate its improved convergence characteristics, reduced computing demand and the robustness of the solution.

In this paper, a load flow algorithm for unbalanced islanded Microgrids (MGs) is developed considering both the multigrounded low voltage (LV) and the medium voltage (MV) network. The method is based on the implicit Z BUS load flow method and it can be applied even in highly meshed MGs regardless of the R/X ratio of lines. It presents fast convergence, low computation time and high robustness. In our analysis we consider a variety of transformer configurations and step voltage regulators. Simulations were conducted in IEEE 4-nodes, 6-nodes and in a highly meshed network of 749 MV and LV nodes.

This study proposes a modified formulation for the popular fast decoupled load flow method to facilitate automatic incorporation of reactive power flow related constraints, i.e. generator reactive power and in-phase transformer tap limits. This formulation has been developed by viewing each device constraint as a set of complementary conditions and adopting the complementarity framework to define one equation to represent this set. The original set of load flow equations is augmented with this set of new equations representing the device constraints and solved to get the adjusted solutions directly. This approach is a significant departure from all the earlier approaches. The earlier approaches generally adopt a two-stage scheme. In the first stage, an approximate unadjusted solution is obtained and in the next stage, adjustments are attempted by ad hoc schemes. The new formulation presented here permits handling both the reactive power related constraints simultaneously. However, it can also be used in situations where only one type of adjustment is needed. Two alternate algorithms in complementarity framework based on mixed complementarity problem and non-linear complementarity problem formulations are presented here. Simulation results are presented to provide evidence of the impressive performance of the new algorithms as compared with the existing ones.

In this paper, we will focus on comparing the two methods for optimisation of intersection control. The first method is a saturation flow method, the second method is an expert system that divides the time for each vehicle a given crossing direction based on expert knowledge. For both methods, simulations are created based on real data of a selected crossroad in the city of Ostrava. Based on these simulations, the methods are compared. Subsequently, the comparison is evaluated together with a description of the advantages and disadvantages of the individual methods. The comparison is provided based on real traffic data of a selected crossroad in the city of Ostrava.

The adsorption and desorption behavior of the refrigerant HFC-134a on pitch-based activated carbon fibers (ACFs) with various Brunauer–Emmett–Teller surface areas was investigated by the flow method. Fixed-bed adsorption experiments performed at 20, 5, –15, –20, and −25 °C showed that the use of lower temperatures resulted in an increase in the adsorption capacity of the ACF. In particular, the complete adsorption time was dramatically increased at −25 °C. Crucially, even after five cycles of adsorption at –20 °C and desorption at 30 °C of HFC-134a in a electrothermal swing adsorption apparatus, significant decreases in the adsorption capability were not observed. The desorption of HFC-134a from saturated ACF was carried out using electric power directly applied to the ACF itself. The electric heating increased the ACF temperature, causing desorption within several minutes. The results of this study show that the regenerative adsorption of HFC-134a by ACF coupled with electric power is possible.

The aero-thermal coupled phenomenon is significant in the modern cooled turbine, and it is necessary to consider the cooling effect and predict the coolant requirement in the through-flow design. A new cooling model was developed for the aero-thermal coupled through-flow method in this paper to predict the temperatures of both the pressure and suction surfaces of the blade. Based on the given blade temperature limitation rather than the mean blade surface temperature in the formal cooling model, the coolant requirement prediction can be more accurate. The equivalent blade thickness and heat exchange area estimation methods were further developed for blades with different cooling structures, and the estimations were carried out for each calculation station instead of the whole blade. The cooled blade was divided into a few calculation stations, and the heat transfer was studied for each station. Three operating conditions for the NASA-Mark II vane were selected for the verification. The predicted temperatures of both the pressure and suction surfaces agree with the experimental data, and the calculation results for the subsonic conditions are more accurate than the one for the transonic conditions.

The seepage control system of a high Concrete Face Rock-Fill Dam (CFRD) may have anti-seepage deficiencies during both construction and operation. In order to solve these, the three-dimensional Finite Element Method (FEM) model was built based on dam body filling, anti-seepage system, defect location and bedrock distribution. The seepage field simulation and computation were carried out using an improved node virtual flux method and the zero-thickness crack model theory. The water head distribution, seepage lines and dam leakage field were obtained by simulation under different conditions, and the seepage characteristics during construction and operation were analyzed systematically. Taking a high CFRD as an example, the results showed that during the flood-control construction period, the incomplete nature of the dam face slab can lead to seepage damage near the second seepage control line. Moreover, during operation period; the seepage control system was still effective when the dam face slab was incomplete.

The emergency evacuation route planning of cruise ships directly affects the safety of all crew members and passengers during emergencies. Research on the planning of emergency evacuation routes for cruise ships is a frontier subject of maritime safety. This study proposes an improved ant colony system (IACS) to solve the evacuation route planning of crowds on cruise ships. The IACS, which is different from common single-path ant colony system (ACS) evacuation algorithms, is used to solve the multipath planning problem of crowd evacuation from cruise ships by considering crowd density and speed in the model. An increasing flow method is introduced into the IACS to improve the efficiency of the proposed algorithm. Numerical experiments show that this method meets the requirements of evacuation analysis guidelines for new and existing passenger ships (MSC.1/Circ.1533)and can effectively and efficiently plan the emergency evacuation path for cruise ship crowd.

In the present study we report the simultaneous determination of glutathione (GSH) and glutathione disulfide (GSSG) by an automated flow method based on the concept of zone fluidics. GSH is quantified selectively in a first run by reaction with o-phthalaldehyde at a mildly basic pH = 8, without interference from GSSG. The latter was also found to react with o-phthalaldehyde but in highly basic medium (0.2 mol L−1 NaOH) and was determined after masking of GSH with N-ethyl-maleimide. Detection was carried out fluorimetrically at 340/425 nm. The flow procedure was optimized and validated, paying special attention to its selectivity. The LOD was 60 nmol L−1 for GSH and for 53 nmol L−1 for GSSG, while the within-day and day-to-day precisions were better than 1.5% and 3.7% respectively. Real yeast samples were successfully analyzed without matrix effect (−2.0 to +4.1%) and with percent recoveries being in the range of 87.0 and 103.3%.

In this paper, a framework of improved risk monitor system that integrates multiple applications of retrospective investigation analysis of risk factors, point-in-time risk monitoring and proactive risk management is presented. Among these applications capabilities, the plant configuration risk management is implemented and demonstrated with a safety injection system in the event of medium-break LOCA at nuclear power plants. The system reliability and safety analysis are conducted on the success-oriented logic models using GO-FLOW method. Both quantitative and qualitative risk measures addressed respectively by risk matrix and goal tree-success tree scheme with risk band display could provide global risk insights regarding plant configuration control.

Two heteroligand volatile magnesium(II) β-diketonate complexes with 2,2′-bipyridine [Mg(bipy)(thd)2] and 1,10-phenanthroline [Mg(phen)(thd)2], CASRN 182566-25-2, (thd = 2,2,6,6-tetramethylheptane-3,5-dionate-anion) have been synthesized. The compounds have been purified and properly characterized to investigate further their sublimation and melting processes. Their vapor pressures have been measured by using the flow method for the first time. Based on these data, thermodynamic characteristics of enthalpy and entropy of sublimation have been calculated at the average temperature of the experimental range. Condensed phase thermal behavior up to melting has been studied by differential scanning calorimetry and the corresponding thermodynamic characteristics have been determined. Data on sublimation has been processed in order to adjust the values of enthalpy and entropy of the processes at the reference temperature of 298.15 K. Whole set of a new thermochemical data could serve as a base for definition of optimal evaporator temperature regimes in chemical vapor deposition of MgO films using [Mg(bipy)(thd)2] and [Mg(phen)(thd)2] as precursors.

A novel measurement approach for power-flow analysis in medium-voltage (MV) networks, based on load power measurements at low-voltage level in each secondary substation (SS) and only one voltage measurement at the MV level at primary substation busbars, was proposed by the authors in previous works. In this paper, the method is improved to cover the case of temporary unavailability of load power measurements in some SSs. In particular, a new load power estimation method based on artificial neural networks (ANNs) is proposed. The method uses historical data to train the ANNs and the real-time available measurements to obtain the load estimations. The load-flow algorithm is applied with the estimated load powers, and the MV network state variables are obtained. The proposed method is validated for the real MV distribution network of the island of Ustica. The loads of selected SSs are estimated for two full days of different seasons. In comparison with previous works, satisfactory results are obtained in terms of uncertainty in the calculated power flows, thus suggesting the applicability of the proposed method for real-time monitoring of MV distribution networks.

Most of the top performing action recognition methods use optical flow as a “black box” input. Here we take a deeper look at the combination of flow and action recognition, and investigate why optical flow is helpful, what makes a flow method good for action recognition, and how we can make it better. In particular, we investigate the impact of different flow algorithms and input transformations to better understand how these affect a state-of-the-art action recognition method. Furthermore, we fine tune two neural-network flow methods end-to-end on the most widely used action recognition dataset (UCF101). Based on these experiments, we make the following five observations: (1) optical flow is useful for action recognition because it is invariant to appearance, (2) optical flow methods are optimized to minimize end-point-error (EPE), but the EPE of current methods is not well correlated with action recognition performance, (3) for the flow methods tested, accuracy at boundaries and at small displacements is most correlated with action recognition performance, (4) training optical flow to minimize classification error instead of minimizing EPE improves recognition performance, and (5) optical flow learned for the task of action recognition differs from traditional optical flow especially inside the human body and at the boundary of the body. These observations may encourage optical flow researchers to look beyond EPE as a goal and guide action recognition researchers to seek better motion cues, leading to a tighter integration of the optical flow and action recognition communities.

The objective of this work was to synthesize and characterize Layered Double Hydroxides (MgAl-LDHs, MgFe-LDHs, and MgAlFe-LDHs) containing phosphate anions and study P release kinetics was conducted with the prepared materials. The release kinetics tests were performed in water by the stirred-flow method to verify the P release profile from LDHs materials. Results showed LDHs have similar characteristics to those of reactive sources of P, such as thermophosphates. The LDHs presented gradual P release and the LDH prepared with the molar ratio of cations Mg:Al = 2:1 showed a more sustained profile of P release compared to other produced materials. Thus, the chemical and structural characteristics of the LDHs make them potential materials for the use and storage of slow P release fertilizer.

This article discusses the possibility of verifying whether the formalism of Petri nets suitable for the optimization of transport systems. This work discusses the optimization of automotive traffic using the saturation flow method. The main aim of the article is to propose and validate a methodology for optimizing transport systems with saturation flow methods. There are discussed several optimization methods that are used for this purpose. The results of this search section were summarized and then a suitable model and an optimization method were chosen according to established criteria. Based on them we have proposed methodology that was verified pursuant to the application of the chosen procedures. One of Ostrava’s most interrupted crossroads was chosen as a model for optimization and simulation. Results of the experimental study are summarized in the conclusion. From the results of the experimental study, it can be stated that the static signaling model has been optimized in terms of time.

Different methods have been developed in the past to formulate and solve steady-state hydraulics of a water distribution system (WDS). The most widely used method nowadays is probably the global gradient algorithm (GGA). The loop-flow method (also known as the Q method) represents a viable alternative to GGA, especially when combined with suitably preprocessed network data. The main advantage of the Q method over the GGA is in the smaller number of unknowns to solve for, which is coming from the fact that real WDSs typically have far less loops than nodes. A new loop-flow-type method, relying on the novel triangulation based loops identification algorithm (TRIBAL) that was implemented in the corresponding new hydraulic solver (Q), is presented in this paper (TRIBAL-Q). The new method aims to exploit this advantage, while overcoming key drawbacks of existing Q methods. The performance of the TRIBAL-Q-based solver is compared with the GGA-based solver on four large real networks of different complexity and topology. The results obtained demonstrate that, despite requiring an increased number of iterations to converge, the TRIBAL-Q method-based solver is substantially computationally faster, has slightly better numerical stability, and is equally accurate in making predictions when compared with the GGA-based hydraulic solver.

A numerical code for calculation of leakage flowand rotordynamic coefficients of labyrinth seals has beendeveloped. The code is based on the solution of Reynolds-averagedNavier-Stokes equations combined with a two-equation turbulencemodel. The numerical solution is achieved with finite volume methodand the rotordynamic coefficients are evaluated from severalsimulations with different rotor precessions. The solution iscompared to single control volume based bulk flow method[Williams, 1998] and to the experimental results for look-throughlabyrinth seal [Schettel, 2004].

Conventional cell-sized well arrays have advantages of high occupancy, simple operation, and low cost for capturing single-cells. However, they have insufficient space for including reagents required for cell treatment or analysis, which restricts the wide application of cell-sized well arrays as a single-cell research tool alone. Here, we present a novel dual-well array chip, which integrates capture-wells (20 μm in diameter) with reaction-wells (100 μm in diameter) and describe a flow method for convenient single-cell analysis requiring neither complicated infra-structure nor high expenditure, while enabling highly efficient single cell trapping (75.8%) with only 11.3% multi-cells. Briefly, the cells are first loaded into the dual-wells by gravity and then multi-cells in the reaction-wells are washed out by phosphate buffer saline. Next, biochemical reagents are loaded into reaction-wells using the scraping method and the chip is packed as a sandwich structure. We thereby successfully measured intracellular β-galactosidase activity of K562 cells at the single-cell level. We also used computational simulations to illustrate the working principle of dual-well structure and found out a relationship between the wall shear stress distribution and the aspect ratio of the dual-well array chip which provides theoretical guidance for designing multi-wells chip for convenient single-cell analysis. Our work produced the first dual-well chip that can simultaneously provide a high occupancy rate for single cells and sufficient space for reagents, as well as being low in cost and simple to operate. We believe that the feasibility and convenience of our method will enhance its use as a practical single-cell research tool.

Solution of the nonlinear system of equations describing the network hydraulics problem can be formulated in several different manners, yielding various methods of solution. The most popular formulation is probably the Global Gradient Algorithm (GGA). Loop-flow formulation is another method revisited by number of researchers in recent years. Loop-flow method has the smaller system matrix to solve, which is a benefit over the GGA’s matrix, coming from the fact that real networks typically have far less loops than nodes. However, need for cumbersome pre-processing to identify network loops and sparsity of solution matrix, which is highly dependent of implemented loop identification algorithm, remain key drawbacks of existing loop-flow methods. In addition, systematic testing on the real life networks of different topologies and complexities is still somewhat lacking in the literature. In this paper, new loop-flow type method based on the novel TRIangulation BAsed Loop identification algorithm (TRIBAL) coupled with efficient implementation of loop-flow based hydraulic solver (ΔQ) is presented. Performance of the new TRIBAL ΔQ method based solver is tested through the comparison with the reference GGA solver. Preliminary results show that significant calculation speedups can be achieved with proposed method, maintaining prediction accuracy and convergence of the reference solver. EPiC Series in Engineering

In the smart grid era, significant penetrations of distributed renewables not only directly impact the secondary low-voltage (LV) distribution network where they are connected, but also indirectly affect the primary medium-voltage (MV) distribution network. Therefore, load flow algorithms are expected to cover both MV and LV levels within a distribution network for more accurate and reasonable analyses. In this study, based on the Direct Load Flow approach and detailed modeling of common Dyn11 distribution transformers, a comprehensive three-phase load flow method which can effectively and efficiently solve the integrated MV and LV distribution networks is proposed. The feasibility and effectiveness as well as superior computational performance in terms of accuracy, efficiency and robustness are verified by simulations on the typical IEEE 4-bus test feeder and a real Australian distribution network over 24 hours.

In this paper, a simplified model of axial incremental rolling process based on the finite element method was established to study the influences of friction conditions on the rolling loads. The results show that the lubricating condition is an important factor for the rolling loads. In order to further reduce the rolling loads, the tooth divided flow method (TDFM) was employed to improve the friction conditions between billet and rolling dies. The finite element experiment results show that the TDFM is an effective way to improve the friction conditions and to reduce the rolling loads.

Tert-butanol is a good additive for improving gasoline performance, but as two of the most important thermodynamic properties, the critical temperature (Tc) and critical pressure (pc) of tert-butanol and alkane systems have not been studied. In this work, the experimental data of the Tc and pc of five binary systems (tert-butanol + cyclohexane, tert-butanol + n-hexane, tert-butanol + n-heptane, tert-butanol + n-octane, and tert-butanol + n-nonane) and a ternary system (tert-butanol + n-heptane + n-octane) were obtained using a flow method. The Tc and pc of the binary systems were fitted using the Redlich–Kister equations with maximum average absolute relative deviations (AARDs) of 0.19% and 0.36% for Tc and pc, respectively. The Tc and pc for tert-butanol + n-heptane + n-octane were correlated by Singh and Sharma's equations and Cibulka's equations with AARDs less than 0.09% and 0.32%, respectively. The experimental data of Tc and pc were also used to verify and improve the accuracy of our previous prediction model.

An automated flow method for the determination of hydrazine based on the concept of zone-fluidics has been developed. The analyte reacts under flow conditions with p-dimethylamino benzaldehyde (25 mmol L&minus, 1) in micellar medium (100 mmol L&minus, 1 SDS) to form a stable derivative (460 nm). Micelles mediated catalysis excludes the use of highly acidic environment typical for this kind of reaction. Following careful examination of chemical and instrumental variables, the method allows the determination of hydrazine at the low micromolar level (0.3&ndash, 10 &mu, mol L&minus, 1) in water samples. Real sample analyses (drinking and boiler feed water) resulted in satisfactory results in terms of accuracy with the percent recoveries being in the range of 82&ndash, 114%.

Critical temperature Tc and critical pressure pc of the mixtures of ethanol and biodiesel surrogates (ethanol + methyl butanoate, ethanol + ethyl propanoate, ethanol + methyl hexanoate, methyl butanoate+ ethyl propanoate and ethanol + methyl butanoate + ethyl propanoate) were measured via a flow method. A linear decrease in Tc and an increase in pc of three binary mixtures can be observed with the increasing mole fraction of ethanol. Despite the mole fraction of ethyl propanoate increases, critical curves of the ternary mixture change almost linearly with the mole fraction of ethanol. Critical properties of the binary mixtures were interrelated with Redlich–Kister equations and PR-WS equations and predicted by He equations. Maximum AADs for Tc and pc using Redlich–Kister equations are 0.08% and 0.65%. There is a great agreement between our experimental data and calculated values from two correlations for the critical parameters of ternary mixture.

Recently, the need for improving the efficiency of distribution network in terms of power losses is being emphasised. A large share of total power losses refers to low-voltage networks which are usually unbalanced. For the power flow analysis, it is necessary to use three-phase modelling. This study presents modelling of distribution network elements and their implementation in backward/forward sweep (BFS) power flow method. An improvement of the BFS method is developed by using the breadth-first search method for network renumbering and creation of modified incidence matrix. The improved method minimises the read elements of each iteration and results in a significant reduction in total calculation time without accuracy loss. This improvement makes this method more suitable for using in real-time calculations. The proposed method is used for calculation of power losses in unbalanced and symmetrical network which are compared. The purpose of this test is to show the advantage of a three-phase power flow analysis compared with a symmetrical model.

In this work we solve the 3D-IC TSV assignment which is formulated as an Integer Minimum Cost Multi Commodity (IMCMC) problem. We propose a multi-level algorithm including graph coarsening and un-coarsening, to greatly reduce the IMCMC problem size; benefiting from it, we transform the IMCMC problem into a mixed single and multi commodity problem and partially solved it using min-cost flow method. Further, we extend the layer by layer method for TSV assignment optimization. The experimental results shows that the our proposal generates initial solutions with 2.8% wire length reduction compared to the existing work, and our extended layer by layer method achieves another 1.7% improvement with slight time overhead.

A sequential injection lab-on valve (SI-LOV) method for the enzymatic determination of hydrogen peroxide was developed. The spectrophotometric assay is based on the reaction between hydrogen peroxide and ABTS (2,2′-Azino-bis(3-Ethylbenzothiazoline 6-sulfonic acid)) in the presence of the enzyme HRP (horseradish peroxidase). The produced oxidized ABTS is measured at 410 nm. The sample consumption was 15 μL/assay and the consumption of HRP and ABTS was 34.6 mg L- 1 and 0.06 g L- 1, respectively with a determination rate of 45 h- 1. Relative deviations lower than 9.0% were found when the results were compared to those obtained by the reference procedure in the analysis of bleaches and disinfection solutions for contact lenses. With the incorporation of an in-line dilution (dialysis) process, was possible to attain a response range up to 342 mg L- 1 of hydrogen peroxide. The developed method was applied to monitor on-line of the disinfection-neutralization process of contact lenses. The study of two different one-step systems for cleaning contact lenses demonstrated that the neutralization of the hydrogen peroxide is completed within 6 h as recommended by the manufactures. The developed flow method was proved to be a useful tool for monitoring the dynamic process of disinfection-neutralization.

NPP’s power supply system is repairable and there is common cause failure between the components. The repair rate is introduced and total signaling is considered in the improved GO-FLOW method, aimed at reliability analysis for NPP’s power supply system. Traditional GO-FLOW operators’ algorithms are improved. Comprehensively considering the effect of total signaling flow in the power supply system, the equivalent reliability parameter model and common cause failure probability model of multimodal repairable components are constructed. The improved GO-FLOW model of NPP’s power supply system is set up. Based on the proposed model, components’ reliability parameters are computed. The failure probability time-varying trend in thirty years, respectively, of NPP’s offsite power source and power supply system, is simulated and analyzed. Compared with calculation results of dynamic fault tree analysis method, the validity and the simplicity of the improved GO-FLOW method are verified. The effectiveness and applicability of the improved GO-FLOW model for NPP’s power supply system are proved by simulation examples.

This paper is concerned with the problem of finding all the real solutions (all components of the solution vector must be real values) of load flow equations. Solutions in which some of the components are complex values are of no interest as they have no physical significance as a load flow solution. This problem is significant not only because of its theoretical challenge but also, its relationship with several system behavior related issues. Approaches suggested so far for solving this problem are rather ad hoc, computationally demanding and have been demonstrated only on very small systems. Further, it has been subsequently shown by others that many of these methods are not capable of finding all solutions. In this work a new approach is proposed which is more systematic and seems to have the potential to handle even large problems. We show that for any system it is possible to find the multiple load flow solutions (MLFS) corresponding to a given operating point extremely easily, starting from a set of points that are referred to as zero load solutions (ZLS) in this paper. It is shown that the complete set of ZLS is unique for a system and MLFS for any other operating point can be obtained starting from these ZLS using only the Newton's load flow method. The set of procedures for implementing the proposed scheme are illustrated and their features are highlighted by considering several sample systems.

A method using gas flow is proposed for testing the quality of fibrous preforms in the resin transfer molding process. The method is based on the idea that preform defects cause variation in permeability and deviation from Darcy's law. This paper presents a gradient-based inverse method that estimate space-varying permeability by examining the consistency between computed and measured pressures at various locations in the mold during steady-state gas flow through the enclosed preform. Such consistency is achieved by the conjugate gradient method. The computed pressures are obtained by the control volume finite element method (CVFEM). The proposed method was demonstrated by using a specially designed mold with multiple ports for gas injection and pressure measurement, and testing for various cases with and without defects.

Nanomanufacturing of nanoparticles is critical for potential translation and commercialization. Continuous flow devices can alleviate this need through unceasing production of nanoparticles. Here we demonstrate the scaled-up production of spherical nanoparticles functionalized with biomedical cargos from the rod-shaped plant virus tobacco mosaic virus (TMV) using a mesofluidic, continued flow method. Production yields were increased 30-fold comparing the mesofluidic device versus batch methods. Finally, we produced MRI contrast agents of select sizes, with per particle relaxivity reaching 979,218 mM–1 s–1 at 60 MHz. These TMV-based spherical nanoparticle MRI contrast agents are in the top echelon of relaxivity per nanoparticle.

To develop cotton derivatives with prolonged antibacterial activity, cotton is derivatized to cotton xanthate (CX) and coupled with metronidazole (Mz) by means of chelate bonding in the presence of Cu(II) using one- and two-bath processes. The effects of coupling methods, concentration, [Mz]/[Cu(II)] ratio, and reaction time on the formation of CX-Cu(II)-Mz are investigated at 10°C. In the one-bath process where CX is treated with a solution of the Cu(II)-Mz complex, binding of Mz takes place readily and rapidly and increases with a higher [Mz]/[Cu(II)] ratio. In the two-bath process, binding of Mz is much lower than in one bath. Release of Mz from CX-Cu(II)-Mz prepared from the one-bath process is investigated by the flow method and takes place steadily during the first 3 hours. The extent of release reaches 65-99% in 20 hours, depending on the concentration of Cu(II) and Mz used to form CX-Cu(II)-Mz. Antibacterial activity of CX-Cu(II)-Mz is tested against G(+) S. aureus, B. subtilis, and G(-) E. coli., and lasts longer than that of free Mz.

Growing long carbon nanotubes (CNTs) is an important prerequisite for practical applications of CNTs. Although gas-flow-guided chemical vapor deposition can be used to produce millimeter-long CNTs, little is known regarding the associated growth mechanism. In the present work, Raman imaging was employed to characterize individual CNTs grown by the gas flow method, and Raman images of a CNT over 1.6 mm long were obtained. Two radial breathing modes were observed and the associated Raman images exhibited exactly identical distributions, indicating that the long CNT most likely had a double-walled structure, in which the CNT diameter was uniform along the whole length.