Penetration Ratio Research Articles

Penetration of Hydrogen into Polymer Electrolyte Membrane for Fuel Cells by Quantum and Molecular Dynamics Simulations.

The advent of the Hydrogen Society created great interest around hydrogen-based energy a decade ago, with several types of vehicles based on hydrogen fuel cells already being produced in the automotive sector. For highly efficient fuel cell systems, the control of hydrogen inside a polymer-based electrolyte membrane is crucial. In this study, we investigated the molecular behavior of hydrogen inside a polymer-based proton-exchange membrane, using quantum and molecular dynamics simulations. In particular, this study focused on the structural difference of the pendent-like side chain polymer, resulting in the penetration ratio of hydrogen into the membrane deriving from the penetration depth of the membrane’s thickness while keeping the simulation time constant. The results reveal that the penetration ratio of the polymer with a shorter side chain was higher than that with the longer side chain. This was justified via two perspectives; electrostatic and van der Waals molecular interactions, and the structural difference of the polymers resulting in the free volume and different behavior of the side chain. In conclusion, we found that a longer side chain is more trembling and acts as an obstruction, dominating the penetration of hydrogen inside the polymer membrane.

An analysis framework for quantitative evaluation of parametric uncertainty in a cooperated energy storage system with multiple energy carriers

In order to increase the penetration of renewable energy into process industries, it is essential to develop an energy storage system for effectively coordinating the intermittent supplies of renewable energy and the fluctuating demands, but parametric uncertainty reigns. In this work, a four-step analysis framework to quantitatively evaluate impacts of parametric uncertainty on a cooperated energy storage system with multiple energy carriers was proposed. It features the quantitative uncertainty analysis associated with global sensitivity analysis based on the deterministic optimization model for the system. The implementation of the quantitative uncertainty analysis was demonstrated by a cooperated energy storage system to bridge the intermittent renewable energy and the fluctuating demands in refineries. The critical parameters and their impacts on the total annual cost of the system were analyzed. Results show that the proposed analysis framework and the developed solution strategy are effective in quantitatively evaluating parametric uncertainty of the system. The critical parameters vary dramatically under different penetration ratios of renewable energy, but the hydrogen demand is the dominant parameter in all cases. The proposed approach provides a useful tool to support quantitative analysis of uncertainties for utilization of renewable energy in process industries.

Influence of Geometry and Separation Walls on The Behaviours of Pull-out Pipe Piles Embedded in Sandy Soil

Predicting of piles capacity and their behavior is always an important and serious problem for a safe geotechnical engineering design. In the present study, experimental model tests have been conducted on a single steel pipe piles driven in sandy soil and subjected to pull-out force. The experimental tests were conducted on vertical open-ended piles with circular and square cross-sectional area and three various diameters 3 cm, 4 cm and 5 cm in a steel soil box have been used. The tested pile’s model has embedment with three penetration ratios (PR=L/D) of 10, 15 and 20. All tests were done in medium density soil (Dr = 50%) with open ended pipe pile to study the effect of pile geometry on pile behavior, and three other tests were conducted on the 5cm diameter and 10 penetration ratio in medium soil density to study the importance of addition of separating wall. The study discovered that the capacity of single piles with circle cross-section area under pull-out force increasing by 211% and 458% with the increasing of pile diameter (width) from 3cm to 4cm and 5cm respectively, and increasing by 210%, 448% and by 112%, 288%. Also, by 79% and 211% with increasing penetrating ratio (PR) from 10 to 15 and 20 for diameters 3cm, 4cm and 5cm respectively, with respect to reference pile. And the same behavior for square cross-section pipe pile, when the pull-out capacity increasing with the increase of pile width and penetration ratio due to the increasing in the friction area. Besides that, It was also found that the separation walls increased the coefficient of lateral pressure in addition to the friction area. At the same time, there are an optimum number of separation walls that can be used to increase the pile pull-out capacity and that when using three separation walls.

Assessment of circular-bored twin tunnel (CBTT) performance using soft computing methods

Circular-bored tunnel (CBTT) machines are used as an alternative to drill and for blasting in rock and conventional "hand mining" in soil. The penetration rate (PR) prediction is a difficult issue plus the related analysis between CBTT and rock mass. Circular tunnels are high proposed for general projects. Experimental and analytical models in analyzing CBTT penetration ratio could not provide a reliable and valid prediction to civil projects and mining because of the nonlinear problems, related risks and high costs. This research provides a novel study of using three algorithms as support vector machine (SVM), grey wolf optimizer (GWO) and k-nearest neighbor (KNN) to predict the PR of CBTT. For this purpose, doing empirical analysis could be time consuming, lead to high cost, inaccuracy of results, and high error percentages. Accordingly, this study, by doing numerical analysis, has tried to accurately predict the PR of CBTT in terms of uniaxial compressive strength and rock quality designation were used as input data. It was followed by the development of SVM, KNN, and GWO to obtain the best predictive model. Accordingly, SVM with the best RMSE value of (0.183), R2 value (0.914) and MAE value of (0.139) was selected as the best model among other two ones in this research, meaning that SVM could predict the PR of CBTT with more accuracy and reliably. Thus, SVM model identified uniaxial compressive strength (0.2) as a significant parameter in CBTT prediction and penetration ratio.

On Determining Critical System Ramp Capability Requirement in High PV Penetration Network Using Graphical Method

Increasing effort of solar power integration to the grid could be accelerated towards sustainability goal. However, high PV penetration ratio (PVR) in turn critically reduces system frequency response performance of an existing power system due to reduction of on‐line rotating generators. Besides intrinsic system inertia, system RC plays a vital role in dynamically securing the power system operation subject to large PV disturbances. This study proposes a graphical method to determine critical values of system RC requirement with respect to the anticipated PVR and PV ramp‐down rate of disturbance; both of which should be forecastable, in practice, in each operating time interval. Impact of PVR on dynamic performance of a power system, through the effective time‐varying of system inertia and governor response characteristic has been examined. The results of the analyses on graphical display will be useful for system operators to prepare enough system RC, economically well in‐advance through Unit Commitment program, to ensure system dynamic security, complying with the N‐1 contingency constraint. In addition, the proposed graphical display can reveal whether the curtailment of aggregated PV's output generation is necessary for that time interval. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Pharmacokinetics of Benznidazole in Experimental Chronic Chagas Disease Using the Swiss Mouse-Berenice-78 Trypanosoma cruzi Strain Model.

Chronic Chagas disease might have an impact on benznidazole pharmacokinetics with potential alterations in the therapeutic dosing regimen. This study aims to investigate the influence of chronic Trypanosoma cruzi infection on the pharmacokinetics and biodistribution of benznidazole in mice. Healthy (n = 40) and chronically T. cruzi (Berenice-78 strain)-infected (n = 40) Swiss female 10-month-old mice received a single oral dose of 100 mg/kg of body weight of benznidazole. Serial blood, heart, colon, and brain samples were collected up to 12 h after benznidazole administration. The serum and tissue samples were analyzed using a high-performance liquid chromatography instrument coupled to a diode array detector. Chronic infection by T. cruzi increased the values of the pharmacokinetic parameters absorption rate constant (Ka ) (3.92 versus 1.82 h-1), apparent volume of distribution (V/F) (0.089 versus 0.036 liters), and apparent clearance (CL/F) (0.030 versus 0.011 liters/h) and reduced the values of the time to the maximum concentration of drug in serum (Tmax) (0.67 versus 1.17 h) and absorption half-life (t1/2a ) (0.18 versus 0.38 h). Tissue exposure (area under the concentration-versus-time curve from 0 h to time t for tissue [AUC0-t,tissue]) was longer and higher in the colon (8.15 versus 21.21 μg · h/g) and heart (5.72 versus 13.58 μg · h/g) of chronically infected mice. Chronic infection also increased the benznidazole tissue penetration ratios (AUC0-t,tissue/AUC0-t,serum ratios) of brain, colon, and heart by 1.6-, 3.25-, and 3-fold, respectively. The experimental chronic Chagas disease inflammation-mediated changes in the regulation of membrane transporters probably influence the benznidazole pharmacokinetics and the extent of benznidazole exposure in tissues. These results advise for potential alterations in benznidazole pharmacokinetics in chronic Chagas disease patients with possibilities of changes in the standard dosing regimen.

Effectiveness of Chin Tuck on Laryngeal Penetration: Quantitative Assessment

The effectiveness of the chin tuck maneuver is still controversial, despite being widely used in clinical practice. The chin tuck maneuver has been shown to be able to reduce or eliminate aspiration in a group of patients with a number of favorable conditions, but its effectiveness in preventing or managing penetration remains unclear. This study was designed to investigate whether the chin tuck maneuver is effective in reducing penetration. Images from a videofluoroscopic swallowing study (VFSS) taken from 76 patients with penetration were collected and reviewed retrospectively. The severity of penetration was assessed by the penetration ratio (ratio of the penetration depth to the length of the epiglottis) measured and calculated from the images in which the deepest penetration was observed. The penetration ratio was significantly decreased in the chin tuck posture compared with the ratio in the neutral position (p = 0.001). Significant reducing effect was observed in 26 (34.2%) out of 76 patients. When comparing other parameters of VFSS, residues in the vallecular and pyriformis sinuses were less severe in the effective group. Chin tuck significantly decreased residues in both effective and ineffective group. The results demonstrate that the chin tuck maneuver can reduce penetration, but its effectiveness is limited.

Influence of activated flux on micro-structural and mechanical properties of AISI 1018 during MIG welding

The strength of weld joint largely depends on depth of penetration of metal at fusion zone. The present study aims to investigate effect of five activated fluxes, viz. Al2 (SO4)3, NaOH, Na2CO3, NaHCO3, and borax in MIG welding on depth of penetration and mechanical properties of AISI 1018. Results reflected that use of flux had paramount influence on the microstructure and hardness of the bead on plate welds. It helps in increasing depth of penetration via reverse Marangoni effect. Out of all five fluxes, Borax flux had provided higher depth of penetration, external and internal aspect ratio and hardness than other fluxes used as well as than without flux.

Optimal Operation of an Integrated Electricity-heat Energy System Considering Flexible Resources Dispatch for Renewable Integration

Large fluctuations may occur on the energy supply and the load sides when large-scale renewable energies are integrated, leading to great challenges in power systems. The renewable power curtailment is especially numerous in the integrated electricity-heat energy system (IEHES) on account of electricity-heat coupling. The flexible resources (FRs) on both the energy supply and load sides are introduced into the optimal dispatch of the IEHES and further modeled to alleviate the renewable fluctuations in this paper. On the energy supply side, three kinds of FRs based on electricity-heat coordination are modeled and discussed. On the load side, the shiftable electricity demand resource is characterized. On this basis, the solution for FRs participating in IEHES dispatch is given, with goals of maximizing the renewable penetration ratio and lowering operation costs. Two scenarios are performed, and the results indicate that the proposed optimal dispatch strategy can effectively reduce the renewable energy curtailment and improve the flexibility of the IEHES. The contribution degrees of different FRs for renewable integration are also explored.

1302. Cefiderocol Population Pharmacokinetics and Probability of Target Attainment in Plasma and Epithelial Lining Fluid in Patients with Pneumonia, Bloodstream Infection/Sepsis, or Complicated Urinary Tract Infections

BackgroundCefiderocol (CFDC) is a novel siderophore cephalosporin with activity against a broad range of Gram-negative bacteria. The aim of this study was to perform population pharmacokinetic (PopPK) analysis and evaluate probability of target attainment (PTA) in plasma and epithelial lining fluid (ELF) based on a modeling and simulation approach.MethodsPopPK analysis in plasma was conducted using 3427 concentration data from 425 patients with pneumonia, bloodstream infection/sepsis (BSI/sepsis), complicated urinary tract infection (cUTI), or acute uncomplicated pyelonephritis in 3 Phase 2 or 3 studies (NCT03032380, NCT02714595, and NCT02321800), and 91 subjects without any infection in Phase 1 studies. In addition, intrapulmonary modeling was conducted using ELF concentration data from 7 pneumonia patients (NCT03862040) and 20 healthy subjects. Monte-Carlo simulations were performed by generating 1000 virtual patients for each infection site (pneumonia, BSI/sepsis, or cUTI) to predict PTA for 75% of time for which free drug concentration in plasma or ELF (only pneumonia patients) exceeds the minimum inhibitory concentration (MIC; 0.25–16 µg/mL) over dosing interval following CFDC 2 g q8h infused over 3 hours with dose adjustment based on renal function, including augmented renal clearance.ResultsThe developed PopPK model described the plasma and ELF CFDC concentrations. Creatinine clearance, body weight, infection site, and albumin concentration were statistically significant covariates on CFDC PK in plasma. There were no clinically significant differences in CFDC plasma exposure based on infection site or with/without ventilation. The penetration ratio of ELF to free plasma in pneumonia patients (0.340) was 1.3-fold higher than that in healthy subjects (0.263). As shown in the table below, plasma PTA was >90% against MICs ≤4 μg/mL, regardless of infection site and renal function. ELF PTA in pneumonia patients was >90% against MICs ≤2 μg/mL and >85% against MICs ≤4 μg/mL, regardless of renal function.Table. Probability of Target Attainment for 75% fT>MIC or 75% fT>MIC,ELF ConclusionThe recommended dosing regimen (2 g, q8h, 3-hr infusion) adjusted by renal function provided adequate exposure to CFDC in patients with infections caused by Gram-negative pathogens, irrespective of infection site and renal function.DisclosuresTakayuki Katsube, PhD, Shionogi & Co., Ltd. (Employee) Nao Kawaguchi, BPharm, Shionogi & Co., Ltd. (Employee) Roger Echols, MD, Shionogi Inc. (Consultant) Toshihiro Wajima, PhD, Shionogi & Co., Ltd. (Employee) David P. Nicolau, PharmD, Cepheid (Other Financial or Material Support, Consultant, speaker bureau member or has received research support.)Merck & Co., Inc. (Consultant, Grant/Research Support, Speaker’s Bureau)Wockhardt (Grant/Research Support)

Globalization and labor demand elasticities: Do trading partners matter

This paper uses industrial level data across 41 developing and emerging economies over the period of 1993–2013, to analyze the impact of globalization on the elasticity of demand for labor. The use of both import penetration ratios and export intensity in our model allows for assessment of relative effectiveness of exports vis à vis imports in influencing the labor elasticities. Furthermore, the disintegration of exports and imports according to their trading partners helps explore a novel source of heterogeneity in labor elasticity originating as a result of trading relationship with developed and developing world. Using system-GMM approach, our results reveal that both exports and imports make labor demand more elastic, with imports leaving the labor demand more vulnerable to wage changes. Trading with developing countries renders labor demand more elastic and that too with respect to low-tech or labor intensive products, while trading with developed countries poses no effect. Overall, the results point towards developing countries encouraging greater exporting and importing ties with developed world to ease its impact on the elasticity of demand for labor. However, trading with developing countries need not be suspended rather labor protection programs need to be in place to counter any consequent adverse effects.

Bone penetration of linezolid in osteoarticular tuberculosis patients of China

BackgroundLinezolid presents strong antimicrobial activity against multidrug-resistant (MDR) pulmonary tuberculosis (TB), but its application in osteoarticular tuberculosis treatment remains understudied. Our objective was to analyze the bone penetration efficiency of linezolid in osteoarticular TB patients. MethodsOsteoarticular TB patients, treated with 600 mg q 24 h linezolid-containing regimens and undergoing surgery, were prospectively and consecutively enrolled. One dose linezolid was administered before surgery. Blood and bone samples were collected simultaneously during operation, and their linezolid concentrations were then detected using high-performance liquid chromatography-tandem mass spectrometry. Pus samples were subjected to mycobacterial culture and GeneXpert MTB/RIF assay. The minimum inhibition concentrations (MICs) and drug susceptibility testing were performed with the recovered isolates. ResultsA total of 36 eligible osteoarticular TB patients were enrolled, including five MDR/rifampicin-resistant cases. All the 12 recovered isolates had MICs ≤0.5 μg/mL for linezolid. Mean concentrations in plasma, collected 100−510 min after the preoperative dosing, were 10.43 ± 4.83 μg/mL (range 3.29−22.26 μg/mL), and median concentrations in bone were 3.93 μg/mL (range 0.61−16.34 μg/mL). The median bone/plasma penetration ratio was 0.42 (range 0.14−0.95 μg/mL). Linezolid concentration in bone had a linear correlation with the drug concentration in plasma (r = 0.7873, p < 0.0001), while plasma concentration could explain 61.98% of the variation of concentration in bone (R2 = 0.6198). Notably, stratification analysis by sampling time demonstrated that samples collected 200−510 min after dosing had very good linear relationships between their bone and plasma concentrations (r = 0.9323). ConclusionsLinezolid penetrates from blood to bone efficiently, and the penetration further stabilizes ∼3 h after dosing.

Revising Transient-Pressure Solution for Vertical Well Intersected by a Partially Penetrating Fracture with Non-Darcy Flow Effect

The principle purpose of this work is to formulate an accurate mathematical model to evaluate the transient pressure behavior of a well intercepted by a partially penetrating vertical fracture (PPVF) with non-Darcy flow effect. Fracture conductivity is taken into account by coupling the three-dimensional flow in reservoir and the two-dimensional flow within fracture; the Barree-Conway model is incorporated into the model to analyze non-Darcy flow behavior in fracture, which leads to the nonlinearity of the governing equations. A high-effective iterative algorithm using a combined technique of fracture-panel discretization and dimension transform is developed to render the nonlinear equations amenable to analytical linear treatment. On the basis of the solutions, the pressure response and its derivative type curves were generated to identify the evolution of flow regimes with time. Furthermore, the influences of fracture conductivity, penetration ratio, and non-Darcy characteristic parameters on pressure response are investigated. The results show that PPVF exhibits five typical flow regimes, and analytical solutions for each flow regime are similar to that for a fully penetrating vertical fracture (FPVF) that can be correlated with the penetration ratio and apparent conductivity. The non-Darcy flow effect is found to have more significant effect on the low and moderate conductivity, especially in early-stage flow regimes. When the penetration ratio is smaller than 0.5, the pressure behavior exhibit a more remarkable variation with penetration ratio. This study provides a better insight into understanding the influence of non-Darcy flow on flow regime identification.

Development of Complex Hydrogen Penetration Ratio As a New Transfer Function for Analysis on Hydrogen Penetration Mechanisms into Metals

Degradation of steels related to the hydrogen embrittlement is a serious problem from the standpoint of infrastructure preservation. The hydrogen embrittlement is related to the hydrogen penetration reaction (HPR) into steel. Some electrochemical methods [1-4] were employed to investigate the HPR mechanisms. One of the major electrochemical methods is electrochemical impedance spectroscopy (EIS). The EIS was applied to the investigation of HPR mechanisms because the time constants observed in impedance spectrum can be discriminated [5]. Another one is Devanatnan-Stachurski permeation technique [6, 7]. In this technique, two independent electrochemical cells are arranged on two surfaces of metal sheet and anodic and cathodic polarizations can be performed with each cell using the three-electrode system. The amount of hydrogen penetration rate can be evaluated by measuring the oxidation current of hydrogen atoms diffused in the metal sheet at the anode side. In this study, we proposed a new transfer function based on the electrochemical reactions and mass transfer during HPR by combining EIS and Devanatnan-Stachurski permeation technique. The complex hydrogen penetration ratio (CHPR), ι, as a new transfer function is defined from ratio of ΔI per and ΔI ent. ι = ΔI per / ΔI ent (1)In this equation, the ΔI per is the current response related to the hydrogen penetrated through metal sheet at anode (detection) side, and the ΔI ent is the current response of cathode (entry) side. The equation (1) can be expressed by the following equation as the theoretical equations for ΔI per and ΔI ent were derived based on Fick's 2nd law,. ι = 1 / K ab exp (-h (jω / D)1 / 2) (2)In the equation (2), K ab is the hydrogen entry ratio against the total cathodic reaction rate, h is the thickness of metal sheet, j is imaginary number unit, and D is the hydrogen diffusion coefficient.The simulations of ι were conducted with the equation (2) assuming arbitrary values of D. The simulation results indicated that the phase shift of ι became large with the decrease of D. The new method to determine the value of D from the phase shift of CHPR was developed.

Effect and Mechanism of Encapsulation-Based Spores on Self-Healing Concrete at Different Curing Ages.

It has become an intelligent and environmental protection method to repair concrete cracks based on microbial-induced calcium carbonate precipitation (MICP). However, due to the high-alkali environment in concrete, even the microbial spores with strong alkali resistance find it difficult to survive for a long time, which affects the long-term self-healing effect of concrete cracks. In this paper, low-alkali sulfo-aluminate cement (SC) was used as a carrier to encapsulate spores, and the effects of the spore group and microbial group on the basic performances of concrete were studied. Then, the area repair ratio, water permeability, the repair ratio of anti-chloride ion penetration, and ultrasonic velocity were used to evaluate the self-healing efficiency of cracks, and the self-healing effects of two kinds of microbial self-healing agents on concrete cracks with different curing ages were further studied. Moreover, the growth, enzyme activity, and microbial morphologies of spores with and without encapsulation immersed in the simulated pore solution of cement-based materials at different times were studied to discuss the protective effect of the carrier on spores. Compared with the reference group, the results showed that the addition of two microbial self-healing agents would slightly affect the basic performances of concrete, but both were within the control range of concrete materials. For the early-age cracks, the two kinds of microbial self-healing agents could achieve a good self-healing effect, but for the later-age cracks, the concrete cracks of the microbial group could still be repaired well, while the self-healing effect of the spore group was greatly reduced. Moreover, the white precipitates generated at the crack mouth were all calcite CaCO3. In addition, the self-healing mechanism of different microbial self-healing agents on concrete cracks was discussed carefully. This study provides a new idea and method for the engineering application of microbial self-healing concrete.

Molecular structure change and anti-aging performance of WFO-CR composite modified asphalts

In order to use the solid and liquid waste resources to improve performances of base asphalt, waste frying oil (WFO) and crumb rubber (CR) are used to modify the asphalt to obtain the sustainable pavement material. The molecular structures and the performances of the modified asphalts with different amounts of WFO and CR are analyzed by conventional asphalt methods, short-term aging test and Fourier transform infrared spectroscopy (FT-IR). The results indicate that the retained penetration ratio (RPR), the softening point increment (SPI) and retained ductility ratio (RDR) indexes of modified asphalts with different amounts of WFO-CR composite are better than those of the base asphalt after short-term aging test. WFO and CR can improve anti-aging performance. Moreover, FT-IR results show that the absorption peaks at 814 cm^-1 and 720 cm^-1, which represent the alkenyl or benzene ring CC in WFO-CR composite modified asphalt after short-term aging, increase obviously. Both the carbonyl absorption peak and the sulfoxide absorption peak are improved for modified asphalts with different amounts of WFO-CR composite. The quantitative analysis shows that the carbonyl and sulfoxide indices of the modified asphalt reach the lowest values with 5.0% WFO and 20.0% CR, which are 36.02% and 32.04% lower than those of the base asphalt, respectively.

Simulation and Optimization of Dynamic Fracture Parameters for an Inverted Square Nine-Spot Well Pattern in Tight Fractured Oil Reservoirs

Dynamic fractures are a geological attribute of water flooding development in tight fractured oil reservoirs. However, previous studies have mainly focused on the opening mechanism of dynamic fractures and the influence of dynamic fractures on development. Few attempts have been made to investigate the optimization of the dynamic fracture parameter. In this study, the inverted square nine-spot well pattern model is established by taking fractured reservoir’s heterogeneity and its threshold pressure gradients into account. This simulation model optimizes the various parameters in a tight fractured oil reservoir with dynamic fractures, that is, the intersection angle between the dynamic fractures and the well array, the number of dynamic fractures, the penetration ratio, and the conductivity of the oil well’s hydraulic fractures. The results of this optimization are used to investigate the oil displacement mechanism of dynamic fractures and to discuss a mechanism to enhance oil recovery using an inverted square nine-spot well pattern. The simulation results indicate that a 45° intersection angle can effectively restrain the increase in the water cut. A single dynamic fracture can effectively control the displacement direction of the injected water and improve the oil displacement efficiency. Moreover, the optimal penetration ratio and the conductivity of the hydraulic fracture are 0.6 and 40 D-cm, respectively.

An Elitist Multi-Objective Particle Swarm Optimization Algorithm for Sustainable Dynamic Economic Emission Dispatch Integrating Wind Farms

In recent years, wind energy has been widely used as an alternative energy source as it is a clean energy with a low running cost. However, the high penetration of wind power (WP) in power networks has created major challenges due to their intermittency. In this study, an elitist multi-objective evolutionary algorithm called non-dominated sorting particle swarm optimization (NSPSO) is proposed to solve the dynamic economic emission dispatch (DEED) problem with WP. The proposed optimization technique referred to as NSPSO uses the non-dominated sorting principle to rank the non-dominated solutions. A crowding distance calculation is added at the end of all iterations of the algorithm. In this study, WP is represented by a chance-constraint which describes the probability that the power balance cannot be met. The uncertainty of WP is described by the Weibull distribution function. In this study, the chance constraint DEED problem is converted into a deterministic problem. Then, the NSPSO is applied to simultaneously minimize the total generation cost and emission of harmful gases. To proof the performance of the proposed method, the ten-unit and forty-unit systems—including wind farms—are used. Simulation results obtained by the NSPSO method are compared with other optimization techniques that were presented recently in the literature. Moreover, the impact of the penetration ratio of WP is investigated.

A cost-effective power ramp rate control strategy based on flexible power point tracking for photovoltaic system

Due to the intermittent nature of renewable power generation, the power ramp-rate control (PRRC) strategy becomes essential for Photovoltaic (PV) systems with the increased penetration ratio recently. However, most of the PRRC strategies are based on energy storage systems, which require high installation cost. Therefore, it is important to find alternative technology to avoid the additional hardware components and make the PV system more cost-effective. In this paper, a novel PRRC strategy is proposed, which is based on a flexible power point tracking (FPPT) strategy without the additional hardware cost. Besides, a ramp-rate measurement (RRM) method is proposed to detect the power ramp-rate event. The proposed PRRC algorithm is suitable for both of the ramp-up and ramp-down cases. Furthermore, it is simple and effective in regulating the PV power fluctuations under the framework of grid code. The effectiveness of the proposed PRRC strategy is validated through simulation and experimental evaluation under various scenarios. The experimental results based on the real-filed meteorological profile validate that the proposed PRRC strategy can effectively regulate the ramp rate under 3 W/s, which is corresponded to 5% of the rated PV power/min.

A comprehensive study on source dependency of conventional, chemical and rheological properties of asphalt binder

Source of the asphalt binder has an important role to play in dictating the properties of a binder. The role is further exacerbated if the specification of binder relies on traditional properties of penetration, softening point, absolute viscosity and ductility. In case the binder supplied from different sources by manufacturers is expected to conform to same grade based on such traditional properties, the flexible nature of traditional grade assigning system may lead to an unwanted divergence in the expected properties. Hence, this study attempts to explore the source dependence of various conventional, chemical and rheological properties of asphalt binders. Five binder sources were adopted. The results indicated that only one binder source satisfied the penetration as per IS 73 specification. Such non-compliance with viscosity specification was also observed in one binder source. Different binder sources were observed to exhibit varying contents of asphaltenes. Age hardening evaluated based on retained penetration ratio (RPR), viscosity ageing index (VAI) and softening point increment (ΔS) differed for diverse binder sources. Similar variable observations for temperature susceptibility were perceived based on penetration index (PI), pen-vis number (PVN) and viscosity temperature susceptibility (VTS). Percent recovery (R) and non-recoverable creep compliance (Jnr) indicated the dependence of rutting characteristics on a binder source whereas linear amplitude sweep (LAS) accentuated the dependence of fatigue life on the source of the binder. Conclusively, statistical analysis indicated mixed results regarding the significance of differences in binders from different sources based on various evaluated parameters.