Computational study of auto ignition, spark ignition and dual fuel droplet ignition in a rapid compression machine, A

2017 Summer.Includes bibliographical references.A series of computational modeling studies were performed using the CONVERGETM computational fluid dynamics (CFD) platform to gain in-depth understanding of the chemically reacting flow field, ignition and combustion phenomena in a various rapid compression machine (RCM) experiments conducted at CSU including homogeneous autoignition, laser ignition and droplet ignition experiments. A three-dimensional, transient computational modeling study was initially performed to examine premixed, homogeneous autoignition of isooctane/air and methane/air mixtures. A reduced chemical kinetic mechanism for isooctane comprising of 159 species and 805 reactions was developed using direct relation graph error propagation and sensitivity analysis (DRGEPSA) method. Computational results showed good agreement with experimental results capturing the negative temperature coefficient (NTC) behavior of isooctane. The premixed computations also revealed the importance of the piston crevice design for maintaining a homogenous flow field inside a RCM. The result showed that, as the volume of the piston crevices is increased, the roll up vortices are eliminated, which reduces the mixing of the lower temperature boundary layer gases with the higher temperature core gases, thereby maintaining the homogeneity of the flow field. Next, three-dimensional computational modeling laser-ignited premixed fuel/air mixtures at elevated temperatures and pressures in the RCM was performed with detailed chemical kinetics (86 species, 393 reactions). For methane/air mixtures, the computational results were compared against previously reported RCM experiments. Computations were also performed on laser-ignited n-heptane/isooctane/air mixtures under similar simulated conditions in the RCM. In the computations, a simulated spark modeled as a localized hotspot was introduced in the center of the combustion chamber resulting in an outwardly propagating flame, which, depending on the fuel reactivity, produced ignition in the end gas upstream of the flame. Methane/air computations were performed at equivalence ratio of 0.4 ≤ Ф ≤ 1.0 for direct comparisons with experimental measurements of instantaneous pressure, flame propagation rate, and lean limit. For compressed temperature of 782 K, a methane/air lean limit of Ф = 0.38 was predicted computationally (combustion efficiency, χ = 0.8), which was in good agreement with the experimental measurement of Ф = 0.43. For n-heptane/isooctane/air computations, auto-ignition of the end gas was predicted depending on the compressed temperature and Octane Number, which suggests the use of the laser ignition/RCM system as a means to quantify fuel reactivity for spark ignited engines. Lastly, RCM experiments in which single n-heptane droplets are suspended and ignited via compression-ignition in a quiescent, high-pressure, high-temperature, lean methane/air environments were simulated using the 86-species dual-fuel chemical kinetic mechanism developed previously. The simulations capture the ignition event in the vicinity of a spherical n-heptane droplet, which bifurcates into a propagating, premixed methane/air flame and stationary n-heptane/air diffusion flame. Comparisons against experimental measurements of droplet gasification rate, premixed flame propagation speed, and non-premixed flame position will be used to develop revised dual-fuel chemical kinetic mechanisms

Effect of micelles on hydrolysis of di-2,3-dichloroaniline phosphate

551-562The effect of anionic surfactant, di-octylsodium sulphosuccinate (AOT) and nonionic surfactant, polyoxyethylene sorbitanmonooleate (Tween-80) on the hydrolysis of di-2,3-dichloroaniline phosphate was studied spectrophotometrically at 303 K. The influence of inorganic salts on the reaction rate was studied. The added salts viz. KCl, KNO3, and K2SO4 accelerated the rate of the reaction in the presence of anionic and nonionic micelles. The role of anionic and non-ionic micelle has been explained by the Menger-Portnoy, and Piszkiewicz models. The binding constant (Ks), rate constant (kψ) in the micellar phase, co-operativity index (n) and various thermodynamic activation parameters viz. ∆Ea, ∆S≠, ∆H≠, ∆G≠ etc. have been evaluated. Possible reaction mechanism has been proposed on the basis of the observed kinetic data

Fea Based Study of Effect of Radial Variation of Outer Link in A Typical Roller Chain Link Assembly

Chain Link assembly is extensively used in the industry, the scope of this paper is to review the applications in the industry and explore the design considerations that go into the design of the assembly. The paper delves into various application aspects and manufacturing aspects to formulate an idea of the system. Finally Finite Element Analysis (FEA) has been used to conduct shape optimization. Since lot of work has already been done in other components, in this paper the focus has been narrowed down to specific component of outer link. Within the outer link, most dimensions in the industry are parametrically defined, however one dimension, the radius that is in between the inter connecting holes is left to manufacturer convenience. In this paper we assess the impact of this radius on the stress in the system, and see if material saving and consequently efficiency increment is possible

IN VITRO ANTIBACTERIAL ACTIVITY OF PHOSPHATE ESTERS SCREENED BY BROTH DILUTION ASSAY METHOD

Objective: The present study was formulated in order to determine the novelty and the potency of the synthesized phosphate esters in terms of their antibacterial activity.Methods: Mono-6-chloro-2,4-dinitroaniline phosphate and di-2-methyl-5-nitroaniline phosphate were screened for antibacterial activity against four pathogenic bacterial strains Staphylococcus aureus MTCC 3160, Klebsiella oxytoca ATCC 13182, Bacillus subtilis BAB 2437 and Bacillus licheniformis MS 17. Antibacterial activity was evaluated by the broth dilution assay method at different concentrations (50-2000µg/ml) of phosphate esters. Solutions of mono-and di phosphate esters were prepared in water and DMSO respectively. Growth of inoculums was noted in terms of optical density.Results: Di-2-methyl-5-nitroaniline phosphate was found more active than mono-6-chloro-2,4-dinitroaniline phosphate against selected bacterial strains. The minimum inhibitory concentration (MIC) of both phosphate esters was found in the range of 25 to 50 µg/ml. Minimum bactericidal concentration (MBC) of mono-6-chloro-2,4-dinitroaniline phosphate was found in the range of 1000 to 1500µg/ml against Staphylococcus aureus, Klebsiella oxytoca, Bacillus subtilis and Bacillus licheniformis. Di-2-methyl-5-nitroaniline phosphate showed MBC of 500 and 400 µg/ml against Staphylococcus aureus and Klebsiella oxytoca respectively, and 1000 µg/ml against Bacillus subtilis and Bacillus licheniformis. Conclusion: Both the phosphate esters have exhibited significant antibacterial activity, therefore these compounds may be a good antibacterial agent.Â

ANTI -ARTHRITIC POTENTIAL OF HELIANTHUS ANNUUS IN LABORATORY ANIMALS

Objective: The present study was carried out to investigate the anti-arthritic potential of ethanolic extract of Helianthus annuus leaves (HA).Methods: The effect of HA was evaluated for chronic inflammation by complete Freud's adjuvant (CFA) induced arthritis in rats.Results: The paw edema was measured along with biochemical, hematological, histopathological, radiographic parameters, and ulcerogenic potential.In this study, pre-treatment with HA significantly decreased paw volume, arthritic index, spleen and thymus weight, ulcerogenic index; and inhibitedhistopathological changes in joint cavity and inhibited destruction of the knee joints induced by CFA in radiographic examination. Treatment ofHA also restored significantly the hematological parameters such as hemoglobin level, total red blood cell, total white blood cell, and erythrocytsedimentation rate along with antioxidant parameters such as superoxide dismutase, catalase glutathione, and lipid peroxide. The serum marker ofarthritis such as C-reactive protein (CRP) and rheumatoid factor were also reduced in the HA-treated arthritic rats.Conclusion: The results of the present study demonstrate the anti-arthritic potential of HA leaves in the anti-arthritic activity.Keywords: Anti-arthritic, C-reactive protein, Complete Freud's adjuvant, Helianthus annuus, Paw volume, Rheumatoid factor

Machine Learning Based Fluid-Transportation Monitoring and Controlling

The discipline of fluid mechanics is developing quickly, propelled by previously unheard-of data volumes from experiments, field measurements, and expansive simulations at various spatiotemporal scales. The field of machine learning (ML) provides a plethora of methods for gleaning insights from data that can be used to inform our understanding of the fluid dynamics at play. As an added bonus, ML algorithms can be used to automate duties associated with flow control and optimization, while also enhancing domain expertise. This article provides a review of the background, current state, and potential future applications of ML in fluid mechanics. We provide an introduction to the most fundamental ML approaches and describe their applications to the study, modelling, optimization, and management of fluid flows. From the standpoint of scientific inquiry, which treats data as an integral aspect of modelling, experiments, and simulations, the benefits and drawbacks of these approaches are discussed. Since ML provides a robust information-processing framework, it can supplement and potentially revolutionize conventional approaches to fluid mechanics study and industrial applications. &nbsp

Genome-wide superior alleles, haplotypes and candidate genes associated with tolerance on sodic-dispersive soils in wheat (Triticum aestivum L.)

Sodic-dispersive soils have multiple subsoil constraints including poor soil structure, alkaline pH and subsoil toxic elemental ion concentration, affecting growth and development in wheat. Tolerance is required at all developmental stages to enhance wheat yield potential on such soils. An in-depth investigation of genome-wide associations was conducted using a field phenotypic data of 206 diverse Focused Identification of Germplasm Strategy (FIGS) wheat lines for two consecutive years from different sodic and non-sodic plots and the exome targeted genotyping by sequencing (tGBS) assay. A total of 39 quantitative trait SNPs (QTSs), including 18 haplotypes were identified on chromosome 1A, 1B, 1D, 2A, 2B, 2D, 3A, 3B, 5A, 5D, 6B, 7A, 7B, 7D for yield and yield-components tolerance. Among these, three QTSs had common associations for multiple traits, indicating pleiotropism and four QTSs had close associations for multiple traits, within 32.38 Mb. The overlapping metal ion binding (Mn, Ca, Zn and Al) and photosynthesis genes and transcription factors (PHD-, Dof-, HTH myb-, BHLH-, PDZ_6-domain) identified are known to be highly regulated during germination, maximum stem elongation, anthesis, and grain development stages. The homozygous/biallelic SNPs having allele frequency above 30% were identified for yield and crop establishment/plants m−2. These SNPs correspond to HTH myb-type and BHLH transcription factors, brassinosteroid signalling pathway, kinase activity, ATP and chitin binding activity. These resources are valuable in haplotype-based breeding and genome editing to improve yield potential on sodic-dispersive soils

Impact of wireless losses on the predictability of end-to-end flow characteristics in Mobile IP Networks

Technological advancements have led to an increase in the number of wireless and mobile devices such as PDAs, laptops and smart phones. This has resulted in an ever- increasing demand for wireless access to the Internet. Hence, wireless mobile traffic is expected to form a significant fraction of Internet traffic in the near future, over the so-called Mobile Internet Protocol (MIP) networks. For real-time applications, such as voice, video and process monitoring and control, deployed over standard IP networks, network resources must be properly allocated so that the mobile end-user is guaranteed a certain Quality of Service (QoS). As with the wired and fixed IP networks, MIP networks do not offer any QoS guarantees. Such networks have been designed for non-real-time applications. In attempts to deploy real-time applications in such networks without requiring major network infrastructure modifications, the end-points must provide some level of QoS guarantees. Such QoS guarantees or QoS control, requires ability of predictive capabilities of the end-to-end flow characteristics. In this research network flow accumulation is used as a measure of end-to-end network congestion. Careful analysis and study of the flow accumulation signal shows that it has long-term dependencies and it is very noisy, thus making it very difficult to predict. Hence, this work predicts the moving average of the flow accumulation signal. Both single-step and multi-step predictors are developed using linear system identification techniques. A multi-step prediction error of up to 17% is achieved for prediction horizon of up to 0.5sec. The main thrust of this research is on the impact of wireless losses on the ability to predict end-to-end flow accumulation. As opposed to wired, congestion related packet losses, the losses occurring in a wireless channel are to a large extent random, making the prediction of flow accumulation more challenging. Flow accumulation prediction studies in this research demonstrate that, if an accurate predictor is employed, the increase in prediction error is up to 170% when wireless loss reaches as high as 15% , as compared to the case of no wireless loss. As the predictor accuracy in the case of no wireless loss deteriorates, the impact of wireless losses on the flow accumulation prediction error decreases