Journal articles: 'Gradient-like system'

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Shavlyuk, A. Yu, and V. V. Semenov. "CONVERGENCE OF GRADIENT-LIKE DYNAMICAL SYSTEM." Journal of Numerical and Applied Mathematics, no. 1 (2022): 120–26. http://dx.doi.org/10.17721/2706-9699.2022.1.09.

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The asymptotic behavior of the gradient system, which is a continuous analogue of the variant of the gradient method from [16] for the minimization of strongly convex functions, is studied. Using the Lyapunov analysis, estimates of the rate of convergence of the gradient system were established.

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Cabot, A. "Inertial Gradient-Like Dynamical System Controlled by a Stabilizing Term." Journal of Optimization Theory and Applications 120, no. 2 (February 2004): 275–303. http://dx.doi.org/10.1023/b:jota.0000015685.21638.8d.

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Wang, Dongqing, Tong Shan, and Rui Ding. "DATA FILTERING BASED STOCHASTIC GRADIENT ALGORITHMS FOR MULTIVARIABLE CARAR-LIKE SYSTEMS." Mathematical Modelling and Analysis 18, no. 3 (June 1, 2013): 374–85. http://dx.doi.org/10.3846/13926292.2013.804889.

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This paper considers identification problems for a multivariable controlled autoregressive system with autoregressive noises. A hierarchical generalized stochastic gradient algorithm and a filtering based hierarchical stochastic gradient algorithm are presented to estimate the parameter vectors and parameter matrix of such multivariable colored noise systems, by using the hierarchical identification principle. The simulation results show that the proposed hierarchical gradient estimation algorithms are effective.

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Torras-Llort, M., J. F. Soriano-García, R. Ferrer, and M. Moretó. "Effect of a lysine-enriched diet onl-lysine transport by the brush-border membrane of the chicken jejunum." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 274, no. 1 (January 1, 1998): R69—R75. http://dx.doi.org/10.1152/ajpregu.1998.274.1.r69.

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The influx ofl-lysine into apical vesicles from the chicken jejunum occurs through two systems, one with low Michaelis constant ( K m) and features of system b0,+ and the other with relatively high K m forl-lysine and with properties of system y+. In the present study the effect of a lysine-enriched diet (Lys, containing 68 g l-lysine/kg dietary protein, control animals 48 g/kg) onl-lysine uptake through both transport systems was investigated. Results show that 1) lysine enrichment had no effect on either body weight or the efficiency of food utilization. 2) In Lys-fed animals, the mediatedl-lysine influx was best fitted to the two-system model with y+and b0,+ activity. 3) In the presence of an Na+ gradient, totall-lysine uptake is significantly higher in Lys-fed animals than in control birds (about 40% increase). 4) Lys diet increases K mb0,+6-fold (KSCN gradient) and 12-fold (NaSCN gradient) and maximum velocity ( V max) by 6- and 20-fold, respectively. The effects of Lys enrichment on the y+-like system are only observed on the V max and in the presence of a Na+ gradient (30% increase). 5) Na+ is involved in the activation of the transport process in the Lys-fed chickens, but there is no correlation between external Na+concentration and l-lysine influx. In conclusion, both b0,+- and y+-like transport systems are upregulated by dietary lysine but with different kinetic profiles; the high-capacity y+-like carrier shows a V maxincrease without changes in K m, whereas the low-capacity b0,+-like system shows an increase in V max as well as in the K m.

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Tran, Minh-Phuong, and Thanh-Nhan Nguyen. "Asymptotic Behavior of Bounded Solutions to a First Order Gradient-like System." Journal of Advanced Engineering and Computation 3, no. 1 (March 31, 2019): 312. http://dx.doi.org/10.25073/jaec.201931.227.

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In this paper, we prove the long time behavior of bounded solutions to a first order gradient-like system with low damping and perturbation terms. Our convergence results are obtained under some hypotheses of KurdykaLojasiewicz inequality and the angle and comparability condition.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

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Alvarez, F., H. Attouch, J. Bolte, and P. Redont. "A second-order gradient-like dissipative dynamical system with Hessian-driven damping." Journal de Mathématiques Pures et Appliquées 81, no. 8 (2002): 747–79. http://dx.doi.org/10.1016/s0021-7824(01)01253-3.

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Wu, F. Y., and F. Tong. "Gradient optimization p-norm-like constraint LMS algorithm for sparse system estimation." Signal Processing 93, no. 4 (April 2013): 967–71. http://dx.doi.org/10.1016/j.sigpro.2012.10.008.

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Smirnova, Vera B., Anton V. Proskurnikov, and Natalia V. Utina. "New results on cycle–slipping in pendulum–like systems." Cybernetics and Physics, Volume 8, 2019, Number 3 (November 30, 2019): 167–75. http://dx.doi.org/10.35470/2226-4116-2019-8-3-167-175.

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n this paper, we examine dynamics of multidimensional control systems obtained as feedback interconnections of stable linear blocks and periodic nonlinearities. The simplest of such systems is the model of mathematical pendulum (with viscous friction), so we call such systems pendulum-like. Other examples include, but are not limited to, coupled vibrating units, networks of oscillators, Josephson junction arrays and numerous synchronization circuits used in radio and telecommunication engineering. Typically, a pendulum-like system has infinite sequence of equilibria, and one of the central problems addressed in the theory of such systems is to find the conditions of “global stability”, or gradient-like behavior ensuring that every solution converges to one of the equilibria points. If a system is gradient-like, another problem arises, being the main concern of this paper: can we find the terminal equilibrium, given the initial condition of the system? It is well known that solutions do not converge, in general, to the nearest equilibrium; this phenomenon is known as cycle-slipping. For a pendulum, cycle-slipping corresponds to multiple rotations of the pendulum about its suspension point. In this paper, we estimate the number of slipped cycles for general pendulum-like systems by means of periodic Lyapunov functions and the Kalman-Yakubovich-Popov lemma.

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Singh, M., and R. K. Gupta. "On thermosolutal convection in presence of compressible fluid with fine dust." International Journal of Applied Mechanics and Engineering 19, no. 1 (February 1, 2014): 133–43. http://dx.doi.org/10.2478/ijame-2014-0010.

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Abstract A layer of a Rivlin-Ericksen elastico-viscous fluid heated and soluted from below in the presence of compressibility and suspended particles (fine dust) effect is considered. For stationary convection, the Rivlin- Ericksen, elastico-viscous fluid behaves like a Newtonian fluid. The oscillatory modes are introduced due to the presence of a stable solute gradient, suspended particles destabilize the system whereas the stable solute gradient has a stabilizing effect on the system and the effect of compressibility is to postpone the onset of thermosolutal convection. The stable solute gradient and compressibility postpone the onset of convection, whereas the suspended particles hasten the onset of convection. The stable solute gradient introduces oscillatory modes in the systems which were non-existent in its absence

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Tran, Phuong Minh, and Nhan Thanh Nguyen. "On the Convergence of Bounded Solutions of Non Homogeneous Gradient-like Systems." Journal of Advanced Engineering and Computation 1, no. 1 (June 8, 2017): 61. http://dx.doi.org/10.25073/jaec.201711.50.

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We study the long time behavior of the bounded solutions of non homogeneous gradient-like system which admits a strict Lyapunov function. More precisely, we show that any bounded solution of the gradient-like system converges to an accumulation point as time goes to infinity under some mild hypotheses. As in homogeneous case, the key assumptions for this system are also the angle condition and the Kurdyka-Lojasiewicz inequality. The convergence result will be proved under a L1 -condition of the perturbation term. Moreover, if the Lyapunov function satisfies a Lojasiewicz inequality then the rate of convergence will be even obtained.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Prasad, Binod Kumar, and Om Prakash Dubey. "Off-line English character recognition system." International Journal of Students' Research in Technology & Management 10, no. 3 (July 25, 2022): 06–11. http://dx.doi.org/10.18510/ijsrtm.2022.1032.

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Purpose of the study: This paper aims to recognition of handwritten English characters in offline mode. It develops an efficient character recognition model avoiding large variations in handwriting by using better feature extraction techniques. Methodology: The samples of characters are preprocessed by applying a sequence of operations in succession like Thickening, Thresholding, Filtering, and Thinning. Efficient features like Gradient features and Zonal features have been extracted. Gradient features are helpful to find out stroke information in the character whereas Zonal features detail out local information in a more précised way. Hidden Markov Model is the classifier. Main Findings: Classification has been started with only a 5-state HMM model but it is observed that as the number of states of HMM model is increased, the corresponding recognition rate is also improved. Finally, with the 36 states HMM model we have got the expected result. This produces an overall average recognition rate of 92.6%. For the letters ‘A’ and ‘W’, the recognition rate is found to be very low, because of a lot of variations in writing style of these letters. Applications of this study: HMM is a flexible tool which is capable of absorbing variations in character images. The future works will be concentrated on improvement of recognition rate of such letters by finding some demarcating features and post processing. The proposed method can be well used in Natural Language Processing, Signature verification, Face recognition like other Pattern Recognition applications. Novelty/Originality of this study: Preprocessing uses Median filter which removes all stray marks in samples and hence avoids any possibility of false pixels. The combination of Gradient features and Zonal features leads to a recognition accuracy of 92.6% which may be used by researchers in any other domains for the purpose of classification. The application of HMM will motivate the readers to use it for better results of classification.

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FORSBERG, NEIL E., ANDRIS J. KANEPS, and THOMAS W. RIEBOLD. "NEUTRAL AMINO ACID TRANSPORT IN SHEEP EXTERNAL INTERCOSTAL MUSCLE." Canadian Journal of Animal Science 68, no. 2 (June 1, 1988): 409–17. http://dx.doi.org/10.4141/cjas88-046.

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The transport of two amino acid anologs, aminoisobutyric acid (AIB) and N-methylaminoisobutyric acid (MeAIB), was studied in external intercostal muscle bundles taken from 12 wether lambs to examine the significance of these transport systems in sheep muscle tissue. Competition for transport between AIB and other amino acids was evaluated to determine proportions of AIB transported on individual carriers. Rates of AIB transport into EIC muscle in relation to previous liveweight gains of lambs and animal weights were also examined. Aminoisobutyric acid was concentrated to approximately fourfold extracellular AIB concentrations via a sodium gradient-dependent process within 2 h of incubation. However, MeAIB was not concentrated by this tissue. Kinetic analyses of MeAIB transport indicated that its entry was entirely nonsaturable. Since MeAIB is a model substrate for transport system A (Na gradient-dependent, hormone and substrate concentration regulated) and since AIB may be transported by both systems A and ASC (Na gradient-dependent, hormone and substrate concentration insensitive), the active transport of AIB is attributed primarily to a system ASC-like agency. Kinetic analyses of the Na gradient-dependent transport of AIB revealed Jmax and Kt values of 2.48 ± 0.35 μmoles g tissue−1 30 min−1 and 11.4 ± 4.2 mM, respectively. Competition studies between AIB and other analogs provided further support for the existence of an ASC-like transport agency and the possible absence of or a repressed system A. A significant relationship between previous liveweight gain and amino acid transport was not detected; however, AIB transport in muscle taken from more mature animals was significantly lower than in muscle taken from younger animals. Key words: Sheep, muscle, amino acid transport, system A, system ASC

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Duan, Jiaqi, Minghan Li, Wenzhi Wang, Ziming Huang, Hong Jiang, and Yanping Ma. "Preparation and Performance of Multilayer Si-B-C-N/Diamond-like Carbon Gradient Films." Materials 16, no. 4 (February 16, 2023): 1665. http://dx.doi.org/10.3390/ma16041665.

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Si-B-C-N/diamond-like carbon (DLC) gradient films with different layers were prepared on a glass substrate by radio frequency magnetron sputtering, and the structure and surface morphology of the resulting films were analyzed by scanning electron microscopy, Raman spectrometry, and X-ray photoelectron spectroscopy. The mechanical and optical properties of the films were studied using a multifunctional material mechanical testing system, UV-Vis spectrophotometer, and micro-Vickers hardness tester. The gradient structure promotes the formation of sp3 bonds and improves the hardness and optical transmittance of the resulting films. Among the prepared films, the single-layer Si-B-C-N/DLC gradient film shows the highest optical transmittance (97%). Film–substrate adherence is strengthened by the introduction of the gradient structure. The best adhesion was obtained with a double-layer Si-B-C-N/DLC gradient film. Suitable anti-wear properties were exhibited in both dry (0.18) and wet (0.07) conditions. In this paper, evaluation of the microstructural, optical, and mechanical properties of the films could provide new insights into improvements in the bonding force of glass-based DLC films and enrich the experimental data of DLC multilayer film systems.

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Gazzola, Silvia, and Paolo Novati. "Some transpose-free CG-like solvers for nonsymmetric ill-posed problems." Journal of Numerical Mathematics 28, no. 1 (March 26, 2020): 15–32. http://dx.doi.org/10.1515/jnma-2018-0107.

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AbstractThis paper introduces and analyzes an original class of Krylov subspace methods that provide an efficient alternative to many well-known conjugate-gradient-like (CG-like) Krylov solvers for square nonsymmetric linear systems arising from discretizations of inverse ill-posed problems. The main idea underlying the new methods is to consider some rank-deficient approximations of the transpose of the system matrix, obtained by running the (transpose-free) Arnoldi algorithm, and then apply some Krylov solvers to a formally right-preconditioned system of equations. Theoretical insight is given, and many numerical tests show that the new solvers outperform classical Arnoldi-based or CG-like methods in a variety of situations.

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OHMORI, CHIHIRO, and J. SCOTT BERG. "UPGRADING EMMA TO USE LOW-FREQUENCY RF CAVITIES." International Journal of Modern Physics A 26, no. 10n11 (April 30, 2011): 1822–32. http://dx.doi.org/10.1142/s0217751x11053213.

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EMMA is an experiment to study beam dynamics in fixed field alternating gradient accelerators (FFAGs). It accelerates the beam in about 10 turns using 1.3 GHz cavities in a mode like that used for muon accelerators. Many applications of FFAGs prefer to have slower acceleration, typically thousands of turns. To do so in EMMA would require the RF system to be replaced with a low-frequency, high-gradient system. This paper describes the motivation for studying slow acceleration in EMMA and the required parameters for an RF system to do that. It then describes the technology needed for the RF system.

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M R, Dr Pooja, Meghana M, Harshith Bhaskar, Anusha Hulatti, Praful Koppalkar, and Bopanna M J. "Sign Language Recognition System." Indian Journal of Software Engineering and Project Management 1, no. 3 (January 10, 2022): 1–3. http://dx.doi.org/10.54105/ijsepm.c9011.011322.

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We witness many people who face disabilities like being deaf, dumb, blind etc. They face a lot of challenges and difficulties trying to interact and communicate with others. This paper presents a new technique by providing a virtual solution without making use of any sensors. Histogram Oriented Gradient (HOG) along with Artificial Neural Network (ANN) have been implemented. The user makes use of web camera, which takes input from the user and processes the image of different gestures. The algorithm recognizes the image and identifies the pending voice input. This paper explains two way means of communication between impaired and normal people which implies that the proposed ideology can convert sign language to text and voice.

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M R, Dr Pooja, Meghana M, Harshith Bhaskar, Anusha Hulatti, Praful Koppalkar, and Bopanna M J. "Sign Language Recognition System." Indian Journal of Software Engineering and Project Management 1, no. 3 (January 10, 2022): 1–3. http://dx.doi.org/10.35940/ijsepm.c9011.011322.

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We witness many people who face disabilities like being deaf, dumb, blind etc. They face a lot of challenges and difficulties trying to interact and communicate with others. This paper presents a new technique by providing a virtual solution without making use of any sensors. Histogram Oriented Gradient (HOG) along with Artificial Neural Network (ANN) have been implemented. The user makes use of web camera, which takes input from the user and processes the image of different gestures. The algorithm recognizes the image and identifies the pending voice input. This paper explains two way means of communication between impaired and normal people which implies that the proposed ideology can convert sign language to text and voice.

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Glimm, Tilmann, Jianying Zhang, and Yun-Qiu Shen. "Stability of Turing-Type Patterns in a Reaction–Diffusion System with an External Gradient." International Journal of Bifurcation and Chaos 27, no. 01 (January 2017): 1750003. http://dx.doi.org/10.1142/s0218127417500031.

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We investigate the stability of Turing-type patterns in one spatial dimension in a system of reaction–diffusion equations with a term depending linearly on the spatial position. The system is a generic model of two interacting chemical species where production rates are dependent on a linear external gradient. This is motivated by mathematical models in developmental biology. In a previous paper, we found analytic approximations of Turing-like steady state patterns. In the present article, we derive conditions for the stability of these patterns and show bifurcation diagrams in two small parameters related to the slope of the external gradient and the ratio of the diffusion coefficients.

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Dong, Ruili, Yonghong Tan, Hui Chen, and Yangqiu Xie. "Nonsmooth Recursive Identification of Sandwich Systems with Backlash-Like Hysteresis." Journal of Applied Mathematics 2012 (2012): 1–16. http://dx.doi.org/10.1155/2012/457603.

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A recursive gradient identification algorithm based on the bundle method for sandwich systems with backlash-like hysteresis is presented in this paper. In this method, a dynamic parameter estimation scheme based on a subgradient is developed to handle the nonsmooth problem caused by the backlash embedded in the system. The search direction of the algorithm is estimated based on the so-called bundle method. Then, the convergence of the algorithm is discussed. After that, simulation results on a nonsmooth sandwich system are presented to validate the proposed estimation algorithm. Finally, the application of the proposed method to anX-Ymoving positioning stage is illustrated.

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Pintanel, Pol, Miguel Tejedo, Sofia Salinas‐Ivanenko, Phillip Jervis, and Andrés Merino‐Viteri. "Predators like it hot: Thermal mismatch in a predator–prey system across an elevational tropical gradient." Journal of Animal Ecology 90, no. 8 (May 31, 2021): 1985–95. http://dx.doi.org/10.1111/1365-2656.13516.

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Ganapathy, V., and F. H. Leibach. "Carrier-mediated reabsorption of small peptides in renal proximal tubule." American Journal of Physiology-Renal Physiology 251, no. 6 (December 1, 1986): F945—F953. http://dx.doi.org/10.1152/ajprenal.1986.251.6.f945.

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Recent studies with a variety of tissue preparations in the kidney have demonstrated that proximal tubular cells possess specific transport systems for di- and tripeptides. In contrast to the well-known amino acid and glucose transport systems, active transport of peptides in these cells is energized by an H+ gradient rather than an Na+ gradient. Like amino acid-Na+ and glucose-Na+ cotransport systems, peptide-H+ cotransport is electrogenic and hence a membrane potential also contributes to the uphill transport of peptides in these cells. Di- and tripeptides that are filtered at the glomerulus, as well as those that are produced in the tubular lumen from larger polypeptides by the action of brush-border peptidases, serve as substrates for the renal peptide transport system under physiological conditions. The H+ gradient that is necessary to drive renal peptide transport is generated in vivo by concerted action of the basolateral Na+-K+-ATPase and the brush-border Na+-H+ exchanger. The peptidases and the peptide transport system in the renal brush-border membrane play a significant role in the reabsorption of peptide-bound amino acids as well as in the regulation of plasma levels of small peptides.

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Limpiyakorn, T., Y. Shinohara, F. Kurisu, and O. Yagi. "Distribution of ammonia-oxidizing bacteria in sewage activated sludge: analysis based on 16S rDNA sequence." Water Science and Technology 50, no. 8 (October 1, 2004): 9–14. http://dx.doi.org/10.2166/wst.2004.0475.

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This study carried out analysis of ammonia-oxidizing bacteria (AOB) communities in 12 sewage activated sludge systems standing in eight sewage treatment plants located in Tokyo. The systems were different in the treatment process configuration: anaerobic/anoxic/aerobic (A2O), anaerobic/aerobic (AO), and conventional activated sludge (AS) processes. AOB communities were analyzed by sequences of 16S rDNA amplicons, which were separated by denaturing gradient gel eletrophoresis (DGGE) after specific polymerase chain reaction (PCR) amplification. The results demonstrated that low ammonium concentrations in the influents of the 12 sewage activated sludge systems resulted in the dominance of Nitrosomonas oligotropha-like sequences. Further, Nitrosomonas europaea- and Nitrosomonas cryotolerans-like sequences were recovered from only one A2O system of which the influent contained higher ammonium and chloride concentrations than those of other systems. Nitrosomonas communis-like sequences were found in every A2O and AO system, but mostly not found in every AS system. In summary, influent characteristics and treatment process configuration affected the AOB communities in the 12 sewage activated sludge systems.

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Alonso, S., A. Portela, and C. Ramis. "First considerations on the structure and development of the Iberian thermal low-pressure system." Annales Geophysicae 12, no. 5 (April 30, 1994): 457–68. http://dx.doi.org/10.1007/s00585-994-0457-x.

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Abstract. During the summer a thermal low-pressure system is locked over the Iberian Peninsula. We present a first analysis of such a system using the potential vorticity approach. Our results show that its main characteristic is the existence of a negative potential vorticity (PV) dome and a funnel-like structure for potential temperature, both located at the centre of the low. The build-up and evolution of this PV dome can be understood in terms of the dot products of the absolute vorticity and the gradient of diabetic heating vectors and the curl of the friction forces and the gradient of potential temperature vectors. The inhibition of the Algerian Mediterranean cyclogenesis during the summer seems to bear some relation to the existence of this kind of low-pressure disturbance over the Iberian Peninsula.

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Srivastava, Praveen Ranjan, and Prajwal Eachempati. "Intelligent Employee Retention System for Attrition Rate Analysis and Churn Prediction." Journal of Global Information Management 29, no. 6 (November 2021): 1–29. http://dx.doi.org/10.4018/jgim.20211101.oa23.

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The paper aims to examine the factors that influence employee attrition rate using the employee records dataset from kaggle.com. It also aims to establish the predictive power of Deep Learning for employee churn prediction over ensemble machine learning techniques like Random Forest and Gradient Boosting on real-time employee data from a mid-sized Fast-Moving Consumer Goods (FMCG) company. The results are further validated through a regression model and also by a multi-criteria Fuzzy Analytical Hierarchy Process (AHP) model which takes into account the relative variable importance and computes weights. The empirical results of the machine learning models indicate that Deep Neural Networks (91.2% accuracy) are a better predictor of churn than Random Forest and Gradient Boosting Algorithm (82.3% and 85.2% respectively). These findings provide useful insights for human resource (HR) managers in an organizational workplace context. The model when recalibrated by the human resource team of organizations helps in better incentivization and employee retention.

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Kumar, P., and H. Mohan. "Thermosolutal Instability in Compressible Viscoelastic Dusty Fluid through Porous Medium." International Journal of Applied Mechanics and Engineering 18, no. 1 (March 1, 2013): 99–112. http://dx.doi.org/10.2478/ijame-2013-0007.

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Thermosolutal instability in a compressible Walters B’ viscoelastic fluid with suspended particles through a porous medium is considered. Following the linearized stability theory and normal mode analysis, the dispersion relation is obtained. For stationary convection, the Walters B’ viscoelastic fluid behaves like a Newtonian fluid and it is found that suspended particles and medium permeability have a destabilizing effect whereas the stable solute gradient and compressibility have a stabilizing effect on the system. Graphs have been plotted by giving numerical values to the parameters to depict the stability characteristics. The stable solute gradient and viscoelasticity are found to introduce oscillatory modes in the system which are non-existent in their absence.

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Lacalli, T. C., D. A. Wilkinson, and L. G. Harrison. "Theoretical aspects of stripe formation in relation to Drosophila segmentation." Development 104, no. 1 (September 1, 1988): 105–13. http://dx.doi.org/10.1242/dev.104.1.105.

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Many aspects of Drosophila segmentation can be discussed in one-dimensional terms as a linear pattern of repeated elements or cell states. But the initial metameric pattern seen in the expression of pair-rule genes is fully two-dimensional, i.e. a pattern of stripes. Several lines of evidence suggest a kinetic mechanism acting globally during the syncytial blastoderm stage may be responsible for generating this pattern. The requirement that the mechanism should produce stripes, not spots or some other periodic pattern, imposes preconditions on this act, namely (1) sharp anterior and posterior boundaries that delimit the pattern-forming region, and (2) an axial asymmetrizing influence in the form of an anteroposterior gradient. Models for Drosophila segmentation generally rely on the gradient to provide positional information in the form of concentration thresholds that cue downstream elements of a hierarchical control system. This imposes restrictions on how such models cope with experimental disturbances to the gradient. A shallower gradient, for example, means fewer pattern elements. This need not be the case if the gradient acts through a kinetic mechanism like reaction-diffusion that involves the whole system. It is then the overall direction of the gradient that is important rather than specific concentration values.(ABSTRACT TRUNCATED AT 250 WORDS)

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Kalenkov, Mikhail S., and Andrei D. Zaikin. "Long-range Josephson effect controlled by temperature gradient and circuit topology." European Physical Journal Special Topics 230, no. 4 (April 21, 2021): 813–20. http://dx.doi.org/10.1140/epjs/s11734-021-00065-5.

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AbstractWe demonstrate that the supercurrent can be strongly enhanced in cross-like superconducting hybrid nanostructures (X-junctions) exposed to a temperature gradient. At temperatures T exceeding the Thouless energy of our X-junction, the Josephson current decays algebraically with increasing T and can be further enhanced by a proper choice of the circuit topology. At large values of the temperature gradient, the non-equilibrium contribution to the supercurrent may become as large as the equilibrium one at low T. We also predict a variety of transitions between 0- and $$\pi $$ π -junction states controlled by the temperature gradient as well as by the system geometry. Our predictions can be directly verified in modern experiments.

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Hernández-Solano, Yadira, and Miguel Atencia. "Numerical Methods That Preserve a Lyapunov Function for Ordinary Differential Equations." Mathematics 11, no. 1 (December 25, 2022): 71. http://dx.doi.org/10.3390/math11010071.

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The paper studies numerical methods that preserve a Lyapunov function of a dynamical system, i.e., numerical approximations whose energy decreases, just like in the original differential equation. With this aim, a discrete gradient method is implemented for the numerical integration of a system of ordinary differential equations. In principle, this procedure yields first-order methods, but the analysis paves the way for the design of higher-order methods. As a case in point, the proposed method is applied to the Duffing equation without external forcing, considering that, in this case, preserving the Lyapunov function is more important than the accuracy of particular trajectories. Results are validated by means of numerical experiments, where the discrete gradient method is compared to standard Runge–Kutta methods. As predicted by the theory, discrete gradient methods preserve the Lyapunov function, whereas conventional methods fail to do so, since either periodic solutions appear or the energy does not decrease. Moreover, the discrete gradient method outperforms conventional schemes when these do preserve the Lyapunov function, in terms of computational cost; thus, the proposed method is promising.

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Joy, Reji, and Hemalatha S. "A Gradient Based Approach for Fingerprint Image Segmentation using Morphological Operators." International Journal of Engineering & Technology 7, no. 4 (September 20, 2018): 2453. http://dx.doi.org/10.14419/ijet.v7i4.16244.

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The advancement of science and technology has made the reliable individual recognition and identification systems to become very popular. From the various biometric characteristics, fingerprint is one of the popular method because of its easiness and not much effort is required to acquire fingerprint. First step for an Automated Fingerprint Identification System (AFIS) is the segmentation of fingerprint from the acquired image. During fingerprint segmentation process the input image is decomposed into foreground and background areas. The foreground area contains information that are needed in the automatic fingerprint recognition systems. However, the background is a noisy region that contributes to the extraction of false features. So in an AFIS, fingerprint image segmentation plays an important role in carefully separating ridge like part (foreground) from noisy background. Gradient based method is commonly used for segmentation process. Since gradient estimation is erroneous in noisy images, the study proposes a combination of gradient mask and morphological operations to segment fingerprint foreground effectively. The results obtained prove that the new method is suited for fingerprint segmentation.

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Jr., J. L. Wyatt,, and I. M. Elfadel. "Time-Domain Solutions of Oja's Equations." Neural Computation 7, no. 5 (September 1995): 915–22. http://dx.doi.org/10.1162/neco.1995.7.5.915.

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Oja's equations describe a well-studied system for unsupervised Hebbian learning of principal components. This paper derives the explicit time-domain solution of Oja's equations for the single-neuron case. It also shows that, under a linear change of coordinates, these equations are a gradient system in the general multi-neuron case. This latter result leads to a new Lyapunov-like function for Oja's equations.

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Akki, Rajesh, Munagala Gayatri Ramya, K. Navyasri, and Singaram Kathirvel. "Formulation and Evaluation of Mupirocin Nimosomal Gel for Topical Drug Delivery System." International Journal of PharmTech Research 13, no. 2 (2020): 7–17. http://dx.doi.org/10.20902/ijptr.2019.130202.

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The present study was to formulate and evaluate the mupirocin niosomal gel using surfactants span 80 & tween 80 for the preparation of niosomes. Mupirocin entrapped niosomes were prepared by ether injection method and transmembrane pH gradient drug uptake process. Niosomes were prepared by altering the ratios between various non-ionic surfactants (span 80 & tween 80) whereas the concentration of cholesterol and drug was kept constant. The prepared niosomes were characterized for size, shape, entrapment efficiency, invitro drug release studies. The highest entrapment efficiency(99.17%) and drug release (96.14%) was obtained for tween 80 (1:5:5) prepared by transmembrane pH gradient method. The best formulation among the two techniques was selected for incorporated into gel formulation. The prepared niosomal gel and plain gel were subjected to evaluation studies like drug content, invitro drug diffusion studies. The studies were demonstrated that niosomal gel was shown beter pharmacological activity than the conventional mupirocin gel. Based on the results it was concluded that niosomal preparations offers more advantageous than the conventional preparations.

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Selwal, Arvind, and Ifrah Raoof. "A multi-layer perceptron based improved thyroid disease prediction system." Indonesian Journal of Electrical Engineering and Computer Science 17, no. 1 (January 1, 2020): 524. http://dx.doi.org/10.11591/ijeecs.v17.i1.pp524-532.

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<p>A challenging task for the medical science is to achieve the accurate diagnosis of diseases prior to its treatment. A pattern classifier is used for solving complex and non-separable computing problems in different fields like biochemical analysis, image processing and chemical analysis etc .The accuracy for thyroid diagnosis system may be improved by considering few additional attributes like heredity ,age, anti-bodies etc. In this paper, a thyroid disease prediction system is developed using multilayer perceptron (MLP). The proposed system uses 7–11 attributes of individuals to classify them in normal, hyperthyroid and hypothyroid classes. The proposed model uses gradient descent backpropogation algorithm for training the multilayer perceptron using dataset of 120 subjects. The thyroid prediction system promises excellent overall accuracy of ~100% for 11 attributes. However, the system results in a lower accuracy of 66.7% using 11 attributes and 70% using 7 attributes with 30 subjects.</p>

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Cantiello, H. F., J. A. Scott, and C. A. Rabito. "Conductive Na+ transport in an epithelial cell line (LLC-PK1) with characteristics of proximal tubular cells." American Journal of Physiology-Renal Physiology 252, no. 4 (April 1, 1987): F590—F597. http://dx.doi.org/10.1152/ajprenal.1987.252.4.f590.

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Na+ influx and efflux from confluent monolayers of an epithelial cell line with multiple differentiated characteristics of the straight segment of the renal proximal tubule were studied in the presence and absence of a pH gradient. The results show that Na+ influx in the absence of a pH gradient is inhibited by amiloride as well as by complete replacement of Cl- by an impermeable anion, such as isethionate. Dissipation of cell membrane potential by increasing the potassium concentration of the extracellular medium in the presence of valinomycin also inhibited Na+ influx, whereas sodium influx induced by an H+ gradient was not affected. Inhibition of Na+ influx by different maneuvers produced hyperpolarization of the plasma cell membrane, as would be expected if the sodium movement involved net displacement of charges. Calcium and other divalent and trivalent cations also inhibited Na+ influx measured in the absence of an H+ gradient. Na+ influx induced by a pH gradient, however, was not affected. Like the Na+-H+-exchange system, the conductive Na+ pathway is localized in the apical membrane of the epithelial cells. From these results, we conclude that at least a fraction of transepithelial Na+ transport in LLC-PK1 monolayers occurs through a simple rheogenic transport system.

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Chen, Xiaopeng, and Jinqiao Duan. "State space decomposition for non-autonomous dynamical systems." Proceedings of the Royal Society of Edinburgh: Section A Mathematics 141, no. 5 (September 26, 2011): 957–74. http://dx.doi.org/10.1017/s0308210510000661.

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The decomposition of state spaces into dynamically different components is helpful for understanding dynamics of complex systems. A Conley-type decomposition theorem is proved for non-autonomous dynamical systems defined on a non-compact but separable state space. Specifically, the state space can be decomposed into a chain-recurrent part and a gradient-like part. This result applies to both non-autonomous ordinary differential equations on a Euclidean space (which is only locally compact), and to non-autonomous partial differential equations on an infinite-dimensional function space (which is not even locally compact). This decomposition result is demonstrated by discussing a few concrete examples, such as the Lorenz system and the Navier–Stokes system, under time-dependent forcing.

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Valani, Rahil N. "Lorenz-like systems emerging from an integro-differential trajectory equation of a one-dimensional wave–particle entity." Chaos: An Interdisciplinary Journal of Nonlinear Science 32, no. 2 (February 2022): 023129. http://dx.doi.org/10.1063/5.0076162.

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Vertically vibrating a liquid bath can give rise to a self-propelled wave–particle entity on its free surface. The horizontal walking dynamics of this wave–particle entity can be described adequately by an integro-differential trajectory equation. By transforming this integro-differential equation of motion for a one-dimensional wave–particle entity into a system of ordinary differential equations (ODEs), we show the emergence of Lorenz-like dynamical systems for various spatial wave forms of the entity. Specifically, we present and give examples of Lorenz-like dynamical systems that emerge when the wave form gradient is (i) a solution of a linear homogeneous constant coefficient ODE, (ii) a polynomial, and (iii) a periodic function. Understanding the dynamics of the wave–particle entity in terms of Lorenz-like systems may prove to be useful in rationalizing emergent statistical behavior from underlying chaotic dynamics in hydrodynamic quantum analogs of walking droplets. Moreover, the results presented here provide an alternative physical interpretation of various Lorenz-like dynamical systems in terms of the walking dynamics of a wave–particle entity.

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Xu, Ting Zhong, Hebibul Rahman, Li Bo Zhao, Yu Long Zhao, and Zhuang De Jiang. "A Novel Method to Order Nanowire Based on Macrofludic System." Advanced Materials Research 1015 (August 2014): 32–36. http://dx.doi.org/10.4028/www.scientific.net/amr.1015.32.

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The rheology of nanowires (NWs) and nanotubes (NTs) in shear flow has been analyzed by molecular dynamics (MD) simulation and macrofludic simulation. A method based on macrofludic system for aligning NWs and NTs is demonstrated. In this method, vortex is generated near the surface of a plane by using a mushroom like turnplate. Then a uniform velocity gradient was generated on the surface of the plane. Through controlling the rotational speed of the turnplate, the rheology of NWs and NTs in suspension can be easily controlled. So it provides a more effective and economical method for the alignment of NWs and NTs, as well as forming the anisotropy NWs and NTs bulk material.

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Lind, Kara R., Oskar Siemianowski, Bin Yuan, Tom Sizmur, Hannah VanEvery, Souvik Banerjee, and Ludovico Cademartiri. "Evidence for root adaptation to a spatially discontinuous water availability in the absence of external water potential gradients." Proceedings of the National Academy of Sciences 118, no. 1 (December 21, 2020): e2012892118. http://dx.doi.org/10.1073/pnas.2012892118.

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We hereby show that root systems adapt to a spatially discontinuous pattern of water availability even when the gradients of water potential across them are vanishingly small. A paper microfluidic approach allowed us to expose the entire root system ofBrassica rapaplants to a square array of water sources, separated by dry areas. Gradients in the concentration of water vapor across the root system were as small as 10−4⋅mM⋅m−1(∼4 orders of magnitude smaller than in conventional hydrotropism assays). Despite such minuscule gradients (which greatly limit the possible influence of the well-understood gradient-driven hydrotropic response), our results show that 1) individual roots as well as the root system as a whole adapt to the pattern of water availability to maximize access to water, and that 2) this adaptation increases as water sources become more rare. These results suggest that either plant roots are more sensitive to water gradients than humanmade water sensors by 3–5 orders of magnitude, or they might have developed, like other organisms, mechanisms for water foraging that allow them to find water in the absence of an external gradient in water potential.

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Voloshina, Elena N., and Yuriy S. Dedkov. "Electronic and Magnetic Properties of the Graphene/Eu/Ni(111) Hybrid System." Zeitschrift für Naturforschung A 69, no. 7 (July 1, 2014): 297–302. http://dx.doi.org/10.5560/zna.2014-0012.

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The electronic and magnetic properties of the graphene/Eu/Ni(111) intercalation-like system are studied in the framework of the general gradient approximation with the effective Coulomb potential (GGA+U) and dispersive interactions taken into account. Intercalation of monoatomic europium layer underneath graphene on Ni(111) leads to the drastic changes of the electronic structure of graphene compared to free-standing graphene as well as graphene/Ni(111). The strong influence of the spin-polarized europium 4 f states, crossing the graphene-derived π states, on magnetic properties of graphene and on spin-filtering properties of the graphene/Eu/Ni(111) trilayer is discussed.

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Chergui, L. "Convergence of Global and Bounded Solutions of a Second Order Gradient like System with Nonlinear Dissipation and Analytic Nonlinearity." Journal of Dynamics and Differential Equations 20, no. 3 (December 15, 2007): 643–52. http://dx.doi.org/10.1007/s10884-007-9099-5.

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Conceição, Marcos Reinan Assis, Luis Felipe Ferreira de Mendonça, Carlos Alessandre Domingos Lentini, André Telles da Cunha Lima, José Marques Lopes, Rodrigo Nogueira de Vasconcelos, Mainara Biazati Gouveia, and Milton José Porsani. "SAR Oil Spill Detection System through Random Forest Classifiers." Remote Sensing 13, no. 11 (May 22, 2021): 2044. http://dx.doi.org/10.3390/rs13112044.

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A set of open-source routines capable of identifying possible oil-like spills based on two random forest classifiers were developed and tested with a Sentinel-1 SAR image dataset. The first random forest model is an ocean SAR image classifier where the labeling inputs were oil spills, biological films, rain cells, low wind regions, clean sea surface, ships, and terrain. The second one was a SAR image oil detector named “Radar Image Oil Spill Seeker (RIOSS)”, which classified oil-like targets. An optimized feature space to serve as input to such classification models, both in terms of variance and computational efficiency, was developed. It involved an extensive search from 42 image attribute definitions based on their correlations and classifier-based importance estimative. This number included statistics, shape, fractal geometry, texture, and gradient-based attributes. Mixed adaptive thresholding was performed to calculate some of the features studied, returning consistent dark spot segmentation results. The selected attributes were also related to the imaged phenomena’s physical aspects. This process helped us apply the attributes to a random forest, increasing our algorithm’s accuracy up to 90% and its ability to generate even more reliable results.

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Wei, Yan, Wei Jiang, Ahmed Rahmani, and Qiang Zhan. "Motion Planning for a Humanoid Mobile Manipulator System." International Journal of Humanoid Robotics 16, no. 02 (April 2019): 1950006. http://dx.doi.org/10.1142/s0219843619500063.

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A high redundant non-holonomic humanoid mobile dual-arm manipulator system (MDAMS) is presented in this paper, where the motion planning to realize “human-like” autonomous navigation and manipulation tasks is studied. First, an improved MaxiMin NSGA-II algorithm, which optimizes five objective functions to solve the problems of singularity, redundancy and coupling between mobile base and manipulator simultaneously, is proposed to design the optimal pose to manipulate the target object. Then, in order to link the initial pose and that optimal pose, an off-line motion planning algorithm is designed. In detail, an efficient direct-connect bidirectional RRT and gradient descent algorithm is proposed to reduce the sampled nodes largely, and a geometric optimization method is proposed for path pruning. Besides, head forward behaviors are realized by calculating the reasonable orientations and assigning them to the mobile base to improve the quality of human-robot interaction. Third, the extension to online planning is done by introducing real-time sensing, collision-test and control cycles to update robotic motion in dynamic environments. Fourth, an EEs’ via-point-based multi-objective genetic algorithm (MOGA) is proposed to design the “human-like” via-poses by optimizing four objective functions. Finally, numerous simulations are presented to validate the effectiveness of proposed algorithms.

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Phan Bui, Khoi, Giang Nguyen Truong, and Dat Nguyen Ngoc. "GCTD3: Modeling of Bipedal Locomotion by Combination of TD3 Algorithms and Graph Convolutional Network." Applied Sciences 12, no. 6 (March 14, 2022): 2948. http://dx.doi.org/10.3390/app12062948.

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In recent years, there has been a lot of research using reinforcement learning algorithms to train 2-legged robots to move, but there are still many challenges. The authors propose the GCTD3 method, which takes the idea of using Graph Convolutional Networks to represent the kinematic link features of the robot, and combines this with the Twin-Delayed Deep Deterministic Policy Gradient algorithm to train the robot to move. Graph Convolutional Networks are very effective in graph-structured problems such as the connection of the joints of the human-like robots. The GCTD3 method shows better results on the motion trajectories of the bipedal robot joints compared with other reinforcement learning algorithms such as Twin-Delayed Deep Deterministic Policy Gradient, Deep Deterministic Policy Gradient and Soft Actor Critic. This research is implemented on a 2-legged robot model with six independent joint coordinates through the Robot Operating System and Gazebo simulator.

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Argáez, Carlos, Peter Giesl, and Sigurdur Freyr Hafstein. "Eigenpairs for the Analysis of Complete Lyapunov Functions." Complexity 2022 (August 8, 2022): 1–17. http://dx.doi.org/10.1155/2022/3160052.

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A complete Lyapunov function describes the qualitative behaviour of a dynamical system: the areas where the orbital derivative vanishes and where it is strictly negative characterise the chain recurrent set and the gradient-like flow, respectively. Moreover, its local maxima and minima show the stability properties of the connected components of the chain recurrent set. In this study, we use collocation with radial basis functions to numerically compute approximations to complete Lyapunov functions and then localise and analyse the stability properties of the connected components of the chain recurrent set using its gradient and Hessian. In particular, we improve the estimation of the chain recurrent set, and we determine the dimension and the stability properties of its connected components.

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Geraldson, C. M. "The Earth Box: A Containerized Gradient Concept." HortScience 31, no. 4 (August 1996): 593e—593. http://dx.doi.org/10.21273/hortsci.31.4.593e.

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The Earth Box, a completely enclosed system made of recycled plastic, is designed to provide a continuing source of water and nutrients to replace that as removed by the crop. Nutrients move by gradient from a surface source to the root; water moves to the root by seepage upward from a water reservoir. The Box holds 2.3 cubic feet of media (soil or potting mix) supported on an aeration screen 0.5 inch above a water reservoir that holds 2.3 gallons. The total concept is designed to synchronize the nutrient–water input with removal, thus, providing an undiminishing nutritional stability in the soil solution. Two tomato plants per box have produced 30 to 50 pounds of fruit with a quality that reflects the continuing optimal nutrition. Other vegetable crops, strawberries, and flowers have been grown in the Earth Box with similar results. Nutritional stability in the conventional soil solution can deteriorate with variations in the soil-plant-season, which limits productivity. Whereas with the gradient, nutritional stability is constant regardless of the soil-plant-season or whether grown in the field or a container. The gradient procedure is not conventional or hydroponic; hydroponic cultures are nutritionally stable to begin with, but like conventional procedure, that stability is vulnerable. The gradient concept, whether it be in a container or in the field, has the potential to become a globally sustainable production system—minimal water, minimal pollution, minimal management with a maximum productivity. The Earth Box is primarily for the home gardener but the feasibility as a commercial edition is now being evaluated.

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Fan, Leia, and Eric Lee. "Diffusiophoresis of a highly charged conducting fluid droplet." Physics of Fluids 34, no. 6 (June 2022): 062013. http://dx.doi.org/10.1063/5.0098144.

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Diffusiophoresis of a perfectly conducting droplet-like liquid metal in electrolyte solutions is investigated theoretically, focusing on the chemiphoresis component, the very heart of diffusiophoresis, where the droplet motion is induced solely by the chemical gradient. The resulting electrokinetic equations are solved with a pseudo-spectral method based on Chebyshev polynomials. For the isothermal electrokinetic system of a perfectly conducting droplet considered here, there is no Marangoni effect, which is a motion-inducing effect due to the variation of interfacial tension along the droplet surface. No Maxwell traction is present as well. The droplet motion is full of hydrodynamic nature. It is found, among other things, that contrary to a dielectric droplet, a conducting droplet always moves up the chemical gradient toward the region with a higher concentration of ions in chemiphoresis. This implies that a perfectly conducting droplet like a gallium or its alloy droplet is superior to the commonly utilized dielectric droplet like a liposome in drug delivery in terms of self-guarding itself toward the desired destination of injured or infected area in the human body, as specific ionic chemicals are often released there. Optimum droplet size yielding the fastest migration rate is predicted.

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Spinelli, Sonia, Vanessa Cossu, Mario Passalacqua, Jacob B. Hansen, Lucrezia Guida, Mirko Magnone, Gianmario Sambuceti, Cecilia Marini, Laura Sturla, and Elena Zocchi. "The ABA/LANCL1/2 Hormone/Receptor System Controls Adipocyte Browning and Energy Expenditure." International Journal of Molecular Sciences 24, no. 4 (February 9, 2023): 3489. http://dx.doi.org/10.3390/ijms24043489.

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The abscisic acid (ABA)/LANC-like protein 1/2 (LANCL1/2) hormone/receptor system regulates glucose uptake and oxidation, mitochondrial respiration, and proton gradient dissipation in myocytes. Oral ABA increases glucose uptake and the transcription of adipocyte browning-related genes in rodent brown adipose tissue (BAT). The aim of this study was to investigate the role of the ABA/LANCL system in human white and brown adipocyte thermogenesis. Immortalized human white and brown preadipocytes, virally infected to overexpress or silence LANCL1/2, were differentiated in vitro with or without ABA, and transcriptional and metabolic targets critical for thermogenesis were explored. The overexpression of LANCL1/2 increases, and their combined silencing conversely reduces mitochondrial number, basal, and maximal respiration rates; proton gradient dissipation; and the transcription of uncoupling genes and of receptors for thyroid and adrenergic hormones, both in brown and in white adipocytes. The transcriptional enhancement of receptors for browning hormones also occurs in BAT from ABA-treated mice, lacking LANCL2 but overexpressing LANCL1. The signaling pathway downstream of the ABA/LANCL system includes AMPK, PGC-1α, Sirt1, and the transcription factor ERRα. The ABA/LANCL system controls human brown and “beige” adipocyte thermogenesis, acting upstream of a key signaling pathway regulating energy metabolism, mitochondrial function, and thermogenesis.

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KURIPLACH, J., and P. NOVÁK. "CALCULATION OF ELECTRIC FIELD GRADIENT AND CRYSTAL FIELD PARAMETERS IN RARE EARTH METALS." International Journal of Modern Physics B 07, no. 01n03 (January 1993): 609–13. http://dx.doi.org/10.1142/s0217979293001281.

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Electronic structure of hcp rare earth metals Gd, Tb, Dy, Lu and rare-earth-like Y is calculated using the spin-polarized version of the full potential LAPW method. The electric field gradient at the nucleus site is determined from the nonspherical part of the charge density. Crystal field parameters are obtained from the nonspherical components of self-consistent potential. The influence of the state of the 4f-system on the valence and semi-core electrons is investigated.

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Tao, Ran, Li Yang, Lu Peng, and Bin Li. "A Host-Based Intrusion Detection System Using Architectural Features to Improve Sophisticated Denial-of-Service Attack Detections." International Journal of Information Security and Privacy 4, no. 1 (January 2010): 18–31. http://dx.doi.org/10.4018/jisp.2010010102.

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Application features like port numbers are used by Network-based Intrusion Detection Systems (NIDSs) to detect attacks coming from networks. System calls and the operating system related information are used by Host-based Intrusion Detection Systems (HIDSs) to detect intrusions toward a host. However, the relationship between hardware architecture events and Denial-of-Service (DoS) attacks has not been well revealed. When increasingly sophisticated intrusions emerge, some attacks are able to bypass both the application and the operating system level feature monitors. Therefore, a more effective solution is required to enhance existing HIDSs. In this article, the authors identify the following hardware architecture features: Instruction Count, Cache Miss, Bus Traffic and integrate them into a HIDS framework based on a modern statistical Gradient Boosting Trees model. Through the integration of application, operating system and architecture level features, the proposed HIDS demonstrates a significant improvement of the detection rate in terms of sophisticated DoS intrusions.

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Liu, Wen, and Qing Sen Meng. "Studies on the Growth Mechanism of Onion-Like Fullerenes by Arc Discharge in Liquid Benzene." Advanced Materials Research 139-141 (October 2010): 47–50. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.47.

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The growth mechanism of Onion-like fullerenes (OLFs) synthesized by arc discharge in liquid benzene was discussed. HRTEM was employed to characterize the morphologies and microstructures of the products. Results showed that the typical OLFs were highly crystallized with uniform diameter of 10-30nm. The growth of OLFs depended on the appropriate temperature gradient and quenching zone provided by the bubbles. The aromatic debris could act as graphite fragments composed of hexagonal carbon rings. The reducing of dangling bonds on the edges of graphite fragments would lower the energy of the system, resulting in formation of a close-caged structure at suitable temperature gradient by the auto-curling of graphite fragments. Based on the impact of the innermost core shape, such as C60 shape, quasi-spherical or polyhedral hollow concentric OLFs was formed. Adding ferrocene, ferrocene directly influenced the morphology and yield of OLFs.

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Singh, Mahinder, and Rajesh Kumar Gupta. "Double-Diffusive Convection in Presence of Compressible Rivlin-Ericksen Fluid with Fine Dust." Journal of Fluids 2014 (February 4, 2014): 1–6. http://dx.doi.org/10.1155/2014/714150.

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An investigation is made on the effect of suspended particles (fine dust) on double-diffusive convection of a compressible Rivlin-Ericksen elastico-viscous fluid. The perturbation equations are analyzed in terms of normal modes after linearizing the relevant set of equations. A dispersion relation governing the effects of viscoelasticity, compressibility, stable solute gradient, and suspended particles is derived. For stationary convection, Rivlin-Ericksen fluid behaves like an ordinary Newtonian fluid due to the vanishing of the viscoelastic parameter. The stable solute gradient compressibility has a stabilizing effect on the system whereas suspended particles hasten the onset of thermosolutal instability. The Rayleigh numbers and the wave numbers of the associated disturbances for the onset of instability as stationary convection are obtained and the behaviour of various parameters on Rayleigh numbers has been depicted graphically. It has been observed that oscillatory modes are introduced due to the presence of viscoelasticity, suspended particles, and stable solute gradient which were not existing in the absence of these parameters.

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Journal articles on the topic 'Gradient-like system'

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