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1
Pucci, Paola. "I territori dell'auto elettrica: oltre il paradigma urbanocentrico." ARCHIVIO DI STUDI URBANI E REGIONALI, no. 128 (August 2020): 14–37. http://dx.doi.org/10.3280/asur2020-128003.
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L'articolo propone quattro scenari per restituire diverse intensità/modalità/velocità di diffusione dei veicoli elettrici nella Regione urbana milanese. Gli scenari, costruiti con un'analisi multicriteri che analizza le relazioni tra mobilità elettrica, pratiche di mobilità, caratteristiche socio-economiche e insediative, offrono elementi per definire politiche di incentivo e di regolazione per una transizione sostenibile ed equa verso una mobilità a basse emissioni di carbonio.
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Alkargole, Hazim M., Abbas S. Hassan, and Raoof T. Hussein. "Analyze and Evaluate the Performance Velocity Control in DC Motor." Radioelectronics. Nanosystems. Information Technologies 12, no. 4 (December 1, 2020): 507–16. http://dx.doi.org/10.17725/rensit.2020.12.507.
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A mathematical model of controlling the DC motor has been applied in this paper. There are many and different types of controllers have been used with purpose of analyzing and evaluating the performance of the of DC motor which are, Fuzzy Logic Controller (FLC), Linear Quadratic Regulator (LQR), Fuzzy Proportional Derivative (FPD) ,Proportional Integral Derivative (PID), Fuzzy Proportional Derivative with integral (FPD plus I) , and Fuzzy Proportional Integral (FPI) with membership functions of 3*3, 5*5, and 7*7 rule bases. The results show that the (FLC) controller with 5*5 rule base provides the best results among all the other controllers to design the DC motor controller.
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Randolph, Brian W., Edward P. Steinhauser, Andrew G. Heydinger, and Jiwan D. Gupta. "In Situ Test for Hydraulic Conductivity of Drainable Bases." Transportation Research Record: Journal of the Transportation Research Board 1519, no. 1 (January 1996): 36–40. http://dx.doi.org/10.1177/0361198196151900105.
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The development and use of an in situ hydraulic conductivity test for drainable bases under existing pavements is presented. Six highway test sections were constructed by the Ohio Department of Transportation to test the drainage characteristics and durability of four unbound and two stabilized base materials. The in situ test was then used to determine the field hydraulic conductivity of the highway test section bases. This test uses an approach to Darcy's law called the direct velocity technique. A standpipe is placed in a cored hole in the pavement to establish steady-state horizontal flow through the base toward the edge drains. Two probes along a radial flow line measure differential pressure and electrical resistance in the water. An electrolytic solution injected at the standpipe is used to determine the water velocity as the median resistance is noted at each probe. The in situ hydraulic conductivity is calculated by dividing the discharge velocity by the hydraulic gradient. The in situ test provided results that compare favorably with published values from carefully controlled laboratory tests. It proved to work well for high-hydraulic-conductivity drainable bases, and it has the potential to be a valuable tool for condition assessment of bases under existing pavements.
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Menrad, Thorben, and Jürgen Edelmann-Nusser. "Validation of Velocity Measuring Devices in Velocity Based Strength Training." International Journal of Computer Science in Sport 20, no. 1 (January 1, 2021): 106–18. http://dx.doi.org/10.2478/ijcss-2021-0007.
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Abstract To control and monitor strength training with a barbell various systems are on the consumer market. They provide the user with information regarding velocity, acceleration and trajectory of the barbell. Some systems additionally calculate the 1-repetition-maximum (1RM) of exercises and use it to suggest individual intensities for future training. Three systems were tested: GymAware, PUSH Band 2.0 and Vmaxpro. The GymAware system bases on linear position transducers, PUSH Band 2.0 and Vmaxpro base on inertial measurement units. The aim of this paper was to determine the accuracy of the three systems with regard to the determination of the average velocity of each repetition of three barbell strength exercises (squat, barbell rowing, deadlift). The velocity data of the three systems were compared to a Vicon system using linear regression analyses and Bland-Altman-diagrams. In the linear regression analyses the smallest coefficient of determination (R2.) in each exercise can be observed for PUSH Band 2.0. In the Bland-Altman diagrams the mean value of the differences in the average velocities is near zero for all systems and all exercises. PUSH Band 2.0 has the largest differences between the Limits of Agreement. For GymAware and Vmaxpro these differences are comparable.
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Mei, Renwei, Ronald J. Adrian, and Thomas J. Hanratty. "Particle dispersion in isotropic turbulence under Stokes drag and Basset force with gravitational settling." Journal of Fluid Mechanics 225 (April 1991): 481–95. http://dx.doi.org/10.1017/s0022112091002136.
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An analysis that includes the effects of Basset and gravitational forces is presented for the dispersion of particles experiencing Stokes drag in isotropic turbulence. The fluid velocity correlation function evaluated on the particle trajectory is obtained by using the independence approximation and the assumption of Gaussian velocity distributions for both the fluid and the particle, formulated by Pismen & Nir (1978). The dynamic equation for particle motion with the Basset force is Fourier transformed to the frequency domain where it can be solved exactly. It is found that the Basset force has virtually no influence on the structure of the fluid velocity fluctuations seen by the particles or on particle diffusivities. It does, however, affect the motion of the particle by increasing (reducing) the intensities of particle turbulence for particles with larger (smaller) inertia. The crossing of trajectories associated with the gravitational force tends to enhance the effect of the Basset force on the particle turbulence. An ordering of the terms in the particle equation of motion shows that the solution is valid for high particle/fluid density ratios and to 0(1) in the Stokes number.
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Meslouhi, A., H. Amellal, Y. Hassouni, M. El Baz, and A. El Allati. "Quantum key distribution protocol using random bases." International Journal of Modern Physics B 30, no. 10 (April 20, 2016): 1650061. http://dx.doi.org/10.1142/s0217979216500612.
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In order to enhance the quantum key distribution (QKD) security, a new protocol, “QKDPRB” based on random bases is proposed. It consists of using standard encoding bases moving circularly with a variable rotational angle [Formula: see text] which depends on angular velocity [Formula: see text]; thus, the traditional bases turn into relative ones. To prove the security and the efficiency of the protocol, we present a universal demonstration which proves a high level security of the proposed protocol, even in the presence of the intercept and resend attack. Finally, the QKDPRB may improve the security of QKD.
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Krasnobaeva, L. A., and L. V. Yakushevich. "Rotational dynamics of bases in the gene coding interferon alpha 17 (IFNA17)." Journal of Bioinformatics and Computational Biology 13, no. 01 (February 2015): 1540002. http://dx.doi.org/10.1142/s0219720015400028.
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In the present work, rotational oscillations of nitrogenous bases in the DNA with the sequence of the gene coding interferon alpha 17 (IFNA17), are investigated. As a mathematical model simulating oscillations of the bases, we use a system of two coupled nonlinear partial differential equations that takes into account effects of dissipation, action of external fields and dependence of the equation coefficients on the sequence of bases. We apply the methods of the theory of oscillations to solve the equations in the linear approach and to construct the dispersive curves determining the dependence of the frequency of the plane waves (ω) on the wave vector (q). In the nonlinear case, the solutions in the form of kink are considered, and the main characteristics of the kink: the rest energy (E0), the rest mass (m0), the size (d) and sound velocity (C0), are calculated. With the help of the energetic method, the kink velocity (υ), the path (S), and the lifetime (τ) are also obtained.
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Cirillo, S., L. Simonetti, F. Di Salle, L. Stella, R. Elefante, and F. Smaltino. "La risonanza magnetica nell'emorragia subaracnoidea." Rivista di Neuroradiologia 2, no. 3 (October 1989): 219–25. http://dx.doi.org/10.1177/197140098900200304.
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La risonanza magnetica per immagine dell'emorragia subaracnoidea ha un ruolo ben definito nelle fasi subacute: l'efficacia della TC si riduce velocemente, mentre l'accuratezza diagnostica della RM aumenta per l'evidente accorciamento del T1 legato alla metemoglobina ed alla lisi cellulare. La velocity di produzione di metemoglobina e di lisi eritrocitaria sono in relazione con la riduzione della concentrazione locale di glucosio. Nel sistema subaracnoideo una molecola soluta può seguire i gradienti di concentrazione: la concentrazione di glucosio non può, perciò, abbassarsi velocemente, come nelle raccolte parenchimali. Comunque, anche se l'iperintensita in T1 è chiaramente dipendente dalla concentrazione, è possibile riconoscere un'emorragia subaracnoidea anche a basse concentrazioni sangue/liquor, come abbiamo riscontrato in 2 pazienti. Nelle fasi iperacute ed acute la sensibilità della RM è basata principalmente sulla riduzione del T2 causata dalla formazione di deossiemoglobina, mentre il segnale in T1 non subisce importanti modificazioni: la bassa velocity di riduzione della pressione parziale di ossigeno negli spazi subaracnoidei rende difficile distinguere miscele sangue-liquor dal liquor puro. Perciò la diagnosi RM di ESA può essere difficile, come abbiamo riscontrato in due pazienti, ma i coaguli possono offrire un utile ausilio semeiologico. Nelle fasi precoci il segnale dell'ESA è completamente modificato dai processi coagulativi, a causa di un chiaro accorgimento del T1, che diviene evidente durante la retrazione del coagulo. Questo carattere può essere considerato un utile marker in vivo di ESA acuta: è stato cosi possibile valutare una lieve iperintensità silviana in un'ESA acuta altrimenti negativa. D'altra parte bisogna considerare che la coagulazione di miscele sangue/liquor a influenzata da vari fattori biochimici, fisici e topografici, e quindi può presentare aspetti molto differenti e necessita di un esame accurato per essere dimostrata.
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Kobanov, N. I., and D. V. Makarchik. "Quasi-periodic line-of-sight velocity variations at the bases of polar coronal holes." Astronomy Reports 47, no. 11 (November 2003): 946–52. http://dx.doi.org/10.1134/1.1626197.
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Zhang, Raoyang, Ilya Staroselsky, and Hudong Chen. "Realization of isotropy of the lattice Boltzmann method via rotation of lattice velocity bases." Journal of Computational Physics 225, no. 2 (August 2007): 1262–70. http://dx.doi.org/10.1016/j.jcp.2007.01.032.
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Lasheras, Juan C., and Kek-Kiong Tio. "Dynamics of a Small Spherical Particle in Steady Two-Dimensional Vortex Flows." Applied Mechanics Reviews 47, no. 6S (June 1, 1994): S61—S69. http://dx.doi.org/10.1115/1.3124442.
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The equation of motion of a small spherical particle in an isolated Rankine vortex is analyzed using an asymptotic scheme valid for the limiting case of small Stokes number St. The effects of particle inertia and added mass, gravity, the acceleration of the fluid, viscous drag, and the Basset history force are taken into consideration. For the case of an isolated Rankine vortex, the analysis shows that in the region where the fluid velocity is large enough, the viscous drag constrains the particle to move with a velocity equal to that of the fluid plus a perturbation of order St. This perturbative term incorporates the effects of gravity, the density difference between the particle and the fluid, and the local acceleration of the fluid. In the region where the fluid velocity is small, the particle moves with a velocity equal to the sum of the fluid velocity and the rising/settling velocity of the particle in still fluid, the effects of particle inertia and fluid acceleration appearing as small perturbations. Throughout the whole region of the flow, the effect of the Basset force always appears at higher order than the other forces acting on the particle and may, consequently, be neglected. The analysis also shows that a particle with a mass density greater than that of the fluid always escapes from the central region of the vortex, but a buoyant particle may be trapped by the equilibrium point located there.
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Bharathraj, S., and V. Kumaran. "Effect of base topography on dynamics and transition in a dense granular flow." Journal of Fluid Mechanics 832 (October 26, 2017): 600–640. http://dx.doi.org/10.1017/jfm.2017.683.
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The effect of base roughness on the transition and dynamics of a dense granular flow down an inclined plane is examined using particle based simulations. Different types of base topographies, rough bases made of frozen particles in either random or hexagonally ordered configurations, as well as sinusoidal bases with height modulation in both the flow and the spanwise directions, are examined. The roughness (characteristic length of the base features scaled by the flowing particle diameter) is defined as the ratio of the base amplitude and particle diameter for sinusoidal bases, and the ratio of frozen and moving particle diameters for frozen-particle bases. There is a discontinuous transition from an ordered to a disordered flow at a critical base roughness for all base topographies studied here, indicating that it is a universal phenomenon independent of base topography. The transition roughness does depend on the base configuration and the height of the flow, but is independent of the contact model and is less than 1.5 times the flowing particle diameter for all of the bases considered here. The bulk rheology is independent of the base topography, and follows the Bagnold law for both the ordered and the disordered flows. The base topography does have a dramatic effect on the flow dynamics at the base. For flows over frozen-particle bases, there is ordering down to the base for ordered flows, and the granular temperature is comparable to that in the bulk. There is virtually no velocity slip at the base, and the mean angular velocity is equal to one-half of the vorticity down to the base. For flows over sinusoidal bases, there is significant slip at the base, and the mean angular velocity is approximately an order of magnitude higher than that in the bulk within a region of height approximately one particle diameter at the base. This large particle spin results in a disordered and highly energetic layer of approximately 5–10 particle diameters at the base, where the granular temperature is an order of magnitude higher than that in the bulk. Thus, this study reveals the paradoxical result that gentler base topographies result in large slip and large agitation at the base, whereas rougher topographies such as frozen-particle bases result in virtually no slip and no agitation at the base for both ordered and disordered flows.
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Phan, Lam Huynh, Nam Thanh Nguyen, and Anh Pham Huy Ho. "Control method for reducing errors prosessing of the SLS machine." Science and Technology Development Journal 17, no. 1 (March 31, 2014): 36–42. http://dx.doi.org/10.32508/stdj.v17i1.1292.
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This article presents a method of the error reducing control in SLS machine. When using SLS machine, there are many factors that cause the errors such as: temperature, trajectory, velocity and laser intensity. Therefore, we need to have a precise method control in order to have an accurate processing sample. This one presents the Fuzzy Control Method to help we achieve highly accurate results when process with SLS machine. We propose control method that establishs the criteria based on many influence processing parameters previously mentioned (*) rather than merely control position, velocity, trajectory as the CNC machines. The processing by SLS machine basse on the control MIMO model. Therefore, estimating and parameterizing control parameters to reducing.
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Yun, Ruide, Yangsheng Zhu, Zhiwei Liu, Jianmei Huang, Xiaojun Yan, and Mingjing Qi. "An Electrostatic Self-Excited Resonator with Pre-Tension/Pre-Compression Constraint for Active Rotation Control." Micromachines 12, no. 6 (June 1, 2021): 650. http://dx.doi.org/10.3390/mi12060650.
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We report a novel electrostatic self-excited resonator driven by DC voltage that achieves variable velocity-position characteristics via applying the pre-tension/pre-compression constraint. The resonator consists of a simply supported micro-beam, two plate electrodes, and two adjustable constraint bases, and it can be under pre-compression or pre-tension constraint by adjusting the distance L between two constraint bases (when beam length l > L, the resonator is under pre-compression and when l < L, it is under pre-tension). The oscillating velocity of the beam reaches the maximum value in the position around electrodes under the pre-compression constraint and reaches the maximum value in the middle position between two electrodes under the pre-tension condition. By changing the constraint of the microbeam, the position of the maximum velocity output of the oscillating beam can be controlled. The electrostatic self-excited resonator with a simple constraint structure under DC voltage has great potential in the field of propulsion of micro-robots, such as active rotation control of flapping wings.
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LUDU, A., G. STOITCHEVA, and J. P. DRAAYER. "SIMILARITY ANALYSIS OF NONLINEAR EQUATIONS AND BASES OF FINITE WAVELENGTH SOLITONS." International Journal of Modern Physics E 09, no. 03 (June 2000): 263–78. http://dx.doi.org/10.1142/s0218301300000167.
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We introduce a generalized similarity analysis which grants a qualitative description of the localised solutions of any nonlinear differential equation. This procedure provides relations between amplitude, width, and velocity of the solutions, and it is shown to be useful in analysing nonlinear structures like solitons, dublets, triplets, compact supported solitons and other patterns. We also introduce kink-antikink compact solutions for a nonlinear-nonlinear dispersion equation, and we construct a basis of finite wavelength functions having self-similar properties.
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Kharche, S., J. P. Moro, C. Baudet, B. Rousset, A. Fuchs, J. Peinke, and A. Girard. "Turbulent velocity measurements in high Reynolds cryogenic helium facilities at Service des Basses Températures (SBT)." IOP Conference Series: Materials Science and Engineering 502 (April 15, 2019): 012201. http://dx.doi.org/10.1088/1757-899x/502/1/012201.
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Liang, Kun Feng, Quan Hai Wang, Chun Lei Ruan, and Zhi Wen Tong. "Motion Characteristics of Microbubble in Water." Advanced Materials Research 960-961 (June 2014): 165–69. http://dx.doi.org/10.4028/www.scientific.net/amr.960-961.165.
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The motion characteristics of microbubble in the water or solution have important influence to crystallization process. In the paper, the movement equation of single bubble was modeled based on force equilibrium, the mechanics factors influence on the single bubble motion were discussed, and the velocity of microbubble was analysed with the different bubble sizes. The results show that the velocity of microbubble in static water is increasing with time increasing, the influence of virtual mass force and Basset force caused by the acceleration on the velocity of microbubble must be considered in the initial stage of microbubble motion. In the processes of microbubble motion, compared with constant microbubble radius the variation laws of velocity fluctuations mean with microbubble radius changing are uniform.
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Sarin, V., and A. H. Sameh. "Hierarchical Divergence-Free Bases and Their Application to Particulate Flows." Journal of Applied Mechanics 70, no. 1 (January 1, 2003): 44–49. http://dx.doi.org/10.1115/1.1530633.
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The paper presents an algebraic scheme to construct hierarchical divergence-free basis for velocity in incompressible fluids. A reduced system of equations is solved in the corresponding subspace by an appropriate iterative method. The basis is constructed from the matrix representing the incompressibility constraints by computing algebraic decompositions of local constraint matrices. A recursive strategy leads to a hierarchical basis with desirable properties such as fast matrix-vector products, a well-conditioned reduced system, and efficient parallelization of the computation. The scheme has been extended to particulate flow problems in which the Navier-Stokes equations for fluid are coupled with equations of motion for rigid particles suspended in the fluid. Experimental results of particulate flow simulations have been reported for the SGI Origin 2000.
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RAMA, S. KALYANA. "CLASSICAL VELOCITY IN κ-DEFORMED POINCARÉ ALGEBRA AND A MAXIMUM ACCELERATION." Modern Physics Letters A 18, no. 07 (March 7, 2003): 527–36. http://dx.doi.org/10.1142/s0217732303009228.
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We study the commutators of the κ-deformed Poincaré algebra (κPA) in an arbitrary basis. It is known that the two recently studied doubly special relativity theories correspond to different choices of κPA bases. We present another such example. We consider the classical limit of κPA and calculate particle velocity in an arbitrary basis. It has standard properties and its expression takes a simple form in terms of the variables in the Snyder basis. We then study the particle trajectory explicitly for the case of a constant force. Assuming that the spacetime continuum, velocity, acceleration, etc. can be defined only at length scales greater than x min ≠ 0, we show that the acceleration has a finite maximum.
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Healy, D., and F. E. Hicks. "Index velocity methods for winter discharge measurement." Canadian Journal of Civil Engineering 31, no. 3 (June 1, 2004): 407–19. http://dx.doi.org/10.1139/l04-001.
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At present, the only truly accurate method of determining discharge under ice-affected conditions is by direct measurement. However, this is a costly undertaking that places technicians at personal risk. Because of this, the Water Survey of Canada often bases winter discharge hydrographs on as few as two direct measurements over the entire ice-affected season. This study explores the viability of using an index velocity approach to winter discharge measurement, which basically involves the determination of streamflow based on a very limited number of actual point velocity measurements in the cross section. Such an approach has the potential to reduce the amount of time required for a single discharge measurement, thus opening the potential for an increase in the number of discharge measurements that can be obtained per year at a given site. Also, a reduction in personal risk to those taking measurements on the ice cover is expected because of the reduction in the time spent on the ice cover for each individual measurement. Here, the viability of using a single point velocity, or alternatively a single panel velocity profile, is explored using detailed velocity measurement data collected by the Water Survey of Canada at a number of sites across Canada, on rivers of varying size. Results suggest that there is a definite potential to streamline winter discharge measurement protocols to increase both safety and frequency of measurement.Key words: winter streamflow measurement, rivers, ice.
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Toskic-Radojicic, Marija, and Zorka Nonkovic. "Influence of base on the release of antibiotics from officinal ointments." Vojnosanitetski pregled 62, no. 5 (2005): 383–87. http://dx.doi.org/10.2298/vsp0505383t.
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Backgraund. Officinal basis for the antibiotic ointments according to the 4th Yugoslav Pharmacopoeia is a hydrophobic base containing only aliphatic hydrocarbons. The fact that antibiotics are predominantly not lipophylic raises the question about the suitability of that particular type of the base for the manufacturing of antibiotic ointments. Recent studies of the lipid analysis of the skin corneal layer indicated that lipids had shown the bilamellar organization in the skin intercorneal space. Such structural organization could be seen in the ambiphylic bases whose structure was based on carefully selected emulsifier couple, consisting of the lyotropic and thermotropic liquid crystals. The aim of this study was to test the velocity of antibiotics (klindamycin hydrochloride, erythromycin base and chloramphenicol) release from the hydrophobic ointment-type bases, and from ambiphylic bases of anionic and non-ionic types. Methods. Membrane-free agar diffusion test as the basic method for testing the release velocity in vitro and Staphylococcus aureus as the strain highly susceptible to the chosen antibiotics were used. All the analyzed samples were manufactured as the suspension-type ointments. Results. The highest growth inhibition zone of the Staphylococcus aureus strain for all three analyzed antibiotics was achieved from the non-ionogenic ambiphylic base; the clear growth inhibition zone area for Staphylococcus aureus strain in the preparations containing anionic ambiphylic base was smaller by 10-31.28%, and in the preparations containing aliphatic hydrocarbon-type base, the decrease was 11.46-31.28%, compared to the results achieved with the non-ionogenic ambiphylic base. Conclusion. The optimal release velocity for the analyzed antibiotics was achieved from the non-ionic ambiphylic base.
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Lukin, S. V. "The effect of a pressure wave on a rigid wall covered with a porous layer." Proceedings of the Mavlyutov Institute of Mechanics 4 (2006): 156–65. http://dx.doi.org/10.21662/uim2006.1.014.
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The influence of the non-stationary Basset-Boussinesq forces on the reflection of a step-type pressure wave from a solid surface coated with a porous layer, a saturated liquid or a gas is investigated. The study of wave processes is carried out within the framework of the multi-velocity continuum model. A comparative analysis of the properties of porous screens saturated with a liquid or gas is carried out. The degree of influence of the non-stationary Basset-Boussinesq force on reflection of a wave from a solid wall covered with a porous substance is established.
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Ounis, H., and G. Ahmadi. "Analysis of Dispersion of Small Spherical Particles in a Random Velocity Field." Journal of Fluids Engineering 112, no. 1 (March 1, 1990): 114–20. http://dx.doi.org/10.1115/1.2909358.
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The equation of motion of a small spherical rigid particle in a turbulent flow field, including the Stokes drag, the Basset force, and the virtual mass effects, is considered. For an isotropic field, the lift force and the velocity gradient effects are neglected. Using the spectral method, responses of the resulting constant coefficient stochastic integrao-differential equation are studied. Analytical expressions relating the Lagrangian energy spectra of particle velocity to that of the fluid are developed and the results are used to evaluate various response statistics. Variations of the mean-square particle velocity and particle diffusivity with size, density ratio and response time are studied. The theoretical predictions are compared with the digital simulation results and the available data and good agreement is observed.
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Fang, Li De, Qing He, Yao Zhang, and Yu Jiao Liang. "Study on Void Fraction Measurement Model of Gas-Liquid Two-Phase Flow Based on the Differential Pressure Sensor." Advanced Materials Research 816-817 (September 2013): 924–27. http://dx.doi.org/10.4028/www.scientific.net/amr.816-817.924.
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The paper bases on the differential pressure signal measured by the differential pressure sensor for the study and measurement of gas-liquid two-phase flow void fraction. We compare theory section void fraction and practical section void fraction with superficial gas velocity, the theoretical derivation formula has been observed and qualitatively explained.
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Chan, S. N., and J. H. W. Lee. "Particle tracking modeling of sediment-laden jets." Advances in Geosciences 39 (June 27, 2014): 107–14. http://dx.doi.org/10.5194/adgeo-39-107-2014.
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Abstract. This paper presents a general model to predict the particulate transport and deposition from a sediment-laden horizontal momentum jet. A three-dimensional (3-D) stochastic particle tracking model is developed based on the governing equation of particle motion. The turbulent velocity fluctuations are modelled by a Lagrangian velocity autocorrelation function that captures the trapping of sediment particles in turbulent eddies, which result in the reduction of settling velocity. Using classical solutions of mean jet velocity, and turbulent fluctuation and dissipation rate profiles derived from computational fluid dynamics calculations of a pure jet, the equation of motion is solved numerically to track the particle movement in the jet flow field. The 3-D particle tracking model predictions of sediment deposition and concentration profiles are in excellent agreement with measured data. The computationally demanding Basset history force is shown to be negligible in the prediction of bottom deposition profiles.
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Cho, Young Sang, Sang Ki Baek, Yong Taeg Lee, Seung Hun Kim, Jun Ho Park, and Seong Uk Hong. "Estimation of Compressive Strength of High-Strength Concrete with Recycled Aggregate Using Ultrasonic Pulse Velocity Method." Advanced Materials Research 680 (April 2013): 226–29. http://dx.doi.org/10.4028/www.scientific.net/amr.680.226.
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Recently, many structures which were built about 30 years ago are watched by reconstruction. Demolished concrete is occurred in the process and these quantity increase about 10% more than the preceding year. Although the government have promoted to use recycled coarse aggregate, many registered architects have not use it, because natural aggregate is still cheaper than recycled coarse aggregate's price and they have question about quality of recycled coarse aggregate. In addition, there are no grounds to rely upon compressive strength and ultrasonic pulse velocity method of recycled coarse aggregate when it is used to high strength concrete. In this paper, bases will be adduced to verify applicative possibility of estimation of compressive strength of high-strength concrete with recycled aggregate using ultrasonic pulse velocity method. For this, compressive strength and ultrasonic pulse velocity method tests of 240 high strength concrete specimens with recycled coarse aggregate were performed, and the high strength concrete specimens were tested within the limits such as compressive strength and ultrasonic pulse velocity
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Hong, Yao Ming, Min Li Chang, Hsueh Chun Lin, Yao Chiang Kan, and Chi Chang Lin. "Experimental Study on Clear Water Scour around Bridge Piers." Applied Mechanics and Materials 121-126 (October 2011): 162–66. http://dx.doi.org/10.4028/www.scientific.net/amm.121-126.162.
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This study analyzed the characteristics of bridge scoured by clear water according to 14 groups of laboratory experiments. The formulation of critical velocity based on historical equations of clear water scour was concluded for the test circumstances in laboratory. The experimental conditions include the variation of flow velocity, sediment cover depth, and diameter of bridge pier/bases. The erosion status prior to the maximum scour depth was recorded by a pinhole camera, and, in general, the equilibrium scour depth was reached after 24 hours. The maximum scour depth increases as the sand cover depth decreases. As the same sediment depth, the fast flow velocity will induce the deep scour depth with respect to the slow flow velocity. The same result can be observed for the large diameter of pier (or base) versus the small one. The maximum scour depths in the front of the pier are always deeper than that behind the pier.
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Krope, A., J. Krope, and L. C. Lipus. "A Model for Velocity Profile in Turbulent Boundary Layer with Drag Reducing Surfactants." Applied Rheology 15, no. 3 (June 1, 2005): 152–59. http://dx.doi.org/10.1515/arh-2005-0009.
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Abstract A new model for mean velocity profile of turbulent water flow with added drag-reducing surfactants is presented in this paper. The general problem of drag due to frictional resistance is reviewed and drag reduction by the addition of polymers or surfactants is introduced. The model bases on modified Prandtl's mixing length hypothesis and includes three parameters, which depend on additives and can be evaluated by numerical simulation from experimental datasets. The advantage of the model in comparison with previously reported models is that it gives uniform curve for whole pipe section and can be determined for a new surfactant with less necessary measurements. The use of the model is demonstrated for surfactant Habon-G as an example.
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Mkhitaryan, Suren M., H. V. Tokmajyan, S. A. Avetisyan, and M. S. Grigoryan. "On Steady-State Filtration of Fluid in Strip-Like and Wedge-Shaped Porous Ground Bases." Advanced Materials Research 1020 (October 2014): 373–78. http://dx.doi.org/10.4028/www.scientific.net/amr.1020.373.
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In statement of the steady-state filtration theory and within the framework of the Darcy`s law plane boundary value problems for the strip-like and wedge-shaped porous ground base are considered when through some system of segments on one face of the base the fluid with a certain vertical velocity or with a certain pressure is injected inside the base. These solutions are reduced to integral equations by means of integral transforms.
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Rinaldi, Antonio M., Cristiano Russo, and Kurosh Madani. "A Semantic Matching Strategy for Very Large Knowledge Bases Integration." International Journal of Information Technology and Web Engineering 15, no. 2 (April 2020): 1–29. http://dx.doi.org/10.4018/ijitwe.2020040101.
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Over the last few decades, data has assumed a central role, becoming one of the most valuable items in society. The exponential increase of several dimensions of data, e.g. volume, velocity, variety, veracity, and value, has led the definition of novel methodologies and techniques to represent, manage, and analyse data. In this context, many efforts have been devoted in data reuse and integration processes based on the semantic web approach. According to this vision, people are encouraged to share their data using standard common formats to allow more accurate interconnection and integration processes. In this article, the authors propose an ontology matching framework using novel combinations of semantic matching techniques to find accurate mappings between formal ontologies schemas. Moreover, an upper-level ontology is used as a semantic bridge. An implementation of the proposed framework is able to retrieve, match, and align ontologies. The framework has been evaluated with the state-of-the-art ontologies in the domain of cultural heritage and its performances have been measured by means of standard measures.
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Ren, Lian Cheng, Jiang Meng, Zhen Zhen Lei, and Jiu Hua Wang. "Effect of Viscosity on the Separation Ability of a Hydrocyclone." Applied Mechanics and Materials 233 (November 2012): 7–10. http://dx.doi.org/10.4028/www.scientific.net/amm.233.7.
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On bases of numerical simulation and theoretical analysis, two cases of media, water and slurry (a kind of pseudoplastic power-law fluids), were used in the same hydrocyclone under the same operating condition. The Compare results show that the effect of the medium viscosity on the radial-velocity profile is slight; on the other hand, the effect of the media viscosity on the tangential-velocity profiles is important. The increase of the media viscosity produces not only the increase of the viscous resistance but also the steep reducing of the peak value of tangential-velocity profiles, which means that the inward viscous force loading upon the particles are enforced, on the other hand , the outward centrifugal force loading on the particles reduces greatly. The increase of the media viscosity leads to the great decrease of the separation ability of a hydrocyclone.
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Tanaka, Hirokazu, and Terrence J. Sejnowski. "Motor adaptation and generalization of reaching movements using motor primitives based on spatial coordinates." Journal of Neurophysiology 113, no. 4 (February 15, 2015): 1217–33. http://dx.doi.org/10.1152/jn.00002.2014.
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The brain processes sensory and motor information in a wide range of coordinate systems, ranging from retinal coordinates in vision to body-centered coordinates in areas that control musculature. Here we focus on the coordinate system used in the motor cortex to guide actions and examine physiological and psychophysical evidence for an allocentric reference frame based on spatial coordinates. When the equations of motion governing reaching dynamics are expressed as spatial vectors, each term is a vector cross product between a limb-segment position and a velocity or acceleration. We extend this computational framework to motor adaptation, in which the cross-product terms form adaptive bases for canceling imposed perturbations. Coefficients of the velocity- and acceleration-dependent cross products are assumed to undergo plastic changes to compensate the force-field or visuomotor perturbations. Consistent with experimental findings, each of the cross products had a distinct reference frame, which predicted how an acquired remapping generalized to untrained location in the workspace. In response to force field or visual rotation, mainly the coefficients of the velocity- or acceleration-dependent cross products adapted, leading to transfer in an intrinsic or extrinsic reference frame, respectively. The model further predicted that remapping of visuomotor rotation should under- or overgeneralize in a distal or proximal workspace. The cross-product bases can explain the distinct patterns of generalization in visuomotor and force-field adaptation in a unified way, showing that kinematic and dynamic motor adaptation need not arise through separate neural substrates.
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Mead, K. S., and M. A. Koehl. "Stomatopod antennule design: the asymmetry, sampling efficiency and ontogeny of olfactory flicking." Journal of Experimental Biology 203, no. 24 (December 15, 2000): 3795–808. http://dx.doi.org/10.1242/jeb.203.24.3795.
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Many crustaceans detect odors from distant sources using chemosensory sensilla (aesthetascs) on their antennules. The greater the flow of water through arrays of aesthetascs, the faster the access of odorant to receptors inside the aesthetascs. Stomatopods facilitate odorant access by flicking their antennules, thus increasing the relative velocity of the water reaching their aesthetascs. We used dynamically scaled physical models to investigate how aesthetasc size and spacing and antennule flicking velocity affect flow penetration into the simple aesthetasc arrays of the stomatopod Gonodactylaceus mutatus. Particle image velocimetry of flow fields near models of juvenile and adult antennules revealed that velocity gradients around the aesthetascs are steeper during the outward part of the flick than during the return stroke and that the velocity gradients are steeper at the aesthetasc tips than at their bases. More fluid per unit time flows between aesthetasc rows during the outward stroke than during the return stroke, ensuring that odor sampling is pulsatile. During flicking, velocity gradients are steeper near adult aesthetascs than near juvenile aesthetascs, and adults process more fluid per unit time than juveniles. The resulting differences in odorant access can be related to size- and age-dependent changes in stomatopod ecology.
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Krzywicki, Alfred, Wayne Wobcke, Michael Bain, John Calvo Martinez, and Paul Compton. "Data mining for building knowledge bases: techniques, architectures and applications." Knowledge Engineering Review 31, no. 2 (March 2016): 97–123. http://dx.doi.org/10.1017/s0269888916000047.
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AbstractData mining techniques for extracting knowledge from text have been applied extensively to applications including question answering, document summarisation, event extraction and trend monitoring. However, current methods have mainly been tested on small-scale customised data sets for specific purposes. The availability of large volumes of data and high-velocity data streams (such as social media feeds) motivates the need to automatically extract knowledge from such data sources and to generalise existing approaches to more practical applications. Recently, several architectures have been proposed for what we callknowledge mining: integrating data mining for knowledge extraction from unstructured text (possibly making use of a knowledge base), and at the same time, consistently incorporating this new information into the knowledge base. After describing a number of existing knowledge mining systems, we review the state-of-the-art literature on both current text mining methods (emphasising stream mining) and techniques for the construction and maintenance of knowledge bases. In particular, we focus on mining entities and relations from unstructured text data sources, entity disambiguation, entity linking and question answering. We conclude by highlighting general trends in knowledge mining research and identifying problems that require further research to enable more extensive use of knowledge bases.
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Bakiev, Masharif, Kuvonchbek Yakubov, Seytxan Koybakov, Kholmurod Khayitov, and Nodira Bobojanova. "Theoretical bases for determining the velocity and suspended matter concentration in the swirling zone beyond the transverse dam." E3S Web of Conferences 264 (2021): 03044. http://dx.doi.org/10.1051/e3sconf/202126403044.
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Design dependencies to determine the velocity and concentration of suspended matter in the swirling zone beyond the transverse dam in the presence of the initial section of the jet are proposed in the article, using the main provisions of the theory of turbulent jets, the scheme of dividing the flow into hydraulic homogeneous zones: a weakly perturbed core, intense turbulent mixing and reverse currents. The distribution of velocities and concentration of suspended matter (turbidity) in the zone of intense turbulent mixing are affine and obey the theoretical Schlichting-Abramovich relationships; this was substantiated by laboratory and field studies. The equations of continuity and conservation of solid matter along the flow were used to solve the problem. To establish the adequacy of the dependencies obtained, a test problem was implemented in which the velocities in the core and the depth along the flow were assumed constant. The problem was implemented for the following contraction ratios of flow nc 0,1; 0.2; 0.3; 0.4; 0.5. Tabular and graphic dependencies obtained show that with all contraction ratios of flow, the relative backflow velocities first increase, and at the end of the swirling zone, they sharply decrease. The maximum is observed at the intersection of the outer boundary of the zone of intense turbulent mixing with the protected coast and reaches m = 0.317. Comparison of the calculation results with the experimental ones shows their qualitative and quantitative agreement. The relative concentration of suspended matter in reverse currents remains practically constant along the entire length of the swirling zone. It is close to unity for all contraction ratios of flow.
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Nigro, Giuseppina, Francesco Malara, Antonio Vecchio, Leonardo Primavera, Francesca Di Mare, Vincenzo Carbone, and Pierluigi Veltri. "Turbulence in a Coronal Loop Excited by Photospheric Motions." Atmosphere 11, no. 4 (April 20, 2020): 409. http://dx.doi.org/10.3390/atmos11040409.
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Photospheric motions are believed to be the source of coronal heating and of velocity fluctuations detected in the solar corona. A numerical model, based on the shell technique applied on reduced magnetohydrodynamics equations, is used to represent energy injection due to footpoint motions, storage and dissipation of energy in a coronal loop. Motions at the loop bases are simulated by random signals whose frequency-wavenumber spectrum reproduces features of photospheric motions: the p-mode peak and the low-frequency continuum. Results indicate that a turbulent state develops, dominated by magnetic energy, where dissipation takes place in an intermittent fashion. The nonlinear cascade is mainly controlled by velocity fluctuations, where resonant modes are dominant at high frequencies. Low frequency fluctuations present a power-law spectra and a bump at p-mode frequency; similar features are observed in velocity spectra detected in the corona. For typical loop parameters the energy input flux is comparable with that necessary to heat the quiet-Sun corona.
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Yin, Zegao, Zhenlu Wang, Bingchen Liang, and Li Zhang. "Initial Velocity Effect on Acceleration Fall of a Spherical Particle through Still Fluid." Mathematical Problems in Engineering 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/9795286.
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A spherical particle’s acceleration fall through still fluid was investigated analytically and experimentally using the Basset-Boussinesq-Oseen equation. The relationship between drag coefficient and Reynolds number was studied, and various parameters in the drag coefficient equation were obtained with respect to the small, medium, and large Reynolds number zones. Next, some equations were used to derive the finite fall time and distance equations in terms of certain assumptions. A simple experiment was conducted to measure the fall time and distance for a spherical particle falling through still water. Sets of experimental data were used to validate the relationship between fall velocity, time, and distance. Finally, the initial velocity effect on the total fall time and distance was discussed with different terminal Reynolds numbers, and it was determined that the initial velocity plays a more important role in the falling motion for small terminal Reynolds numbers than for large terminal Reynolds number scenarios.
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Thomas, P. J. "A numerical study of the influence of the Basset force on the statistics of LDV velocity data sampled in a flow region with a large spatial velocity gradient." Experiments in Fluids 23, no. 1 (May 22, 1997): 48–53. http://dx.doi.org/10.1007/s003480050085.
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Alkaissi, Zainab Ahmed, and Hassan Adnan. "Prediction Model of Elastic Modulus for Granular Road Bases." Sustainable Development Research (ISSN 2690-9898 e-ISSN 2690-9901) 2, no. 1 (April 2, 2020): p35. http://dx.doi.org/10.30560/sdr.v2n1p35.
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The estimation of elastic modulus for road bases is the primary objective of this research which is implemented a significant role in transmitting the vertical loading to the pavement foundation layers. In this study, the effect of weathering conditions on the stiffness of base course is investigated and implied the durability test by subjecting the prepared samples to a different numbers of wet-dry cycles (0,2, 4, 6, 8 and 10). A conventional base materials of local natural gravel aggregate and treated base materials with recycled concrete aggregate RCA at different percentages (0%, 25%, 50% 75% and 100%) is adopted in this research.
The elastic characteristics are estimated in terms of elastic modulus. Elastic modulus are estimated by passing the ultrasonic pulse velocity through the untreated and treated base materials laboratory specimens. This test can be used to study the elastic modulus properties of base materials. A multiple linear regression analysis is used for prediction the elastic modulus using the SPSS (software ver.21). Elastic Modulus (kPa) is the dependent variable whereas the independent variable are; No. of wet- dry cycle and Percent (%) of RCA stabilizer. The obtained results for elastic modulus (Es) of granular base material layer showed increasing in elastic modulus with percentage of RCA%., results revealed that the (Es) values reached a maximum value of (6927kPa) for 100%.
For the OMC’s values increases due to the percentage increment of RCA in granular base material mixture, this increment in water contents is refer to high absorption capacity of the paste clinging to the RCA. On other side the dry density decrease gradually with adding percentage of (RCA) in granular base material mixture.
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Cho, John Y. N., and Edward S. Chornoboy. "Multi-PRI Signal Processing for the Terminal Doppler Weather Radar. Part I: Clutter Filtering." Journal of Atmospheric and Oceanic Technology 22, no. 5 (May 1, 2005): 575–82. http://dx.doi.org/10.1175/jtech1730.1.
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Abstract Multiple pulse repetition interval (multi-PRI) transmission is part of an adaptive signal transmission and processing algorithm being developed to aggressively combat range–velocity ambiguity in weather radars. In the past, operational use of multi-PRI pulse trains has been hampered due to the difficulty in clutter filtering. This paper presents finite impulse response clutter filter designs for multi-PRI signals with excellent magnitude and phase responses. These filters provide strong suppression for use on low-elevation scans and yield low biases of velocity estimates so that accurate velocity dealiasing is possible. Specifically, the filters are designed for use in the Terminal Doppler Weather Radar (TDWR) and are shown to meet base data bias requirements equivalent to the Federal Aviation Administration’s specifications for the current TDWR clutter filters. Also an adaptive filter selection algorithm is proposed that bases its decision on clutter power estimated during an initial long-PRI surveillance scan. Simulations show that this adaptive algorithm yields satisfactory biases for reflectivity, velocity, and spectral width. Implementation of such a scheme would enable automatic elimination of anomalous propagation signals and constant adjustment to evolving ground clutter conditions, an improvement over the current TDWR clutter filtering system.
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Prasath, S. Ganga, Vishal Vasan, and Rama Govindarajan. "Accurate solution method for the Maxey–Riley equation, and the effects of Basset history." Journal of Fluid Mechanics 868 (April 11, 2019): 428–60. http://dx.doi.org/10.1017/jfm.2019.194.
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The Maxey–Riley equation has been extensively used by the fluid dynamics community to study the dynamics of small inertial particles in fluid flow. However, most often, the Basset history force in this equation is neglected. Analytical solutions have almost never been attempted because of the difficulty in handling an integro-differential equation of this type. Including the Basset force in numerical solutions of particulate flows involves storage requirements which rapidly increase in time. Thus the significance of the Basset history force in the dynamics has not been understood. In this paper, we show that the Maxey–Riley equation in its entirety can be exactly mapped as a forced, time-dependent Robin boundary condition of the one-dimensional diffusion equation, and solved using the unified transform method. We obtain the exact solution for a general homogeneous time-dependent flow field, and apply it to a range of physically relevant situations. In a particle coming to a halt in a quiescent environment, the Basset history force speeds up the decay as a stretched exponential at short time while slowing it down to a power-law relaxation, ${\sim}t^{-3/2}$, at long time. A particle settling under gravity is shown to relax even more slowly to its terminal velocity (${\sim}t^{-1/2}$), whereas this relaxation would be expected to take place exponentially fast if the history term were to be neglected. An important mechanism for the growth of raindrops is by the gravitational settling of larger drops through an environment of smaller droplets, and repeatedly colliding and coalescing with them. Using our solution we estimate that the rate of growth rate of a raindrop can be grossly overestimated when history effects are not accounted for. We solve exactly for particle motion in a plane Couette flow and show that the location (and final velocity) to which a particle relaxes is different from that due to Stokes drag alone. For a general flow, our approach makes possible a numerical scheme for arbitrary but smooth flows without increasing memory demands and with spectral accuracy. We use our numerical scheme to solve an example spatially varying flow of inertial particles in the vicinity of a point vortex. We show that the critical radius for caustics formation shrinks slightly due to history effects. Our scheme opens up a method for future studies to include the Basset history term in their calculations to spectral accuracy, without astronomical storage costs. Moreover, our results indicate that the Basset history can affect dynamics significantly.
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Malara, Francesco, Giuseppina Nigro, and Pierluigi Veltri. "Energy balance and cascade in MHD turbulence in the solar corona." Proceedings of the International Astronomical Union 4, S257 (September 2008): 543–53. http://dx.doi.org/10.1017/s1743921309029846.
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AbstractThe dynamics of fluctuations in a closed coronal structure is regulated both by resonance with motions at bases that stores energy in the structure in form of discrete eigenmodes, and by nonlinear couplings that move this energy along the spectrum to smaller scales. The energy balance is evaluated both analytically and, numerically, using an hybrid shell model. The input energy flux is independent of nonlinear effects and is determined by slow (DC) perturbations. Coherent eigenmode couplings determine the nonlinear energy flux and, consequently, the level of fluctuations at large scales. The estimated velocity fluctuation level is in agreement with measures of nonthermal velocity in corona. The resulting turbulence spectrum contains both a pre-inertial range where coherent interactions dominate, and a standard inertial range where the turbulence behaves as in an unbounded system.
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Zhang, Wei, Xian Wen, and Yan Qun Jiang. "Global Stability Analysis of the Wake behind a Circular Cylinder Based on the POD-Chiba Method." Applied Mechanics and Materials 137 (October 2011): 72–76. http://dx.doi.org/10.4028/www.scientific.net/amm.137.72.
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A proper orthogonal decomposition (POD) method is applied to study the global stability analysis for flow past a stationary circular cylinder. The flow database at Re=100 is obtained by CFD software, i.e. FLUENT, with which POD bases are constructed by a snapshot method. Based on the POD bases, a low-dimensional model is established for solving the two-dimensional incompressible NS equations. The stability of the flow solution is evaluated by a POD-Chiba method in the way of the eigensystem analysis for the velocity disturbance. The linear stability analysis shows that the first Hopf bifurcation takes place at Re=46.9, which is in good agreement with available results by other high-order accurate stability analysis methods. However, the calculated amount of POD is little, which shows the availability and advantage of the POD method.
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German, Péter, Mauricio Tano, Jean C. Ragusa, and Carlo Fiorina. "REDUCED-ORDER MODELLING OF PARAMETERIZED TRANSIENT FLOWS IN CLOSED-LOOP SYSTEMS." EPJ Web of Conferences 247 (2021): 06055. http://dx.doi.org/10.1051/epjconf/202124706055.
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In this paper, two Galerkin projection based reduced basis approaches are investigated for the reduced-order modeling of parameterized incompressible Navier-Stokes equations for laminar transient flows. The first approach solves only the reduced momentum equation with additional, physics-based approximations for the dynamics of the pressure field. On the other hand, the second approach solves both the reduced momentum and continuity equations. The reduced bases for the velocity and pressure fields are generated using the method of snapshots combined with Proper Orthogonal Decomposition (POD) for data compression. To remedy the stability issues of the two-equation model, the reduced basis of the velocity is enriched with supremizer functions. Both reduced-order modeling approaches have been implemented in GeN-Foam, an OpenFOAM-based multi-physics solver. A numerical example is presented using a two-dimensional axisymmetric model of the Molten Salt Fast Reactor (MSFR) and the dynamic viscosity as the uncertain parameter. The results indicate that the one-equation model is slightly more accurate in terms of velocity, while the two-equation model, built with the same amount of modes for the velocity, is far more accurate in terms of pressure. The speed-up factors for the reduced-order models are 3060 for the one-equation model and 2410 for the two-equation model.
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Gürgöze, M., and F. Terzioğlu. "On establishing equations of motion of mechanical vibration systems placed on moving bases." International Journal of Mechanical Engineering Education 45, no. 3 (April 27, 2017): 209–27. http://dx.doi.org/10.1177/0306419017705522.
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The first author has been teaching the postgraduate course, “The Dynamics of Mechanical Systems” in The ITU Faculty of Mechanical Engineering for nearly 20 years. He has observed that students frequently have problems in obtaining the equations of motion of the vibrating systems which were placed on moving bases. Starting from this observation, he has found that the homework stated below, which was given to the students occasionally, was very helpful in learning the subject. The main idea of the homework is the derivation of the equations of motion, with the help of formulating the Lagrange’s equations with respect to a moving set of axis for a vibration system with two degrees of freedom which consists of a horizontal table rotating with a constant angular velocity around a vertical axis. The students were also asked to solve the same problem with a different method of their choice and to determine the reaction forces as well. We want to share this problem with the reader, which we have assessed as very instructive and appropriate from the viewpoint of applicability of different methods.
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Lahboub, D., A. Bakak, M. Lotfi, R. Heyd, and A. Koumina. "Modeling and simulation of complex flows using Basset digital filters." E3S Web of Conferences 297 (2021): 01018. http://dx.doi.org/10.1051/e3sconf/202129701018.
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Taking into account the Basset force (memory term), in the balance of the forces exerted on a colloidal particle (CP) suspended in a fluid, results in an equation of motion of integrodifferential form. This type of equation allows for example to modeling a colloidal particle settling in an quiescent fluid or in a fluid flowing at low particle’s Reynolds number. It also allows to study the transport of pathogens via aerosols, thus giving access to important information on the airborne propagation of respiratory viruses, such as COVID-19 and its variants for example. Most studies of the PCs motion in a fluid are usually simplified by not taking into account the Basset memory force, as it considerably complicates the numerical solution of the equations of motion of these PCs. This simplification can lead to considerable errors in the evaluation of the trajectory and velocity of the PCs, which can subsequently lead to errors in the calculation of the physical and rheological properties of colloidal suspensions. The present study deals with the numerical solution of Basset’s integro-differential equation, by two significantly different approaches, namely : a piecewise linear approximation (PLA) and the method of Basset numerical filters (BNF). These methods are first exposed and compared on test cases, they are then applied to the study of the sedimentation of spherical PCs with micrometer radii. This study has shown that the usual dynamics of PCs, which does not take into account the Basset memory term, can be very different from the exact dynamics using the Basset force. The BNF approach is finally applied to the study of the motion of PCs driven by flows through complex geometries (pipes, porous media, …).
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Vettorello, M., B. Eisenbart, and C. Ranscombe. "PARADOXICAL TENSION: BALANCING CONTEXTUAL AMBIDEXTERITY." Proceedings of the Design Society: DESIGN Conference 1 (May 2020): 1385–94. http://dx.doi.org/10.1017/dsd.2020.74.
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AbstractThe concepts of high-velocity, complexity and interdependency are nowadays vividly discussed in design-led innovation management. Design organisations seek to manage innovation in a more dynamic way to ensure competitive advantage and long-term competitiveness. Contextual ambidexterity is advised to be a dynamic capability that can facilitate firms to effectively manage incremental and radical innovation alike. This paper proposes an approach that focuses on the individual and the underlying thinking which bases its foundations on ambidextrous leadership, abductive reasoning and strategic fit.
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Barela, Ana Maria Forti, Diego Alveno, Claudia Garcia, and Cássio A. Pereira. "Comparison of two methods of postural control analysis during upright and quiet stance." Brazilian Journal of Motor Behavior 4, no. 1 (March 23, 2009): 30–36. http://dx.doi.org/10.20338/bjmb.v4i1.22.
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The goal of this study was to compare two methods of analysis, the use of force platform and based on video system, to investigate the postural control of young adults during upright stance on three bases of support. Fifteen young adults (30±4.96 years old) were asked to maintain an upright and quiet stance on a force platform for 30 s on bipedal, semi-tandem stance, and reduced bipedal bases of support. One reflective marker was placed on their back to acquire the space coordinates. Mean sway amplitude and mean velocity in anterior-posterior (AP) and medial-lateral (ML) directions and the area of stabilogram were calculated and used to compare the two methods of analysis and the effects of bases of support. Coefficient of correlation values indicated strong relation between trajectories of center of pressure and reflective marker in both directions (AP and ML), and statistical analysis of both methods indicated similar results in terms of effects of base of support. According to these results it might be suggested that both methods of analysis to investigate the control of upright and quiet stance in young adults can be used.
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Basha, S. Farook, and M. Syed Ali Padusha. "Ultrasonic Studies on the Nature of Molecular Interaction of Synthesized Mannich Bases in DMSO at Different Temperatures." Asian Journal of Chemistry 31, no. 4 (February 27, 2019): 960–64. http://dx.doi.org/10.14233/ajchem.2019.21893.
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This work deals with the ultrasonic studies of the Mannich bases (morpholin-4-yl)(pyridin-3- yl)methyl]hydrazine carboxamide (MPH) and (morpholino)(thiophen-2-yl)methyl)nicotine hydrazide (MTN) by the measurements of parameters such as ultrasonic velocity (U), density (ρ), viscosity (η), adiabatic compressibility (κ), intermolecular free length (Lf), molar volume (Vm), relaxation time (τ), specific acoustic impedance (Z), lenard jones potential (LJP), internal pressure (πi), free volume (Vf) and molecular cohesive energy (MCE), available volume (Va), Gibbs free energy (ΔG) and absorption coefficient (α/f2). These results are inferred that the strong interaction exists between the solvent (DMSO) and solute (MPH and MTN).
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Gopi, C., and N. Santhi. "Acoustical Studies of Some Synthesized Schiff Base Derivatives in Dimethylsulphoxide at 303.15 K, by Ultrasonic Velocity Measurement." International Letters of Chemistry, Physics and Astronomy 36 (July 2014): 50–66. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.36.50.
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The density, viscosity and sound velocity of five Schiff bases (1-5) derivatives in DMSO solutions have been studied at 303.15 K over a wide range of concentration. From these experimental data, some acoustical parameters such as Molar volume (Vm), Specific Acoustic Impedance (Z), Adiabatic compressibility (βad), Intermolecular Free Length (Lf), Rao’s Constant (R), Molar compressibility (W), Relaxation time(τ), van der Waals constant (b), Relaxation strength (r), Relative association (RA), Isothermal compressibility ( ) , Isothermal expansion co-efficient (α) ,Free volume (Vf) and Internal pressure (πi) and Ultrasonic attenuation (α/f²) have been evaluated. A fairly good correlation between a given parameter and concentration is observed. The results are interpreted in terms of molecular interactions like solvent-solvent, solvent-solute and solute-solute interactions.