Inertia Models Research Articles

Comparison of Surface Irrigation Simulation Models: Full Hydrodynamic, Zero Inertia, Kinematic Wave

Some phenomena such as surface irrigation are so complex that it is very difficult to implement them in nature. For this purpose, simulation models are used. In this study, ability of full hydrodynamic, zero inertia, and kinematic wave models has been investigated in surface irrigation simulation. Using SIRMOD software, their performance has been compared. The results showed that full hydrodynamic and zero inertia models were very powerful in simulation process. For increasing of filed slope until amount of 0.01 full hydrodynamic and zero inertia models had not any difference but for more increasing of S0 due to the increasing of velocity, accuracy of zero inertia model dropped. In full hydrodynamic and zero inertia models for increase in Manning’s roughness coefficient amount of error was increased until n=0.15. After this amount, error remained constant thus n=0.15 determined as critical discharge. Accuracy of kinematic wave model reduced in clay and heavy clay soils, high discharges, high Manning’s roughness coefficient, and basin irrigation. However, in many situations all three models had the same answers and were capable tools to simulating of surface irrigation processes.

Field evaluation of various mathematical models for furrow and border irrigation systems

In this study, three mathematical models in the SIRMOD package including the hydrodynamic (HD), zero inertia (ZI), and kinematic wave (KW) models were tested using the data from several field experiments for both border and furrow irrigation systems. Five data sets for borders and seven data sets for furrows were used in this assessment. The results indicated that the performance of all models was satisfactory for the prediction of the advance and recession times. There was no difference in the prediction of the advance and recession times and infiltrated and runoff volumes between the hydrodynamic and zero-inertia approaches of the SIRMOD software. The HD, ZI, and KW models predicted the recession times better than the advance times for both the experimental borders and furrows. The predicted advance and recession times were estimated by these models more accurately than the infiltrated and runoff volumes. Also the accuracy of these models for the prediction of the advance and recession times was better for the experimental furrows in comparison with the experimental borders.

Explaining the riddle of effective moment of inertia models for FRP concrete beams

The current provisions in ACI Committee 440 for calculating deflections of flexural structures reinforced with fibre reinforced polymer (FRP) bars or reinforcements require the use of an effective moment of inertia. Many equations giving its expression have been developed over the past years and show significant difference between them among the CEB-FIP and Benmokrane formula, largely used in literature are selected. The discrepancy of response curves shows that the variation between them can be explained by the bond character and tension stiffening effect. The comparison between responses of various FRP reinforced concrete (RC) beams shows a relative accuracy via the experimental data. For this object, an analytical expression is proposed to quantify the effective moment of inertia and accurately results are shown. Obtained results show a favourite accuracy using the novel expression of the effective moment of inertia model of an in-service FRP bars RC beam subjected to a monotonic loading.

A study on the effect of road friction on driveline vibrations

The aim of this article is to assess the influence of the tyre/road contact interface on driveline vibrations. The mode shapes of a vehicle driveline are obtained and analysed, initially using three tyre models: a simple torsional spring, linear slip, and relaxation length-based models. Additionally, a fully transient load- and slip-dependent non-linear relaxation length model is incorporated into the driveline to determine the dynamic response on different surfaces. Simulations of pull-away manoeuvres on various surfaces are carried out. The halfshaft torque in each case is analysed and conclusions drawn on the effect of tyre dynamics on the frequency and intensity of driveline vibrations. In order to investigate the influence of higher-frequency tyre dynamics, a model incorporating tyre belt inertia is simulated for the same cases. It is found that the higher-order dynamics introduced by the tyre belt result in additional frequencies in the response, as well as differences in response amplitude. Using the non-linear relaxation length and belt inertia models it is observed that low-μ surfaces promote driveline vibrations at higher and more numerous frequencies compared with the typical shuffle response observed on a high-μ surface. It is shown that this frequency migration can be physically explained by considering the effect of decoupling between driveline and vehicle on low-μ surfaces. It is also shown that the observed frequencies can be predicted by appropriately modified linear models.

Field Evaluation of Zero Inertia and Kinematic Wave Models under Furrow Irrigated Bed System in Vertisols

In this field study zero inertia and kinematic wave models have been applied to predict advance and recession times under furrow irrigated bed system. SRFR Version 4.06 software of surface irrigation has been used to obtain the numerical solution of Saint-Venant equation. The predicted advance and recession times were compared with the observed ones. Slope of best fit line, coefficient of determination and standard error indices were calculated and used to evaluate the performance of the models. Zero inertia and Kinematic wave model under estimated (ℷ < 1) the advance and recession time in furrow irrigated bed system. The Zero inertia model predicted comparatively more reliable result in predicting advance and recession time for the field conditions encountered in the study. Both the models, zero inertia and kinematic wave, however predicted advance and recession times slightly more accurately in stream size 2 Ips than 1 Ips per furrow.

Workforce modernization, outsourcing and the “permanent revolution” in policing

Successive governments have attempted to modernize policing in England and Wales along managerialist lines, as part of wider public service reform. These pressures have contributed to a ‘permanent revolution’ in policing. The current government is committed through its workforce modernization programme to making the most effective use of police officers and to improving career structures for police support staff. However, the use of outsourcing within the reform programme is under-researched. We explore workforce modernization here, drawing on our evaluation of a Home Office project concerning outsourcing in police detention suites. The project proved efficient in its own terms, but raised wider issues. Consequently, we present three models of organizational development that may emerge through workforce modernization: the inertia, market and professional models. Workforce modernization may achieve efficient mixed teams which undertake policing effectively, contributing to the government's community safety objectives. However, it also risks developing a fragmented service that is low in morale and equity.

Dominance Style Among Macaca thibetana on Mt. Huangshan, China

The dominance style concept has proven useful for understanding covariation patterns in relationship qualities, particularly among macaques. However, the dominance styles of many macaques, including Tibetan macaques (Macaca thibetana), have not been examined in detail. We describe patterns of bidirectionality of aggression, postconflict affiliation and kin bias in a group of wild, but provisioned Tibetan macaques over a 2-yr period in order make an initial assessment of their dominance style. Bidirectional aggression, including percentage of counteraggression (1.9%), and conciliatory tendencies (6.4%) were consistently low across partner combinations, seasons and locations (forest vs. provisioning area). In addition, females consistently displayed high levels of kin bias in affiliation and tolerance. Compared with macaque species with better known dominance styles, the Tibetan data generally fell within the range for despotic species and outside the range for relaxed species. Although other researchers have tentatively classified them as tolerant or relaxed, we conclude that Tibetan macaques display a despotic dominance style. This conclusion poses complications to explanations based both on phylogenetic inertia and socio-ecological models.

SW—Soil and Water: Field Evaluation of Furrow Irrigation Models

In this study, four furrow irrigation models, referred to as the Ross, Walker, Strelkoff and Elliott models are evaluated for their prediction of advance and recession times and runoff, and for their computational time per simulation run and volume balance error under three field conditions in south-east Australia. The models simulated irrigation events based on hydrodynamic (HD), zero-inertia (ZI) and kinematic-wave (KW) approaches. Eighty-one irrigation events were monitored over a 3-year period. The models were applied to all the events, and it was found that the Walker HD, Walker ZI, Ross ZI and Elliott ZI models performed best in predicting advance times and the Strelkoff ZI and Strelkoff KW models performed best in predicting recession times. Considering the overall suitability of the models, both the Walker hydrodynamic and Walker zero inertia models are the most suitable for the field conditions encountered in the study.

Optimal inertia lumping from modal mass matrices for structural dynamics

An optimal inertia lumping formulation using modal mass matrices obtained from structural analysis is presented, enabling recovery of lumped inertia information even when substructuring has been employed. The method is implemented with a commercial optimization program and uses reduced mass and stiffness formulations employed in commercial finite element analysis programs. The result is lumped inertia models of complex flexible bodies for use in structural dynamics, including flexible multibody dynamic simulation. A method for dealing with nondifferentiability of repeated eigenvalues that arise in the optimization process is derived and implemented in the proposed formulation. Numerical examples are presented to validate the method, relative to conventional mass lumping approaches.

Estimation of Surface Volume in Hydrological Models for Border Irrigation

A procedure was developed to obtain better estimations of the surface volumes than in hydrological models and more rapid results than running zero inertia models. Using a zero inertia model, a database was created of the surface volume during advance in dimensionless form. Through an interpolation process it is possible to calculate the surface volume using the independent variables of the phenomenon. The empirical estimates of the surface volume and the method presented in this work were compared with the results of the zero inertia model, and it was found that the empirical estimates have a validity that is restricted to particular conditions. The proposed procedure rapidly provides precise values of this volume. The error in the estimate of the infiltrated volume that occurs in the inverse methods based on the hydrological model, due to the empirical estimates of the surface volume, was also calculated, and it was found that this error is great for short distances and low values of the dimensionless parameters.

A NEW THERMAL INERTIA MODEL BASED ON EFFUSIVITY

In the framework of the PASCOOL project, theoretical and experimental studies have been performed to improve the quantitative understanding of the presence and distribution of massive building elements for the passive cooling of buildings. A new thermal model, based on effusivity, a parameter that can be analytically derived from the solution of the heat equation for a semi-infinite wall, was developed. The transient thermal response of a variety of building zones to a series of steps in heat gain has been measured for the validation of the thermal inertia models. It was observed that, for each step in gain, the mean surface temperature of the spaces increases proportionally to the square root of time, as predicted by the effusivity model. The results allowed the formulation of simple passive cooling design guidelines for buildings.

Advanced dynamic spark ignition engine modelling for diagnostics and control

For years, control engineers have used engine models with constant mass moments of inertia to simulate internal combustion engines. These models showed satisfactory results at low–speed operations but deviated from real engine operations at high speed. Also, there are some problems in using the constant inertia models for engine diagnostics because of inaccurate estimates of inertial forces at high speed, and many of the components that degrade or fail in an engine are not modelled with that methodology. In this paper, two approaches are used to formulate more accurate nonlinear engine models; one applies the Newtonian method; the other uses the Lagrangian method to derive the nonlinear governing equations for internal combustion engine kinematics and dynamic forces. Also included is the discussion of the discrepancy between the nonlinear time–varying inertia model and previous constant inertia model in their shaft velocity and acceleration fluctuations, and in the reconstructed cylinder pressure using the Sliding Observer.

Model of superfluid liquid with triplet pairing, cranking model and model of variable moment of inertia in superdeformed bands inA?190 region

The triplet pairing model, which has been shown, in some cases, to be equivalent to the cranking and/or variable moment of inertia models, is used to describe the superdeformed bands inA∼190 region. The two-parameter expression for theγ-transition energiesEγ(I), common to these three models, allows a good description of experimental data and an unambiguous spin assignment for the states of these superdeformed bands.

We Interrupt This Program. Attention for Television Sequences.

This experiment assesses the variable amounts of attention that are required for a viewer to process two kinds of interruptions common to television: the shift from one message to a different, unexpected message and the reference to previously presented material that follows an interruption. Respondents viewed 24 television sequences composed of three segments: an initial segment drawn from one program, an interrupt segment drawn from a second program, and a reorient segment that continued the presentation from the first program. Initial and interrupt segment lengths were either 10 seconds or 30 seconds in length to produce a factorial combination of four message sequences. Attention to these interruptions was measured using reaction times to audio tones located 1 and 6 seconds after a shift. More attention was required to view the interrupt segments following 30-second initial sequences, especially at the 6-second tone location. For the reorient segments, sequences containing 30-second initial segments required more attention, as did 30-second interrupt segments. These results are interpreted in terms of limited capacity and attentional inertia models of attention.

The particle size of Martian aeolian dunes

The effective particle size of unconsolidated materials on the Martian surface can be determined from thermal inertia, due to a pore size dependence of thermal conductivity at Martian atmospheric pressures. Because dunes consist of a narrow range of well‐sorted, unconsolidated particles, they provide for a test of the relationship between particle size and thermal inertia calculated from midinfrared emission data for the Martian surface. We use two independent approaches. First, thermal inertia data indicate that Martian dunes have an average particle size of about 500±100 μm, or medium to coarse sand. Second, we determine expected dune particle sizes from grain trajectory calculations and the particle size transition from suspension to saltation. On Earth, the transition occurs for a grain when the ratio of the terminal fall velocity to the wind friction speed (u*t) is near unity; for grains at u*t, this occurs at about 52 μm. Terrestrial dune sands have a mean of 250 μm and are composed entirely of grains >52 μm. The corresponding Martian transition grain size is about 210 μm, suggesting that Martian dunes should be significantly coarser than terrestrial dunes. Grain saltation path length as a function of particle size also shows that under Martian conditions, larger grains than on Earth will become suspended. Both approaches indicate that Martian dune sand should be coarser than terrestrial dune sand. Thus, while terrestrial dune grains are in the fine to medium sand range, the average Martian dune sediments are probably medium to coarse sands. These results closely match the grain sizes determined from thermal inertia models, providing the first direct test of the validity of these models for actual Martian surface materials.

Modeling and Experimental Analysis of A Fluidic Generator

A fluidic generator is a device that converts air flow into electrical power. The mechanical portion of this generator is modeled for its dynamic characteristics so that optimization of the power output may be attained through mechanical system modification. Further, a regression analysis is carried out on experimentally obtained data to allow specific definition of defects in the analytic model. A lumped parameter mechanical network is used to model the system. Structural inertia, stiffness, viscous damping, and internal structural damping models are used to model a corrugated diaphragm, a connecting rod, coupling nuts, and a cantilever laminated reed. Special attention is given to the modeling of the corrugated diaphragm laminated reed. A computer algorithm, IMPV, (Impedance Modeling Program, version V), is used to solve the impedance formulation of this model. The result is the dynamic compliance matrix of the structural assembly. Specifically, the displacement response at the end of the reed is computer per unit force applied at the center of the diaphragm. The resultant dynamic transfer compliance is compared to the experimental Fast Fourier Transform (FFT) dynamic transfer compliance as measured on the actual structure.

Microscopic study of the macroscopic rotational parameters

A systematic procedure, based on the theory of probability, is described to calculate the collective parameters of the variable moment of inertia models. Its advantages over the generalized Skyrme procedure are discussed. The numerical calculations on the nucleus 20Ne using Ripka's (1968) deformed Hartree-Fock wavefunctions show that the values of the energies EJ using the method of moments are as good as those calculated using Skyrme's procedure, where one has to handle much higher-rank particle operators. An approximate scheme is described to evaluate the matrix elements of the square root and other complicated functions of J2 with respect to the intrinsic wavefunction mod Phi ) which are generated by large-scale Hartree-Fock calculations.

Mallmann curves and variable moment of inertia models for nuclei

The plot of R J (R J = E J 1 + E 2 1 + ) against R 4, J = 6, 8, …, provides a clear picture of the trends of nuclear (quasi)rotational behavior in doubly even nuclei. Plots are presented up to J = 16, based upon recent experimental data. Corresponding curves predicted by various variable moment of inertia (VMI) models are calculated within the framework of Mantri and Sood's formalism and a comparison is made with these (Mallmann) curves. The comparison clearly shows how well various VMI recipes can be fitted to the experimental data and permits a discussion of the contributing microscopic factors.

A study of the variable moment of inertia models

The variable moment of inertia (VMI) model proposed by Holmberg and Lipas has been shown to be a special case of the VMI model of Mariscottiet al. The solution of Mariscotti’s model is expressed in terms of hypergeometric functions, which directly give the rotational energies or their expansions in terms of the quantityF(F+1), whereF is the total angular momentum. The present way of looking at the VMI model also tells us how to write the general dependence of the vibrational energy and the moment of inertia on the energyEJ.

Theoretical foundation of variable moment of inertia models

A derivation of the VMI model is presented which is general enough to account for its successful application to both deformed and spherical nuclei. A derivation of multiband generalization is also outlined.