Magnitude Of Instability Research Articles

Instability Analysis and Decomposition of Output of Oilseeds Crops in Rajasthan and India

Aim: The study deals with analysis of instability of area production and productivity of major oilseeds in Rajasthan and India. It also includes calculation of sources of growth of production over the period of study. Area effect, yield effect and interaction effect for crop production were calculated. Place and Duration: The time series data of thirty years, 1990-91 to 2019-20, was analyzed. The data were further divided into Three decades, period I(1990-91 to 1999-2000), period II (2000-01 to 2009-10) and period III (2010-11 to 2019-20). Area production and productivity of major oilseed crops (Rapeseed-mustard, groundnut and soybean) for all three decade in Rajasthan and India were analyzed. Methodology: This paper deals with the analysis of instability in area production and productivity of major oilseed crops in Rajasthan and India. The Cuddy Della Vella Index has been used for instability analysis. It also includes the decomposition analysis to determine factors that were responsible for the change in production of the crops. The additive decomposition method has been used to determine area, yield and interaction effect. Results: Calculations revealed that the magnitude of instability in Rajasthan during period II (2000-01 to 2009-10) remained high for all the selected crops. There was instability of 32.49 percent and 34.40 percent for area and production, respectively, while 13.34 percent of variation was found in productivity. In Rajasthan, the lowest instability was observed during period III (2010-11 to 2019-20) with variation of 7.44 percent, 9.47 percent and 6.62 percent for area production and productivity of groundnut. In India, the highest instability was during period II. The area of Rapeseed-mustard has shown the highest (17.72%) instability compared to the instability of the area of other crops. Variation of production and productivity of groundnut was recorded at 24.79 and 21.88 percent, respectively, which is highest among the selected crops. The decomposition analysis revealed that the area effect was a major source for the growth of production of oilseed in Rajasthan as compared to the yield effect and interaction effect. During period I (1990-91 to 1999-2000), the area effect for rapeseed mustard, groundnut and soybean was 68.08, 87.97 and 91.35 percent. In India, both area and yield effect have a major contribution to the growth of production. During period I, the yield effect (57.50 %) was responsible for growth of rapeseed-mustard production, while groundnut and soybean had a high contribution of area effect with magnitudes of 70.86 percent and 84 percent. Area effects for groundnut and soybean were 118.44 percent and 58.06 percent during period II, respectively. Area effect (42.90%) and yield effect (45.76%) were equally responsible for the growth of rapeseed-mustard. During period III, the yield effect for rapeseed-mustard and soybean was 101.34 percent and 257.7 percent, respectively, while the area effect (52.29 %) was responsible for growth in groundnut production. Conclusion: It has been found that groundnut was the most stable crop in term of area production and productivity. The major source for the growth of production was area effect and Yield effect while interaction effect has least impact on production of crops.

OSTEOCHONDRAL GLENOID LOSS: REMAINING GLENOID DEPTH AND CONCAVITY ARE STRONGER PREDICTIVE PARAMETERS FOR SHOULDER INSTABILITY THAN DEFECT SIZE

Osteochondral glenoid loss is associated with recurrent shoulder instability. The critical threshold for surgical stabilization is multidimensional and conclusively unknown. The aim of this work was to provide a well- measurable surrogate parameter of an unstable shoulder joint for the frequent anterior-inferior dislocation direction.The shoulder stability ratio (SSR) of 10 paired human cadaveric glenoids was determined in anterior-inferior dislocation direction. Osteochondral defects were simulated by gradually removing osteochondral structures in 5%-stages up to 20% of the intact diameter. The glenoid morphological parameters glenoid depth, concavity gradient, and defect radius were measured at each stage by means of optical motion tracking. Based on these parameters, the osteochondral stability ratio (OSSR) was calculated. Correlation analyses between SSR and all morphological parameters, as well as OSSR were performed.The loss of SSR, concavity gradient, depth and OSSR with increasing defect size was significant (all p<0.001). The loss of SSR strongly correlated with the losses of concavity gradient (PCC = 0.918), of depth (PCC = 0.899), and of OSSR (PCC = 0.949). In contrast, the percentage loss based on intact diameter (defect size) correlated weaker with SSR (PCC=0.687). Small osteochondral defects (≤10%) led to significantly higher SSR decrease in small glenoids (diameter <25mm) compared to large (≥ 25mm) ones (p ≤ 0.009).From a biomechanical perspective, the losses of concavity gradient, glenoid depth and OSSR correlate strong with the loss of SSR. Therefore, especially the loss of glenoidal depth may be considered as a valid and reliable alternative parameter to describe shoulder instability. Furthermore, smaller glenoids are more vulnerable to become unstable in case of small osteochondral loosening. On the other hand, the standardly used percentage defect size based on intact diameter correlates weaker with the magnitude of instability and may therefore not be a valid parameter for judgement of shoulder instability.

Simulation of Alfvénic avalanche onset in NSTX

In some tokamak discharges, a number of Alfvén eigenmodes (AEs) have been observed to cause a large-scale collapse of the high energy particle distribution, a phenomenon referred to as an avalanche. We examine the necessary conditions for an avalanche using the available experimental information from NSTX on the equilibrium and mode properties for two cases, one with a measurable but benign AE activity and one with an AE activity leading up to an avalanche. To produce an avalanche, the modes present in the discharge must possess resonances that can overlap with a modest increase in instability magnitude, providing a path to global particle stochastic motion. We find that the modes present in the avalanche-free discharge do not provide such a path even at a very large amplitude. During the discharge which subsequently produces an avalanche, the high energy population is growing and the Alfvén frequency is dropping due to increasing density, and we find that both these changes, producing a small increased drive or an increased resonance width for the Alfvén modes, can lead in this case to uncontrolled mode growth and large-scale beam particle loss.

Strongly Coupled Fluid–Structure Interaction in a Three-Dimensional Model Combustor During Limit Cycle Oscillations

Due to the high temperature of the flue gas flowing at high velocity and pressure, the wall cooling is extremely important for the liner of a gas turbine engine combustor. The liner material is heat-resistant steel with relatively low heat conductivity. To accommodate outside wall forced air cooling, the liner is designed to be thin, which unfortunately facilitates the possibility of high-amplitude wall vibrations (and failure due to fatigue) in case of pressure fluctuations in the combustor. The latter may occur due to a possible occurrence of a feedback loop between the aerodynamics, the combustion, the acoustics, and the structural vibrations. The structural vibrations act as a source of acoustic emitting the acoustic waves to the confined fluid. This leads to amplification in the acoustic filed and hence the magnitude of instability in the system. The aim of this paper is to explore the mechanism of fluid–structure interaction (FSI) on the LIMOUSINE setup which leads to limit cycle of pressure oscillations (LCO). Computational fluid dynamics (CFD) analysis using a RANS approach is performed to obtain the thermal and mechanical loading of the combustor liner, and finite element model (FEM) renders the temperature, stress distribution, and deformation in the liner. Results are compared to other numerical approaches like zero-way interaction and conjugated heat transfer model (CHT). To recognize the advantage/disadvantage of each method, validation is made with the available measured data for the pressure and vibration signals, showing that the thermoacoustic instabilities are well predicted using the CHT and two-way coupled approaches, while the zero-way interaction model prediction gives the largest discrepancy from experimental results.

Growth dynamics and acreage response of paddy in eastern Vidarbha zone of Maharashtra

The present study entitled Acreage response of paddy in eastern Vidarbha (M.S.) was undertaken to know rate of growth in area, magnitude of instability, correlation, acrage response, price elasticity of paddy. The study has been undertaken in eastern Vidarbha zone. Data pertains for the year 1984-2014. The decomposition analysis model (Minhas, 1964) and regression model of the Nerlovian lagged adjustment model (1958) was used in the present study. The following conclusions were drawn from the study. The growth rate for area and production under paddy has increased in all the districts of eastern Vidarbha region of Maharashtra for the study period. The area, production and productivity instability in paddy was observed in almost all districts in the state. It may be because the crop largely depends on vagaries of nature which causes heavy losses. Per cent contribution of area effect was more responsible for paddy production in the initial period but later yield effect was more pronounced. In the overall period of 30 years, area effect and interaction effect showed proportional share (177.59 % and 54.79 %, respectively) in the Bhandara district. The lagged acreage variable was found significant in Bhandara and Gadchiroli districts of eastern Vidarbha mostly with 5 per cent level of significance. The current year acreage was influenced by farm harvest price nor by one year lagged yield of the paddy in all the districts. The regression co-efficient for lagged area was positive and statistically significant in two districts indicated more rigidity in the adjustment of area under paddy. Long run price elasticities were more than short run elasticities in paddy indicating that farmers was not market oriented in short run period.

Robustness of Forecast Combination in Unstable Environment: A Monte Carlo Study of Advanced Algorithms

Based on a set of carefully designed Monte Carlo exercises, this paper documents the behavior and performance of several newly developed advanced forecast combination algorithms in unstable environments, where performance of candidate forecasts are cross-sectionally heterogeneous and dynamically evolving over time. Results from these exercises provide guidelines regarding the selection of forecast combination method based on the nature, frequency, and magnitude of instabilities in forecasts as well as the target variable. Following these guidelines, a simple forecast combination procedure is proposed and demonstrated through a real-time forecast combination exercise using the U.S. Survey of Professional Forecasters, where combined forecasts are shown to have superior performance that is not only statistically significant but also of practical importance.

Computational investigation of blood flow in fusiform models of aortic aneurysms: a steady state analysis

Laminar, turbulent and transitional numerical simulations of steady flow in an aneurysmal aorta with different aneurysm diameters were carried out using Computational Fluid Dynamic (CFD) technique. The simulation of steady flow condition in normal aorta was also carried out to provide the data for comparison with an aneurysmal aorta data. Results were calculated for Wall Shear Stress (WSS) patterns, pressure and velocity fields from normal aorta and aneurysmal aorta models. The pressure drop values were also calculated analytically for each model to compare with numerically simulated one. The larger aneurysm models demonstrated unstable flow with greater magnitude of instability at the distal portion of aneurysm, the flow in the smaller models became stable. The results of pressure drop value show that the laminar fluid flow model is desirable for normal aorta and smaller aneurysm models, the transitional flow model is suitable for larger aneurysm models.

Consistent factor estimation in dynamic factor models with structural instability

This paper considers the estimation of approximate dynamic factor models when there is temporal instability in the factor loadings. We characterize the type and magnitude of instabilities under which the principal components estimator of the factors is consistent and find that these instabilities can be larger than earlier theoretical calculations suggest. We also discuss implications of our results for the robustness of regressions based on the estimated factors and of estimates of the number of factors in the presence of parameter instability. Simulations calibrated to an empirical application indicate that instability in the factor loadings has a limited impact on estimation of the factor space and diffusion index forecasting, whereas estimation of the number of factors is more substantially affected.

Through-bond instability in polyphenol tautomers

Unusual instability of keto tautomers in polyphenols is theoretically analyzed. Apart from ordinary resonance energy and bond energy, it is shown that there should be additional keto instability originated from through-bond interactions between the true and pseudo π orbitals. The interactions are characteristic of non-bonding like amplitude pattern in the frontier π orbitals. The magnitude of instability is estimated to be 4kcal/mol per carbonyl group by modern DFT calculations and experimental results.

Modeling on Grass Pea and Mung Bean Pulse Production in Bangladesh Using ARIMA Model

In this study an attempt has been made to examine the rate of growth, measure the instability as well as forecasting of grass pea and mung bean pulse production. For forecasting, deterministic and ARIMA model have been fitted and projections have been made on the basis of the best fitted deterministic and ARIMA model. The magnitude of instability in grass pea and mung bean pulse production was estimated by computing the coefficient of variation (CV) and the percentage deviations from three years moving average values. The study reveals that the grass pea pulse production was observed to be relatively stable (CV being 44.38%) compared to mung bean pulse production (CV being 52.87%). The variation of the growth rates in grass pea pulse production was -19.51% to 14.44% and mung bean pulse production was -21.55% to 20.26% during the study period. The projection of production indicated the vital potential of grass pea and mung bean pulse in Bangladesh. Thus, policy makers, stake holders and beneficiaries (farmers) should take necessary steps to check the decline in area under sugarcane without further delay.

DETECTING AND QUANTIFYING GLOBAL INSTABILITY USING KINETIC AND KINEMATIC PARAMETERS

Instability during gait can be identified in many different ways [Bloem 1998]. Recent studies have suggested utilizing spatiotemporal parameters to detect instability during gait [Hollman 2007]. Detecting instability using kinetic and kinematic gait parameters has not yet been examined fully. In addition, these studies have not yet identified measures that are capable of assessing the magnitude of instability. The objective of the present study was to identify kinetic and kinematic gait parameters that can best identify instability and quantify its magnitude.

Instability of electromagnetic waves with radial polarization in a rotating relativistic electron beam guided by ion channel

AbstractDispersion characteristics of electromagnetic waves with radial and azimuthal polarization in a rotating relativistic electron beam guided by an ion channel are investigated. Ion-channel electrostatic field and self-fields of relativistic electron beam were included in the formalism. It is shown that the wave with radial polarization is unstable in two regions due to coupling with fast space charge wave. The behaviors of the instability magnitude and spread are analyzed as a function of equilibrium parameters. The introduced instability can be used for amplification and production of high-intensity laser pulse with radial polarization.

Instability Dependency of Osteoarthritis Development in a Rabbit Model of Graded Anterior Cruciate Ligament Transection

Joint instability has long been empirically recognized as a leading risk factor for osteoarthritis. However, formal mechanistic linkage of instability to osteoarthritis development has not been established. This study aimed to support a clinically accepted, but heretofore scientifically unproven, concept that the severity and rapidity of osteoarthritis development in unstable joints is dependent on the degree of instability. In a survival rabbit knee model of graded joint instability, the relationship between the magnitude of instability and the intensity of cartilage degeneration was studied at the organ level in vivo. Sixty New Zealand White rabbits received either complete or partial (medial half) transection of the anterior cruciate ligament or sham surgery (control) on the left knee. At the time that the animals were killed at eight or sixteen weeks postoperatively (ten animals for each treatment and/or test-period combination), the experimental knees were subjected to sagittal plane stability measurement, followed by whole-joint cartilage histological evaluation with use of the Mankin score. Sagittal plane instability created in the partial transection group was intermediate between those in the complete transection and sham surgery groups. The partial and complete transection groups exhibited cartilage degeneration on the medial femoral and/or medial tibial surfaces. The average histological score (and standard deviation) for the medial compartment in the partial transection group (2.9 ± 0.9) was again intermediate, significantly higher than for the sham surgery group (1.9 ± 0.8) and significantly lower than for the complete transection group (4.5 ± 2.3). The average histological scores for the medial compartment in the partial transection group correlated significantly with the magnitude of instability, with no threshold effect being evident. The significance level of alpha was set at 0.05 for all tests. The severity of cartilage degeneration increased continuously with the degree of instability in this survival rabbit knee model of graded instability.

Modulation instabilities in a system of four coupled, nonlinear Schrödinger equations

The modulation instability of continuous waves for a system of four coupled nonlinear Schrödinger equations, two of which are in the unstable regime, is studied. In earlier studies, plane or continuous waves for a system of two coupled, nonlinear Schrödinger equations is shown to exhibit modulation instability (MI), even if both modes are in the normal dispersion regime, provided that the coefficient of cross phase modulation (XPM) is larger than that of self phase modulation (SPM). Requirements for MI in this system of four coupled, nonlinear Schrödinger equations can be relaxed. MI can occur even if the magnitude of XPM is less than that of SPM, and the magnitude of instability is generally larger than that of each mode alone. The implications for parametric process and wavelength exchange in optical physics with two pump waves are discussed.

Effects of Dissolved Air on Subcooled Flow Boiling of a Dielectric Coolant in a Microchannel Heat Sink

The effects of dissolved air in the dielectric liquid FC-77 on flow boiling in a microchannel heat sink containing ten parallel channels, each 500μm wide and 2.5mm deep, were experimentally investigated. Experiments were conducted before and after degassing, at three flow rates in the range of 30-50ml∕min. The dissolved air resulted in a significant reduction in wall temperature at which bubbles were first observed in the microchannels. Analysis of the results suggests that the bubbles observed initially in the undegassed liquid were most likely air bubbles. Once the boiling process is initiated, the wall temperature continues to increase for the undegassed liquid, whereas it remains relatively unchanged in the case of the degassed liquid. Prior to the inception of boiling in the degassed liquid, the heat transfer coefficients with the undegassed liquid were 300-500% higher than for degassed liquid, depending on the flow rate. The heat transfer coefficients for both cases reach similar values at high heat fluxes (>120kW∕m2) once the boiling process with the degassed liquid was well established. The boiling process induced a significant increase in pressure drop relative to single-phase flow; the pressure drop for undegassed liquid was measured to be higher than for degassed liquid once the boiling process became well established in both cases. Flow instabilities were induced by the boiling process, and the magnitude of the instability was quantified using the standard deviation of the measured pressure drop at a given heat flux. It was found that the magnitude of flow instability increased with increasing heat flux in both the undegassed and degassed liquids, with greater flow instability noted in the undegassed liquid.

Instability of chromosome 8 as an indicator of aggressive tumor phenotype in pancreatic cancer.

Chromosomal instability is a common feature of pancreatic carcinoma, but its biological significance remains unclear. In this study, we investigated the association between chromosomal instability and biological aggressiveness in human pancreatic cancer cells. Fluorescence in situ hybridization was performed to examine changes in chromosomal numbers in a total of 13 pancreatic cancer cell lines. We also assessed the potential for tumor aggressiveness within cancer cells by in vitro migration and invasion assay and by subcutaneous implantation into nude mice. Chromosomal instability, characterized by numerical variations in copy numbers of chromosome 8, was observed in most cell lines, and the magnitude of instability was correlated well with both motility (P < 0.001) and invasion rate (P < 0.001) of these cells. Furthermore, a significant positive correlation existed between chromosome instability and tumor growth in vivo (P < 0.01). These results suggest that the increased level of chromosomal instability may play a critical role in the development of aggressive tumor phenotype during pancreatic cancer progression. J. Surg. Oncol. 2001;76:181-187.

Can deglaciation trigger earthquakes in N. America?

A spherical, self‐gravitating viscoelastic earth model is used to calculate the spatial and temporal evolution of the glacially induced lithospheric stress and fault stability in North America. The predicted onset time of a pulse of earthquake activities, the mode of failure and the magnitude of instability are investigated for three sites with different distance from the former ice margin. It is found that glacial unloading is able to trigger paleo‐earthquakes within the ice margin near Charlevoix (47.5°N, 70.1°W) and in Wabash Valley (38.5°N, 87°W) outside the ice margin. However, rebound stress decays away from the former ice margin, thus glacial unloading is unlikely to have triggered the large M8 earthquakes in New Madrid (36.6°N, 89.5°W).

On-off diffusion: onset and statistics

A particle motion in a 2D periodic potential with the symmetry such that a particular motion can be restricted on the x-axis, subject to the external periodic force in the x-direction, is studied. It is found that by changing the amplitude of the external force, the 1D diffusive motion in the x-direction undergoes the instability at an amplitude, above which the diffusive motion in the y-direction, showing on-off intermittency, is observed. We call it on-off diffusion. By introducing a simple mapping model, the diffusion coefficient in the y-direction is found to take the scaling form slightly above the instability point where and . and L, respectively, are the transverse Lyapunov exponent evaluating the magnitude of instability and its fluctuation in the y-direction. The scaling function h(z) takes the asymptotic form, for and for .

The initiation of cyclonic circulation in a vertically unstable stagnant air mass

AbstractEquations of motion are derived in cylindrical co‐ordinates and they are applied to investigate the perturbations in a vertically unstable stagnant air mass having infinite lateral extent and confined between two horizontal planes. A complete solution of the perturbation equation with the boundary conditions is derived. The boundary conditions are then varied by surrounding and surmounting the unstable air mass by stable air. It is shown that the horizontal extent of the unstable air mass has a definite upper limit which depends on the magnitude of instability, height of the disturbance, and the Coriolis parameter.The mathematical analysis is then applied to show that a tropical cyclone may originate from vertical instability. It is shown by a numerical illustration that the distribution and order of magnitude of the different meteorological elements are the same in the mathematical model as observed in the initial stages of a tropical cyclone.