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1
Sutikto, Tarsicius, and Kunihide Chikamori. "Evaluation of Philip's infiltration equation for cultivated upland terraces in Indonesia." Journal of Hydrology 143, no. 3-4 (March 1993): 279–95. http://dx.doi.org/10.1016/0022-1694(93)90196-g.
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NAKAEGAWA, Tosiyuki, Taikan OKI, and Katumi MUSIAKE. "Aggregation of distributions of infiltration parameters using its aggregation criteria derived from Philip's equation." Doboku Gakkai Ronbunshu, no. 642 (2000): 1–18. http://dx.doi.org/10.2208/jscej.2000.642_1.
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R. J. Kunze and W. H. Shayya. "ASSESSING THE VALIDITY OF THE PHILIP'S TWO-TERM EQUATION IN DOWNWARD INHLTRATION AND CAPILLARY RISE." Transactions of the ASAE 34, no. 5 (1991): 2047–51. http://dx.doi.org/10.13031/2013.31835.
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Marino, John A. "Creative accounting in the age of Philip II? Determining the ‘just’ rate of interest." Historical Journal 36, no. 4 (December 1993): 761–83. http://dx.doi.org/10.1017/s0018246x00014497.
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ABSTRACTDeficit financing, revenue projections and interest rates in Spanish Naples provide the context to reflect upon the exigencies of debt resolution, the illusions of mathematical certainty and the perils of temporizing in political decision-making. ‘Creative accounting’ explores the micro-history of an equation, which provided the mathematical rationale to lower Spanish interest rates to 3·3 per cent and to resolve the controversy over the ‘just’ rate of interest. In an attempt to generate revenues during the Spanish financial crisis of the 1570s that surrounded Philip II's second bankruptcy in Castile, Philip's Castilian accountants devised a proposal to suspend the hearth census in the Kingdom of Naples for fifteen years in exchange for a prepayment at discount. An analysis of the mathematics of the discount schedule raises questions about early modern economic realities. Changes in the significance of figures and quantitative relationships, like changes in the meaning of words, reveal the mental processes used to represent economic fact and to construct solutions to economic difficulties even in the midst of crises.
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Cundy, Terrance W., and Scott W. Tento. "Solution to the Kinematic Wave Approach to Overland Flow Routing With Rainfall Excess Given by Philip's Equation." Water Resources Research 21, no. 8 (August 1985): 1132–40. http://dx.doi.org/10.1029/wr021i008p01132.
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Dumbrovský, Miroslav, Ivana Kameníčková, Jana Podhrázská, František Pavlík, and Veronika Sobotková. "Evaluation of soil conservation technologies from the perspective of selected physical soil properties and infiltration capacity of the soil." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 59, no. 1 (2011): 37–48. http://dx.doi.org/10.11118/actaun201159010037.
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This paper evaluates different technologies of soil cultivation (conventional and minimization) in terms of physical properties and water regime of soils, where infiltration of surface water is a major component of subsurface water. Soil physical properties (the current humidity, reduced bulk density, porosity, water retention capacity of soil, pore distribution and soil aeration) is determined from soil samples taken from the organic horizon according to standard methodology. To observe the infiltration characteristics of surface layers of topsoil, the drench method (double ring infiltrometers) was used. For the evaluation of field measurements of infiltration, empirical and physically derived equations by Kostiakov and Philip and the three-parameter Philip-type equation were used. The Philip three-parameter equation provides physical based parameters near the theoretical values, a good estimation of saturated hydraulic conductivity Ks and sorptivity C1. The parameter S of Philip’s equation describes the real value of the sorptivity of the soil. Experimental research work on the experimental plots H. Meziříčko proceeded in the years 2005–2008.
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Jagani, A. H., P. K. Shrivastava, and D. K. Dwivedi. "Evaluation of Kostiakov’s and Philip’s infiltration models on the soil of Dediapada, India." Journal of Applied and Natural Science 10, no. 3 (September 2, 2018): 1073–77. http://dx.doi.org/10.31018/jans.v10i3.1845.
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Infiltration models are used in designing and optimizing irrigation projects as they are capable of predicting infiltration rate and accumulated infiltration depth to a reasonable level of accuracy. The objective of this study deals with obtaining the parameters of infiltration models like Kostiakov and Philip, applying these models to the soil of Dediapada and evaluating their performance by comparing it with the observed infiltration. Firstly, the accumulated infiltration and infiltration rates were determined by the field measurement using a double ring infiltrometer. Kostiakov’s and Philip’s infiltration models were then applied to obtain simulated data once its parameters were ascertained. The estimated parameters ‘m’ and ‘n’ for the Kostiakov model were 0.1311 and -0.3092 respectively and the corresponding equations obtained for estimating infiltration rate and accumulated infiltration depth were 0.13t-0.30 and 0.19t0.69. The estimated parameters ‘s’ and ‘k’ for the Philip model were 0.32 and 0.014 respectively and the corresponding equations obtained for estimating infiltration rate and accumulated infiltration depth were 0.16t-0.5+0.014 and 0.32t0.5+0.014t. The coefficient of determination values for evaluating the performance of the model were obtained in excess of 0.95 for both the models. Due to lack of research on the application of infiltration models on the clay loam soil of Dediapada, this study would prove to be useful for estimation of infiltration rate and depth.
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Poulovassilis, Alexander, and Ioannis Argyrokastritis. "A new approach for studying vertical infiltration." Soil Research 58, no. 5 (2020): 509. http://dx.doi.org/10.1071/sr19266.
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The exact contribution of the pressure head gradient term during the vertical infiltration process, occurring in homogeneous porous media under zero ponding head, is determined analytically to advance the knowledge related to the infiltration phenomenon. This contribution is smaller than that of the horizontal infiltration by a factor at which is a measurable function of the infiltration time t, characteristic of each porous body. By adding to this contribution that of gravity, a new two-term analytical equation is formulated which exactly reproduces an available vertical cumulative curve and satisfies the physics governing infiltration process. The properties of at allow the derivation of an equation accurate for small and moderate t and of another one accurate for all t, including large values. By applying new methodologies, the values of the sorptivity and hydraulic conductivity are determined analytically from an available cumulative infiltration curve. Philip’s two-term equation, which does not satisfy the physical requirements at the upper extreme of t, and three other equations that do satisfy it, are examined in the light of the findings of the present work. The proposed equations are able to describe the vertical infiltration process and may be used to provide the hydraulic properties.
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Mollerup, M. "Philip’s infiltration equation for variable-head ponded infiltration." Journal of Hydrology 347, no. 1-2 (December 2007): 173–76. http://dx.doi.org/10.1016/j.jhydrol.2007.09.015.
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Ma, Wenmei, Xingchang Zhang, Qing Zhen, and Yanjiang Zhang. "Effect of soil texture on water infiltration in semiarid reclaimed land." Water Quality Research Journal 51, no. 1 (August 18, 2015): 33–41. http://dx.doi.org/10.2166/wqrjc.2015.025.
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The infiltration of water and its influencing factors in disturbed or reclaimed land are not well understood. A better understanding would provide essential information for assessing the hydrological processes in disturbed ecosystems. We measured the infiltration of water in soils from loamy and sandy reclaimed land. The relationships between infiltration and soil properties were analyzed based on three models: the Kostiakov, Philip, and Green–Ampt equations. Our objectives were to understand water infiltration in reclaimed land with a variety of soil textures and to establish the dependence of water infiltration on soil properties. Both the rate of infiltration and the cumulative infiltration were higher in sandy than in loamy soils. The rate of infiltration and the cumulative infiltration decreased with soil depth in undisturbed land. The sorptivity rate (S) from the Philip equation, empirical coefficient (K) from the Kostiakov equation, and the satiated hydraulic conductivity (Ksl) from the Green–Ampt equation were 22%, 16%, and 7.1% higher, respectively, in sandy than in loamy soils. The Ksl increased significantly with Ks (saturated hydraulic conductivity) in both sandy and loamy soils. These indicated that the Green–Ampt equation can be used to describe Ks and the characteristics of infiltration for soils on disturbed land.
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Molina, A., G. Govers, A. Van den Putte, and V. Vanacker. "Reducing the hydrological connectivity of gully systems through vegetation restoration: combined field experiment and numerical modelling approach." Hydrology and Earth System Sciences Discussions 6, no. 2 (March 23, 2009): 2537–71. http://dx.doi.org/10.5194/hessd-6-2537-2009.
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Abstract. Restoration of degraded land in the southern Ecuadorian Andes has led to alterations in the functioning of degraded catchments. Recovery of vegetation on areas affected by overgrazing, as well as the reforestation or afforestation of gully areas have given rise to modifications of hydrological connectivity within the catchments. Recent research has highlighted the ability of gully channels to trap sediment eroded from steep slopes, especially if vegetation is established along the gully bed. However, vegetation cover not only induces sediment deposition in the gully bed, but may also have a potential to reduce runoff water volume. The performance of gully beds in reducing the transfer of runoff water was investigated by conducting controlled concentrated flow experiments in the field. Experimental field data for 9 gullies were derived by pouring concentrated inflow into the upstream end of the gully channel and measuring the outflow at the downstream end of the channel. Two consecutive flow experiments per gully were carried out, so that data for dry and wet soil conditions were collected. The hydrological response to concentrated flow was estimated for each experiment by calculating its cumulative infiltration coefficient, IC (%). The results showed a great difference in IC between dry and wet soil conditions. The IC for wet soil conditions was on average 24%, whereas it was 60% for dry conditions. Gullies with more than 50% surface vegetation cover exhibit the highest cumulative infiltration coefficients (81% for "dry runs", and 34% for "wet runs"), but runoff transmission losses were not as clearly related to vegetation cover as sediment storage. The experimental field data of 16 experiments were used to calibrate a hydrological model in order to simulate the transfer of concentrated flow along the gully beds. The model is based on (i) the Philip's equation to simulate runoff water infiltration and (ii) the kinematic wave approximation to simulate runoff routing. The model is able to predict the transfer of runoff water generally well, as the error on the predicted total outflow volumes is below 13% for 15 out of 16 cases. The sensitivity analysis indicates that the most sensitivity parameters to predictions of transfer of runoff flow in the gully channel are sorptivity S, hydraulic conductivity K and runoff width W. The high sensitivity of model results to some crucial hydraulic parameters is one of the reasons why the relationships between model parameter values and gully features are relatively weak. The results obtained from the field experiments and the kinematic wave model show that gully systems are key elements in the hydrological connectivity of degraded landscapes. The transfer of overland flow and sediment from the slopes towards the river system highly depends on the presence/absence of vegetation in the gully beds and should therefore be accounted for in assessments of landscape degradation and/or recovery.
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SIEBERT, DIOGO NARDELLI, LUIZ ADOLFO HEGELE, RODRIGO SURMAS, LUÍS ORLANDO EMERICH DOS SANTOS, and PAULO CESAR PHILIPPI. "THERMAL LATTICE BOLTZMANN IN TWO DIMENSIONS." International Journal of Modern Physics C 18, no. 04 (April 2007): 546–55. http://dx.doi.org/10.1142/s0129183107010784.
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The velocity discretization is a critical step in deriving the lattice Boltzmann (LBE) from the Boltzmann equation. The velocity discretization problem was considered in a recent paper (Philippi et al., From the continuous to the lattice Boltzmann equation: the discretization problem and thermal models, Physical Review E 73: 56702, 2006) following a new approach and giving the minimal discrete velocity sets in accordance with the order of approximation that is required for the LBE with respect to the Boltzmann equation. As a consequence, two-dimensional lattices and their respective equilibrium distributions were derived and discussed, considering the order of approximation that was required for the LBE. In the present work, a Chapman-Enskog (CE) analysis is performed for deriving the macroscopic transport equations for the mass, momentum and energy for these lattices. The problem of describing the transfer of energy in fluids is discussed in relation with the order of approximation of the LBE model. Simulation of temperature, pressure and velocity steps are also presented to validate the CE analysis.
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NAKAEGAWA, Tosiyuki, Taikan OKI, and Katumi MUSIAKE. "DERIVATION OF EQUATIONS OF SPATIALLY-AVERAGED INFILTRATION AND THEIR AGGREGATION CRITERIA BY USING PHILIP'S EQUATIONS." PROCEEDINGS OF HYDRAULIC ENGINEERING 42 (1998): 175–80. http://dx.doi.org/10.2208/prohe.42.175.
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Madani, Douib, Salah Zitouni, and Djebabla Abdelhak. "Well-posedness and exponential decay for a laminated beam in thermoelasticity of type III with delay term." MATHEMATICA 63 (86), no. 1 (May 20, 2021): 58–76. http://dx.doi.org/10.24193/mathcluj.2021.1.06.
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We study the well-posedness and asymptotic behaviour of solutions to a laminated beam in thermoelasticity of type III with delay term in the first equation. We show that the system is well-posed by using Lumer-Philips theorem and prove that the system is exponentially stable if and only if the wave speeds are equal.
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Coxeter, H. S. M. "The Simplicial Helix and the Equation tan nθ = n tan θ." Canadian Mathematical Bulletin 28, no. 4 (December 1, 1985): 385–93. http://dx.doi.org/10.4153/cmb-1985-045-5.
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AbstractBuckminster Fuller has coined the name tetrahelix for a column of regular tetrahedra, each sharing two faces with neighbours, one 'below' and one 'above' [A. H. Boerdijk, Philips Research Reports 7 (1952), p. 309]. Such a column could well be employed in architecture, because it is both strong and attractive. The (n — 1)-dimensional analogue is based on a skew polygon such that every n consecutive vertices belong to a regular simplex. The generalized twist which shifts this polygon one step along itself is found to have the characteristic equation(λ - 1)2{(n - 1)λn-2 + 2(n - 2)λn-3 + 3(n - 3)λn-4 + . . . + (n - 2)2λ + (n - 1)} = 0,which can be derived from tan nθ = n tan θ by setting λ = exp (2θi).
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Miller, John Boris. "The foliage density equation revisited." Journal of the Australian Mathematical Society. Series B. Applied Mathematics 27, no. 4 (April 1986): 387–401. http://dx.doi.org/10.1017/s0334270000005038.
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AbstractThe foliage density equation is the means by which the foliage density g in a leaf canopy, as a function of the angle of inclination of the leaves, is to be estimated from discrete data gathered using photometric methods or point quadrats. It is an integral equation relating f, a function of angle estimated from measurements, to the unknown function g. The explicit formula for g is known and depends upon f and its first three derivatives; the operator f →, g is unbounded, and the problem is ill posed.In this paper we give the form of g when f is a trigonometric polynomial, extending earlier results due to J. R. Philip. This provides a means of estimating g without directly estimating the derivatives of f from numerical data. To assess the reliability of the method we discuss the convergence of Fourier series representations of f and g.
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Bristow, KL, and MJ Savage. "Estimation of parameters for the Philip two-term infiltration equation applied to field soil experiments." Soil Research 25, no. 4 (1987): 369. http://dx.doi.org/10.1071/sr9870369.
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Two methods based on least squares analysis used to estimate coefficients in the Philip two-term infiltration equation are compared. The one method maintains the infiltration equation in its original form, while the other involves a mathematical transformation which introduces self-correlation and yields different estimates of the coefficients. Data from field infiltration experiments are used to illustrate these differences, and the need to distinguish between fitting data to empirical models and deriving system parameters from analysis of physically based models is emphasized.
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Mollerup, Mikkel. "Erratum to “Philip’s infiltration equation for variable-head ponded infiltration” [J. Hydrol. 347 (2007) 173–176]." Journal of Hydrology 355, no. 1-4 (June 2008): 214. http://dx.doi.org/10.1016/j.jhydrol.2008.03.024.
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Liu, Ning Ning. "The Numerical Solution of Richards Equation Using the Lattice Boltzmann Method." Applied Mechanics and Materials 188 (June 2012): 90–95. http://dx.doi.org/10.4028/www.scientific.net/amm.188.90.
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The Richards equation is applied to describe the unsaturated soil moisture movement. The Lattice Boltzmann method is developed to solve this partial differential equation. The accuracy and efficiency of the Lattice Boltzmann method in modeling unsaturated soil moisture movement are compared to the Philip series method as well as Crank-Nicolson finite difference scheme. The results reveal that all three methods provide solutions of comparable accuracy. The computation efficiency, accuracy and simplicity of the Lattice Boltzmann method indicate that it has the capacity to model unsaturated soil moisture movement.
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Zerbe, Gary O., Philip G. Archer, Natalio Banchero, and Andrew J. Lechner. "On comparing regression lines with unequal slopes." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 251, no. 6 (December 1, 1986): R1239. http://dx.doi.org/10.1152/ajpregu.1986.251.6.r1239-r.
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Page R178: Gary O. Zerbe, Philip G. Archer, Natalio Banchero, and Andrew J. Lechner. “On comparing regression lines with unequal slopes.” Page R179: first column, the paragraph after Equation 7 should read Case II. If A < 0 and D > 0, then the tests will be significant for X's satisfying (See PDF)
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PHILIPPI, PAULO CESAR, LUIZ ADOLFO HEGELE, RODRIGO SURMAS, DIOGO NARDELLI SIEBERT, and LUÍS ORLANDO EMERICH DOS SANTOS. "FROM THE BOLTZMANN TO THE LATTICE-BOLTZMANN EQUATION: BEYOND BGK COLLISION MODELS." International Journal of Modern Physics C 18, no. 04 (April 2007): 556–65. http://dx.doi.org/10.1142/s0129183107010796.
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In this work, we present a derivation for the lattice-Boltzmann equation directly from the linearized Boltzmann equation, combining the following main features: multiple relaxation times and thermodynamic consistency in the description of non isothermal compressible flows. The method presented here is based on the discretization of increasingly order kinetic models of the Boltzmann equation. Following a Gross-Jackson procedure, the linearized collision term is developed in Hermite polynomial tensors and the resulting infinite series is diagonalized after a chosen integer N, establishing the order of approximation of the collision term. The velocity space is discretized, in accordance with a quadrature method based on prescribed abscissas (Philippi et al., Phys. Rev E 73, 056702, 2006). The problem of describing the energy transfer is discussed, in relation with the order of approximation of a two relaxation-times lattice Boltzmann model. The velocity-step, temperature-step and the shock tube problems are investigated, adopting lattices with 37, 53 and 81 velocities.
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Xing, Weimin, Peiling Yang, Chang Ao, Shumei Ren, and Yao Xu. "Mathematical Model of Ammonium Nitrogen Transport to Runoff with Different Slope Gradients under Simulated Rainfall." Water 11, no. 4 (April 1, 2019): 675. http://dx.doi.org/10.3390/w11040675.
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The removal of nutrients by overland flow remains a major source of non-point pollution in agricultural land. In this study, a mathematical model of ammonium nitrogen transport from soil solution to overland flow was established. The model treated the mass transfer coefficient (km) as a time-dependent parameter, which was not a constant value as in previous studies, and it was evaluated with a four-slope gradient and three rainfall intensities. The kinematic-wave equation for overland flow was solved by an approximately semi-analytical solution based on Philip’s infiltration model, while the diffusion-based mass conversation equation for overland nutrient transport was solved numerically. The results showed that the simulated runoff processes and ammonium nitrogen concentration transport to the overland flow agreed well with the experimental data. Further correlation analyses were made to determine the relationships between the slope gradient, rainfall intensity and the hydraulic and nutrient transport parameters. It turned out that these parameters could be described as a product of exponential functions of slope gradient and rainfall intensity. Finally, a diffusion-based model with a time-dependent mass transfer coefficient was established to predict the ammonium nitrogen transport processes at the experimental site under different slope gradients and rainfall intensities.
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Hamzah, Hamzah, and Moh Toifur. "ANALISIS KETAHANAN PRODUK SOLAR CELL BERBANTUAN SOFTWARE LOGGER PRO." ORBITA: Jurnal Kajian, Inovasi dan Aplikasi Pendidikan Fisika 5, no. 2 (November 28, 2019): 73. http://dx.doi.org/10.31764/orbita.v5i2.1191.
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ABSTRAKPenelitian ini bertujuan untuk menentukan kualitas solar cell pada nilai fill factor (ff) dan efisiensinya ( ). Data tegangan Vi dan Ii diambil secara otomatis menggunakan software logger pro dan menggunakan analisis persamaan eksponensial . Data diambil dari solar cell merk polikristal type (99×69) mm2 yang dipaparkan di depan sumber cahaya lampu bohlam philips 100W/220V sejauh 18 cm pada Ir sebesar 983, 344 W/m2. Nilai Pmax terbesar besar berada pada sudut kemiringan 30o sebesar 0,0231 watt. ff yaitu 67%, efisiensi 22%. Pada sudut 30o tersebut arah cahaya datang tegak lurus dengan bidang solar cell. Sedangkan ff terendah kemiringan 70o yaitu 0,5362 dan efisiensi 13%. Kata kunci: Fill factor dan efisiensi solar cell; logger pro. ABSTRACTThis study aims to determine the quality of solar cell on the value of the fill factor (ff) and efficiency (h). The voltage data Vi and Ii are taken automatically using logger pro software and using exponential equation analysis. The data was taken from polycrystalline solar cell type (99×69) mm2 which was presented in front of the light source of Philips lamp bulb 100W/220V as far as 18 cm at Ir of 983, 344 W/m2. The largest Pmax value is at a slope angle of 30o of 0,0231 watts. ff is 67%, efficiency is 22%. At the 30o angle the direction of the light comes perpendicular to the plane of the solar cell. While the lowest ff is 70o, which is 0,5362 and efficiency is 13%. Keywords: Fill factor and efficiency solar cell; logger pro.
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Tong, Bing, Thomas J. Sauer, Zhiqiu Gao, Xinhua Xiao, and Robert Horton. "Improving Soil Heat Flux Accuracy with the Philip Correction Technique." Journal of Hydrometeorology 20, no. 7 (July 1, 2019): 1435–48. http://dx.doi.org/10.1175/jhm-d-18-0243.1.
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Abstract Soil heat flux Gs is an important component of the surface energy balance. Soil heat flux plates (SHFPs) are widely used to measure Gs, although several errors are known to occur. The Philip correction has been applied to minimize errors in Gs measured by SHFPs (Gp) if the soil thermal conductivity λs, SHFP thermal conductivity λp, and plate geometry function H are known. The objective of this study is to evaluate the effectiveness of the Philip correction for a variety of SHFPs. The λp were determined without thermal contact resistance and differed from the manufacturer-specified λp. A simplified H formulation was similar to or less than the full H equation for different SHFP shapes. The G ratio (Gp/Gs) was sensitive to λs/λp and H when they were relatively small. Compared with the Gs determined by a gradient method (Gs_grad), the Gp measured under a full corn (Zea mays, L.) canopy in the field underestimated Gs by 38%–62%. After applying the Philip correction, almost all Gp agreed better with Gs_grad. Generally, the Gp corrected with measured plate parameters agreed better with Gs_grad than those corrected with manufacturer-specified values. The Gp corrected with the simplified and full H expression differed for different SHFPs. These results indicate that SHFPs always underestimate Gs and that the performance of the Philip correction is affected by λp, plate dimensions, and H. An alternative method to measure Gs by a three-needle heat-pulse sensor or a gradient method, in which soil temperature and water content are measured at several depths, is recommended.
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Joachimiak, Magda. "Choice of the regularization parameter for the Cauchy problem for the Laplace equation." International Journal of Numerical Methods for Heat & Fluid Flow 30, no. 10 (January 16, 2020): 4475–92. http://dx.doi.org/10.1108/hff-10-2019-0730.
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Purpose In this paper, the Cauchy-type problem for the Laplace equation was solved in the rectangular domain with the use of the Chebyshev polynomials. The purpose of this paper is to present an optimal choice of the regularization parameter for the inverse problem, which allows determining the stable distribution of temperature on one of the boundaries of the rectangle domain with the required accuracy. Design/methodology/approach The Cauchy-type problem is ill-posed numerically, therefore, it has been regularized with the use of the modified Tikhonov and Tikhonov–Philips regularization. The influence of the regularization parameter choice on the solution was investigated. To choose the regularization parameter, the Morozov principle, the minimum of energy integral criterion and the L-curve method were applied. Findings Numerical examples for the function with singularities outside the domain were solved in this paper. The values of results change significantly within the calculation domain. Next, results of the sought temperature distributions, obtained with the use of different methods of choosing the regularization parameter, were compared. Methods of choosing the regularization parameter were evaluated by the norm Nmax. Practical implications Calculation model described in this paper can be applied to determine temperature distribution on the boundary of the heated wall of, for instance, a boiler or a body of the turbine, that is, everywhere the temperature measurement is impossible to be performed on a part of the boundary. Originality/value The paper presents a new method for solving the inverse Cauchy problem with the use of the Chebyshev polynomials. The choice of the regularization parameter was analyzed to obtain a solution with the lowest possible sensitivity to input data disturbances.
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KAO, PAN-FU, HSUN-NAN KUO, SHIH-JYUN LIU, DA-MING YEH, and LUNG-KWANG PAN. "BIOKINETIC AND DOSIMETRIC ASSESSMENT OF FLUORINE 18 IN HEALTHY VOLUNTEERS SUBJECTED TO 18F–NaF PET/CT BONE SCANS VIA COMPARTMENTAL/MATLAB MODELS AND IN-VIVO STUDY." Journal of Mechanics in Medicine and Biology 18, no. 08 (December 2018): 1840022. http://dx.doi.org/10.1142/s0219519418400225.
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Objective: This study quantified the time-dependent concentration of [Formula: see text]F–NaF in critical organs according to a simplified compartmental biokinetic model with clinical verification. Methods: The eleven volunteers were given [Formula: see text][Formula: see text]MBq [Formula: see text]F–NaF administration, then scanned (with 15[Formula: see text]min-collection, every 20[Formula: see text]min, for 200 consecutive min) with a Philips Gemini GXL PET/CT. The empirical data were collected and normalized as the input dataset for MATLAB program. A six-compartmental model was created as a set of time-dependent differential equations and analyzed by the MATLAB to optimize the correlation between the in vivo data and calculated results. The six compartments were: body fluid, bone, kidney, liver, remainder and excretion, while kidney and liver compartments were conventionally split into two subunits with different half-lives to fit properly the empirical data. Results: The average biological half-lives of body fluid, bone, kidney-1, kidney-2, liver-1, liver-2 and the remainder (rest of body) were assessed as [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text][Formula: see text]min, respectively. A dimensionless AT index of disagreement between the empirical data and MATLAB optimal solutions was proposed of validating the applied acquisition system and analytical method feasibility. The body fluid and bone AT values did not exceed 20%. The proposed refined equation yielded the internal dose from both gamma- and beta-rays ([Formula: see text] cSv as [Formula: see text] cSv/MBq), which exhibited good correlation with literature (0.00168–0.00270 cSv/MBq). Conclusion: The proposed MATLAB-based fitting of in-vivo data with the theoretical results was instrumental for assessing the radiation dose received by the PET/CT bone scan participants.
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McCartney, M. R. "Electron Holographic Imaging of Magnetic Materials at Nanometer Scale Resolution." Microscopy and Microanalysis 3, S2 (August 1997): 519–20. http://dx.doi.org/10.1017/s143192760000948x.
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Traditional electron microscopy techniques for imaging magnetic microstructure include out-of-focus Fresnel or Lorentz imaging, Foucault imaging and differential phase contrast (DPC). Off-axis electron holography provides access to both the amplitude and phase of the electron wave which has passed through the sample and therefore can provide direct, quantitative information about the in-plane component of the magnetic induction. The Philips CM200-FEG microscope which was used for the holography described here is equipped with a powerful mini-lens below the specimen enabling 2nm spatial resolution and only a small residual field at the sample. The combination of high coherence and increased magnification enable quantitative mapping of magnetic induction at the nanometer scale.Electrostatic or magnetic potentials give rise to phase shifts in the holographic interference fringes which can be quantified following reconstruction. In the presence of a magnetic field, the phase equation (for constant composition and neglecting diffraction effects) becomes:
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Yacoubi, Samir, Adel Slatni, and Khemaies Zayani. "Analysis of Saturation Risk in Sprinkler Irrigation: Case of Cherfech Irrigation Perimeter in Tunisia." Journal of Agricultural Science 10, no. 2 (January 12, 2018): 130. http://dx.doi.org/10.5539/jas.v10n2p130.
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This study is targeted to the assessment of the saturation risk in sprinkler irrigation. For this purpose, in situ field trials were carried out to infer the saturated hydraulic conductivity (Ks) and sorptivity (S) using the disc infiltrometer method. Since the measured values of Ks are very close to prescribed application rate, caution is required. In a first step, the pressure head at the wetting front (hf) and the useful porosity (θs – θi) are assumed to be constant. Thus, the logarithmic derivation of the sorptivity provides a relation between relative variations of S and Ks. The ponding time (Ts) is estimated from Green and Ampt (1911) and Philip (1957b) infiltration equations. The risk of saturation is deemed to be inexistent inasmuch as simulated values of Ts are greater than the irrigation times practiced in the zone. In a second step, the values of the pressure head at the wetting front and saturated water content were assumed to be variable with soil texture. Simulations of the ponding time were carried out based on Rawls and al. (1981) data. For the recommended sprinkler spacing in the Cherfech perimeter (12 m × 12 m), the simulations show a good agreement between Ts values generated from Green and Ampt and Philip equations for Ks ranging from 1.5 to 6 mm/h. Moreover, it was established that saturation risk due to a gradual texture variation is virtually inexistent in the conditions prevailing in Cherfech perimeter.
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Philippi, Paulo C., Keijo K. Mattila, Diogo N. Siebert, Luís O. E. dos Santos, Luiz A. Hegele Júnior, and Rodrigo Surmas. "Lattice-Boltzmann equations for describing segregation in non-ideal mixtures." Journal of Fluid Mechanics 713 (October 26, 2012): 564–87. http://dx.doi.org/10.1017/jfm.2012.473.
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AbstractIn fluid mechanics, multicomponent fluid systems are generally treated either as homogeneous solutions or as completely immiscible parts of a multiphasic system. In immiscible systems, the main task in numerical simulations is to find the location of the interface evolving over time, driven by normal and tangential surface forces. The lattice-Boltzmann method (LBM), on the other hand, is based on a mesoscopic description of the multicomponent fluid systems, and appears to be a promising framework that can lead to realistic predictions of segregation in non-ideal mixtures of partially miscible fluids. In fact, the driving forces in segregation are of a molecular nature: there is competition between the intermolecular forces and the random thermal motion of the molecules. Since these microscopic mechanisms are not accessible from a macroscopic standpoint, the LBM can provide a bridge linking the microscopic and macroscopic domains. To this end, the first purpose of this article is to present the kinetic equations in their continuum forms for the description of the mixing and segregation processes in mixtures. This paper is limited to isothermal segregation; non-isothermal segregation was discussed by Philippi et al. (Phil. Trans. R. Soc., vol. 369, 2011, pp. 2292–2300). Discretization of the kinetic equations leads to evolution equations, written in LBM variables, directly amenable for numerical simulations. Here the dynamics of the kinetic model equations is demonstrated with numerical simulations of a spinodal decomposition problem with dissolution. Finally, some simplified versions of the kinetic equations suitable for immiscible flows are discussed.
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Tsai, Sung-Yi, Hsien-Chun Tseng, Zhipeng Ruan, Zumei Xu, Yonggui Liao, Sheng-Pin Changlai, and Chien-Yi Chen. "Extra radiation dose of lungs in male examinees during cardiac computed tomography." Nuclear Technology and Radiation Protection 32, no. 4 (2017): 350–57. http://dx.doi.org/10.2298/ntrp1704350t.
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The use of multi-detector row computed tomography in cardiac examinations is increasing globally. Several hospitals are yet to establish a practical method for evaluating the extra scattering dose in the lungs (Dlung) of male examinees with different body-weights undergoing cardiac computed tomography. To measure the dose in each slice of a lung (Dlung,i), thermoluminescent dosimeters are inserted into Rando and tissue-equivalent phantoms made of polymethylmethacrylate and derived from ICRU 48 with masses from 10 to 90 kg. Dlung was evaluated by weighing the scanned volume of each slice. A practical method for determining Dlung involves 64-slice computed tomography scans using a Philips Brilliance computed tomography at 120 kV and 200 mAs, with a thickness of 1.0 mm. Dlung,i increased with distance from the scanning region. This experiment yielded Dlung values from 12.1 ? 2.1 mSv (90 kg) to 23.0 ? 3.8 mSv (10 kg). Finally, a simple equation can be used to derive the relationship between Dlung and the body-weights of a male examinee. Experimental results are compared with others in the literature.
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Wang, Y. C., T. M. Chou, and M. Libera. "Electron Refraction of Amorphous Nanospheres." Microscopy and Microanalysis 3, S2 (August 1997): 1055–56. http://dx.doi.org/10.1017/s1431927600012162.
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The phase shift imparted to an incident high-energy electron wave in a TEM is related to the specimen’s electron-refractive properties. These, in turn, are related to the electrostatic potential and, by Fourier transform (1), to the electron scattering factors fei(s) for the various atom species i in the specimen and scattering vectors s. The average refractive index is determined by the mean electrostatic (inner) potential, Φo, and can be modelled as Φo = (C/Ω) Σfei(s0) [equation 1] where C = 47.878 (V-Å2) and the summation runs over all of the atoms in the unit volume Ω (2). Calculated fei(s) data are available from the literature (e.g. 3). These calculations have only been done for neutral atoms and some fully ionized cations and anions. They do not account for electron redistribution due to covalent bonding to which Φo is quite sensitive (4).This research is making Φo measurements using transmission electron holography. Holograms were collected using a 200keV Philips CM20 FEG TEM equipped with a non-rotatable biprism (5) and a Gatan 794 Multiscan camera.
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Xin, Yan, Yun Xie, and Yuxin Liu. "Effects of Residue Cover on Infiltration Process of the Black Soil Under Rainfall Simulations." Water 11, no. 12 (December 9, 2019): 2593. http://dx.doi.org/10.3390/w11122593.
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Residue cover is widely used for soil conservation after crop harvesting in the black soil region of the Northeastern China, which influences infiltration. It is necessary to optimize infiltration models for accurate predictions under bare and residue cover slope conditions. Rainfall simulation experiments were conducted to quantify the infiltration for the black soil under four rainfall intensities (30, 60, 90, and 120 mm/h), five residue coverage controls (15%, 35%, 55%, 75%, and bare slope), and two soil moisture (8% and approximately 30%) conditions. The observed data were used to fit and compare four infiltration models by Kostiakov, Mein and Larson (short for GAML, a modification of GreenAmpt model made by Mein and Larson), Horton, and Philip under the bare slope conditions. The residue cover infiltration factor (RCFi) was derived to predict the infiltration under the residue cover slopes, which was defined as the ratio of infiltration from residue-covered soil to that from bare soil. The results showed that the newly derived equation coupling the Philip model with the RCFi was the most accurate way of predicting the cumulative infiltration of black soil under various residue covers, and could be applied to the black soil region for residue cover infiltration predictions.
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Hakim, Lukmanul, Nanis Susanti, and Ujianto. "Influence of Customer Relationship Management, Brand Equity, Perceived Product Quality, Perceived Price on Customer Value and Purchase Intention (Studies Philips Light Bulb in Batam)." International Journal of Economics and Finance 9, no. 7 (June 12, 2017): 122. http://dx.doi.org/10.5539/ijef.v9n7p122.
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This study tried to determine and analyze the deeper understanding of the influence of customer relationship management, brand equity, perceived of product quality, perceived value and price to the customer at the customer's purchase intention Philips light bulb in Batam.The population in this study are all users (consumers) electric light bulb philips brands in the city of Batam. Testing of the model in this study, with Generalized Least Square Estimation (GLS), analysis of structural equation modeling (SEM), proportional random sampling method and software assistance Amos 22, on 240 respondents from eight times the 30 indicators the study variables. The test results indicate the model (fit) seen from the GFI, AGFI, TLI, CFI, RMSEA and CMIN / DF, each of 0915, 0901, 0949, 0953, 0063, and 1,376 are all that are in the range of expected values so that the model can be accepted.The results showed that: 1). Customer relationship management influence on customer value, it shows that with good customer relationship management program, will increase customer value. 2) Customer relationship management influence on purchase intention, it shows that with good customer relationship management program, will increase customer value. 3) Brand equity effect on customer value, it shows that with a good brand equity, will increase customer value. 4). Brand equity effect on purchase intention, it shows that with a good brand equity, will increase customer value. 5) Perceived quality of product effect on customer value, it indicates that the perceived quality of a good product, will increase customer value. 6). Perceived quality of product effect on purchase intention, this suggests that the perceived quality of a good product, will increase purchase intention. 7). Perceived price effect on customer value, it indicates that the perceived price friendly, will increase customer value. 8) Perceived price effect on purchase intention, this suggests that the perceived price friendly, will increase purchase intention. 9). Customer value effect on purchase intention, it shows that with high customer value, will raise the purchase intention.
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Ho, Ruoya, Lijie Zhao, Yun-Yu Wang, Zhifeng Shao, and Andrew P. Somlyo. "Thickness measurements by Electron Energy Loss Spectroscopy (EELS)." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 434–35. http://dx.doi.org/10.1017/s0424820100148009.
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An estimate of specimen mass-thickness is an essential requirement for evaluate with EELS the absolute elemental concentration in biological specimens. The conventional method used for measuring specimen thickness by EELS is: where t is the specimen thickness, λi is the total inelastic mean free path, It is the total count in an EELS spectrum and I0 is the count in the zero loss peak. This equation is rigorously correct, only if the electrons are collected over all scattering angles and the spectrum covers all energy losses. But in most experiments with a finite energy loss region, because of the limited collection semi-angle, we can only collect a fraction of scattered electrons. Omitting the high loss electrons will result in a cut-off error that is usually less than 5%, if we use an energy window from 0 eV to 150 eV or above. But the effect of the limited semi-angle is more serious. Fig. 1 shows the ln(It/I0) measured on the same specimen in both TEM and STEM mode at 80 keV with a magnetic sector spectrometer equipped with a parallel detector on Philips 400 FEG.
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Teng, Shiang-Yu, and Sheng-Jye Hwang. "Simulations of Process-Induced Warpage During IC Encapsulation Process." Journal of Electronic Packaging 129, no. 3 (December 11, 2006): 307–15. http://dx.doi.org/10.1115/1.2753936.
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Warpage during integrated circuit encapsulation process is a serious problem. Previous researchers had focused on warpage analysis with thermal-induced shrinkage and the cure-induced shrinkage was neglected. A new approach considering both cure- and thermal-induced shrinkage during encapsulation process was presented to predict the amount of warpage. The cure-induced shrinkage was described by the pressure-volume-temperature-cure (P-V-T-C) equation of epoxy. The thermal-induced shrinkage was described by the coefficients of thermal expansion of the component materials. The thin small outline package (TSOP) DBS-27P and low-profile quad flat package (LQFP) LQFP-64, which were manufactured by Philips Semiconductor located in Taiwan and Siliconware Precision Industries Corporation, respectively, were chosen to be the simulation models. By comparing the amount of predicted warpage with the experimental results, it showed that the approach could better predict the amount of warpage than that considering only thermal-induced shrinkage. It was also found that the sign of cure-induced warpage could be opposite to the thermal-induced warpage. Appropriate design of a package to make cure- and thermal-induced shrinkage to be of opposite sign could minimize the warpage of a package.
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Joachimiak, Magda, Michał Ciałkowski, and Andrzej Frąckowiak. "Stable method for solving the Cauchy problem with the use of Chebyshev polynomials." International Journal of Numerical Methods for Heat & Fluid Flow 30, no. 3 (October 5, 2019): 1441–56. http://dx.doi.org/10.1108/hff-05-2019-0416.
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Purpose The purpose of this paper is to present the method for solving the inverse Cauchy-type problem for the Laplace’s equation. Calculations were made for the rectangular domain with the target temperature on three boundaries and, additionally, on one of the boundaries, the heat flux distribution was selected. The purpose of consideration was to determine the distribution of temperature on a section of the boundary of the investigated domain (boundary Γ1) and find proper method for the problem regularization. Design/methodology/approach The solution of the direct and the inverse (Cauchy-type) problems for the Laplace’s equation is presented in the paper. The form of the solution is noted as the linear combination of the Chebyshev polynomials. The collocation method in which collocation points had been determined based on the Chebyshev nodes was applied. To solve the Cauchy problem, the minimum of functional describing differences between the target and the calculated values of temperature and the heat flux on a section of the domain’s boundary was sought. Various types of the inverse problem regularization, based on Tikhonov and Tikhonov–Philips regularizations, were analysed. Regularization parameter α was chosen with the use of the Morozov discrepancy principle. Findings Calculations were performed for random disturbances to the heat flux density of up to 0.01, 0.02 and 0.05 of the target value. The quality of obtained results was next estimated by means of the norm. Effect of the disturbance to the heat flux density and the type of regularization on the sought temperature distribution on the boundary Γ1 was investigated. Presented methods of regularization are considerably less sensitive to disturbances to measurement data than to Tikhonov regularization. Practical implications Discussed in this paper is an example of solution of the Cauchy problem for the Laplace’s equation in the rectangular domain that can be applied for determination of the temperature distribution on the boundary of the heated element where it is impossible to measure temperature or the measurement is subject to a great error, for instance on the inner wall of the boiler. Authors investigated numerical examples for functions with singularities outside the domain, for which values of gradients change significantly within the calculation domain what corresponds to significant changes in temperature on the wall of the boiler during the fuel combustion. Originality/value In this paper, a new method for solving the Cauchy problem for the Laplace’s equation is described. To solve this problem, the Chebyshev polynomials and nodes were used. Various types of regularization of this problem were considered.
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Debasish, Sathya Swaroop. "Analysis of Long-Term Relationship between Spot and Futures prices Using Johansen’s Test of Cointegration." Information Management and Business Review 2, no. 2 (February 15, 2011): 65–80. http://dx.doi.org/10.22610/imbr.v2i2.884.
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The main objective of the study is to examine the long-term relationship between spot prices and futures prices A. The study has used daily prices (closing, opening, high and low) in both spot market and futures market for the 40 sample individual stocks drawn from six leading sectors namely, Automobiles, Banking, Cement, Gas, Oil & Refineries, Information Technology and Pharmaceutical. The period of study is from 1st January 1997 to 31st May 2009. The study begins by testing the stationarity of the spot price series and futures price series using two econometric methods namely, Philips Perron (PP) test and Augmented Dickey-Fuller (ADF) test. The long term relationship between spot prices and futures prices is statistically tested using Johansen’s test of Cointegration employing likelihood Ratio (L.R.), under the hypothesis that there exists a single cointegration equation between spot and future prices. It is found that both spot prices and futures prices for the selected companies are not stationary in the level form, but there is evidence of stationarity in the first difference form. The study finds a single long-term relationship for each of the selected companies across the six sectors. Among the selected companies in each sector, those evidencing strongest relation in respective sector are Tata Motors, Punjab National Bank, Gujrat Ambuja Cements, Bongaigaon Refineries, I-Flex and GLAXO Pharma.
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Huang, F., S. L. Patel, D. Combs, and S. Parthasarathy. "0656 Mortality and Hospitalization in Patients With Heart Failure and Sleep Apnea: A Retrospective Study of Positive Airway Pressure Therapy in Medicare Beneficiaries." Sleep 43, Supplement_1 (April 2020): A250—A251. http://dx.doi.org/10.1093/sleep/zsaa056.652.
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Abstract Introduction Sleep apnea is common in patients with heart failure (HF) and can be treated with positive airway pressure (PAP) therapy. In patients with both HF and sleep apnea, whether treatment of PAP therapy is associated with reduction in hospitalization or mortality is unclear. Methods We used 5% Medicare limited-dataset (LDS) from 2013-2015 to perform a retrospective study of hospitalizations and mortality in HF patients with sleep apnea who received or did not receive PAP therapy over an 18-month time period. All-cause mortality during post-treatment period, any and HF-related hospitalizations in baseline, pre-treatment and post-treatment periods were measured and compared. Propensity score matching, generalized estimating equations (GEE) model for repeated measures analysis and COX-survival analysis adjusted by multiple covariates were used for longitudinal comparisons and mortality. Results We have identified 281,161 patients with at least two distinct HF onsets and 62,800 of them had sleep apnea diagnosis (22%). Of these patients, 5,540 of them had initiated their PAP therapy while 12,129 of them only had their sleep apnea diagnosis during the selection time frame from Jan 1st, 2014 to June 30th, 2015 without PAP treatment (control group). After adjusting for various confounders and propensity score matching, bilevel PAP was strongly associated with lower hospitalization and HF-associated hospitalization (Bilevel-PAP vs. Control: Any hospitalization, OR=0.62, 95%CI=0.53-0.74, p<0.0001; HF-associated hospitalization, OR=0.65, 95%CI=0.55-0.78, p<0.0001). Cox proportional hazards survival analysis revealed that all of the PAP-treated groups had a better 6-month survival after treatment initiation when compared to controls (any PAP therapy vs. Control: HR=0.32, 95%CI=0.28-0.37, p<0.0001). Conclusion In a retrospective analysis, PAP therapy was associated with lower 6-month all-cause mortality among Medicare beneficiaries with HF and sleep apnea. Bilevel-PAP therapy was consistently associated with significant reduction in hospitalization among these patients. Our observational findings warrant confirmation by future prospective intervention trials. Support NIH (HL126140; MD011600; HL138377; HL140144; IPA-014264-00001), PCORI (PPRND-1507-31666; PCS-1504-30430), American Academy of Sleep Medicine Foundation (169-SR-17), and Philips Healthcare/ Philips-Respironics Inc.
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Rosser, Gervase, Mark Jenner, and Bill Luckin. "Review of periodical articles." Urban History 27, no. 1 (May 2000): 110–35. http://dx.doi.org/10.1017/s0963926800000171.
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One of the attractions of medieval urban history is the fact that major conceptual problems in the field continue to be debated. In a stimulating review article by J.H. Mundy, ’Philip Jones and the medieval Italian city-state‘, J. of European Economic History, 28 (1999), 185–200, one distinguished scholar is taxed for holding views now dismissed by some, but of which he is by no means a unique surviving representative. One of these views assumes a clear distinction between the antique city, supposedly a bureaucratic centre with limited economic functions, and the medieval city, as the home of industrious artisans and nascent capitalism. The image of the non-profit-making ancient town may be overly indebted to the nature of the literary sources and to the prevalent interests of classicists; but, although many would now agree that both the elements in the above equation need qualifying, a more focused comparison is presently lacking, and a fine book is still waiting to be written on the transition from the ancient world to the middle ages in urban history.
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ZHANG, DAWEI, LIU ZE YU, PHILIP LIN HUANG, SYLVIA LEE-HUANG, and JOHN Z. H. ZHANG. "COMPUTATIONAL DESIGN OF NORBORNANE-BASED HIV-1 PROTEASE INHIBITORS." Journal of Theoretical and Computational Chemistry 09, no. 02 (April 2010): 471–85. http://dx.doi.org/10.1142/s0219633610005773.
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A series of norbornane-based HIV-1 protease (PR) inhibitors are designed theoretically to displace the tetrahedrally coordinated internal water molecule that bridges inhibitor to flaps via hydrogen bonds. These designed inhibitors use the norbornenone oxygen atom to mimic this structural water molecule and contain diols to interact with the carboxylate oxygens of catalytic aspartates. The binding free energies were estimated by modified linear interaction energy approach [Zoete H, Michielin O, Karplus M, J Comput Aided Mol Des17:861, 2003], in which the binding free energy is written as a linear combination of the electrostatic interaction energy between PR and the ligand, E elec , the van der Waals interaction energy between PR and the ligand, E vdW , and the difference of the solvation free energies of the complex, the receptor, and the isolated ligand, ΔG solv . The equation obtained in previous work [Da W. Zhang, Philip Lin Huang, Sylvia Lee-Huang, John Z. H. Zhang, J Theor Comput Chem7:485, 2008] is applied directly to calculate the binding free energy of designed norbornane-based HIV-1 PR inhibitors.
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Mardare, Cristinel, and Tong Yang. "Partial Differential Equations and Continuum Mechanics: a Collection of Papers Dedicated to Professor Philippe G. Ciarlet on the Occasion of His 80th Birthday." Acta Mathematicae Applicatae Sinica, English Series 35, no. 1 (January 2019): 1–2. http://dx.doi.org/10.1007/s10255-019-0807-9.
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Vu, Hong Thai, and Evangelos Tsotsas. "Mass and Heat Transport Models for Analysis of the Drying Process in Porous Media: A Review and Numerical Implementation." International Journal of Chemical Engineering 2018 (2018): 1–13. http://dx.doi.org/10.1155/2018/9456418.
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The modeling and numerical simulation of drying in porous media is discussed in this work by revisiting the different models of moisture migration during the drying process of porous media as well as their restrictions and applications. Among the models and theories, we consider those are ranging from simple ones like the diffusion theory to more complex ones like the receding front theory, the model of Philip and de Vries, Luikov’s theory, Krischer’s theory, and finally Whitaker’s model, in which all mass, heat transport, and phase change (evaporation) are taken into account. The review of drying models as such serves as the basis for the development of a framework for numerical simulation. In order to demonstrate this, the system of equations governing the drying process in porous media resulting from Whitaker’s model is presented and used in our numerical implementation. A numerical simulation of drying is presented and discussed to show the capability of the implementation.
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Leão, Tairone Paiva, and Edmund Perfect. "Modeling water movement in horizontal columns using fractal theory." Revista Brasileira de Ciência do Solo 34, no. 4 (August 2010): 1463–68. http://dx.doi.org/10.1590/s0100-06832010000400042.
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Fractal mathematics has been used to characterize water and solute transport in porous media and also to characterize and simulate porous media properties. The objective of this study was to evaluate the correlation between the soil infiltration parameters sorptivity (S) and time exponent (n) and the parameters dimension (D) and the Hurst exponent (H). For this purpose, ten horizontal columns with pure (either clay or loam) and heterogeneous porous media (clay and loam distributed in layers in the column) were simulated following the distribution of a deterministic Cantor Bar with fractal dimension H" 0.63. Horizontal water infiltration experiments were then simulated using Hydrus 2D software. The sorptivity (S) and time exponent (n) parameters of the Philip equation were estimated for each simulation, using the nonlinear regression procedure of the statistical software package SAS®. Sorptivity increased in the columns with the loam content, which was attributed to the relation of S with the capillary radius. The time exponent estimated by nonlinear regression was found to be less than the traditional value of 0.5. The fractal dimension estimated from the Hurst exponent was 17.5 % lower than the fractal dimension of the Cantor Bar used to generate the columns.
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Leung, Man Chun. "Blow-up solutions of nonlinear elliptic equations in ? n with critical exponent Dedicated to Philippe Dufour, whose exquisite horology artwork ??Simplicity?? inspires so much." Mathematische Annalen 327, no. 4 (December 1, 2003): 723–44. http://dx.doi.org/10.1007/s00208-003-0468-z.
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Tinet, A. J., A. Chanzy, I. Braud, D. Crevoisier, and F. Lafolie. "Development and evaluation of an efficient soil-atmosphere model (FHAVeT) based on the Ross fast solution of the Richards equation for bare soil conditions." Hydrology and Earth System Sciences 19, no. 2 (February 20, 2015): 969–80. http://dx.doi.org/10.5194/hess-19-969-2015.
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Abstract. In agricultural management, a good timing in operations, such as irrigation or sowing, is essential to enhance both economical and environmental performance. To improve such timing, predictive software are of particular interest. Optimal decision-software would require process modules which provide robust, efficient and accurate predictions while being based on a minimal amount of parameters easily available. The objective of this study is to assess the accuracy of a physically based model with high efficiency. To this aim, this paper develops a coupled model with climatic forcing based on the Ross fast solution for Richards' equation, heat transfer and detailed surface energy balance. The present study is limited to bare soil, but the impact of vegetation can be easily included. The developed model, FHAVeT (Fast Hydro Atmosphere Vegetation Temperature), is evaluated against the coupled model based on the Philip and De Vries (1957) description, TEC. The two models were compared for different climatic and soil conditions. Moreover, the model allows using various pedotransfer functions. The FHAVeT model showed better performance in regards to mass balance, mostly below 0.002 m, and generally improved computation time. In order to allow for a more precise comparison, six time windows were selected. The study demonstrated that the FHAVeT behaviour is quite similar to the TEC behaviour except under some dry conditions. The ability of the models to detect the occurrence of soil intermediate water content thresholds with a 1 day tolerance was also evaluated. Both models agreed in more than 90% of the cases.
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BANDERIER, CYRIL, and MICHAEL DRMOTA. "Formulae and Asymptotics for Coefficients of Algebraic Functions." Combinatorics, Probability and Computing 24, no. 1 (December 11, 2014): 1–53. http://dx.doi.org/10.1017/s0963548314000728.
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We study the coefficients of algebraic functions ∑n≥0fnzn. First, we recall the too-little-known fact that these coefficientsfnalways admit a closed form. Then we study their asymptotics, known to be of the typefn~CAnnα. When the function is a power series associated to a context-free grammar, we solve a folklore conjecture: the critical exponents α cannot be 1/3 or −5/2; they in fact belong to a proper subset of the dyadic numbers. We initiate the study of the set of possible values forA. We extend what Philippe Flajolet called the Drmota–Lalley–Woods theorem (which states that α=−3/2 when the dependency graph associated to the algebraic system defining the function is strongly connected). We fully characterize the possible singular behaviours in the non-strongly connected case. As a corollary, the generating functions of certain lattice paths and planar maps are not determined by a context-free grammar (i.e., their generating functions are not ℕ-algebraic). We give examples of Gaussian limit laws (beyond the case of the Drmota–Lalley–Woods theorem), and examples of non-Gaussian limit laws. We then extend our work to systems involving non-polynomial entire functions (non-strongly connected systems, fixed points of entire functions with positive coefficients). We give several closure properties for ℕ-algebraic functions. We end by discussing a few extensions of our results (infinite systems of equations, algorithmic aspects).
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Kameníčková, Ivana, L. Larišová, and A. Stoklásková. "The impact of different tillage treatments on hydraulic conductivity of loamy soil." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 60, no. 5 (2012): 109–14. http://dx.doi.org/10.11118/actaun201260050109.
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Water infiltration into the soil profile, surface runoff and soil erosion in arable lands depend on the conditions of the top layer. The tillage treatment of the top layer plays a key role in changes of the hydro-physical properties, mainly saturated hydraulic conductivity Ks of the surface layer. The aim of this study was to asses the impact of different tillage treatments on hydraulic conductivity in the locality Bohaté Málkovice. Field experimental works in this area were performed in 2009 and were repeted in 2011 on Haplic Chernozem, medium heavy loamy soil. The experimental area was divided into two parts; top layer of these plots was cultivated by applying conventional and reduced tillage treatment. Both these plots were sown with spring barley (Hordeum vulgare). For the field measurement of water infiltration into the soil was used double-ring infiltrometer (2009, 2011) and Minidisk infiltrometer (2011). Near the point were the infiltration was measured, the soil samples were always collected for laboratory determination of basic physical properties of soil (bulk density, porosity, initial and saturated water content, aeration of the soil) and saturated hydraulic conductivity Ks. For laboratory determination of Ks was used permeameter with constant gradient.For evaluation of saturated hydraulic conductivity Ks using the double-ring infiltration method was used Philip’s three-parameter equation and for evaluation of unsaturated hydraulic conductivity K(h) using Minidisk infiltrometer was used Zang’s method. After two years of using repeatedly applied different tillage treatments was significantly influenced saturated hydraulic conductivity Ks. The Ks value increased approximately six times for reduced tillage and more than three times for conventional tillage. Laboratory determined average values of Ks were compared with the average estimates of Ks from infiltration tests. The results were burdened by a number of errors (compaction, preferential flow). These mean values were higher for conventional and reduced tillage. Unsaturated hydraulic conductivity K(−2cm) for reduced tillage was higher, for conventional tillage decreased approximately three times.
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Chandio, Abbas Ali, Yuansheng Jiang, and Abdul Rehman. "Energy consumption and agricultural economic growth in Pakistan: is there a nexus?" International Journal of Energy Sector Management 13, no. 3 (September 2, 2019): 597–609. http://dx.doi.org/10.1108/ijesm-08-2018-0009.
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Purpose This study aims to empirically examine the relationship between energy consumption and agricultural economic growth in Pakistan over the period from 1984 to 2016. Design/methodology/approach This study used the autoregressive distributed lag (ARDL) bounds testing approach to cointegration to investigate the long-run and short-run determinants of agricultural economic growth in Pakistan. Findings The results of the ARDL bounds testing approach to cointegration revealed that long-run linkage exists among the study variables. The findings of this paper showed that agricultural economic growth is positively affected by gas consumption and electricity consumption both in the long-run and short run. The long-run and short-run coefficients of gas consumption and electricity consumption were estimated to be 0.906, 0.421, 0.595 and 0.276, respectively. The estimated equation remains stable during the period from 1984 to 2016 as analyzed by the stability tests. Originality/value This study considers the relationship between energy consumption and agricultural economic growth in Pakistan by using an ARDL bounds testing approach to cointegration. The study has three contributions to economic literature:this study used different unit root tests to test stationarity of the variables such as ADF unit root test by Dicky and Fuller and P-P unit root test by Philip and Perron; the ARDL bounds testing approach to cointegration is applied to test the existence of long-run analysis between energy consumption and agricultural economic growth; and to check the robustness, the authors used the Johansen cointegration test to examine the long-run relationship between dependent and independent variables.
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Ovcharenko, E. A., K. Yu Klyshnikov, I. N. Sizova, N. V. Kondyukova, and L. S. Barbarash. "Numerical assessment of the anatomy of the annulus fibrosus of the mitral valve in health and disease as per three-dimensional echocardiography." Patologiya krovoobrashcheniya i kardiokhirurgiya 25, no. 2 (June 28, 2021): 50. http://dx.doi.org/10.21688/1681-3472-2021-2-50-59.
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<p><strong>Aim.</strong> We analysed the geometry and dynamics of the annulus fibrosus of the mitral valve in normal conditions, with mitral regurgitation of degenerative and ischaemic aetiology based on three-dimensional echocardiography with subsequent mathematical processing.</p><p><strong>Methods.</strong> We included the data of transesophageal three-dimensional echocardiography of 50 patients in the following three groups: 10 patients with degenerative regurgitation, 10 patients with ischaemic mitral regurgitation and 30 patients in the ‘normal’ group without mitral valve pathology. Transesophageal echocardiography was performed using an iE33 expert level equipment (Philips, USA), to quantitatively analyse the anterior-posterior diameter, anterolateral-posterior median diameter, intercommissural diameter, three-dimensional circumference of mitral valve, two-dimensional height of the coaptation zone, leaf height, maximum height, front and back angles of the valves, nonplanar angle, planarity coefficient and ellipticity coefficient. The measurements were performed for both the phases of the cardiac cycle, the period of expulsion of systole and the period of diastole filling, corresponding to the closed and open states of the valve. In addition, the treated data sets were processed in the QLAB programme (Philips, USA) where sets of points describing the geometry of the mitral valve were obtained. Thereafter, we used the in-house algorithm in the MATLAB R2015a environment (MathWorks, Massachusetts, USA). Mathematical models of the anatomy of the annulus rings were obtained for all the three studied groups.</p><p><strong>Results.</strong> A functional study of the mitral valve showed a similar nature of changes in the geometric features of the annulus fibrosus for both the pathologies. The dynamic performance of the fibrous rings during systole-diastole cycle significantly differed among the studied groups. We present the equations for the averaged models of the annulus fibrosus of the groups analysed in the study that can be used in design, verification and computer modelling problems.</p><p><strong>Conclusion.</strong> Pathological changes in the geometry of the mitral valve during ischaemic and degenerative regurgitation work on a similar principle, although there are aetiological differences. However, these pathologies differ when the changes in the geometry of the dynamics of ‘systole-diastole’ are analysed that warrant the use of different approaches and devices for their correction.</p><p>Received 5 November 2020. Revised 12 December 2020. Accepted 22 December 2020.</p><p><strong>Funding:</strong> The work is supported by a grant of the President of the Russian Federation No. 075-15-2020-067.</p><p><strong>Conflict of interest:</strong> Authors declare no conflict of interest.</p><p><strong>Author contributions</strong><br />Conception and study design: E.A. Ovcharenko, L.S. Barbarash<br />Data collection and analysis: K.Yu. Klyshnikov, I.N. Sizova, N.V. Kondyukova<br />Statistical analysis: K.Yu. Klyshnikov<br />Drafting the article: E.A. Ovcharenko, K.Yu. Klyshnikov<br />Critical revision of the article: E.A. Ovcharenko, K.Yu. Klyshnikov, I.N. Sizova, N.V. Kondyukova<br />Final approval of the version to be published: E.A. Ovcharenko, K.Yu. Klyshnikov, I.N. Sizova, N.V. Kondyukova, L.S. Barbarash</p>
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Webster, James. "Haydn’s sensibility." Studia Musicologica 51, no. 1-2 (March 1, 2010): 13–27. http://dx.doi.org/10.1556/smus.51.2010.1-2.2.
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Recent interpretations of both Haydn’s personality (as a man) and his musical style (or ‘persona’) have focused on the two opposed categories earnestness and wit . The present essay adds a third category on both sides of the equation: sensibility (German Empfindsamkeit ), and argues that it is equally important. The various meanings of sensibility are laid out and their applicability to Haydn discussed, including his rich and varied relationships with lovers and intimate friends. The problematics of the possible correlations between an artist’s personality and his style are discussed; it is argued that, contrary to recent theories of their separation into different domains, these are in fact closely related. Sensibility was a central aspect of mid- and late 18th-century aesthetics, both in ideas about ideal human behavior, and in prose fiction, opera and drama, etc. — as well as instrumental music (Carl Philipp Emanuel Bach). In Haydn’s case, not surprisingly, it has so far been located in genres destined primarily for private use: keyboard music and lieder; this is illustrated by an analysis and interpretation of “Das Leben ist ein Traum” (Hob. XXVIa:21; published 1784). In such works we may imagine Haydn as ‘speaking to’ the dedicatee of the work, as well as the sympathetic listener. However, sensibility is also an important aspect of style in the string quartet and symphony, where it has almost never been considered relevant. Examples are discussed in the slow movements from the quartet op. 76 no. 5 and the symphonies nos. 75, 88, 92, 98, 99, and 102. It is argued that the old notion of ‘Classical style’ (fortunately now on the decline), with its rigid demarcation of ‘high’ instrumental genres from both vocal music (Haydn’s operas) and earlier instrumental Empfindsamkeit (Emanuel Bach), was the primary reason that scholars and listeners have until now remained unmoved by Haydn’s sensibility.