Factors Hindering Pakistani Farmers' Choices Towards Adoption of Crop Insurance
Institute of Scientific and Technical Information of China (English)
Sidra Ghazanfar; Zhang Qi-wen; Muhammad Abdullah; Jaleel Ahmed; Imran Khan; Zeeshan Ahmad
2015-01-01
This study was conducted to analyze the factors that negatively influence Pakistani farmers' willingness to participate in crop insurance. Probit model was applied to identify the significant factors which influenced our dependent variable "not willing to participate". The results of the analyses showed that crop insurance premium was the most influencing factor which had positive and significant impact on dependent variable. Similarly dissatisfaction with crop loan insurance scheme, lacking of knowledge about crop insurance, believing of being against Islamic rules and time taking process was also found to be positive and significantly influenced the dependent variable. While limited decision power and limited perils were not found to be significant in the results.
Degenerate Euler zeta function
Kim, Taekyun
2015-01-01
Recently, T. Kim considered Euler zeta function which interpolates Euler polynomials at negative integer (see [3]). In this paper, we study degenerate Euler zeta function which is holomorphic function on complex s-plane associated with degenerate Euler polynomials at negative integers.
Generalizations of Euler Numbers and Euler Numbers of Higher Order
Institute of Scientific and Technical Information of China (English)
LUOQiu-ming; QIFeng
2005-01-01
The purpose of this paper is to define the generalized Euler numbers and the generalized Euler numbers of higher order, their recursion formula and some properties were established, accordingly Euler numbers and Euler numbers of higher order were extended.
Taylor, Jerry D.
1983-01-01
Provides a brief, condensed biography of the eighteenth-century mathematician, Leonard Euler, focusing on some of his contributions to mathematics. Also presents several problems and suggests how Euler might have solved them. (JN)
Suisky, Dieter
2008-01-01
"Euler as Physicist" analyzes the exceptional role of Leonhard Euler (1707 - 1783) in the history of science and emphasizes especially his fundamental contributions to physics. Although Euler is famous as the leading mathematician of the 18th century, his contributions to physics are as important for their innovative methods and solutions. Several books are devoted to Euler as mathematician, but none to Euler as physicist, like in this book. Euler’s contributions to mechanics are rooted in his life-long plan presented in two volume treatise programmatically entitled "Mechanics or the science of motion analytically demonstrated". Published in 1736, Euler’s treatise indicates the turn over from the traditional geometric representation of mechanics to a new approach. In writing Mechanics Euler did the first step to put the plan and his completion into practice through 1760. It is of particular interest to study how Euler made immediate use of his mathematics for mechanics and coordinated his progress in math...
Symmetric Euler orientation representations for orientational averaging.
Mayerhöfer, Thomas G
2005-09-01
A new kind of orientation representation called symmetric Euler orientation representation (SEOR) is presented. It is based on a combination of the conventional Euler orientation representations (Euler angles) and Hamilton's quaternions. The properties of the SEORs concerning orientational averaging are explored and compared to those of averaging schemes that are based on conventional Euler orientation representations. To that aim, the reflectance of a hypothetical polycrystalline material with orthorhombic crystal symmetry was calculated. The calculation was carried out according to the average refractive index theory (ARIT [T.G. Mayerhöfer, Appl. Spectrosc. 56 (2002) 1194]). It is shown that the use of averaging schemes based on conventional Euler orientation representations leads to a dependence of the result from the specific Euler orientation representation that was utilized and from the initial position of the crystal. The latter problem can be overcome partly by the introduction of a weighing factor, but only for two-axes-type Euler orientation representations. In case of a numerical evaluation of the average, a residual difference remains also if a two-axes type Euler orientation representation is used despite of the utilization of a weighing factor. In contrast, this problem does not occur if a symmetric Euler orientation representation is used as a matter of principle, while the result of the averaging for both types of orientation representations converges with increasing number of orientations considered in the numerical evaluation. Additionally, the use of a weighing factor and/or non-equally spaced steps in the numerical evaluation of the average is not necessary. The symmetrical Euler orientation representations are therefore ideally suited for the use in orientational averaging procedures.
Inductively generating Euler diagrams.
Stapleton, Gem; Rodgers, Peter; Howse, John; Zhang, Leishi
2011-01-01
Euler diagrams have a wide variety of uses, from information visualization to logical reasoning. In all of their application areas, the ability to automatically layout Euler diagrams brings considerable benefits. In this paper, we present a novel approach to Euler diagram generation. We develop certain graphs associated with Euler diagrams in order to allow curves to be added by finding cycles in these graphs. This permits us to build Euler diagrams inductively, adding one curve at a time. Our technique is adaptable, allowing the easy specification, and enforcement, of sets of well-formedness conditions; we present a series of results that identify properties of cycles that correspond to the well-formedness conditions. This improves upon other contributions toward the automated generation of Euler diagrams which implicitly assume some fixed set of well-formedness conditions must hold. In addition, unlike most of these other generation methods, our technique allows any abstract description to be drawn as an Euler diagram. To establish the utility of the approach, a prototype implementation has been developed.
Rubillo, James M.
1987-01-01
Euler's discovery about the centroid of a triangle trisecting the line segment joining its circumference to its orthocenter is discussed. An activity that will help students review fundamental concepts is included. (MNS)
Soil Chemistry Factors Confounding Crop Salinity Tolerance—A Review
Directory of Open Access Journals (Sweden)
Pichu Rengasamy
2016-10-01
Full Text Available The yield response of various crops to salinity under field conditions is affected by soil processes and environmental conditions. The composition of dissolved ions depend on soil chemical processes such as cation or anion exchange, oxidation-reduction reactions, ion adsorption, chemical speciation, complex formation, mineral weathering, solubility, and precipitation. The nature of cations and anions determine soil pH, which in turn affects crop growth. While the ionic composition of soil solution determine the osmotic and ion specific effects on crops, the exchangeable ions indirectly affect the crop growth by influencing soil strength, water and air movement, waterlogging, and soil crusting. This review mainly focuses on the soil chemistry processes that frustrate crop salinity tolerance which partly explain the poor results under field conditions of salt tolerant genotypes selected in the laboratory.
Van der Kallen, Wilberd
2015-01-01
Let R be a noetherian ring of dimension d and let n be an integer so that n≤d≤2n-3. Let (a
Predicting factors influencing crop raiding by elephants in the ...
African Journals Online (AJOL)
Nyirenda et al.
Farm sizes, vegetation types in peripherals of crop fields and types of counter- measures used by ..... pstd Rank. Log (farm size). 28.711. -4.281. 0.014 0.001*** <0.001. 1 ..... perception of the human wildlife conflict in Kariba Urban. J. Sustain.
Assessing meteorological key factors influencing crop invasion by pollen beetle (
Directory of Open Access Journals (Sweden)
Jürgen Junk
2016-09-01
Full Text Available The pollen beetle, Meligethes aeneus F. (Coleoptera: Nitidulidae, is a severe pest of winter oilseed rape. A phenological model to forecast the first spring invasion of crops in Luxembourg by M. aeneus was developed in order to provide a tool for improving pest management and for assessing the potential effects of climate change on this pest. The model was derived using long-term, multi-site observational datasets of pollen beetle migration and meteorological data, as the timing of crop invasion is determined mainly by meteorological variables. Daily values of mean air and soil temperature, accumulated sunshine duration and precipitation were used to create a threshold-based model to forecast crop invasion. Minimising of the root mean squared error (RMSE of predicted versus observed migration dates was used as the quality criterion for selecting the optimum combination of threshold values for meteorological variables. We identified mean air temperature 8.0 °C, mean soil temperature 4.6 °C, and sunshine duration of 3.4 h as the best threshold values, with a cut-off of 1 mm precipitation and with no need for persistence of those conditions for more than one day (RMSE=9.3days$RMSE=9.3\\,\\text{days}$. Only in six out of 30 cases, differences between observed and predicted immigration dates were >5$>5$ days. In the future, crop invasion by pollen beetles will probably be strongly affected by changes in air temperature and precipitation related to climate change. We used a multi-model ensemble of 15 regional climate models driven by the A1B emission scenario to assess meteorological changes in two 30‑year future periods, near future (2021–2050 and far future (2069–2098 in comparison with the reference period (1971–2000. Air temperature and precipitation were predicted to increase in the first three months of each year, both in the near future and the far future. The pollen beetle migration model indicated that this change would
Enhancement of crop photosynthesis by diffuse light: quantifying the contributing factors.
Li, T; Heuvelink, E; Dueck, T A; Janse, J; Gort, G; Marcelis, L F M
2014-07-01
Plants use diffuse light more efficiently than direct light. However, experimental comparisons between diffuse and direct light have been obscured by co-occurring differences in environmental conditions (e.g. light intensity). This study aims to analyse the factors that contribute to an increase in crop photosynthesis in diffuse light and to quantify their relative contribution under different levels of diffuseness at similar light intensities. The hypothesis is that the enhancement of crop photosynthesis in diffuse light results not only from the direct effects of more uniform vertical and horizontal light distribution in the crop canopy, but also from crop physiological and morphological acclimation. Tomato (Solanum lycopersicum) crops were grown in three greenhouse compartments that were covered by glass with different degrees of light diffuseness (0, 45 and 71 % of the direct light being converted into diffuse light) while maintaining similar light transmission. Measurements of horizontal and vertical photosynthetic photon flux density (PPFD) distribution in the crop, leaf photosynthesis light response curves and leaf area index (LAI) were used to quantify each factor's contribution to an increase in crop photosynthesis in diffuse light. In addition, leaf temperature, photoinhibition, and leaf biochemical and anatomical properties were studied. The highest degree of light diffuseness (71 %) increased the calculated crop photosynthesis by 7·2 %. This effect was mainly attributed to a more uniform horizontal (33 % of the total effect) and vertical PPFD distribution (21 %) in the crop. In addition, plants acclimated to the high level of diffuseness by gaining a higher photosynthetic capacity of leaves in the middle of the crop and a higher LAI, which contributed 23 and 13 %, respectively, to the total increase in crop photosynthesis in diffuse light. Moreover, diffuse light resulted in lower leaf temperatures and less photoinhibition at the top of the canopy when
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
Emission factors of particulate matter (PM), element carbon (EC), organic carbon (OC), SO2, NOx, CO, CO2, and ten ions (Na+, NH4+, K+, Mg2+, Ca2+, F-, Cl-, NO2-, NO3-, SO42-) were estimated from the domestic burning of four types of commonly produced crop residues in rural China: rice straw, wheat straw, corn stover, and cotton stalk, which were collected from the representative regions across China. A combustion tower was designed to simulate the cooking conditions under which the peasants burned their crop residues in rural China, to measure the emission factors. Results show that wheat straw has the highest emission factor for the total PM (8.75 g/kg) among the four crop residues, whereas, corn stover and wheat straw have the highest emission factor for EC (0.95 g/kg) and OC (3.46 g/kg), respectively. Corn stover also presents as having the highest emission factors of NO, NOx, and CO2 whereas, wheat straw, rice straw, and cotton stalk have the highest emission factors of NO2, SO2, and CO, respectively. The water-soluble ions, K+ and Cl-, have the highest emission factors from all the crops. Wheat straw has a relatively higher emission factor of cation species and F-, Cl-, NO2- than other residues.
Generalization of the Euler Angles
Bauer, Frank H. (Technical Monitor); Shuster, Malcolm D.; Markley, F. Landis
2002-01-01
It is shown that the Euler angles can be generalized to axes other than members of an orthonormal triad. As first shown by Davenport, the three generalized Euler axes, hereafter: Davenport axes, must still satisfy the constraint that the first two and the last two axes be mutually perpendicular if these axes are to define a universal set of attitude parameters. Expressions are given which relate the generalized Euler angles, hereafter: Davenport angles, to the 3-1-3 Euler angles of an associated direction-cosine matrix. The computation of the Davenport angles from the attitude matrix and their kinematic equation are presented. The present work offers a more direct development of the Davenport angles than Davenport's original publication and offers additional results.
Pulliam, Tom; Kwak, Dochan (Technical Monitor)
1997-01-01
Implicit methods have been the workhorse for the Euler and Navier-Stokes equations for the last 25 years. The ground breaking work of Dr. Joe Steger in implementing such techniques in practical Euler and Navier-Stokes codes provided the basis for all the success in this area. This presentation will highlight his contribution and technical excellence in the area of implicit methods for CFD.
A proof of image Euler Number formula
Institute of Scientific and Technical Information of China (English)
LIN Xiaozhu; SHA Yun; JI Junwei; WANG Yanmin
2006-01-01
Euler Number is one of the most important characteristics in topology. In two- dimension digital images, the Euler characteristic is locally computable. The form of Euler Number formula is different under 4-connected and 8-connected conditions. Based on the definition of the Foreground Segment and Neighbor Number, a formula of the Euler Number computing is proposed and is proved in this paper. It is a new idea to locally compute Euler Number of 2D image.
ANALYSIS OF THE MAIN CLIMATIC FACTORS AND THEIR IMPACT ON CROP PRODUCTION
Directory of Open Access Journals (Sweden)
Elena COFAS
2014-06-01
Full Text Available The data records of crop productivity shows wide fluctuations from one year to another, these being influencedsignificantly by the conditions climate variability. In general, climate variability affects all sectors of the economy,but, in particular, the agricultural sector it is the most exposed. This study aims an statistical analyze the effectsinduced by climatological factors on the main agricultural crops, quantified in agroclimatic risks at local andregional levels, for the period 1990-2000, in Ialomita county. Thus, we used statistical data relating to the twogroups of variables: 1 agricultural productions (for the main crops – wheat and rye, corn, sunflower, sugar beet,potatoes, vegetables and 2 climatology data (for the main climatological factors – average temperatures, rainfall,the sunshine duration and the nebulosity and we analysed the possible correlations for those major variables.
Directory of Open Access Journals (Sweden)
RADEN RIJANTA
2013-01-01
Full Text Available Local food crops are believed to be important alternatives in facing the problems of continuously growing price of food stuff worldwide. There has been a strong bias in national agricultural development policy towards the production of rice as staple food in Indonesia. Local food crops have been neglected in the agricultural development policy in the last 50 years, leading to the dependency on imported commodities and creating a vulnerability in the national food security. This paper aims at assessing the factors constraining local food production in Indonesia based on empirical experiences drawn from a research in Kulon Progo Regency, Yogyakarta Province. The government of Kulon Progo Regency has declared its commitment in the development of local food commodities as a part of its agricultural development policy, as it is mentioned in the long-term and medium-term development planning documents. There is also a head regency decree mandating the use of local food commodities in any official events organized by the government organisations. The research shows that there are at least six policy-related problems and nine technical factors constraining local food crops production in the regency. Some of the policy-related and structural factors hampering the production of local food crops consist of (1 long-term policy biases towards rice, (2 strong biases on rice diet in the community, (3 difficulties in linking policy to practices, (4 lack of information on availability of local food crops across the regency and (5 external threat from the readily available instant food on local market and (6 past contra-productive policy to the production of local food crops. The technical factors constraining local food production comprises (1 inferiority of the food stuff versus the instantly prepared food, (2 difficulty in preparation and risk of contagion of some crops, lack of technology for processing, (3 continuity of supply (some crops are seasonally
Coupled Effects of Climatic and Socio-economic Factors on Winter Cropping in India
Jain, M.; Mondal, P.; Galford, G. L.; DeFries, R. S.
2015-12-01
India is predicted to be one of the most vulnerable regions in terms of agricultural sensitivity to future climate changes. Approximately 69% of India's population is rural, and over 55% of the working population relies on agriculture for sustenance and livelihoods. Indian smallholder farmers who own less than 2 ha of farmland represent 78% of the total Indian farmers and produce 41% of the country's food crops. These smallholder farmers are among some of the most vulnerable communities to climatic and economic changes due to limited access to technology, infrastructure, markets, and institutional or financial support in the case of adverse climatic events. Baseline information on agricultural sensitivity to climate variability will provide useful information for regional-level, and eventually state- and national-level, strategies and policies that promote adaption to climate variability. We use a decade of remote sensing analysis of cropping patterns and climatic factors along with census data for irrigation and demographic factors to understand winter cropping trajectories across agro-ecological zones in India. Findings from multiple agro-ecological zones indicate that there are three primary trajectories in winter cropping in India - increasing, fluctuating, and decreasing. In the Central Indian Highlands, for example, the most dominant trend is that of fluctuating cropped area, ranging between ~37,300 km2 in 2010 and ~21,100 km2 in 2013, which is associated with village-level access to irrigation and local labor dynamics. Clay soil type and increasing irrigation coverage were associated with intensification. Yet, suitable soil type and access to irrigation do not reduce vulnerability to high daytime temperatures that is negatively associated with winter crop cover. With pronounced winter warming projected in the coming decades, effective adaptation by smallholder farmers would require additional strategies, such as access to fine-scale temperature forecasts
Radiation model for row crops: I. Geometric view factors and parameter optimization
Row crops with partial cover result in different radiation partitioning to the soil and canopy compared with full cover; however, methods to account for partial cover have not been adequately investigated. The objectives of this study were to: (i) develop geometric view factors to account for the sp...
Functions and Application of the AP2/ERF Transcription Factor Family in Crop Improvement
Institute of Scientific and Technical Information of China (English)
Zhao-Shi Xu; Ming Chen; Lian-Cheng Li; You-Zhi Ma
2011-01-01
Plants have acquired sophisticated stress response systems to adapt to changing environments. It is important to understand plants' stress response mechanisms in the effort to improve crop productivity under stressful conditions. The AP2/ERF transcription factors are known to regulate diverse processes of plant development and stress responses.In this study, the molecular characteristics and biological functions of AP2/ERFs in a variety of plant species were analyzed. AP2/ERFs,especially those in DREB and ERF subfamilies, are ideal candidates for crop improvement because their overexpression enhances tolerances to drought, salt, freezing, as well as resistances to multiple diseases in the transgenic plants. The comprehensive analysis of physiological functions is useful in elucidating the biological roles of AP2/ERF family genes in gene interaction, pathway regulation, and defense response under stress environments, which should provide new opportunities for the crop tolerance engineering.
Effects of meteorological factors on the levels of Alternaria spores on a potato crop
Escuredo, Olga; Seijo, Maria Carmen; Fernández-González, Maria; Iglesias, Isabel
2011-03-01
Alternaria solani Soraeur produces early blight in Solanum tuberosum L., leading to significant agricultural losses. The current study was carried out on the extensive potato crop situated in north-western of Spain during 2007, 2008 and 2009. In this area potato crops are the most important source of income. In this work we used a Hirst-type volumetric spore-trap for the aerobiological monitoring of Alternaria spores. The highest spore concentrations were recorded during the 2009 cycle (10,555 spores), and the lowest concentrations were recorded during the 2008 cycle (5,471 spores). Over the 3 years of study, the highest concentrations were registered during the last stage of the crop. The aim of the study was to observe the influence of meteorological factors on the concentration of Alternaria spores, which can lead to serious infection and early blight. Prediction of the stages during which a crop is particularly vulnerable to infection allows for adjustment of the application of fungicide and is of environmental and agricultural importance. For this reason, we tested three models (P-Days, DD and IWP) to predict the first treatment and decrease the negative effect that these spores have on potato crops. The parameter that showed the most significant correlation with spore concentrations was minimum temperature. We used ARIMA (autoregressive integrated model of running mean) time-series models to determine the forecast. We considered weather data as predictor variables and the concentration of spores on the previous day as the fixed variable.
Generalizations of Euler Numbers and Euler Numbers of Higher Order%Euler数和高阶Euler数的推广
Institute of Scientific and Technical Information of China (English)
雒秋明; 祁锋
2005-01-01
The purpose of this paper is to define the generalized Euler numbers and the generalized Euler numbers of higher order, their recursion formula and some properties were established, accordingly Euler numbers and Euler numbers of higher order were extended.
Euler Products Beyond the Boundary
Kimura, Taro; Koyama, Shin-ya; Kurokawa, Nobushige
2014-01-01
We investigate the behavior of the Euler products of the Riemann zeta function and Dirichlet L-functions on the critical line. A refined version of the Riemann hypothesis, which is named "the Deep Riemann Hypothesis", is examined. We also study various analogs for global function fields. We give an interpretation for the nontrivial zeros from the viewpoint of statistical mechanics.
Brocard Point and Euler Function
Sastry, K. R. S.
2007-01-01
This paper takes a known point from Brocard geometry, a known result from the geometry of the equilateral triangle, and bring in Euler's [empty set] function. It then demonstrates how to obtain new Brocard Geometric number theory results from them. Furthermore, this paper aims to determine a [triangle]ABC whose Crelle-Brocard Point [omega]…
Wild, Walter J.
1980-01-01
Discusses the simplest three-body problem, known as Euler's problem. The article, intended for students in the undergraduate mathematics and physics curricula, shows how the complex equations for a specific three-body problem can be solved on a small calculator. (HM)
Nitrogen-to-Protein Conversion Factors for Crop Residues and Animal Manure Common in China.
Chen, Xueli; Zhao, Guanglu; Zhang, Yang; Han, Lujia; Xiao, Weihua
2017-10-02
Accurately determining protein content is essential in exploiting biomass as feed and fuel. A survey of biomass samples in China indicated protein contents from 2.65 to 3.98 % for crop residues and from 6.07 to 10.24 % for animal manure. Conversion factors based on amino acid nitrogen (kA) ranged from 5.42 to 6.00 for the former and from 4.78 to 5.36 for the latter, indicating that the traditional factor of 6.25 is not suitable for biomass samples. On the other hand, conversion factors from Kjeldahl nitrogen (kP) ranged from 3.97 to 4.57 and from 2.76 to 4.31 for crop residues and animal manure, respectively. Of note, conversion factors were strongly affected by amino acid composition and levels of nonprotein nitrogen. Thus, kP values of 4.23 for crop residues, 4.11 for livestock manure, and 3.11 for poultry manure are recommended to better estimate protein content from total nitrogen.
Regulatory Network of Transcription Factors in Response to Drought in Arabidopsis and Crops
Institute of Scientific and Technical Information of China (English)
Chen Li-miao; Li Wen-bin; Zhou Xin-an
2012-01-01
Drought is one of the most important environmental constraints limiting plant growth, development and crop yield. Many drought-inducible genes have been identified by molecular and genomic analyses in Arabidopsis, rice and other crops. To better understand reaction mechanism of plant to drought tolerance, we mainly focused on introducing the research of transcription factors (TFs) in signal transduction and regulatory network of gene expression conferring drought. A TF could bind multiple target genes to increase one or more kinds of stress tolerance. Sometimes, several TFs might act together with a target gene. So drought-tolerance genes or TFs might respond to high-salinity, cold or other stresses. The crosstalk of multiple stresses signal pathways is a crucial aspect of understanding stress signaling.
Abd-Elmabod, S. K.; Jordán, A.; Anaya-Romero, M.; Ali, R. R.; Muñoz-Rojas, M.; Zavala, L. M.; de la Rosa, D.
2012-04-01
The aim of this research is to study the influence of topography and soil factors on crop suitability two Mediterranean areas: Sevilla (southern Spain) and El-Fayoum (northern Egypt). The Shuttle Radar Topography Mission (SRTM) images were processed using ENVI 4.7 software to extract elevation data, slope gradient and slope direction. North-south toposequences from both areas were extracted and studied using Arc-GIS 9.3 software. Soil characteristics along these toposequences were extracted from regional soil maps, as well as land surveying and laboratory analyses. The Almagra model (included in the agro-ecological system MicroLEIS DSS) was used to evaluate agricultural soil suitability using soil factors of useful depth, texture, drainage, carbonate content, salinity, sodium saturation, and degree of development of the profile. Changes of soil characteristics through the toposequences are discussed. The results of Almagra model indicate that the crop suitability main limiting factors are soil texture, drainage, soil salinity and sodium saturation percent and topography factors elevation, slope gradient, slope direction.
Directory of Open Access Journals (Sweden)
D. JAKPERIK
2013-02-01
Full Text Available This study identified the essential factors of production in the Tono irrigation dam of the Upper East Region. The accessibility and patronage of these factors by farmers in this area was studied and how they influence crop production in the Region. A total of two hundred questionnaires designed by the Ministry of Food and Agriculture for farmers in Navrongo were administered. A snowball sampling design was employed to identify farmers on these facilities in the study area. Pearson correlation coefficient, principal component analysis, and subset regression analysis were used to unveil the relevant information in the study. The results revealed a high correlation between the factors of production being studied with each pair having a probability level less than 0.0001. The full general linear model was highly significant (F=662.50, psmaller tahn 0.0001 with only two factors (Farm size and Fertilizer accounting for 98.86% of the total variation in yield. This is a clear indication of multicollinearity and a subset regression analysis was used to identify the best subset that improves yield in the irrigation dam. The best subset comprised of Age, Farm size, seed, and Fertilizer accounting for 97.75% of the total variation in crop production in Navrongo. To enhance yield in Navrongo therefore, high yielding seeds, timely granting of fertilizer credit to farmers who mature enough and responsible with reasonable farm sizes should be encouraged.
Transfer factors of radioiodine from volcanic-ash soil (Andosol) to crops
Energy Technology Data Exchange (ETDEWEB)
Ban-Nai, Tadaaki; Muramatsu, Yasuyuki [National Inst. of Radiological Sciences, Chiba (Japan). Environmental and Toxicological Sciences Research Group
2003-03-01
In order to obtain soil-to-plant transfer factors (TFs) of radioiodine from volcanic-ash soil to agricultural crops, we carried out radiotracer experiments. The mean values of TFs (on a wet weight basis) of radioiodine from Andosol to edible parts of crops were as follows: water dropwort, 0.24; lettuce, 0.00098; onion, 0.0011; radish, 0.0044; turnip, 0.0013 and eggplant, 0.00010. The mean value of the TFs of radioiodine for edible parts of wheat (on a dry weight basis) was 0.00015. We also studied the distributions of iodine in crops. There was a tendency for the TFs of leaves to be higher than those of tubers, fruits and grains. A very high TF was found for water dropwort, because this plant was cultivated under a waterlogged condition, in which iodine desorbed from soil into soil solution with a drop in the Eh value. The data obtained in this study should be helpful to assess the long-lived {sup 129}I (half life: 1.57 x l0{sup 7} yr) pathway related to the fuel cycle. (author)
Institute of Scientific and Technical Information of China (English)
Qin WANG; Chunmei GENG; Sihua LU; Wentai CHEN; Min SHAO
2013-01-01
Experiments were performed to measure the emission factors （EFs） of gaseous carbonaceous species, such as CO2, CO, CH4, and non-methane volatile organic compounds （NMVOCs）, from the combustion of five types of coal of varying organic maturity and two types of biomass briquettes under residential burning conditions. Samples were collected in stainless steel canisters and 2,4- dinitrophenylhydrazine （DNPH） cartridges and were analyzed by GC FID/MS and HPLC, respectively. The EFs from crop residue briquette burning were generally higher than those from coals, with the exception of CO2. The dominant NMVOC species identified in coal smoke were carbonyls （41.7%）, followed by C2 unsaturated hydrocarbons （29.1%） and aromatics （12.1%）, while C2 unsaturated hydrocarbons were the dominant species （68.9%） emitted from the combustion of crop residue briquettes, followed by aromatics （14.4%）. A comparison of burning normal crop residues in stoves and the open field indicated that briquettes emitted a larger proportion of ethene and acetylene. Both combustion efficiency and coal organic maturity had a significant impact on NMVOC EFs from burning coal： NMVOC emissions increased with increasing coal organic maturity but decreased as the combustion efficiency improved. Emissions from the combustion of crop residue briquettes from stoves occurred mainly during the smoldering process, with low combustion efficiency. Therefore, an improved stove design to allow higher combustion efficiency would be beneficial for reducing emissions of carbonaceous air pollutants.
Effects of No-Till on Yields as Influenced by Crop and Environmental Factors
Energy Technology Data Exchange (ETDEWEB)
Toliver, Dustin K.; Larson, James A.; Roberts, Roland K.; English, B.C.; De La Torre Ugarte, D. G.; West, Tristram O.
2012-02-07
Th is research evaluated diff erences in yields and associated downside risk from using no-till and tillage practices. Yields from 442 paired tillage experiments across the United States were evaluated with respect to six crops and environmental factors including geographic location, annual precipitation, soil texture, and time since conversion from tillage to no-till. Results indicated that mean yields for sorghum [Sorghum bicolor (L.) Moench] and wheat (Triticum aestivum L.) with no-till were greater than with tillage. In addition, no-till tended to produce similar or greater mean yields than tillage for crops grown on loamy soils in the Southern Seaboard and Mississippi Portal regions. A warmer and more humid climate and warmer soils in these regions relative to the Heartland, Basin and Range, and Fruitful Rim regions appear to favor no-till on loamy soils. With the exception of corn (Zea mays L.) and cotton (Gossypium hirsutum L.) in the Southern Seaboard region, no-till performed poorly on sandy soils. Crops grown in the Southern Seaboard were less likely to have lower no-till yields than tillage yields on loamy soils and thus had lower downside yield risk than other farm resource regions. Consistent with mean yield results, soybean [Glycine max (L.) Merr.] and wheat grown on sandy soils in the Southern Seaboard region using no-till had larger downside yield risks than when produced with no-till on loamy soils. Th e key fi ndings of this study support the hypothesis that soil and climate factors impact no-till yields relative to tillage yields and may be an important factor infl uencing risk and expected return and the adoption of the practice by farmers.
A new angle on the Euler angles
Markley, F. Landis; Shuster, Malcolm D.
1995-01-01
We present a generalization of the Euler angles to axes beyond the twelve conventional sets. The generalized Euler axes must satisfy the constraint that the first and the third are orthogonal to the second; but the angle between the first and third is arbitrary, rather than being restricted to the values 0 and pi/2, as in the conventional sets. This is the broadest generalization of the Euler angles that provides a representation of an arbitrary rotation matrix. The kinematics of the generalized Euler angles and their relation to the attitude matrix are presented. As a side benefit, the equations for the generalized Euler angles are universal in that they incorporate the equations for the twelve conventional sets of Euler angles in a natural way.
Key factors influencing the potential of catch crops for methane production
DEFF Research Database (Denmark)
Molinuevo-Salces, Beatriz; Fernandez-Varela, Raquel; Uellendahl, Hinrich
2014-01-01
Catch crops are grown in crop rotation primarily for soil stabilization. The excess biomass of catch crops was investigated for its potential as feedstock for biogas production. Ten variables affecting catch crop growth and methane potential were evaluated. Field trials and methane potential were...
Key factors influencing the potential of catch crops for methane production.
Molinuevo-Salces, Beatriz; Fernández-Varela, Raquel; Uellendahl, Hinrich
2014-08-01
Catch crops are grown in crop rotation primarily for soil stabilization. The excess biomass of catch crops was investigated for its potential as feedstock for biogas production. Ten variables affecting catch crop growth and methane potential were evaluated. Field trials and methane potential were studied for 14 different catch crops species, with 19 samples harvested in 2010 and 36 harvested in 2011. Principal component analysis was applied to the data to identify the variables characterizing the potential for the different catch crops species for methane production. Two principal components explained up to 84.6% and 71.6% of the total variation for 2010 and 2011 samples, respectively. Specific methane yield, climate conditions (rainfall and temperature) and total nitrogen in the biomass were the variables classifying the different catch crops. Catch crops in the Brassicaceae and Graminaceae botanical families showed the highest methane yield. This study demonstrates the importance of the crop species when choosing a suitable catch crop for biogas production.
How Do Various Maize Crop Models Vary in Their Responses to Climate Change Factors?
Bassu, Simona; Brisson, Nadine; Grassini, Patricio; Durand, Jean-Louis; Boote, Kenneth; Lizaso, Jon; Jones, James W.; Rosenzweig, Cynthia; Ruane, Alex C.; Adam, Myriam; Baron, Christian; Basso, Bruno; Biernath, Christian; Boogaard, Hendrik; Conijn, Sjaak; Corbeels, Marc; Deryng, Delphine; DeSanctis, Giacomo; Gayler, Sebastian; Grassini, Patricio; Hatfield, Jerry; Hoek, Steven; Izaurralde, Cesar; Jongschaap, Raymond; Kemanian, Armen R.; Kersebaum, K. Christian
2014-01-01
Potential consequences of climate change on crop production can be studied using mechanistic crop simulation models. While a broad variety of maize simulation models exist, it is not known whether different models diverge on grain yield responses to changes in climatic factors, or whether they agree in their general trends related to phenology, growth, and yield. With the goal of analyzing the sensitivity of simulated yields to changes in temperature and atmospheric carbon dioxide concentrations [CO2], we present the largest maize crop model intercomparison to date, including 23 different models. These models were evaluated for four locations representing a wide range of maize production conditions in the world: Lusignan (France), Ames (USA), Rio Verde (Brazil) and Morogoro (Tanzania). While individual models differed considerably in absolute yield simulation at the four sites, an ensemble of a minimum number of models was able to simulate absolute yields accurately at the four sites even with low data for calibration, thus suggesting that using an ensemble of models has merit. Temperature increase had strong negative influence on modeled yield response of roughly -0.5 Mg ha(sup 1) per degC. Doubling [CO2] from 360 to 720 lmol mol 1 increased grain yield by 7.5% on average across models and the sites. That would therefore make temperature the main factor altering maize yields at the end of this century. Furthermore, there was a large uncertainty in the yield response to [CO2] among models. Model responses to temperature and [CO2] did not differ whether models were simulated with low calibration information or, simulated with high level of calibration information.
Rendon, Dalila; Whitehouse, Mary E A; Hulugalle, Nilantha R; Taylor, Phillip W
2015-02-01
Wolf spiders (Lycosidae) are the most abundant ground-hunting spiders in the Australian cotton (Gossypium hirsutum L.) agroecosystems. These spiders have potential in controlling pest bollworms, Helicoverpa spp. (Lepidoptera: Noctuidae) in minimum-tilled fields. A study was carried out during a wet growing season (2011-2012) in Narrabri, New South Wales, Australia, to determine how different crop rotations and tillage affect wolf spider assemblages in cotton fields. Spider abundance and species richness did not differ significantly between simple plots (no winter crop) and complex plots (cotton-wheat Triticum aestivum L.-vetch Vicia benghalensis L. rotation). However, the wolf spider biodiversity, as expressed by the Shannon-Weaver and Simpson's indices, was significantly higher in complex plots. Higher biodiversity reflected a more even distribution of the most dominant species (Venatrix konei Berland, Hogna crispipes Koch, and Tasmanicosa leuckartii Thorell) and the presence of more rare species in complex plots. T. leuckartii was more abundant in complex plots and appears to be sensitive to farming disturbances, whereas V. konei and H. crispipes were similarly abundant in the two plot types, suggesting higher resilience or recolonizing abilities. The demographic structure of these three species varied through the season, but not between plot types. Environmental variables had a significant effect on spider assemblage, but effects of environment and plot treatment were overshadowed by the seasonal progression of cotton stages. Maintaining a high density and even distribution of wolf spiders that prey on Helicoverpa spp. should be considered as a conservation biological control element when implementing agronomic and pest management strategies.
Euler and His Contribution Number Theory
Len, Amy; Scott, Paul
2004-01-01
Born in 1707, Leonhard Euler was the son of a Protestant minister from the vicinity of Basel, Switzerland. With the aim of pursuing a career in theology, Euler entered the University of Basel at the age of thirteen, where he was tutored in mathematics by Johann Bernoulli (of the famous Bernoulli family of mathematicians). He developed an interest…
Euler-Heisenberg lagrangian through Krein regularization
Refaei, A
2013-01-01
The Euler-Heisenberg effective action at the one-loop for a constant electromagnetic field is derived in Krein space quantization with Ford's idea of uctuated light-cone. In this work we present a perturbative, but convergent solution of the effective action. Without using any renormalization procedure, the result coincides with the famous renormalized Euler-Heisenberg action.
Multiple Twisted -Euler Numbers and Polynomials Associated with -Adic -Integrals
Directory of Open Access Journals (Sweden)
Jang Lee-Chae
2008-01-01
Full Text Available By using -adic -integrals on , we define multiple twisted -Euler numbers and polynomials. We also find Witt's type formula for multiple twisted -Euler numbers and discuss some characterizations of multiple twisted -Euler Zeta functions. In particular, we construct multiple twisted Barnes' type -Euler polynomials and multiple twisted Barnes' type -Euler Zeta functions. Finally, we define multiple twisted Dirichlet's type -Euler numbers and polynomials, and give Witt's type formula for them.
Luan, Mingda; Tang, Ren-Jie; Tang, Yumei; Tian, Wang; Hou, Congong; Zhao, Fugeng; Lan, Wenzhi; Luan, Sheng
2017-06-01
Potassium (K) and phosphate (Pi) are both macronutrients essential for plant growth and crop production, but the unrenewable resources of phosphorus rock and potash have become limiting factors for food security. One critical measure to help solve this problem is to improve nutrient use efficiency (NUE) in plants by understanding and engineering genetic networks for ion uptake, translocation, and storage. Plants have evolved multiple systems to adapt to various nutrient conditions for growth and production. Within the NUE networks, transport proteins and their regulators are the primary players for maintaining nutrient homeostasis and could be utilized to engineer high NUE traits in crop plants. A large number of publications have detailed K+ and Pi transport proteins in plants over the past three decades. Meanwhile, the discovery and validation of their regulatory mechanisms are fast-track topics for research. Here, we provide an overview of K+ and Pi transport proteins and their regulatory mechanisms, which participate in the uptake, translocation, storage, and recycling of these nutrients in plants. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.
NAC Transcription Factors in Senescence: From Molecular Structure to Function in Crops
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Dagmara Podzimska-Sroka
2015-07-01
Full Text Available Within the last decade, NAC transcription factors have been shown to play essential roles in senescence, which is the focus of this review. Transcriptome analyses associate approximately one third of Arabidopsis NAC genes and many crop NAC genes with senescence, thereby implicating NAC genes as important regulators of the senescence process. The consensus DNA binding site of the NAC domain is used to predict NAC target genes, and protein interaction sites can be predicted for the intrinsically disordered transcription regulatory domains of NAC proteins. The molecular characteristics of these domains determine the interactions in gene regulatory networks. Emerging local NAC-centered gene regulatory networks reveal complex molecular mechanisms of stress- and hormone-regulated senescence and basic physiological steps of the senescence process. For example, through molecular interactions involving the hormone abscisic acid, Arabidopsis NAP promotes chlorophyll degradation, a hallmark of senescence. Furthermore, studies of the functional rice ortholog, OsNAP, suggest that NAC genes can be targeted to obtain specific changes in lifespan control and nutrient remobilization in crop plants. This is also exemplified by the wheat NAM1 genes which promote senescence and increase grain zinc, iron, and protein content. Thus, NAC genes are promising targets for fine-tuning senescence for increased yield and quality.
On Generalized Euler Spirals in E^3
Saracoglu, Semra
2012-01-01
The Cornu spirals on plane are the curves whose curvatures are linear. Generalized planar cornu spirals and Euler spirals in E^3, the curves whose curvatures are linear are defined in [1,5]. In this study, these curves are presented as the ratio of two rational linear functions. Also here, generalized Euler spirals in E^3 has been defined and given their some various characterizations. The approach I used in this paper is useful in understanding the role of Euler spirals in E^3 in differentia...
Directory of Open Access Journals (Sweden)
Maria R. Davis
2012-07-01
Full Text Available Botrytis cinerea is a necrotrophic fungus infecting over 230 plant species worldwide. This highly adaptable pathogen can afflict agricultural products from seed to storage, causing significant economic losses and instability in the food supply. Small protein virulence factors secreted by B. cinerea during infection play an important role in initiation and spread of disease. BcSnod1 was found to be abundantly expressed upon exposure to media containing strawberry extract. From sequence similarity, BcSnod2 was also identified and both were recognized as members of the Ceratoplatanin family of small phytotoxic proteins. Recombinant BcSnod1 was shown to have a phytotoxic effect and play an important role in pathogenicity while the role of BcSnod2 remains less clear. Both bacterial and yeast production systems are reported, though the bacterial protein is less toxic and mostly unfolded relative to that made in yeast. Compared to BcSnod1, recombinant bacterial BcSnod2 shows similar, but delayed phytotoxicity on tomato leaves. Further studies of these critical virulence factors and their inhibition promise to provide new avenues for crop protection.
Black holes with constant topological Euler density
Bargueño, Pedro
2016-01-01
A class of four dimensional spherically symmetric and static geometries with constant topological Euler density is studied. These geometries are shown to solve the coupled Einstein-Maxwell system when non-linear Born-Infeld-like electrodynamics is employed.
EULER - A Real Virtual Library for Mathematics
Jost, Michael
2004-01-01
The EULER project completed its work in November 2002. It forms the last part of a very successful project in the specialized but global discipline of mathematics. After a successful RTD project had created the technology, a take-up project has effectively exploited it to the point where its future is assured through a not-for-profit consortium. EULER is a European based, world class, real virtual library for mathematics with up-to-date technological solutions, well accepted by users. In particular, EULER provides a world reference and delivery service, transparent to the end user and offering full coverage of the mathematics literature world-wide, including bibliographic data, peer reviews and/or abstracts, indexing, classification and search, transparent access to library services, co-operation with commercial information providers (publishers, bookstores). The EULER services provide a gateway to the electronic catalogues and repositories of participating institutions, while the latter retain complete respo...
Simulating Stochastic Crop Management in Cropping Systems
Introduction -- Crop simulation models are uniquely suitable for examining long term crop responses to environmental variability due to changes in climate or other factors. Long-term studies typically emphasize variability related to weather conditions; certain weather-dependent cropping practices m...
Combined Effects of Numerical Method Type and Time Step on Water Stressed Actual Crop ET
Directory of Open Access Journals (Sweden)
B. Ghahraman
2016-02-01
Full Text Available Introduction: Actual crop evapotranspiration (Eta is important in hydrologic modeling and irrigation water management issues. Actual ET depends on an estimation of a water stress index and average soil water at crop root zone, and so depends on a chosen numerical method and adapted time step. During periods with no rainfall and/or irrigation, actual ET can be computed analytically or by using different numerical methods. Overal, there are many factors that influence actual evapotranspiration. These factors are crop potential evapotranspiration, available root zone water content, time step, crop sensitivity, and soil. In this paper different numerical methods are compared for different soil textures and different crops sensitivities. Materials and Methods: During a specific time step with no rainfall or irrigation, change in soil water content would be equal to evapotranspiration, ET. In this approach, however, deep percolation is generally ignored due to deep water table and negligible unsaturated hydraulic conductivity below rooting depth. This differential equation may be solved analytically or numerically considering different algorithms. We adapted four different numerical methods, as explicit, implicit, and modified Euler, midpoint method, and 3-rd order Heun method to approximate the differential equation. Three general soil types of sand, silt, and clay, and three different crop types of sensitive, moderate, and resistant under Nishaboor plain were used. Standard soil fraction depletion (corresponding to ETc=5 mm.d-1, pstd, below which crop faces water stress is adopted for crop sensitivity. Three values for pstd were considered in this study to cover the common crops in the area, including winter wheat and barley, cotton, alfalfa, sugar beet, saffron, among the others. Based on this parameter, three classes for crop sensitivity was considered, sensitive crops with pstd=0.2, moderate crops with pstd=0.5, and resistive crops with pstd=0
Directory of Open Access Journals (Sweden)
P. S. Amaza
2006-10-01
Full Text Available The objective of this study was to examine the determinants of food crop production and technical efficiency in the guinea savannas of Borno State, Nigeria. A stochastic frontier production function, using the maximum likelihood estimation (MLE technique was applied in the analysis of data collected from 1086 sample farmers in 2004. The MLE results reveal that farm size; fertilizer and hired labour are the major factors that are associated with changes in the output of food crops. The effect of land area on output is positive and the coefficient found to be significant (p = 0.01. Fertilizer and hired labour have positive effects on output and their coefficients are significant (p = 0.01. Mean farmers’ technical efficiency index was found to be 0.68. Farmer-specific efficiency factors, which comprise age, education, credit, extension and crop diversification, were found to be the significant factors that account for the observed variation in efficiency among the farmers. The implication of the study is that technical efficiency in food crop production could be increased by 32 percent through better use of available resources, given the current state of technology.
Factors involved in alleviating water stress by partial crop removal in pear trees.
Marsal, Jordi; Mata, Merce; Arbones, Amadeu; Del Campo, Jesus; Girona, Joan; Lopez, Gerardo
2008-09-01
We studied the relief of water stress associated with fruit thinning in pear (Pyrus communis L.) trees during drought to determine what mechanisms, other than stomatal adjustment, were involved. Combinations of control irrigation (equal to crop water use less effective rainfall) and deficit irrigation (equal to 20% of control irrigation), fruit load (unthinned and thinned to 40 fruits per tree) and root pruning (pruned and unpruned) treatments were applied to pear (cv. 'Conference') trees during Stage II of fruit development. Daily patterns of midday stem water potential (Psi(stem)) and leaf conductance to water vapor (g(l)) of deficit-irrigated trees differed after fruit thinning. In response to fruit thinning, gl progressively declined with water stress until 30 days after fruit thinning and then leveled off, whereas the effects of decreased fruit load on Psi(stem) peaked 30-40 days after fruit thinning and then tended to decline. Soil water depletion was significantly correlated with fruit load during drought. Our results indicate that stomatal adjustment and the resulting soil water conservation were the factors determining the Psi(stem) response to fruit thinning. However, these factors could not explain differences in daily patterns between g(l) and Psi(stem) after fruit thinning. In all cases, effects of root pruning treatments on Psi(stem) in deficit-irrigated trees were transitory (Psi(stem) recovered from root pruning in less than 30 days), but the recovery of Psi(stem) after root pruning was faster in trees with low fruit loads. This behavior is compatible with the concept that the water balance (reflected by Psi(stem) values) was better in trees with low fruit loads compared with unthinned trees, perhaps because more carbon was available for root growth. Thus, a root growth component is hypothesized as a mechanism to explain the bimodal Psi(stem) response to fruit thinning during drought.
Directory of Open Access Journals (Sweden)
Hongling Guo
2014-03-01
Full Text Available Seed production and quality are important factors influencing population regeneration in many seed plants. We used structural equation modeling to investigate how plant and fruit traits interact with each other to influence the fruit crops and seed fates of Pistacia chinensis. From May to September 2009, we sampled 45 fruiting female trees and measured plant traits (height, DBH and crown area, fruit traits (infructescence size, fruit size and the fruit crop of each sampled tree in Jiyuan City of Henan Province, Central China. The fruit crops of P. chinensis were positively correlated with tree height, crown area and infructescence size but not significantly correlated with DBH or fruit size. The fruit crop of an individual tree had no negative direct effect on the infestation of seeds by wasps (Eurytoma plotnikovi. Such a direct effect would be predicted by the predator satiation hypothesis. Tree height and fruit size had a positive direct effect on the seed predation rate, but a significant negative correlation was found between the seed predation rate and the rate of seedlessness. Our results indicate that seedless fruits may serve as a defensive mechanism against insect seed predators. In addition, both seedless and insect-infested fruits had a negative direct effect on seed survival, and DBH, infructescence size and fruit crop had a positive indirect effect on seed survival. However, tree height and fruit size had negative indirect effects on seed survival. In conclusion, we have shown that both plant and fruit traits can strongly influence fruit crops and insect seed predation and subsequently determine the seed quality and population regeneration of P. chinensis.
Interpolation Functions of -Extensions of Apostol's Type Euler Polynomials
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Kim Young-Hee
2009-01-01
Full Text Available The main purpose of this paper is to present new -extensions of Apostol's type Euler polynomials using the fermionic -adic integral on . We define the - -Euler polynomials and obtain the interpolation functions and the Hurwitz type zeta functions of these polynomials. We define -extensions of Apostol type's Euler polynomials of higher order using the multivariate fermionic -adic integral on . We have the interpolation functions of these - -Euler polynomials. We also give -extensions of Apostol's type Euler polynomials of higher order and have the multiple Hurwitz type zeta functions of these - -Euler polynomials.
Factors influencing the feasibility of using catch crops for biogas production
DEFF Research Database (Denmark)
Molinuevo-Salces, Beatriz; Ahring, Birgitte Kiær; Uellendahl, Hinrich
2013-01-01
in three different locations of Jutland, Denmark. Differences in climate and soil conditions between locations determined mainly the biomass yield. Methane potentials were in the range of 252-435 ml CH4/ g VS depending on catch crops species. The use of catch crops for biogas production has large......In order to secure an economically feasible operation of manure-based biogas plants in Denmark there is a need for supplying the plants with high yielding biomass feedstock. The aim of this study was to investigate the biomass yield and the methane potential of three different catch crop species...... perspectives since it would combine renewable energy production with agricultural and environmental benefits....
Analogues of Euler and Poisson Summation Formulae
Indian Academy of Sciences (India)
Vivek V Rane
2003-08-01
Euler–Maclaurin and Poisson analogues of the summations $\\sum_{a < n ≤ b}(n)f(n), \\sum_{a < n ≤ b}d(n) f(n), \\sum_{a < n ≤ b}d(n)(n) f(n)$ have been obtained in a unified manner, where (()) is a periodic complex sequence; () is the divisor function and () is a sufficiently smooth function on [, ]. We also state a generalised Abel's summation formula, generalised Euler's summation formula and Euler's summation formula in several variables.
Leonhard Euler's Wave Theory of Light
DEFF Research Database (Denmark)
Pedersen, Kurt Møller
2008-01-01
Euler's wave theory of light developed from a mere description of this notion based on an analogy between sound and light to a more and more mathematical elaboration on that notion. He was very successful in predicting the shape of achromatic lenses based on a new dispersion law that we now know...... is wrong. Most of his mathematical arguments were, however, guesswork without any solid physical reasoning. Guesswork is not always a bad thing in physics if it leads to new experiments or makes the theory coherent with other theories. And Euler tried to find such experiments. He saw the construction...
Energy Technology Data Exchange (ETDEWEB)
Egorov, Yurii V [Institute de Mathematique de Toulouse, Toulouse (France)
2013-04-30
We consider the classical problem on the tallest column which was posed by Euler in 1757. Bernoulli-Euler theory serves today as the basis for the design of high buildings. This problem is reduced to the problem of finding the potential for the Sturm-Liouville equation corresponding to the maximum of the first eigenvalue. The problem has been studied by many mathematicians but we give the first rigorous proof of the existence and uniqueness of the optimal column and we give new formulae which let us find it. Our method is based on a new approach consisting in the study of critical points of a related nonlinear functional. Bibliography: 6 titles.
HIGHER ORDER MULTIVARIABLE NORLUND EULER-BERNOULLI POLYNOMIALS
Institute of Scientific and Technical Information of China (English)
刘国栋
2002-01-01
The definitions of higher order multivariable Norlund Euler polynomials and Norlund Bernoulli polynomials are presented and some of their important properties are expounded. Some identities involving recurrence sequences and higher order multivariable Norlund Euler-Bernoulli polynomials are established.
The Euler-Maclaurin Formula and Extensions - An Elementary Approach
Gearhart, W. B.; Qian, Maijian
2005-01-01
This note offers a derivation of the Euler-Maclaurin formula that is simple and elementary. In addition, the paper shows that the derivation provides Euler-Maclaurin formulas for a variety of functionals other than the trapezoid rule.
Whole-genome duplication as a key factor in crop domestication.
Salman-Minkov, Ayelet; Sabath, Niv; Mayrose, Itay
2016-08-01
Polyploidy is commonly thought to be associated with the domestication process because of its concurrence with agriculturally favourable traits and because it is widespread among the major plant crops(1-4). Furthermore, the genetic consequences of polyploidy(5-7) might have increased the adaptive plasticity of those plants, enabling successful domestication(6-8). Nevertheless, a detailed phylogenetic analysis regarding the association of polyploidy with the domestication process, and the temporal order of these distinct events, has been lacking(3). Here, we have gathered a comprehensive data set including dozens of genera, each containing one or more major crop species and for which sufficient sequence and chromosome number data exist. Using probabilistic inference of ploidy levels conducted within a phylogenetic framework, we have examined the incidence of polyploidization events within each genus. We found that domesticated plants have gone through more polyploidy events than their wild relatives, with monocots exhibiting the most profound difference: 54% of the crops are polyploids versus 40% of the wild species. We then examined whether the preponderance of polyploidy among crop species is the result of two, non-mutually-exclusive hypotheses: (1) polyploidy followed by domestication, and (2) domestication followed by polyploidy. We found support for the first hypothesis, whereby polyploid species were more likely to be domesticated than their wild relatives, suggesting that the genetic consequences of polyploidy have conferred genetic preconditions for successful domestication on many of these plants.
Todd A. Ontl; Cynthia A. Cambardella; Lisa A. Schulte; Randall K. Kolka
2015-01-01
Bioenergy crops have the potential to enhance soil carbon (C) pools from increased aggregation and the physical protection of organic matter; however, our understanding of the variation in these processes over heterogeneous landscapes is limited. In particular, little is known about the relative importance of soil properties and root characteristics for the physical...
IMPACT OF TEHNICAL SPRAYING FACTORS ON LEAF AREA COVERAGE IN PERMANENT CROPS
Directory of Open Access Journals (Sweden)
Vjekoslav Tadić
2013-12-01
Full Text Available Researches are conducted in vineyard and apple orchard with two different types of mist blowers, axial (Hardi Zaturn and radial (Hardi Arrow. The influence of major technical spraying factors (type of nozzle, working speed and spray volume were observed on coverage of the treated area, average droplet diameter, number of droplets per cm2 and drift. The working speed of sprayer was set at 6 and 8 km/h, and spray volume on 250, 325 and 400 l/ha for apple orchard and 250, 300 and 350 l/ha for vineyard. Researchers used Lechler blue (TR 8003, yellow (TR 8002 and green (TR 80015 nozzles. The research was set as three - factorial field experiment with 18 treatments in 4 repetitions, for different type of sprayer and permanent crops. We used 60 water sensitive papers for that treatment, which were processed with digital image analysis and ImageJ software. In addition to the main features of the research, research showed leaf area index and density, speed and flow of air current, working pressure, orientation of the nozzles and weather conditions, which were monitored during the study. Before the research, mist blowers are tested according to the European standard 13790. By decreasing the ISO number of nozzles and by increasing the working speed and spray volume, we found increase of area coverage, number of droplets per cm2and drift, and decrease of average droplet diameter. Also, by comparing the results of research exploitation by axial and radial mist blower in the vineyards and apple orchards, better results are achieved with radial mist blower (Hardi Arrow in both cases. The best relationship of area coverage and liquid drift in vineyard were achieved with 64.22% area coverage and 17.11% of liquid drift (green nozzle, working speed of 6 km/h, spray volume of 350 l/ha, and working pressure of 10.99 bar. In apple orchard the best relationship of area coverage and liquid drift were achieved with 59.55% area coverage and 21.10% of liquid drift (green
Regularity and Energy Conservation for the Compressible Euler Equations
Feireisl, Eduard; Gwiazda, Piotr; Świerczewska-Gwiazda, Agnieszka; Wiedemann, Emil
2017-03-01
We give sufficient conditions on the regularity of solutions to the inhomogeneous incompressible Euler and the compressible isentropic Euler systems in order for the energy to be conserved. Our strategy relies on commutator estimates similar to those employed by Constantin et al. for the homogeneous incompressible Euler equations.
Financial integration in Europe : Evidence from Euler equation tests
Lemmen, J.J.G.; Eijffinger, S.C.W.
1995-01-01
This paper applies Obstfeld's Euler equation tests to assess the degree of financial integration in the European Union. In addition, we design a new Euler equation test which is intimately related to Obstfeld's Euler equation tests. Using data from the latest Penn World Table (Mark 6), we arrive at
Discretization vs. Rounding Error in Euler's Method
Borges, Carlos F.
2011-01-01
Euler's method for solving initial value problems is an excellent vehicle for observing the relationship between discretization error and rounding error in numerical computation. Reductions in stepsize, in order to decrease discretization error, necessarily increase the number of steps and so introduce additional rounding error. The problem is…
Discretization vs. Rounding Error in Euler's Method
Borges, Carlos F.
2011-01-01
Euler's method for solving initial value problems is an excellent vehicle for observing the relationship between discretization error and rounding error in numerical computation. Reductions in stepsize, in order to decrease discretization error, necessarily increase the number of steps and so introduce additional rounding error. The problem is…
Euler and the Fundamental Theorem of Algebra.
Duham, William
1991-01-01
The complexity of the proof of the Fundamental Theorem of Algebra makes it inaccessible to lower level students. Described are more understandable attempts of proving the theorem and a historical account of Euler's efforts that relates the progression of the mathematical process used and indicates some of the pitfalls encountered. (MDH)
Summing up the Euler [phi] Function
Loomis, Paul; Plytage, Michael; Polhill, John
2008-01-01
The Euler [phi] function counts the number of positive integers less than and relatively prime to a positive integer n. Here we look at perfect totient numbers, number for which [phi](n) + [phi]([phi](n)) + [phi]([phi]([phi](n))) + ... + 1 = n.
Euler Polynomials, Fourier Series and Zeta Numbers
DEFF Research Database (Denmark)
Scheufens, Ernst E
2012-01-01
Fourier series for Euler polynomials is used to obtain information about values of the Riemann zeta function for integer arguments greater than one. If the argument is even we recover the well-known exact values, if the argument is odd we find integral representations and rapidly convergent series....
Euler's Amazing Way to Solve Equations.
Flusser, Peter
1992-01-01
Presented is a series of examples that illustrate a method of solving equations developed by Leonhard Euler based on an unsubstantiated assumption. The method integrates aspects of recursion relations and sequences of converging ratios and can be extended to polynomial equation with infinite exponents. (MDH)
An Automatic Proof of Euler's Formula
Directory of Open Access Journals (Sweden)
Jun Zhang
2005-05-01
Full Text Available In this information age, everything is digitalized. The encoding of functions and the automatic proof of functions are important. This paper will discuss the automatic calculation for Taylor expansion coefficients, as an example, it can be applied to prove Euler's formula automatically.
Euler Polynomials, Fourier Series and Zeta Numbers
DEFF Research Database (Denmark)
Scheufens, Ernst E
2012-01-01
Fourier series for Euler polynomials is used to obtain information about values of the Riemann zeta function for integer arguments greater than one. If the argument is even we recover the well-known exact values, if the argument is odd we find integral representations and rapidly convergent series....
Environmental conditions and crop density as the limiting factors of forage maize production
Directory of Open Access Journals (Sweden)
Dragičević Vesna D.
2016-01-01
Full Text Available In rain-fed cropping, defining the best combination of practices could achieve high forage yield and silage quality. The aim of this study was to compare energetic quality of produced silage with productive characteristics of forage maize cultivated on alluvium and hydromorphous black soil in rain-fed conditions at four plant densities (68-74,000 plants ha-1 during the period 2005- 2010. Yield and energy parameters were increased to some extent at higher crop densities indicating that higher densities (74,000 plants ha-1 were potentially better for high forage and DM yields, while lower densities (70,000 plants ha-1 were better for the increase of energy parameters of produced silage. [Projekat Ministarstva nauke Republike Srbije, br. TR-31037
Dobbie, K. E.; McTaggart, I. P.; Smith, K. A.
1999-11-01
Emissions of nitrous oxide from intensively managed agricultural fields were measured over 3 years. Exponential increases in flux occurred with increasing soil water- filled pore space (WFPS) and temperature; increases in soil mineral N content due to fertilizer application also stimulated emissions. Fluxes were low when any of these variables was below a critical value. The largest fluxes occurred when WFPS values were very high (70-90%), indicating that denitrification was the major process responsible. The relationships with the driving variables showed strong similarities to those reported for very different environments: irrigated sugar cane crops, pastures, and forest in the tropics. Annual emissions varied widely (0.3-18.4 kg N2O-N ha-1). These variations were principally due to the degree of coincidence of fertilizer application and major rainfall events. It is concluded therefore that several years' data are required from any agricultural ecosystem in a variable climate to obtain a robust estimate of mean N2O fluxes. The emissions from small-grain cereals (winter wheat and spring barley) were consistently lower (0.2-0.7 kg N2O-N per 100 kg N applied) than from cut grassland (0.3-5.8 kg N2O- N per 100 kg N). Crops such as broccoli and potatoes gave emissions of the same order as those from the grassland. Although these differences between crop types are not apparent in general data comparisons, there may well be distinct regional differences in the relative and absolute emissions from different crops, due to local factors relating to soil type, weather patterns, and agricultural management practices. This will only be determined by more detailed comparative studies.
Euler Characteristic and Quadrilaterals of Normal Surfaces
Indian Academy of Sciences (India)
Tejas Kalelkar
2008-05-01
Let be a compact 3-manifold with a triangulation . We give an inequality relating the Euler characteristic of a surface normally embedded in with the number of normal quadrilaterals in . This gives a relation between a topological invariant of the surface and a quantity derived from its combinatorial description. Secondly, we obtain an inequality relating the number of normal triangles and normal quadrilaterals of , that depends on the maximum number of tetrahedrons that share a vertex in .
Stabilities for nonisentropic Euler-Poisson equations.
Cheung, Ka Luen; Wong, Sen
2015-01-01
We establish the stabilities and blowup results for the nonisentropic Euler-Poisson equations by the energy method. By analysing the second inertia, we show that the classical solutions of the system with attractive forces blow up in finite time in some special dimensions when the energy is negative. Moreover, we obtain the stabilities results for the system in the cases of attractive and repulsive forces.
Hypoallergenic legume crops and food allergy: factors affecting feasibility and risk.
Riascos, John J; Weissinger, Arthur K; Weissinger, Sandra M; Burks, A Wesley
2010-01-13
Currently, the sole strategy for managing food hypersensitivity involves strict avoidance of the trigger. Several alternate strategies for the treatment of food allergies are currently under study. Also being explored is the process of eliminating allergenic proteins from crop plants. Legumes are a rich source of protein and are an essential component of the human diet. Unfortunately, legumes, including soybean and peanut, are also common sources of food allergens. Four protein families and superfamilies account for the majority of legume allergens, which include storage proteins of seeds (cupins and prolamins), profilins, and the larger group of pathogenesis-related proteins. Two strategies have been used to produce hypoallergenic legume crops: (1) germplasm lines are screened for the absence or reduced content of specific allergenic proteins and (2) genetic transformation is used to silence native genes encoding allergenic proteins. Both approaches have been successful in producing cultivars of soybeans and peanuts with reduced allergenic proteins. However, it is unknown whether the cultivars are actually hypoallergenic to those with sensitivity. This review describes efforts to produce hypoallergenic cultivars of soybean and peanut and discusses the challenges that need to be overcome before such products could be available in the marketplace.
Solving Nonlinear Euler Equations with Arbitrary Accuracy
Dyson, Rodger W.
2005-01-01
A computer program that efficiently solves the time-dependent, nonlinear Euler equations in two dimensions to an arbitrarily high order of accuracy has been developed. The program implements a modified form of a prior arbitrary- accuracy simulation algorithm that is a member of the class of algorithms known in the art as modified expansion solution approximation (MESA) schemes. Whereas millions of lines of code were needed to implement the prior MESA algorithm, it is possible to implement the present MESA algorithm by use of one or a few pages of Fortran code, the exact amount depending on the specific application. The ability to solve the Euler equations to arbitrarily high accuracy is especially beneficial in simulations of aeroacoustic effects in settings in which fully nonlinear behavior is expected - for example, at stagnation points of fan blades, where linearizing assumptions break down. At these locations, it is necessary to solve the full nonlinear Euler equations, and inasmuch as the acoustical energy is of the order of 4 to 5 orders of magnitude below that of the mean flow, it is necessary to achieve an overall fractional error of less than 10-6 in order to faithfully simulate entropy, vortical, and acoustical waves.
Chaotic dynamics of flexible Euler-Bernoulli beams.
Awrejcewicz, J; Krysko, A V; Kutepov, I E; Zagniboroda, N A; Dobriyan, V; Krysko, V A
2013-12-01
Mathematical modeling and analysis of spatio-temporal chaotic dynamics of flexible simple and curved Euler-Bernoulli beams are carried out. The Kármán-type geometric non-linearity is considered. Algorithms reducing partial differential equations which govern the dynamics of studied objects and associated boundary value problems are reduced to the Cauchy problem through both Finite Difference Method with the approximation of O(c(2)) and Finite Element Method. The obtained Cauchy problem is solved via the fourth and sixth-order Runge-Kutta methods. Validity and reliability of the results are rigorously discussed. Analysis of the chaotic dynamics of flexible Euler-Bernoulli beams for a series of boundary conditions is carried out with the help of the qualitative theory of differential equations. We analyze time histories, phase and modal portraits, autocorrelation functions, the Poincaré and pseudo-Poincaré maps, signs of the first four Lyapunov exponents, as well as the compression factor of the phase volume of an attractor. A novel scenario of transition from periodicity to chaos is obtained, and a transition from chaos to hyper-chaos is illustrated. In particular, we study and explain the phenomenon of transition from symmetric to asymmetric vibrations. Vibration-type charts are given regarding two control parameters: amplitude q(0) and frequency ω(p) of the uniformly distributed periodic excitation. Furthermore, we detected and illustrated how the so called temporal-space chaos is developed following the transition from regular to chaotic system dynamics.
NAC Transcription Factors in Senescence: From Molecular Structure to Function in Crops
DEFF Research Database (Denmark)
Podzimska, Dagmara Agata; O'Shea, Charlotte; Gregersen, Per L.;
2015-01-01
of these domains determine the interactions in gene regulatory networks. Emerging local NAC-centered gene regulatory networks reveal complex molecular mechanisms of stress- and hormone-regulated senescence and basic physiological steps of the senescence process. For example, through molecular interactions...... involving the hormone abscisic acid, Arabidopsis NAP promotes chlorophyll degradation, a hallmark of senescence. Furthermore, studies of the functional rice ortholog, OsNAP, suggest that NAC genes can be targeted to obtain specific changes in lifespan control and nutrient remobilization in crop plants....... This is also exemplified by the wheat NAM1 genes which promote senescence and increase grain zinc, iron, and protein content. Thus, NAC genes are promising targets for fine-tuning senescence for increased yield and quality....
Self-Constrained Euler Deconvolution Using Potential Field Data of Different Altitudes
Zhou, Wenna; Nan, Zeyu; Li, Jiyan
2016-06-01
Euler deconvolution has been developed as almost the most common tool in potential field data semi-automatic interpretation. The structural index (SI) is a main determining factor of the quality of depth estimation. In this paper, we first present an improved Euler deconvolution method to eliminate the influence of SI using potential field data of different altitudes. The different altitudes data can be obtained by the upward continuation or can be directly obtained by the airborne measurement realization. Euler deconvolution at different altitudes of a certain range has very similar calculation equation. Therefore, the ratio of Euler equations of two different altitudes can be calculated to discard the SI. Thus, the depth and location of geologic source can be directly calculated using the improved Euler deconvolution without any prior information. Particularly, the noise influence can be decreased using the upward continuation of different altitudes. The new method is called self-constrained Euler deconvolution (SED). Subsequently, based on the SED algorithm, we deduce the full tensor gradient (FTG) calculation form of the new improved method. As we all know, using multi-components data of FTG have added advantages in data interpretation. The FTG form is composed by x-, y- and z-directional components. Due to the using more components, the FTG form can get more accurate results and more information in detail. The proposed modification method is tested using different synthetic models, and the satisfactory results are obtained. Finally, we applied the new approach to Bishop model magnetic data and real gravity data. All the results demonstrate that the new approach is utility tool to interpret the potential field and full tensor gradient data.
Institute of Scientific and Technical Information of China (English)
Sidra Ghazanfar; Zhang Qi-wen; Muhammad Abdullah; Zeeshan Ahmad; Majid Lateef
2015-01-01
This study has been conducted in three districts of Punjab Province namely, Dera Ghazi Khan, RajanPur and Bahawalpur of Pakistan. The study showed the results of a survey of 300 farmers which was organized to assess awareness level of farmers regarding crop insurance, factors affecting the awareness level among farmers and the perception of farmers about crop insurance. Based on exploratory research work upon the responses of farmers, the average and standard deviation were calculated. Probit model was applied to explore the factors affecting the awareness level of farmers. SPSS was used for the analysis of the collected data. The results revealed that out of 300 farmers, 184 farmers were aware with crop insurance and rests of the 116 farmers were not aware. Banks and E-media were found to be the two most important sources of the awareness for the respondent farmers. In the study area, the climatic risks were reported as the most severe risks faced by the farmers. The results also revealed the existence of negative perceptions of the farmers about crop insurance i.e. farmers perceived crop insurance as a kind of tax and they believed premium was so high that it was out of range of poor farmers and only large scale farmers could afford it. Results obtained by applying Probit model revealed that "education" and "previously availed agricultural credit" were the two most important factors which affected the awareness of the farmers regarding crop insurance.
Convergence of Compressible Euler-Maxwell Equations to Compressible Euler-Poisson Equations
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
In this paper, the convergence of time-dependent Euler-Maxwell equations to compressible Euler-Poisson equations in a torus via the non-relativistic limit is studied.The local existence of smooth solutions to both systems is proved by using energy estimates for first order symmetrizable hyperbolic systems. For well prepared initial data the convergence of solutions is rigorously justified by an analysis of asymptotic expansions up to any order. The authors perform also an initial layer analysis for general initial data and prove the convergence of asymptotic expansions up to first order.
Incompressible limit of solutions of multidimensional steady compressible Euler equations
Chen, Gui-Qiang G.; Huang, Feimin; Wang, Tian-Yi; Xiang, Wei
2016-06-01
A compactness framework is formulated for the incompressible limit of approximate solutions with weak uniform bounds with respect to the adiabatic exponent for the steady Euler equations for compressible fluids in any dimension. One of our main observations is that the compactness can be achieved by using only natural weak estimates for the mass conservation and the vorticity. Another observation is that the incompressibility of the limit for the homentropic Euler flow is directly from the continuity equation, while the incompressibility of the limit for the full Euler flow is from a combination of all the Euler equations. As direct applications of the compactness framework, we establish two incompressible limit theorems for multidimensional steady Euler flows through infinitely long nozzles, which lead to two new existence theorems for the corresponding problems for multidimensional steady incompressible Euler equations.
Euler European Libraries and Electronic Resources in Mathematical Sciences
The Euler Project. Karlsruhe
The European Libraries and Electronic Resources (EULER) Project in Mathematical Sciences provides the EulerService site for searching out "mathematical resources such as books, pre-prints, web-pages, abstracts, proceedings, serials, technical reports preprints) and NetLab (for Internet resources), this outstanding engine is capable of simple, full, and refined searches. It also offers a browse option, which responds to entries in the author, keyword, and title fields. Further information about the Project is provided at the EULER homepage.
Stochastic Euler-Poincaré reduction
Energy Technology Data Exchange (ETDEWEB)
Arnaudon, Marc, E-mail: marc.arnaudon@math.u-bordeaux1.fr [Institut de Mathématiques de Bordeaux (UMR 5251) Université Bordeaux 1 351, Cours de la Libération F33405 TALENCE Cedex (France); Chen, Xin, E-mail: chenxin-217@hotmail.com [Grupo de Física-Matemática Univ. Lisboa, Av.Prof. Gama Pinto 2 1649-003 Lisboa (Portugal); Cruzeiro, Ana Bela, E-mail: abcruz@math.ist.utl.pt [GFMUL and Dep. de Matemática Instituto Superior Técnico (UL), Av. Rovisco Pais 1049-001 Lisboa (Portugal)
2014-08-15
We prove a Euler-Poincaré reduction theorem for stochastic processes taking values on a Lie group, which is a generalization of the reduction argument for the deterministic case [J. E. Marsden and T. S. Ratiu, Introduction to Mechanics and Symmetry: A Basic Exposition of Classical Mechanical Systems, Texts in Applied Mathematics (Springer, 2003)]. We also show examples of its application to SO(3) and to the group of diffeomorphisms, which includes the Navier-Stokes equation on a bounded domain and the Camassa-Holm equation.
Potential singularity mechanism for the Euler equations
Brenner, Michael P.; Hormoz, Sahand; Pumir, Alain
2016-12-01
Singular solutions to the Euler equations could provide essential insight into the formation of very small scales in highly turbulent flows. Previous attempts to find singular flow structures have proven inconclusive. We reconsider the problem of interacting vortex tubes, for which it has long been observed that the flattening of the vortices inhibits sustained self-amplification of velocity gradients. Here we consider an iterative mechanism, based on the transformation of vortex filaments into sheets and their subsequent instability back into filaments. Elementary fluid mechanical arguments are provided to support the formation of a singular structure via this iterated mechanism, which we analyze based on a simplified model of filament interactions.
Principal symbol of Euler-Lagrange operators
Fatibene, L.; Garruto, S.
2016-07-01
We shall introduce the principal symbol for quite a general class of (quasi linear) Euler-Lagrange operators and use them to characterise well-posed initial value problems in gauge covariant field theories. We shall clarify how constraints can arise in covariant Lagrangian theories by extending the standard treatment in GR and without resorting to Hamiltonian formalism. Finally as an example of application, we sketch a quantisation procedure based on what is done in LQG by framing it in a more general context which applies to general gauge covariant field theories.
Multiblock, Multigrid Solution Of Euler Equations
Melson, N. Duane; Cannizzaro, Frank E.; Von Lavante, E.
1994-01-01
Method of numerical solution of Euler equations of three-dimensional flow of compressible fluid involves combination of multiblock and multigrid strategies. In multiblock strategy, flow field divided, into multiple smaller, more computationally-convenient zones and computational grid fitted to applicable flow boundaries generated in each block. In multigrid strategy used here, different quantities computed, variously, on finer or coarser grids. Minimizing cost of computation by using fewest grid points yielding acceptably accurate values of affected variable. Multigrid strategy found effective in accelerating convergence to steady state, while multiblock strategy provides geometric flexibility.
Euler and the Ordinary Differential Equations
Taborda, Jonathan
2010-01-01
The following notes are intended to make a small digression on the topics mentioned in the title of the same, since these were not addressed in the past tribute by the Institute of Physics of the UdeA. We believe more than platitude try to justify the importance and effectiveness in the development of mathematics and physics during the eighteenth century and present such issues, therefore a brief description of the methods and problems attacked by Euler and his contemporaries using the heuristics. Note in advance that they constitute a strong impoverished attempt to honor the memory of who is considered the Shakespeare of Mathematics: Universal, rich in detail and inexhaustible.
Iterative methods for compressible Navier-Stokes and Euler equations
Energy Technology Data Exchange (ETDEWEB)
Tang, W.P.; Forsyth, P.A.
1996-12-31
This workshop will focus on methods for solution of compressible Navier-Stokes and Euler equations. In particular, attention will be focused on the interaction between the methods used to solve the non-linear algebraic equations (e.g. full Newton or first order Jacobian) and the resulting large sparse systems. Various types of block and incomplete LU factorization will be discussed, as well as stability issues, and the use of Newton-Krylov methods. These techniques will be demonstrated on a variety of model transonic and supersonic airfoil problems. Applications to industrial CFD problems will also be presented. Experience with the use of C++ for solution of large scale problems will also be discussed. The format for this workshop will be four fifteen minute talks, followed by a roundtable discussion.
The total factor productivity in strategic food crops industry of Malaysia
Directory of Open Access Journals (Sweden)
Kamarudin Othman
2015-09-01
Full Text Available Total Factor Productivity (TFP may indicate the long-term economic growth of a country. In addition, it is also a comprehensive measure of the level of productivity in the economy. Therefore, these study attempts to investigate the TFP for Malaysia paddy sub-sector. The study was conducted in four Muda Agricultural Development Authorities (MADA regions and employed a seasonal the series of data from 1996 to 2011. Result has found that the actual TFP growth is below than 5 percent for each season. The study also found that the actual TFP trend has been volatile over time. Study has further investigated the factors affecting TFP growth in the Malaysian paddy industry for the entire period. Seven selected factors are found to be associated with striking TFP growth. The result has discovered that all the selected factors are important in influencing the paddy production in Malaysia. However, the magnitude is different for each region.
Velásquez-Milla, Dora; Casas, Alejandro; Torres-Guevara, Juan; Cruz-Soriano, Aldo
2011-12-06
The Peruvian Andean region is a main center of plant domestication of the world. There, several tuber species were domesticated and the area lodges one of the most important reservoirs of their varieties and wild relatives. It is also the setting of traditional cultures using and conserving them. However, crop genetic erosion has been reported in the region since several decades ago; therefore, understanding factors influencing both loss and maintenance of crop variation is relevant to design conservation policies. Previous researches have examined factors influencing agrobiodiversity conservation in the region but additional case studies are recognized to be still necessary for a deeper understanding of causes of genetic erosion and for policy design to prevent and remedy it. Our study focused on analyzing (1) variation in richness of traditional varieties of tubers cultivated among households, (2) changes in varieties richness occurred in four consecutive agricultural cycles, and (3) ecological, social, and cultural factors influencing loss and conservation of varieties. Richness of farmer varieties of tuber species cultivated by 28 peasant households was monitored in communities of Cajamarca and Huánuco, Peru during four consecutive agricultural cycles (from 2001 to 2005). In-depth interviews were conducted with 12 of the households with higher reputation as conservationists, in order to document farmers' perception of tubers qualities in ecological, social, economic, technological and culinary aspects and how these influence their decisions of conservation priorities. Traditional varieties were identified according to their local names, which were then confronted among farmers and with scientific catalogues in order to identify synonyms. Based on the information documented, indexes of ecological and socio-cultural factors affecting agricultural practices were designed, and their linear correlations and multivariate relations with varieties richness managed per
Directory of Open Access Journals (Sweden)
Velásquez-Milla Dora
2011-12-01
Full Text Available Abstract Background The Peruvian Andean region is a main center of plant domestication of the world. There, several tuber species were domesticated and the area lodges one of the most important reservoirs of their varieties and wild relatives. It is also the setting of traditional cultures using and conserving them. However, crop genetic erosion has been reported in the region since several decades ago; therefore, understanding factors influencing both loss and maintenance of crop variation is relevant to design conservation policies. Previous researches have examined factors influencing agrobiodiversity conservation in the region but additional case studies are recognized to be still necessary for a deeper understanding of causes of genetic erosion and for policy design to prevent and remedy it. Our study focused on analyzing (1 variation in richness of traditional varieties of tubers cultivated among households, (2 changes in varieties richness occurred in four consecutive agricultural cycles, and (3 ecological, social, and cultural factors influencing loss and conservation of varieties. Methods Richness of farmer varieties of tuber species cultivated by 28 peasant households was monitored in communities of Cajamarca and Huánuco, Peru during four consecutive agricultural cycles (from 2001 to 2005. In-depth interviews were conducted with 12 of the households with higher reputation as conservationists, in order to document farmers' perception of tubers qualities in ecological, social, economic, technological and culinary aspects and how these influence their decisions of conservation priorities. Traditional varieties were identified according to their local names, which were then confronted among farmers and with scientific catalogues in order to identify synonyms. Based on the information documented, indexes of ecological and socio-cultural factors affecting agricultural practices were designed, and their linear correlations and multivariate
Irrigation modeling with AquaCrop
AquaCrop is a crop water productivity model developed by the Land and Water Division of UN-FAO. It simulates yield response to water of herbaceous crops, and is suited to address conditions where water is a key limiting factor in crop production. AquaCrop attempts to balance accuracy, simplicity, an...
Shepherd, Anita; Yan, Xiaoyuan; Nayak, Dali; Newbold, Jamie; Moran, Dominic; Dhanoa, Mewa Singh; Goulding, Keith; Smith, Pete; Cardenas, Laura M
2015-12-01
China accounts for a third of global nitrogen fertilizer consumption. Under an International Panel on Climate Change (IPCC) Tier 2 assessment, emission factors (EFs) are developed for the major crop types using country-specific data. IPCC advises a separate calculation for the direct nitrous oxide (N2O) emissions of rice cultivation from that of cropland and the consideration of the water regime used for irrigation. In this paper we combine these requirements in two independent analyses, using different data quality acceptance thresholds, to determine the influential parameters on emissions with which to disaggregate and create N2O EFs. Across China, the N2O EF for lowland horticulture was slightly higher (between 0.74% and 1.26% of fertilizer applied) than that for upland crops (values ranging between 0.40% and 1.54%), and significantly higher than for rice (values ranging between 0.29% and 0.66% on temporarily drained soils, and between 0.15% and 0.37% on un-drained soils). Higher EFs for rice were associated with longer periods of drained soil and the use of compound fertilizer; lower emissions were associated with the use of urea or acid soils. Higher EFs for upland crops were associated with clay soil, compound fertilizer or maize crops; lower EFs were associated with sandy soil and the use of urea. Variation in emissions for lowland vegetable crops was closely associated with crop type. The two independent analyses in this study produced consistent disaggregated N2O EFs for rice and mixed crops, showing that the use of influential cropping parameters can produce robust EFs for China.
Theory and applications of the problem of Euler elastica
Energy Technology Data Exchange (ETDEWEB)
Zelikin, Mikhail I [Steklov Mathematical Institute, Russian Academy of Sciences, Moscow (Russian Federation)
2012-04-30
The paper is devoted to the theory of extremal problems on Euler elastica. The Riccati equation method is used to study sufficient optimality conditions for the associated problem of minimization of the energy of a physical pendulum. Numerous applications are described for the problem of Euler elastica, and its connections with the theory of completely integrable Hamiltonian systems are discussed. Bibliography: 10 titles.
On Euler's Theorem for Homogeneous Functions and Proofs Thereof.
Tykodi, R. J.
1982-01-01
Euler's theorem for homogenous functions is useful when developing thermodynamic distinction between extensive and intensive variables of state and when deriving the Gibbs-Duhem relation. Discusses Euler's theorem and thermodynamic applications. Includes six-step instructional strategy for introducing the material to students. (Author/JN)
Euler-Poincare Reduction of Externall Forced Rigid Body Motion
DEFF Research Database (Denmark)
Wisniewski, Rafal; Kulczycki, P.
2004-01-01
. Assuming that the system possesses symmetry and the configuration manifold corresponds to a Lie group, the Euler-Poincaré reduction breaks up the motion into separate equations of dynamics and kinematics. This becomes of particular interest for modelling, estimation and control of mechanical systems......-known Euler-Poincaré reduction to a rigid body motion with forcing....
Euler-Lagrange Forms and Cohomology Groups on Jet Bundles
Institute of Scientific and Technical Information of China (English)
CHEN Jing-Bo
2005-01-01
@@ Using the language of jet bundles, we generalize the definitions of Euler-Lagrange one-form and the associated cohomology which were introduced by Guo et al. [Commun. Theor. Phys. 37(2002)1]. Continuous and discreteLagrange mechanics and field theory are presented. Higher order Euler-Lagrange cohomology groups are also introduced.
Euler-Poincaré Reduction of a Rigid Body Motion
DEFF Research Database (Denmark)
Wisniewski, Rafal; Kulczycki, P.
2004-01-01
. Assuming that the system possesses symmetry and the configuration manifold corresponds to a Lie group, the Euler-Poincaré reduction breaks up the motion into separate equations of dynamics and kinematics. This becomes of particular interest for modelling, estimation and control of mechanical systems......-known Euler-Poincaré reduction to a rigid body motion with forcing....
COMPARISON OF STABILITY BETWEEN NAVIER-STOKES AND EULER EQUATIONS
Institute of Scientific and Technical Information of China (English)
SHI Wei-hui; WANG Yue-peng; SHEN Chun
2006-01-01
The stability about Navier-Stokes equation and Euler equation was brought into comparison. And by taking their typical initial value problem for example, the reason of leading to the difference in stability between Navier-Stokes equation and Euler equation was also analyzed.
Euler-Poincare Reduction of a Rigid Body Motion
DEFF Research Database (Denmark)
Wisniewski, Rafal; Kulczycki, P.
2005-01-01
. Assuming that the system possesses symmetry and the configuration manifold corresponds to a Lie group, the Euler-Poincare reduction breaks up the motion into separate equations of dynamics and kinematics. This becomes of particular interest for modeling, estimation and control of mechanical systems......-known Euler-Poincare reduction to a rigid body motion with forcing....
The Hamiltonian Canonical Form for Euler-Lagrange Equations
Institute of Scientific and Technical Information of China (English)
ZHENG Yu
2002-01-01
Based on the theory of calculus of variation, some suffcient conditions are given for some Euler-Lagrangcequations to be equivalently represented by finite or even infinite many Hamiltonian canonical equations. Meanwhile,some further applications for equations such as the KdV equation, MKdV equation, the general linear Euler Lagrangeequation and the cylindric shell equations are given.
Applications of an Explicit Formula for the Generalized Euler Numbers
Institute of Scientific and Technical Information of China (English)
Guo Dong LIU; Wen Peng ZHANG
2008-01-01
The authors establish an explicit formula for the generalized Euler Numbers E(x)2n ,and obtain some identities and congruences involving the higher-order Euler numbers, Stirling numbers,the central factorial numbers and the values of the Riemann zeta-function.
A review of propeller modelling techniques based on Euler methods
Zondervan, G.J.D.
1998-01-01
Future generation civil aircraft will be powered by new, highly efficient propeller propulsion systems. New, advanced design tools like Euler methods will be needed in the design process of these aircraft. This report describes the application of Euler methods to the modelling of flowfields generate
Leonhard Euler and his contributions to fluid mechanics
Salas, M. D.
1988-01-01
The career of Leonhard Euler, one of the world's most gifted scientists, is reviewed. The paper focuses on Euler's contributions to fluid mechanics and gives a perspective of how this science was born. A bibliography is included to provide the history enthusiast with a starting point for further study.
Directory of Open Access Journals (Sweden)
Abdul Razaque Sahito
2013-04-01
Full Text Available Kinetic studies of AD (Anaerobic Digestion process are useful to predict the performance of digesters and design appropriate digesters and also helpful in understanding inhibitory mechanisms of biodegradation. The aim of this study was to assess the anaerobic kinetics of crop residues digestion with buffalo dung. Seven crop residues namely, bagasse, banana plant waste, canola straw, cotton stalks, rice straw, sugarcane trash and wheat straw were selected from the field and were analyzed on MC (Moisture Contents, TS (Total Solids and VS (Volatile Solids with standard methods. In present study, three first order exponential models namely exponential model, exponential lag phase model and exponential curve factor model were used to assess the kinetics of the AD process of crop residues and the effect of lag phase and curve factor was analyzed based on statistical hypothesis testing and on information theory. Assessment of kinetics of the AD of crop residues and buffalo dung follows the first order kinetics. Out of the three models, the simple exponential model was the poorest model, while the first order exponential curve factor model is the best fit model. In addition to statistical hypothesis testing, the exponential curve factor model has least value of AIC (Akaike's Information Criterion and can generate methane production data more accurately. Furthermore, there is an inverse linear relationship between the lag phase period and the curve factor.
Crepant Terminalisations and Orbifold Euler Numbers for SL(4) Singularities
Sardo Infirri, A V
1996-01-01
Let $X$ and $Y$ be two analytic canonical Gorenstein orbifolds. A resolution of singularities $Y\\to X$ is called an Euler resolution if $Y$ and $X$ have the same orbifold Euler number. If $Y$ is only terminal rather than smooth, it is called an Euler terminalisation. It is proved that Euler terminalisations exist for toric varieties in any dimension, for 4-dimensional toroidal varieties, and for singularities $\\C^4/G$ where $G$ belongs to certain classes of $\\SL(4)$ subgroups. The method of proof is expected to be applicable to a sizeable number of finite $\\SL(4)$ subgroups and to lead to a generalisation of the Dixon-Harvey-Vafa-Witten orbifold Euler number conjecture to dimension~4.
Chaotic dynamics of flexible Euler-Bernoulli beams
Energy Technology Data Exchange (ETDEWEB)
Awrejcewicz, J., E-mail: awrejcew@p.lodz.pl [Department of Automation, Biomechanics and Mechatronics, Lodz University of Technology, 1/15 Stefanowski St., 90-924 Lodz, Poland and Department of Vehicles, Warsaw University of Technology, 84 Narbutta St., 02-524 Warsaw (Poland); Krysko, A. V., E-mail: anton.krysko@gmail.com [Department of Applied Mathematics and Systems Analysis, Saratov State Technical University, Politehnicheskaya 77, 410054 Saratov (Russian Federation); Kutepov, I. E., E-mail: iekutepov@gmail.com; Zagniboroda, N. A., E-mail: tssrat@mail.ru; Dobriyan, V., E-mail: Dobriy88@yandex.ru; Krysko, V. A., E-mail: tak@san.ru [Department of Mathematics and Modeling, Saratov State Technical University, Politehnicheskaya 77, 410054 Saratov (Russian Federation)
2013-12-15
Mathematical modeling and analysis of spatio-temporal chaotic dynamics of flexible simple and curved Euler-Bernoulli beams are carried out. The Kármán-type geometric non-linearity is considered. Algorithms reducing partial differential equations which govern the dynamics of studied objects and associated boundary value problems are reduced to the Cauchy problem through both Finite Difference Method with the approximation of O(c{sup 2}) and Finite Element Method. The obtained Cauchy problem is solved via the fourth and sixth-order Runge-Kutta methods. Validity and reliability of the results are rigorously discussed. Analysis of the chaotic dynamics of flexible Euler-Bernoulli beams for a series of boundary conditions is carried out with the help of the qualitative theory of differential equations. We analyze time histories, phase and modal portraits, autocorrelation functions, the Poincaré and pseudo-Poincaré maps, signs of the first four Lyapunov exponents, as well as the compression factor of the phase volume of an attractor. A novel scenario of transition from periodicity to chaos is obtained, and a transition from chaos to hyper-chaos is illustrated. In particular, we study and explain the phenomenon of transition from symmetric to asymmetric vibrations. Vibration-type charts are given regarding two control parameters: amplitude q{sub 0} and frequency ω{sub p} of the uniformly distributed periodic excitation. Furthermore, we detected and illustrated how the so called temporal-space chaos is developed following the transition from regular to chaotic system dynamics.
1994-01-01
dquations d’Euler) Edited by * S J.W. SLOOFF National Aerospace Laboratory NLR Anthony Fokkerweg 2 1059 CM Amsterdam Netherlands Dr. W. SCHMIDT Air Vehicle...CHAKRAVARTHY. S. R., RIBA , W.* * T.. BYERLY. J. and DRESSER. H. S.. "Multi-Zone Euler 41. DESLANDES R.M.. "Theoretisebe bestimmung der Marching Technique
Directory of Open Access Journals (Sweden)
Ketut Kariyasa
2013-10-01
Full Text Available The main target of Integrated Crop Management Farmer Field School (ICM-FFS development is to boost rice production in order to accelerate the achievement of sustainable rice self-sufficient in Indonesia. Nevertheless, aside from its achievements, as an approach it was not fully effectual for farmers. The study aims at analyzing factors influencing the adoption of ICM-FFS at swampy lands using survey and stratified random sampling approaches with involving total respondents of 159 people. Analysis the adoption factors were estimated by logistic regression model. Variables significantly affected the level of improvement opportunities of adoption were age, education, distance to agricultural technology information sources, distance to the meeting place and productivity. Among these variables, productivity level was as the main consideration of the farmers to adopt the ICMFFS program. Therefore, the continuously effort to improve rice productivity should be taken into account as the priority to encourage more farmers to adopt this program. The opportunities for farmers to adopt this program are also expected to be even wider when efforts to increase productivity are also accompanied by efforts to improve quality and increase efficiency of inputs uses.
Genuinely Multidimensional Kinetic Scheme For Euler Equations
Tiwari, Praveer
2015-01-01
A new framework based on Boltzmann equation which is genuinely multidimensional and mesh-less is developed for solving Euler's equations. The idea is to use the method of moment of Boltzmann equation to operate in multidimensions using polar coordinates. The aim is to develop a framework which is genuinely multidimensional and can be implemented with different methodologies, no matter whether it is in finite difference, finite volume or finite element form. There is a considerable improvement in capturing shocks and other discontinuities. Also, since the method is multidimensional, the flow features are captured isotropically. The method is further extended to second order using 'Arc of Approach' concept. The framework is developed as a finite difference method (called as GINEUS) and is tested on the benchmark test cases. The results are compared against Kinetic Flux Vector Splitting Method.
Central differences, Euler numbers and symbolic methods
Dowker, J S
2013-01-01
I relate some coefficients encountered when computing the functional determinants on spheres to the central differentials of nothing. In doing this I use some historic works, in particular transcribing the elegant symbolic formalism of Jeffery (1861) into central difference form which has computational advantages for Euler numbers, as discovered by Shovelton (1915). I derive sum rules for these, and for the central differentials, the proof of which involves an interesting expression for powers of sech x as multiple derivatives. I present a more general, symbolic treatment of central difference calculus which allows known, and unknown, things to be obtained in an elegant and compact fashion gaining, at no cost, the expansion of the powers of the inverse sinh, a basic central function. Systematic use is made of the operator 2 asinh(D/2). Umbral calculus is employed to compress the operator formalism. For example the orthogonality/completeness of the factorial numbers, of the first and second kinds, translates, ...
The Euler current and parity odd transport
Golkar, Siavash; Son, Dam T
2014-01-01
For a spacetime of odd dimensions endowed with a unit vector field, we introduce a new topological current that is identically conserved and whose charge is equal to the Euler character of the even dimensional spacelike foliations. The existence of this current allows us to introduce new Chern-Simons-type terms in the effective field theories describing relativistic quantum Hall states and (2+1) dimensional superfluids. Using effective field theory, we calculate various correlation functions and identify transport coefficients. In the quantum Hall case, this current provides the natural relativistic generalization of the Wen-Zee term, required to characterize the shift and Hall viscosity in quantum Hall systems. For the superfluid case this term is required to have nonzero Hall viscosity and to describe superfluids with non s-wave pairing.
DEFF Research Database (Denmark)
Doltra, J; Olesen, Jørgen E; Báez, D;
2015-01-01
-based cropping systems. Forage maize was grown in a conventional dairy system at Mabegondo (NW Spain) and wheat and barley in organic and conventional crop rotations at Foulum (NW Denmark). These two European sites represent agricultural areas with high and low to moderate emission levels, respectively. Field...
A Universal Formula for Extracting the Euler Angles
Shuster, Malcolm D.; Markley, F. Landis
2004-01-01
Recently, the authors completed a study of the Davenport angles, which are a generalization of the Euler angles for which the initial and final Euler axes need not be either mutually parallel or mutually perpendicular or even along the coordinate axes. During the conduct of that study, those authors discovered a relationship which can be used to compute straightforwardly the Euler angles characterizing a proper-orthogonal direction-cosine matrix for an arbitrary Euler-axis set satisfying n(sub 1) x n(sub 2) = 0 and n(sub 3) x n(sub 1) = 0, which is also satisfied by the more usual Euler angles we encounter commonly in the practice of Astronautics. Rather than leave that relationship hidden in an article with very different focus from the present Engineering note, we present it and the universal algorithm derived from it for extracting the Euler angles from the direction-cosine matrix here. We also offer literal "code" for performing the operations, numerical examples, and general considerations about the extraction of Euler angles which are not universally known, particularly, the treatment of statistical error.
Bong, Lee-Jin; Neoh, Kok-Boon; Lee, Chow-Yang; Jaal, Zairi
2013-10-01
Paederus fuscipes Curtis, a dermatitis linearis causing agent, has received increasing attention from the public, as it poses a serious health threat after mass dispersal into human-dominated areas. Preventive measures against this insect have so far been unsuccessful partly because of limited knowledge about its dispersal pattern. In this study, the dispersal activity of P. fuscipes was studied at infestation-prone residential buildings in Mainland Penang, Malaysia. The dispersal activity of P. fuscipes showed two peaks, that is, from February to April and August to October. Overall, there was no statistical significant correlation between dispersal and climatic parameters, that is, temperature, relative humidity, total rainfall, at all sampling localities. However, dispersal was primarily caused by human activities in rice fields, which accounted for >60% of the variability in dispersal. Particularly, rice harvesting, including straw burning, and cultivation were the major factors triggering P. fuscipes dispersal. These activities presumably disrupted the habitat and normal activities of P. fuscipes and rendered the rice fields unfavorable refuges. In addition, the beetles might also face food shortages after the disturbance of their prey base in the crop fields. The current study provides a predictive tool of P. fuscipes flight periods to ensure insecticide residual spraying is timed in the infestation-prone residential areas before the onset of infestation.
A novel bit-quad-based Euler number computing algorithm.
Yao, Bin; He, Lifeng; Kang, Shiying; Chao, Yuyan; Zhao, Xiao
2015-01-01
The Euler number of a binary image is an important topological property in computer vision and pattern recognition. This paper proposes a novel bit-quad-based Euler number computing algorithm. Based on graph theory and analysis on bit-quad patterns, our algorithm only needs to count two bit-quad patterns. Moreover, by use of the information obtained during processing the previous bit-quad, the average number of pixels to be checked for processing a bit-quad is only 1.75. Experimental results demonstrated that our method outperforms significantly conventional Euler number computing algorithms.
Women and Mathematics in the Time of Euler
Mayfield, Betty
2013-01-01
We explore mathematics written both by and for women in eighteenth-century Europe, and some of the interesting personalities involved: Maria Agnesi, Emilie du Chatelet, Laura Bassi, Princess Charlotte Ludovica Luisa, John Colson, Francesco Algarotti, and Leonhard Euler himself.
The Euler Line and Nine-Point-Circle Theorems.
Eccles, Frank M.
1999-01-01
Introduces the Euler line theorem and the nine-point-circle theorem which emphasize transformations and the power of functions in a geometric concept. Presents definitions and proofs of theorems. (ASK)
Lorentz-violating Euler-Heisenberg effective action
Furtado, J
2014-01-01
In this work, we study the radiative generation of the Lorentz-violating Euler-Heisenberg action, in the weak field approximation. For this, we first consider a nonperturbative calculation in the coefficient $c_{\\mu\
On a continued fraction expansion for Euler's constant
Pilehrood, Khodabakhsh Hessami
2010-01-01
Recently, A.~I.~Aptekarev and his collaborators found a sequence of rational approximations to Euler's constant $\\gamma$ defined by a third-order homogeneous linear recurrence. In this paper, we give a new interpretation of Aptekarev's approximations to $\\gamma$ in terms of Meijer $G$-functions and hypergeometric-type series. This approach allows us to describe a very general construction giving linear forms in $1$ and $\\gamma$ with rational coefficients. Using this construction we find new rational approximations to $\\gamma$ generated by a second-order inhomogeneous linear recurrence with polynomial coefficients. This leads to a continued fraction (though not a simple continued fraction) for Euler's constant. It seems to be the first non-trivial continued fraction expansion convergent to Euler's constant sub-exponentially, the elements of which can be expressed as a general pattern. It is interesting to note that the same homogeneous recurrence generates a continued fraction for the Euler-Gompertz constant f...
Leonhard Euler and the mechanics of rigid bodies
Marquina, J. E.; Marquina, M. L.; Marquina, V.; Hernández-Gómez, J. J.
2017-01-01
In this work we present the original ideas and the construction of the rigid bodies theory realised by Leonhard Euler between 1738 and 1775. The number of treatises written by Euler on this subject is enormous, including the most notorious Scientia Navalis (1749), Decouverte d’un noveau principe de mecanique (1752), Du mouvement de rotation des corps solides autour d’un axe variable (1765), Theoria motus corporum solidorum seu rigidorum (1765) and Nova methodus motu corporum rigidorum determinandi (1776), in which he developed the ideas of the instantaneous rotation axis, the so-called Euler equations and angles, the components of what is now known as the inertia tensor, the principal axes of inertia, and, finally, the generalisation of the translation and rotation movement equations for any system. Euler, the man who ‘put most of mechanics into its modern form’ (Truesdell 1968 Essays in the History of Mechanics (Berlin: Springer) p 106).
N=1 Euler Anomaly from RG-dependent metric-Background
Prochazka, Vladimir; Zwicky, Roman
2017-03-01
We consider N = 1supersymmetric gauge theories in the conformal window. By applying a suitable matter superfield- and Weyl-transformation the renormalisation group running of the theory is absorbed into the metric. The latter becomes a function of the Z-factor and the infrared anomalous dimension of the matter superfield. The Euler flow Δa ≡ aUV - aIR|N=1 becomes equivalent to a computation of a free theory with the non-trivial dynamics coming from expanding the Euler invariant in the flow dependent metric. The result is therefore directly obtained in terms of the infrared anomalous dimension confirming an earlier result using the matching of R-currents.
Directory of Open Access Journals (Sweden)
Song Fu
2015-01-01
Full Text Available Although the uniform theory of diffraction (UTD could be theoretically applied to arbitrarilyshaped convex objects modeled by nonuniform rational B-splines (NURBS, one of the great challenges in calculation of the UTD surface diffracted fields is the difficulty in determining the geodesic paths along which the creeping waves propagate on arbitrarilyshaped NURBS surfaces. In differential geometry, geodesic paths satisfy geodesic differential equation (GDE. Hence, in this paper, a general and efficient adaptive variable step Euler method is introduced for solving the GDE on arbitrarilyshaped NURBS surfaces. In contrast with conventional Euler method, the proposed method employs a shape factor (SF ξ to efficiently enhance the accuracy of tracing and extends the application of UTD for practical engineering. The validity and usefulness of the algorithm can be verified by the numerical results.
Stochastic Euler Equations of Fluid Dynamics with Lvy Noise
2016-08-10
Asymptotic Analysis 99 (2016) 67–103 67 DOI 10.3233/ASY-161376 IOS Press Stochastic Euler equations of fluid dynamics with Lévy noise Manil T. Mohan...References [1] D. Applebaum, Lévy Processes and Stochastic Calculus , Cambridge Studies in Advanced Mathematics, Vol. 93, Cam- bridge University Press...2004. [2] H. Bessaih and F. Flandoli, 2-D Euler equation perturbed by noise, Nonlinear Differential Equations and Applications 6 (1998), 35–54. doi
Small values of the Euler function and the Riemann hypothesis
Nicolas, Jean-Louis
2012-01-01
Let $\\vfi$ be Euler's function, $\\ga$ be Euler's constant and $N_k$ be the product of the first $k$ primes. In this article, we consider the function $c(n) =(n/\\vfi(n)-e^\\ga\\log\\log n)\\sqrt{\\log n}$. Under Riemann's hypothesis, it is proved that $c(N_k)$ is bounded and explicit bounds are given while, if Riemann's hypothesis fails, $c(N_k)$ is not bounded above or below.
Euler solutions for an unbladed jet engine configuration
Stewart, Mark E. M.
1992-01-01
An Euler solution for an axisymmetric jet engine configuration without blade effects is presented. The Euler equations are solved on a multiblock grid which covers a domain including the inlet, bybass duct, core passage, nozzle, and the far field surrounding the engine. The simulation is verified by considering five theoretical properties of the solution. The solution demonstrates both multiblock grid generation techniques and a foundation for a full jet engine throughflow calculation.
Institute of Scientific and Technical Information of China (English)
GUO Han-Ying; LI Yu-Qi; WU Ke; WANG Shi-Kun
2002-01-01
In this second papcr of a scries of papers, we explore the differcnce discrete versions for the Euler-Lagrange cohomology and apply them to the symplectic or multisymplectic geometry and their preserving propertiesin both the Lagrangian and Hamiltonian formalisms for discrete mechanics and field theory in the framework of multi-parameter differential approach. In terns of the difference discrete Euler-Lagrange cohomological concepts, we show thatthe symplcctic or multisymplectic geometry and their difference discrete structure-preserving properties can always beestablished not only in thc solution spaces of the discrete Euler-Lagrange or canonical equations derived by the differencediscrete variational principle but also in the function space in each case if and only if the relevant closed Euler-Lagrangecohomological conditions are satisfied.
Wong, Sen; Yuen, Manwai
2014-01-01
We study, in the radial symmetric case, the finite time life span of the compressible Euler or Euler-Poisson equations in R (N) . For time t ≥ 0, we can define a functional H(t) associated with the solution of the equations and some testing function f. When the pressure function P of the governing equations is of the form P = Kρ (γ) , where ρ is the density function, K is a constant, and γ > 1, we can show that the nontrivial C (1) solutions with nonslip boundary condition will blow up in finite time if H(0) satisfies some initial functional conditions defined by the integrals of f. Examples of the testing functions include r (N-1)ln(r + 1), r (N-1) e (r) , r (N-1)(r (3) - 3r (2) + 3r + ε), r (N-1)sin((π/2)(r/R)), and r (N-1)sinh r. The corresponding blowup result for the 1-dimensional nonradial symmetric case is also given.
Willführ, Alper; Brandenberger, Christina; Piatkowski, Tanja; Grothausmann, Roman; Nyengaard, Jens Randel; Ochs, Matthias; Mühlfeld, Christian
2015-12-01
The lung parenchyma provides a maximal surface area of blood-containing capillaries that are in close contact with a large surface area of the air-containing alveoli. Volume and surface area of capillaries are the classic stereological parameters to characterize the alveolar capillary network (ACN) and have provided essential structure-function information of the lung. When loss (rarefaction) or gain (angiogenesis) of capillaries occurs, these parameters may not be sufficient to provide mechanistic insight. Therefore, it would be desirable to estimate the number of capillaries, as it contains more distinct and mechanistically oriented information. Here, we present a new stereological method to estimate the number of capillary loops in the ACN. One advantage of this method is that it is independent of the shape, size, or distribution of the capillaries. We used consecutive, 1 μm-thick sections from epoxy resin-embedded material as a physical disector. The Euler-Poincaré characteristic of capillary networks can be estimated by counting the easily recognizable topological constellations of "islands," "bridges," and "holes." The total number of capillary loops in the ACN can then be calculated from the Euler-Poincaré characteristic. With the use of the established estimator of alveolar number, it is possible to obtain the mean number of capillary loops per alveolus. In conclusion, estimation of alveolar capillaries by design-based stereology is an efficient and unbiased method to characterize the ACN and may be particularly useful for studies on emphysema, pulmonary hypertension, or lung development.
The Euler characteristic correction to the Kaehler potential - revisited
Bonetti, Federico
2016-01-01
We confirm the leading $\\alpha'^3$ correction to the 4d, $\\mathcal N = 1$ K\\"{a}hler potential of type IIB orientifold compactifications, proportional to the Euler characteristic of the Calabi-Yau threefold (BBHL correction). We present the explicit solution for the $\\alpha'^3$-modified internal background metric in terms of the non-harmonic part of the third Chern form of the leading order Calabi-Yau manifold. The corrected internal manifold is almost Calabi-Yau and admits an $SU(3)$ structure with non-vanishing torsion. We also find that the full ten-dimensional Einstein frame background metric is multiplied by a non-trivial Weyl factor. Performing a Kaluza-Klein reduction on the modified background we derive the $\\alpha'^3$-corrected kinetic terms for the dilaton and the K\\"{a}hler deformations of the internal Calabi-Yau threefold for arbitrary $h^{1,1}$. We analyze these kinetic terms in the 4d, $\\mathcal N = 2$ un-orientifolded theory, confirming the expected correction to the K\\"ahler moduli space prepo...
Bontsema, J.; Hemming, J.; Pekkeriet, E.J.
2015-01-01
In the EU-funded CROPS project robots are developed for site-specific spraying and selective harvesting of fruit
and fruit vegetables. The robots are being designed to harvest crops, such as greenhouse vegetables, apples,
grapes and for canopy spraying in orchards and for precision target sp
Kim, Gil Won; Das, Suvendu; Hwang, Hyun Young; Kim, Pil Joo
2017-03-01
Assessment of nitrous oxide (N2O) emission factor (EF) for N2O emission inventory from arable crops fertilized with different nitrogen sources are under increased scrutiny because of discrepancies between the default IPCC EFs and low EFs reported by many researchers. Mixing ratio of leguminous and non-leguminous cover crop residues incorporation and plastic film mulching (PFM) in upland soil has been recommended as a vital agronomic practice to enhance yield and soil quality. However, how these practices together affect N2O emissions, yield-scaled emissions and the EFs remain uncertain. Field experiments spanning two consecutive years were conducted to evaluate the effects of PFM on N2O emissions, yield-scaled emissions and the seasonal EFs in cover crop residues amended soil during maize cultivation. The mixture of barley (Hordeum vulgare) and hairy vetch (Vicia villosa) seeds with 75% recommended dose (RD 140 kg ha-1) and 25% recommended dose (RD 90 kg ha-1), respectively, were broadcasted during the fallow period and 0, 25, 50 and 100% of the total aboveground harvested biomass that correspond to 0, 76, 152 and 304 kg N ha-1 were incorporated before maize transplanting. It was found that the mean seasonal EFs from cover crop residues amended soil under No-mulching (NM) and PFM were 1.13% (ranging from 0.81 to 1.23%) and 1.49% (ranging from 1.02 to 1.63%), respectively, which are comparable to the IPCC (2006) default EF (1%) for emission inventories of N2O from crop residues. The emission fluxes were greatly influenced by NH4+sbnd N, NO3--N, DOC and DON contents of soil. The cumulative N2O emissions markedly increased with the increase in cover crop residues application rates and it was more prominent under PFM than under NM. However, the yield-scaled emissions markedly decreased under PFM compared to NM due to the improved yield. With relatively low yield-scaled N2O emissions, 25% biomass mixing ratio of barley and hairy vetch (76 kg N ha-1) under PFM could be
Komissarova, Olga; Paramonova, Tatiana
2017-04-01
One of the notable lessons obtained from nuclear accidents could be revealing the general features of 137Cs root uptake by agricultural crops for prediction the radionuclide accumulation in plants and its further distribution via food chains. Transfer factors (TFs) (the ratio of 137Cs activities in vegetation and in soil) have become a basis for such assessment when the characteristics of radioactive contamination, soil properties and phylogenetic features of different plant taxons important for root uptake are known. For the sake of simplicity the concept of conversion factor (CF) was accepted by IAEA (2006) to obtain unknown value of TF from the TF value of the reference crop cultivated on the same soil. Cereals were selected like reference group of agricultural crops. Presuming TF for cereals equal 1, CFs for tubers and fodder leguminous are 4, for grasses - 4.5, for leafy vegetables - 9, ets. To verify TFs and corresponding CFs values under environmental conditions of post-Chernobyl agricultural landscape the study in the area of Plavsky radioactive hotspot (Tula region, Russia) was conducted. Nowadays, after 30 years after the Chernobyl accident ( the first half-life period of 137Cs), arable chernozems of the territory are still polluted at the level 126-282 kBq/m2. The main crops of field rotation: wheat and barley (cereals), potatoes (tubers), soybean (leguminous), amaranth (non-leafy vegetables), rape ("other crops"), as well as galega-bromegrass mixture (cultivated species of grasses) and pasture grasses of semi-natural dry and wet meadows have been studied. Accumulation parameters of 137Cs in aboveground biomass, belowground biomass and edible parts of the plants were examined separately. Experimentally obtained 137Cs TFs in cereals are 0.24-0.32 for total biomass, 0.07-0.14 for aerial parts, 0.54-0.64 for roots and 0.01-0.02 for grain. Thus, (i) 137Cs transfer in grain of wheat and barley is insignificant and (ii) corresponding TFs values in both crops
Warren Raffa, D.; Bogdanski, A.; Tittonell, P.
2015-01-01
The current advancement of the bioenergy sector along with the need for sustainable agricultural systems call for context-specific crop residue management options - implying variable degrees of removal - across climatic regions, soil types and farming systems around the world. A large database
BIOGAS PRODUCTION FROM CATCH CROPS
DEFF Research Database (Denmark)
Molinuevo-Salces, Beatriz; Larsen, Søren U.; Ahring, Birgitte Kiær
2014-01-01
Catch crop cultivation combined with its use for biogas production would increase renewable energy production in the form of methane, without interfering with the production of food and fodder crops. The low biomass yield of catch crops is the main limiting factor for using these crops as co......-substrate in manure-based biogas plants and the profit obtained from the sale of biogas barely compensates for the harvest costs. A new agricultural strategy to harvest catch crops together with the residual straw of the main crop was investigated to increase the biomass and thereby the methane yield per hectare...... biomass. Leaving the straw on the field until harvest of the catch crop in the autumn could benefit biogas production due to the organic matter degradation of the straw taking place on the field during the autumn months. This new agricultural strategy may be a good alternative to achieve economically...
African Journals Online (AJOL)
however, their success in addressing the credit needs of food crop farmers remains a ..... will to carry such policies through in the match .... farmer, his mental capacity to cope with the daily .... had stated that farm level credit when properly.
Marvasi, Massimiliano; Hochmuth, George J; Giurcanu, Mihai C; George, Andrée S; Noel, Jason T; Bartz, Jerry; Teplitski, Max
2013-01-01
Fresh fruits and vegetables become increasingly recognized as vehicles of human salmonellosis. Physiological, ecological, and environmental factors are all thought to contribute to the ability of Salmonella to colonize fruits and vegetables pre- and post-harvest. The goal of this study was to test how irrigation levels, fruit water congestion, crop and pathogen genotypes affect the ability of Salmonella to multiply in tomatoes post-harvest. Fruits from three tomato varieties, grown over three production seasons in two Florida locations, were infected with seven strains of Salmonella and their ability to multiply post-harvest in field-grown tomatoes was tested. The field experiments were set up as a two-factor factorial split plot experiment, with the whole-plot treatments arranged in a randomized complete-block design. The irrigation treatment (at three levels) was the whole-plot factor, and the split-plot factor was tomato variety, with three levels. The significance of the main, two-way, and three-way interaction effects was tested using the (type III) F-tests for fixed effects. Mean separation for each significant fixed effect in the model was performed using Tukey's multiple comparison testing procedure. The irrigation regime per se did not affect susceptibility of the crop to post-harvest proliferation of Salmonella. However, Salmonella grew significantly better in water-congested tissues of green tomatoes. Tomato maturity and genotype, Salmonella genotype, and inter-seasonal differences were the strongest factors affecting proliferation. Red ripe tomatoes were significantly and consistently more conducive to proliferation of Salmonella. Tomatoes harvested in the driest, sunniest season were the most conducive to post-harvest proliferation of the pathogen. Statistically significant interactions between production conditions affected post-harvest susceptibility of the crop to the pathogen. UV irradiation of tomatoes post-harvest promoted Salmonella growth.
Directory of Open Access Journals (Sweden)
Massimiliano Marvasi
Full Text Available MAIN OBJECTIVES: Fresh fruits and vegetables become increasingly recognized as vehicles of human salmonellosis. Physiological, ecological, and environmental factors are all thought to contribute to the ability of Salmonella to colonize fruits and vegetables pre- and post-harvest. The goal of this study was to test how irrigation levels, fruit water congestion, crop and pathogen genotypes affect the ability of Salmonella to multiply in tomatoes post-harvest. EXPERIMENTAL DESIGN: Fruits from three tomato varieties, grown over three production seasons in two Florida locations, were infected with seven strains of Salmonella and their ability to multiply post-harvest in field-grown tomatoes was tested. The field experiments were set up as a two-factor factorial split plot experiment, with the whole-plot treatments arranged in a randomized complete-block design. The irrigation treatment (at three levels was the whole-plot factor, and the split-plot factor was tomato variety, with three levels. The significance of the main, two-way, and three-way interaction effects was tested using the (type III F-tests for fixed effects. Mean separation for each significant fixed effect in the model was performed using Tukey's multiple comparison testing procedure. MOST IMPORTANT DISCOVERIES AND SIGNIFICANCE: The irrigation regime per se did not affect susceptibility of the crop to post-harvest proliferation of Salmonella. However, Salmonella grew significantly better in water-congested tissues of green tomatoes. Tomato maturity and genotype, Salmonella genotype, and inter-seasonal differences were the strongest factors affecting proliferation. Red ripe tomatoes were significantly and consistently more conducive to proliferation of Salmonella. Tomatoes harvested in the driest, sunniest season were the most conducive to post-harvest proliferation of the pathogen. Statistically significant interactions between production conditions affected post-harvest susceptibility
ENTROPIES AND FLUX-SPLITTINGS FOR THE ISENTROPIC EULER EQUATIONS
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The authors establish the existence of a large class of mathematical entropies (the so-called weak entropies) associated with the Euler equations for an isentropic, compressible fluid governed by a general pressure law. A mild assumption on the behavior of the pressure law near the vacuum is solely required. The analysis is based on an asymptotic expansion of the fundamental solution (called here the entropy kernel) of a highly singular Euler-Poisson-Darboux equation. The entropy kernel is only H lder continuous and its regularity is carefully investigated. Relying on a notion introduced earlier by the authors, it is also proven that, for the Euler equations, the set of entropy flux-splittings coincides with the set of entropies-entropy fluxes. These results imply the existence of a flux-splitting consistent with all of the entropy inequalities.
Crop responses to climatic variation
DEFF Research Database (Denmark)
Porter, John R.; Semenov, Mikhail A.
2005-01-01
production. However, crops can respond nonlinearly to changes in their growing conditions, exhibit threshold responses and are subject to combinations of stress factors that affect their growth, development and yield. Thus, climate variability and changes in the frequency of extreme events are important...... of adaptation possibilities for crops in response to drought and argues that characters that enable better exploration of the soil and slower leaf canopy expansion could lead to crop higher transpiration efficiency....
A Simple Approach for Boundary Improvement of Euler Diagrams.
Simonetto, Paolo; Archambault, Daniel; Scheidegger, Carlos
2016-01-01
General methods for drawing Euler diagrams tend to generate irregular polygons. Yet, empirical evidence indicates that smoother contours make these diagrams easier to read. In this paper, we present a simple method to smooth the boundaries of any Euler diagram drawing. When refining the diagram, the method must ensure that set elements remain inside their appropriate boundaries and that no region is removed or created in the diagram. Our approach uses a force system that improves the diagram while at the same time ensuring its topological structure does not change. We demonstrate the effectiveness of the approach through case studies and quantitative evaluations.
Implicit finite-difference methods for the Euler equations
Pulliam, T. H.
1985-01-01
The present paper is concerned with two-dimensional Euler equations and with schemes which are in use of the time of this writing. Most of the development presented carries over directly to three dimensions. The characteristics of the two-dimensional Euler equations in Cartesian coordinates are considered along with generalized curvilinear coordinate transformations, metric relations, invariants of the transformation, flux Jacobian matrices and eigensystems, numerical algorithms, flux split algorithms, implicit and explicit nonlinear control (smoothing), upwind differencing in supersonic regions, unsteady and steady-state computation, the diagonal form of implicit algorithm, metric differencing and invariants, boundary conditions, geometry and mesh generation, and sample solutions.
A novel bit-quad-based Euler number computing algorithm
Yao, Bin; He, Lifeng; Kang, Shiying; Chao, Yuyan; Xiao ZHAO
2015-01-01
The Euler number of a binary image is an important topological property in computer vision and pattern recognition. This paper proposes a novel bit-quad-based Euler number computing algorithm. Based on graph theory and analysis on bit-quad patterns, our algorithm only needs to count two bit-quad patterns. Moreover, by use of the information obtained during processing the previous bit-quad, the average number of pixels to be checked for processing a bit-quad is only 1.75. Experimental results ...
The Euler Function of Fibonacci and Lucas Numbers and Factorials
2013-01-01
the Fibonacci sequence given by F0 = 0, F1 = 1 and Fn+2 = Fn+1+Fn for all n ≥ 0. Let (Ln)n≥0 be the companion Lucas sequence satisfying the same...Annales Univ. Sci. Budapest., Sect. Comp. 40 (2013) nn–nnn THE EULER FUNCTION OF FIBONACCI AND LUCAS NUMBERS AND FACTORIALS Florian Luca (Morelia...Communicated by Bui Minh Phong (Received December 22, 2012; accepted July 18, 2013) Abstract. Here, we look at the Fibonacci and Lucas numbers whose Euler
On the Identities of Symmetry for the -Euler Polynomials of Higher Order
Directory of Open Access Journals (Sweden)
Park KyoungHo
2009-01-01
Full Text Available The main purpose of this paper is to investigate several further interesting properties of symmetry for the multivariate -adic fermionic integral on . From these symmetries, we can derive some recurrence identities for the -Euler polynomials of higher order, which are closely related to the Frobenius-Euler polynomials of higher order. By using our identities of symmetry for the -Euler polynomials of higher order, we can obtain many identities related to the Frobenius-Euler polynomials of higher order.
Genetic Engineering and Crop Production.
Jones, Helen C.; Frost, S.
1991-01-01
With a spotlight upon current agricultural difficulties and environmental dilemmas, this paper considers both the extant and potential applications of genetic engineering with respect to crop production. The nonagricultural factors most likely to sway the impact of this emergent technology upon future crop production are illustrated. (JJK)
Genetic Engineering and Crop Production.
Jones, Helen C.; Frost, S.
1991-01-01
With a spotlight upon current agricultural difficulties and environmental dilemmas, this paper considers both the extant and potential applications of genetic engineering with respect to crop production. The nonagricultural factors most likely to sway the impact of this emergent technology upon future crop production are illustrated. (JJK)
Ozden, Hacer
2011-09-01
The aim of this paper is to define the generating functions of the Bernoulli, Euler and Genocchi polynomials of higher order. By using these generating functions, we derive some identities and relations on these polynomials. Our results generalize the classical Bernoulli, Euler, Genocchi polynomials and also Apostol-Bernoulli, Apostol-Euler and Apostol-Genocchi polynomials.
Padé approximation and Apostol-Bernoulli and Apostol-Euler polynomials
Prévost, Marc
2010-04-01
Using the Padé approximation of the exponential function, we obtain recurrence relations between Apostol-Bernoulli and between Apostol-Euler polynomials. As applications, we derive some new lacunary recurrence relations for Bernoulli and Euler polynomials with gap of length 4 and lacunary relations for Bernoulli and Euler numbers with gap of length 6.
Quasi-neutral limit of the full bipolar Euler-Poisson system
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
The quasi-neutral limit of the multi-dimensional non-isentropic bipolar Euler-Poisson system is considered in the present paper. It is shown that for well-prepared initial data the smooth solution of the non-isentropic bipolar Euler-Poisson system converges strongly to the compressible non-isentropic Euler equations as the Debye length goes to zero.
Euler potentials for the MHD Kamchatnov-Hopf soliton solution
Semenov, VS; Korovinski, DB; Biernat, HK
2002-01-01
In the MHD description of plasma phenomena the concept of magnetic helicity turns out to be very useful. We present here an example of introducing Euler potentials into a topological MHD soliton which has non-trivial helicity. The MHD soliton solution (Kamchatnov, 1982) is based on the Hopf invarian
Dynamic Response of Axially Loaded Euler-Bernoulli Beams
DEFF Research Database (Denmark)
Bayat, M.; Barari, Amin; Shahidi, M.
2011-01-01
The current research deals with application of a new analytical technique called Energy Balance Method (EBM) for a nonlinear problem. Energy Balance Method is used to obtain the analytical solution for nonlinear vibration behavior of Euler-Bernoulli beams subjected to axial loads. Analytical...
Two Identities for the Bernoulli-Euler Numbers
Gauthier, N.
2008-01-01
Two identities for the Bernoulli and for the Euler numbers are derived. These identities involve two special cases of central combinatorial numbers. The approach is based on a set of differential identities for the powers of the secant. Generalizations of the Mittag-Leffler series for the secant are introduced and used to obtain closed-form…
Non-Linear Vibration of Euler-Bernoulli Beams
DEFF Research Database (Denmark)
Barari, Amin; Kaliji, H. D.; Domairry, G.
2011-01-01
In this paper, variational iteration (VIM) and parametrized perturbation (PPM)methods have been used to investigate non-linear vibration of Euler-Bernoulli beams subjected to the axial loads. The proposed methods do not require small parameter in the equation which is difficult to be found...
Large time behavior of Euler-Poisson system for semiconductor
Institute of Scientific and Technical Information of China (English)
2008-01-01
In this note,we present a framework for the large time behavior of general uniformly bounded weak entropy solutions to the Cauchy problem of Euler-Poisson system of semiconductor devices.It is shown that the solutions converges to the stationary solutions exponentially in time.No smallness and regularity conditions are assumed.
Newton's Laws, Euler's Laws and the Speed of Light
Whitaker, Stephen
2009-01-01
Chemical engineering students begin their studies of mechanics in a department of physics where they are introduced to the mechanics of Newton. The approach presented by physicists differs in both perspective and substance from that encountered in chemical engineering courses where Euler's laws provide the foundation for studies of fluid and solid…
Euler Teaches a Class in Structural Steel Design
Boyajian, David M.
2009-01-01
Even before steel was a topic of formal study for structural engineers, the brilliant eighteenth century Swiss mathematician and physicist, Leonhard Euler (1707-1783), investigated the theory governing the elastic behaviour of columns, the results of which are incorporated into the American Institute of Steel Construction's (AISC's) Bible: the…
Drawing Euler Diagrams with Circles: The Theory of Piercings.
Stapleton, Gem; Leishi Zhang; Howse, John; Rodgers, Peter
2011-07-01
Euler diagrams are effective tools for visualizing set intersections. They have a large number of application areas ranging from statistical data analysis to software engineering. However, the automated generation of Euler diagrams has never been easy: given an abstract description of a required Euler diagram, it is computationally expensive to generate the diagram. Moreover, the generated diagrams represent sets by polygons, sometimes with quite irregular shapes that make the diagrams less comprehensible. In this paper, we address these two issues by developing the theory of piercings, where we define single piercing curves and double piercing curves. We prove that if a diagram can be built inductively by successively adding piercing curves under certain constraints, then it can be drawn with circles, which are more esthetically pleasing than arbitrary polygons. The theory of piercings is developed at the abstract level. In addition, we present a Java implementation that, given an inductively pierced abstract description, generates an Euler diagram consisting only of circles within polynomial time.
Euler's Identity, Leibniz Tables, and the Irrationality of Pi
Jones, Timothy W.
2012-01-01
Using techniques that show that e and pi are transcendental, we give a short, elementary proof that pi is irrational based on Euler's identity. The proof involves evaluations of a polynomial using repeated applications of Leibniz formula as organized in a Leibniz table.
The Legacy of Leonhard Euler--A Tricentennial Tribute
Debnath, Lokenath
2009-01-01
This tricentennial tribute commemorates Euler's major contributions to mathematical and physical sciences. A brief biographical sketch is presented with his major contributions to certain selected areas of number theory, differential and integral calculus, differential equations, solid and fluid mechanics, topology and graph theory, infinite…
Discovering Euler Circuits and Paths through a Culturally Relevant Lesson
Robichaux, Rebecca R.; Rodrigue, Paulette R.
2006-01-01
This article describes a middle school discrete mathematics lesson that uses the context of catching crawfish to provide students with a hands-on experience related to Euler circuits and paths. The lesson promotes mathematical communication through the use of cooperative learning as well as connections between mathematics and the real world…
Exponentially Fitted Variants of Euler's Method for ODEs
Kanwar, V.; Tomar, S. K.
2008-01-01
A new class of Euler's method for the numerical solution of ordinary differential equations is presented in this article. The methods are iterative in nature and admit their geometric derivation from an exponentially fitted osculating straight line. They are single-step methods and do not require evaluation of any derivatives. The accuracy and…
Euler-Poincaré Reduction of a Rigid Body Motion
DEFF Research Database (Denmark)
Wisniewski, Rafal; Kulczycki, P.
2004-01-01
. Assuming that the system possesses symmetry and the configuration manifold corresponds to a Lie group, the Euler-Poincaré reduction breaks up the motion into separate equations of dynamics and kinematics. This becomes of particular interest for modelling, estimation and control of mechanical systems...
An improved front tracking method for the Euler equations
J.A.S. Witteveen (Jeroen); B. Koren (Barry); P.G. Bakker
2007-01-01
textabstractAn improved front tracking method for hyperbolic conservation laws is presented. The improved method accurately resolves discontinuities as well as continuous phenomena. The method is based on an improved front interaction model for a physically more accurate modeling of the Euler
Euler y la Conjetura de Fermat sobre Números Triangulares
Directory of Open Access Journals (Sweden)
José Manuel Sánchez Muñoz
2011-04-01
Full Text Available Este artículo describe la historia de como Euler demostró la existencia de infinitos números triangulares bicuadráticos, desde su correspondencia con su amigo Christian Goldbach hasta la publicación de sus resultados en la Academia de San Petesburgo.
Non-uniform Euler-Bernoulli beams’ natural frequencies
Directory of Open Access Journals (Sweden)
Hugo Aya
2011-05-01
Full Text Available This paper has studied the problem of natural frequencies for Euler-Bernoulli beams having non-uniform cross-section. The numerically-obtained solutions were compared to asymptotic solutions obtained by the Wentzel-Kramers-Brillouin (WKB method. It was established that WKB formula precision was higher than 3% for high frequencies (≥ 4 mode.
Multipliers for the Absolute Euler Summability of Fourier Series
Indian Academy of Sciences (India)
Prem Chandra
2001-05-01
In this paper, the author has investigated necessary and sufficient conditions for the absolute Euler summability of the Fourier series with multipliers. These conditions are weaker than those obtained earlier by some workers. It is further shown that the multipliers are best possible in certain sense.
A note on singularities of the 3-D Euler equation
Tanveer, S.
1994-01-01
In this paper, we consider analytic initial conditions with finite energy, whose complex spatial continuation is a superposition of a smooth background flow and a singular field. Through explicit calculation in the complex plane, we show that under some assumptions, the solution to the 3-D Euler equation ceases to be analytic in the real domain in finite time.
An improved front tracking method for the Euler equations
Witteveen, J.A.S.; Koren, B.; Bakker, P.G.
2007-01-01
An improved front tracking method for hyperbolic conservation laws is presented. The improved method accurately resolves discontinuities as well as continuous phenomena. The method is based on an improved front interaction model for a physically more accurate modeling of the Euler equations, as comp
Newton's Laws, Euler's Laws and the Speed of Light
Whitaker, Stephen
2009-01-01
Chemical engineering students begin their studies of mechanics in a department of physics where they are introduced to the mechanics of Newton. The approach presented by physicists differs in both perspective and substance from that encountered in chemical engineering courses where Euler's laws provide the foundation for studies of fluid and solid…
A Historical Discussion of Angular Momentum and its Euler Equation
Sparavigna, Amelia Carolina
2015-01-01
We propose a discussion of angular momentum and its Euler equation, with the aim of giving a short outline of their history. This outline can be useful for teaching purposes too, to amend some problems that students can have in learning this important physical quantity.
Generalized Burgers equations and Euler-Painlevé transcendents. III
Sachdev, P. L.; Nair, K. R. C.; Tikekar, V. G.
1988-11-01
It was proposed earlier [P. L. Sachdev, K. R. C. Nair, and V. G. Tikekar, J. Math. Phys. 27, 1506 (1986); P. L. Sachdev and K. R. C. Nair, ibid. 28, 977 (1987)] that the Euler-Painlevé equations y(d2y/dη2)+a(dy/dη)2 +f(η)y(dy/dη)+g(η)y2+b(dy/dη) +c=0 represent generalized Burgers equations (GBE's) in the same way as Painlevé equations represent the Korteweg-de Vries type of equations. The earlier studies were carried out in the context of GBE's with damping and those with spherical and cylindrical symmetry. In the present paper, GBE's with variable coefficients of viscosity and those with inhomogeneous terms are considered for their possible connection to Euler-Painlevé equations. It is found that the Euler-Painlevé equation, which represents the GBE ut+uβux=(δ/2)g(t)uxx, g(t)=(1+t)n, β>0, has solutions, which either decay or oscillate at η=±∞, only when -1Kamke [Differential Gleichungen : Lösungsmethoden und Lösungen (Akademische Verlagsgesellschaft, Leipzig, 1943)] and Murphy [Ordinary Differential Equations and their Solutions (Van Nostrand, Princeton, NJ, 1960)]. These latter equations arise from a wide range of physical applications and are of some historical interest as well. They are all special cases of a slightly generalized form of the Euler-Painlevé equation.
State vector splitting for the Euler equations of gasdynamics
Öksüzoglu, H.
2001-01-01
A new upwind scheme is introduced for the Euler equations of gasdynamics in multi- dimensions. Its relation to Steger-Warming Flux Vector Splitting is discussed. Imple- mentation of the conservative boundary condi- tions on solid walls is also given. The method is intuitive, easy to implement and do
A Characterization of the Euler Numbers%Euler 数的一个特征
Institute of Scientific and Technical Information of China (English)
张之正
2003-01-01
设E2n为Euler数以及矩阵E2n(t)定义为En(t)=(et+I+j)0≤I,j≤n,这里en=En,若n为偶数0,若n为奇数,我们得到了E2n(t)的一个一般分解形式；进而得到了detE2n(0),detE2n(1)与 detE2n(2)的计算公式.%Let E2n be the Euler numbers and the matrices En(t)(t=0,1,2,…)defined by En(t)=(et+i+j)0≤i,j≤n,where en=En if n is even ,and en=0 if n odd.We give the factorial result of En(t).Furthermore,the computational formulae of det En(0),det En(1) and det En(2) are obtained.
Llorens, A; Mateo, R; Hinojo, M J; Valle-Algarra, F M; Jiménez, M
2004-07-01
Various species of Fusarium can produce trichothecene mycotoxins that contaminate food commodities and can represent a risk for human and animal health. In this paper, a full factorial design was applied to study the influence of incubation temperature, water activity (a(w)) and type of isolate on the production of deoxynivalenol (DON), nivalenol (NIV) and 3-acetyldeoxynivalenol (3-AcDON) in corn kernel cultures by three isolates of Fusarium graminearum and three isolates of Fusarium culmorum from crops grown in Spain. The tested temperatures were 15, 20, 28 and 32 degrees C. The a(w)-values were 0.960, 0.970 and 0.980. Moisture of cultures (within the studied range) did not affect significantly production of trichothecenes; however, the temperature affected significantly mycotoxin production and the optimal values were 28, 20 and 15 degrees C for DON, NIV and 3-AcDON, respectively. Four additional isolates of F. graminearum and two additional isolates of F. culmorum were examined for production of these mycotoxins at the optimal temperatures. Of the seven isolates of F. graminearum, four produced DON (0.88-3.97 microg/g), seven produced NIV (1.53-124 microg/g), and three produced 3-AcDON (0.65-10.6 microg/g). Of the five isolates of F. culmorum, four produced DON (1.20-4.93 microg/g), four produced NIV (6.94-701 microg/g), and four produced 3-AcDON (0.83-7.70 microg/g). Practically all isolates seem to belong to the NIV-chemotype. This is the first study done with regard to interaction between strain and ecological variables on type B trichothecene production by isolates of these two species from crops grown in Spain.
Savary, S; Mila, A; Willocquet, L; Esker, P D; Carisse, O; McRoberts, N
2011-06-01
Plant disease epidemiology requires expansion of its current methodological and theoretical underpinnings in order to produce full contributions to global food security and global changes. Here, we outline a framework which we applied to farmers' field survey data set on rice diseases in the tropical and subtropical lowlands of Asia. Crop health risks arise from individual diseases, as well as their combinations in syndromes. Four key drivers of agricultural change were examined: labor, water, fertilizer, and land availability that translate into crop establishment method, water shortage, fertilizer input, and fallow period duration, respectively, as well as their combinations in production situations. Various statistical approaches, within a hierarchical structure, proceeding from higher levels of hierarchy (production situations and disease syndromes) to lower ones (individual components of production situations and individual diseases) were used. These analyses showed that (i) production situations, as wholes, represent very large risk factors (positive or negative) for occurrence of disease syndromes; (ii) production situations are strong risk factors for individual diseases; (iii) drivers of agricultural change represent strong risk factors of disease syndromes; and (iv) drivers of change, taken individually, represent small but significant risk factors for individual diseases. The latter analysis indicates that different diseases are positively or negatively associated with shifts in these drivers. We also report scenario analyses, in which drivers of agricultural change are varied in response to possible climate and global changes, generating predictions of shifts in rice health risks. The overall set of analyses emphasizes the need for large-scale ground data to define research priorities for plant protection in rapidly evolving contexts. They illustrate how a structured theoretical framework can be used to analyze emergent features of agronomic and
Shuai, Yanmin; Xie, Donghui; Wang, Peijuan; Wu, Menxin
2014-03-01
Land surface phenology is an efficient bio-indicator for monitoring terrestrial ecosystem variation in response to climate change. Numerous studies point out climate change plays an important role in modulating vegetation phenological events, especially in agriculture. In turn, surface changes caused by geo-biological processes can affect climate transition regionally and perhaps globally, as concluded by Intergovernmental Panel on Climate Change (IPCC) in 2001. Large amounts of research concluded that crops, as one of the most sensitive bio-indicators for climate change, can be strongly influenced by local weather such as temperature, moisture and radiation. Thus, investigating the details of weather impact and the feedback from crops can help improve our understanding of the interaction between crops and climate change at satellite scale. Our efforts start from this point, via case studies over the famous agriculture region in the Northeast China's plain to examine the response of spring maize under temperature and moisture stress. MODIS-based daily green vegetation information together with frequent field specification of the surface phenology as well as continuous measurements of the routine climatic factors during seven years (2003-2009) is used in this paper. Despite the obvious difference in scale between satellite estimations and field observations, the inter- and intra-annual variation of maize in seven-years' growth was captured successfully over three typical spring maize regions (Fuyu, Changling, and Hailun) in Northeast China. The results demonstrate that weather conditions such as changes of temperature and moisture stress provide considerable contribution to the year-to-year variations in the timing of spring maize phenological events.
Wang, X; Hopkins, C
2016-10-01
Advanced Statistical Energy Analysis (ASEA) is used to predict vibration transmission across coupled beams which support multiple wave types up to high frequencies where Timoshenko theory is valid. Bending-longitudinal and bending-torsional models are considered for an L-junction and rectangular beam frame. Comparisons are made with measurements, Finite Element Methods (FEM) and Statistical Energy Analysis (SEA). When beams support at least two local modes for each wave type in a frequency band and the modal overlap factor is at least 0.1, measurements and FEM have relatively smooth curves. Agreement between measurements, FEM, and ASEA demonstrates that ASEA is able to predict high propagation losses which are not accounted for with SEA. These propagation losses tend to become more important at high frequencies with relatively high internal loss factors and can occur when there is more than one wave type. At such high frequencies, Timoshenko theory, rather than Euler-Bernoulli theory, is often required. Timoshenko theory is incorporated in ASEA and SEA using wave theory transmission coefficients derived assuming Euler-Bernoulli theory, but using Timoshenko group velocity when calculating coupling loss factors. The changeover between theories is appropriate above the frequency where there is a 26% difference between Euler-Bernoulli and Timoshenko group velocities.
Weyl-Euler-Lagrange Equations of Motion on Flat Manifold
Directory of Open Access Journals (Sweden)
Zeki Kasap
2015-01-01
Full Text Available This paper deals with Weyl-Euler-Lagrange equations of motion on flat manifold. It is well known that a Riemannian manifold is said to be flat if its curvature is everywhere zero. Furthermore, a flat manifold is one Euclidean space in terms of distances. Weyl introduced a metric with a conformal transformation for unified theory in 1918. Classical mechanics is one of the major subfields of mechanics. Also, one way of solving problems in classical mechanics occurs with the help of the Euler-Lagrange equations. In this study, partial differential equations have been obtained for movement of objects in space and solutions of these equations have been generated by using the symbolic Algebra software. Additionally, the improvements, obtained in this study, will be presented.
Textbook Multigrid Efficiency for the Steady Euler Equations
Roberts, Thomas W.; Sidilkover, David; Swanson, R. C.
2004-01-01
A fast multigrid solver for the steady incompressible Euler equations is presented. Unlike time-marching schemes, this approach uses relaxation of the steady equations. Application of this method results in a discretization that correctly distinguishes between the advection and elliptic parts of the operator, allowing efficient smoothers to be constructed. Solvers for both unstructured triangular grids and structured quadrilateral grids have been written. Computations for channel flow and flow over a nonlifting airfoil have computed. Using Gauss-Seidel relaxation ordered in the flow direction, textbook multigrid convergence rates of nearly one order-of-magnitude residual reduction per multigrid cycle are achieved, independent of the grid spacing. This approach also may be applied to the compressible Euler equations and the incompressible Navier-Stokes equations.
The Radially Symmetric Euler Equations as an Exterior Differential System
Baty, Roy; Ramsey, Scott; Schmidt, Joseph
2016-11-01
This work develops the Euler equations as an exterior differential system in radially symmetric coordinates. The Euler equations are studied for unsteady, compressible, inviscid fluids in one-dimensional, converging flow fields with a general equation of state. The basic geometrical constructions (for example, the differential forms, tangent planes, jet space, and differential ideal) used to define and analyze differential equations as systems of exterior forms are reviewed and discussed for converging flows. Application of the Frobenius theorem to the question of the existence of solutions to radially symmetric converging flows is also reviewed and discussed. The exterior differential system is further applied to derive and analyze the general family of characteristic vector fields associated with the one-dimensional inviscid flow equations.
On $p$-adic Hurwitz-type Euler zeta functions
Kim, Min-Soo
2010-01-01
Henri Cohen and Eduardo Friedman constructed the $p$-adic analogue for Hurwitz zeta functions, and Raabe-type formulas for the $p$-adic gamma and zeta functions from Volkenborn integrals satisfying the modified difference equation. In this paper, we define the $p$-adic Hurwitz-type Euler zeta functions. Our main tool is the fermionic $p$-adic integral on $\\mathbb Z_p$. We find that many interesting properties for the $p$-adic Hurwitz zeta functions are also hold for the $p$-adic Hurwitz-type Euler zeta functions, including the convergent Laurent series expansion, the distribution formula, the functional equation, the reflection formula, the derivative formula, the $p$-adic Raabe formula and so on.
Control theory based airfoil design using the Euler equations
Jameson, Antony; Reuther, James
1994-01-01
This paper describes the implementation of optimization techniques based on control theory for airfoil design. In our previous work it was shown that control theory could be employed to devise effective optimization procedures for two-dimensional profiles by using the potential flow equation with either a conformal mapping or a general coordinate system. The goal of our present work is to extend the development to treat the Euler equations in two-dimensions by procedures that can readily be generalized to treat complex shapes in three-dimensions. Therefore, we have developed methods which can address airfoil design through either an analytic mapping or an arbitrary grid perturbation method applied to a finite volume discretization of the Euler equations. Here the control law serves to provide computationally inexpensive gradient information to a standard numerical optimization method. Results are presented for both the inverse problem and drag minimization problem.
Einstein-Euler-Heisenberg Theory and Charged Black Holes
Ruffini, Remo; Xue, She-Sheng
2013-01-01
Taking into account the Euler-Heisenberg effective Lagrangian of one-loop nonperturbative Quantum Electrodynamics (QED) contributions, we formulate the Einstein-Euler-Heisenberg theory, and study the solutions of non-rotating black holes with electric and magnetic charges in spherical geometry. In the limit of strong and weak electromagnetic fields of black holes, we calculate the black hole horizon radius, area, and total energy up to the leading order of QED corrections, and discuss the black hole irreducible mass, entropy, and maximally extractable energy as well as the Christodoulou-Ruffini mass formula. We find that these black hole quantities receive the QED corrections, in comparison with their counterparts in the Reissner-Nortstr\\"om solution. The QED corrections show the screening effect on black hole electric charges and the paramagnetic effect on black hole magnetic charges. As a result, the black hole horizon area, irreducible mass, and entropy increase, however the black hole total energy and max...
Euler-Heisenberg-Weiss action for QCD+QED
Ozaki, Sho; Hattori, Koichi; Itakura, Kazunori
2015-01-01
We derive an analytic expression for one-loop effective action of QCD+QED at zero and finite temperatures by using the Schwinger's proper time method. The result is a nonlinear effective action not only for electromagnetic and chromo-electromagnetic fields but also the Polyakov loop, and thus reproduces the Euler-Heisenberg action in QED, QCD, and QED+QCD, and also the Weiss potential for the Polyakov loop at finite temperature. As applications of this "Euler-Heisenberg-Weiss" action in QCD+QED, we investigate quark pair productions induced by QCD+QED fields at zero temperature and the Polyakov loop in the presence of strong electromagnetic fields. Quark one-loop contribution to the effective potential of the Polyakov loop explicitly breaks the center symmetry, and is found to be enhanced by the magnetic field, which is consistent with the inverse magnetic catalysis observed in lattice QCD simulation.
Singularity formation for one dimensional full Euler equations
Pan, Ronghua; Zhu, Yi
2016-12-01
We investigate the basic open question on the global existence v.s. finite time blow-up phenomena of classical solutions for the one-dimensional compressible Euler equations of adiabatic flow. For isentropic flows, it is well-known that the solutions develop singularity if and only if initial data contain any compression (the Riemann variables have negative spatial derivative). The situation for non-isentropic flow is not quite clear so far, due to the presence of non-constant entropy. In [4], it is shown that initial weak compressions do not necessarily develop singularity in finite time, unless the compression is strong enough for general data. In this paper, we identify a class of solutions of the full (non-isentropic) Euler equations, developing singularity in finite time even though their initial data do not contain any compression. This is in sharp contrast to the isentropic flow.
INTERNAL EXACT OBSERVABILITY OF A PERTURBED EULER-BERNOULLI EQUATION
Directory of Open Access Journals (Sweden)
Nicolae Cîndea
2011-01-01
Full Text Available In this work we prove that the exact internal observability for theEuler-Bernoulli equation is robust with respect to a class of linear perturbations. Our results yield,in particular,that for rectangular domains we have the exact observability in an arbitrarily small time and with an arbitrarily small observation region. The usual method of tackling lower order terms,using Carleman estimates, cannot be applied in this context. More precisely, it is not known if Carleman estimates hold for the evolution Euler-Bernoulli equation with arbitrarily small observation region. Therefore we use a method combining frequency domain techniques,a compactness-uniqueness argument and a Carleman estimate for elliptic problems.
Rational approximants for the Euler-Gompertz constant
Bolbachan, Vasily
2011-01-01
We obtain two sequences of rational numbers which converge to the Euler-Gompertz constant. Denote by the integral of f(x)e^{-x} from 0 to infinity. Recall that the Euler-Gompertz constant \\delta is . Main idea. Let P_n(x) be a polynomial with integer coefficients. It is easy to prove that =a_n+b_n$ for some integers a_n, b_n. Hence if /b_n converges to zero, a_n/b_n converges to - \\delta . Main Theorem. Let u be positive real. There exists polynomials P_n(x)(they are explicitly given in the paper) such that tends to u as n tends to infinity. Proof of Main Theorem is elementary.
Existence of Weak Solutions for the Incompressible Euler Equations
Wiedemann, Emil
2011-01-01
Using a recent result of C. De Lellis and L. Sz\\'{e}kelyhidi Jr. we show that, in the case of periodic boundary conditions and for dimension greater or equal 2, there exist infinitely many global weak solutions to the incompressible Euler equations with initial data $v_0$, where $v_0$ may be any solenoidal $L^2$-vectorfield. In addition, the energy of these solutions is bounded in time.
Euler equation existence, non-uniqueness and mesh converged statistics.
Glimm, James; Sharp, David H; Lim, Hyunkyung; Kaufman, Ryan; Hu, Wenlin
2015-09-13
We review existence and non-uniqueness results for the Euler equation of fluid flow. These results are placed in the context of physical models and their solutions. Non-uniqueness is in direct conflict with the purpose of practical simulations, so that a mitigating strategy, outlined here, is important. We illustrate these issues in an examination of mesh converged turbulent statistics, with comparison to laboratory experiments.
Euler Sequence and Koszul complex of a module
Andreas, Bjorn; de Salas, Fernando Sancho
2015-01-01
We construct relative and global Euler sequences of a module. We apply it to prove some acyclicity results of the Koszul complex of a module and to compute the cohomology of the sheaves of (relative and absolute) differential $p$-forms of a projective bundle. In particular we generalize Bott's formula for the projective space to a projective bundle over a scheme of characteristic zero.
Euler sequence and Koszul complex of a module
Andreas, Björn; Sánchez Gómez, Darío; Sancho de Salas, Fernando
2016-10-01
We construct relative and global Euler sequences of a module. We apply it to prove some acyclicity results of the Koszul complex of a module and to compute the cohomology of the sheaves of (relative and absolute) differential p-forms of a projective bundle. In particular we generalize Bott's formula for the projective space to a projective bundle over a scheme of characteristic zero.
Non-Linear Vibration of Euler-Bernoulli Beams
DEFF Research Database (Denmark)
Barari, Amin; Kaliji, H. D.; Domairry, G.
2011-01-01
In this paper, variational iteration (VIM) and parametrized perturbation (PPM)methods have been used to investigate non-linear vibration of Euler-Bernoulli beams subjected to the axial loads. The proposed methods do not require small parameter in the equation which is difficult to be found for no...... for nonlinear problems. Comparison of VIM and PPM with Runge-Kutta 4th leads to highly accurate solutions....
On the Equivalence of Euler-Lagrange and Noether Equations
Energy Technology Data Exchange (ETDEWEB)
Faliagas, A. C., E-mail: apostol.faliagas@gmail.com [University of Athens, Department of Mathematics (Greece)
2016-03-15
We prove that, under the condition of nontriviality, the Euler-Lagrange and Noether equations are equivalent for a general class of scalar variational problems. Examples are position independent Lagrangians, Lagrangians of p-Laplacian type, and Lagrangians leading to nonlinear Poisson equations. As applications we prove certain propositions concerning the nonlinear Poisson equation and its generalisations, and the equivalence of admissible and inner variations for the systems under consideration.
Compact Lie groups: Euler constructions and generalized Dyson conjecture
Cacciatori, S L; Scotti, A
2012-01-01
In this paper we present a very general method to construct generalized Euler parameterizations for compact simple Lie groups w.r.t. maximally symmetrically embedded simple Lie groups. Our construction is based on a detailed analysis of the geometry of these groups, which moreover gives rise to an interesting connection with certain generalized Dyson integrals. In particular, we obtain a geometry based proof of the generalized Macdonald conjecture correspondent to the root systems associated to all irreducible symmetric spaces.
Viscous Regularization of the Euler Equations and Entropy Principles
Guermond, Jean-Luc
2014-03-11
This paper investigates a general class of viscous regularizations of the compressible Euler equations. A unique regularization is identified that is compatible with all the generalized entropies, à la [Harten et al., SIAM J. Numer. Anal., 35 (1998), pp. 2117-2127], and satisfies the minimum entropy principle. A connection with a recently proposed phenomenological model by [H. Brenner, Phys. A, 370 (2006), pp. 190-224] is made. © 2014 Society for Industrial and Applied Mathematics.
Application of Artificial Intelligence For Euler Solutions Clustering
Mikhailov, V.; Galdeano, A.; Diament, M.; Gvishiani, A.; Agayan, S.; Bogoutdinov, Sh.; Graeva, E.; Sailhac, P.
Results of Euler deconvolution strongly depend on the selection of viable solutions. Synthetic calculations using multiple causative sources show that Euler solutions clus- ter in the vicinity of causative bodies even when they do not group densely about perimeter of the bodies. We have developed a clustering technique to serve as a tool for selecting appropriate solutions. The method RODIN, employed in this study, is based on artificial intelligence and was originally designed for problems of classification of large data sets. It is based on a geometrical approach to study object concentration in a finite metric space of any dimension. The method uses a formal definition of cluster and includes free parameters that facilitate the search for clusters of given proper- ties. Test on synthetic and real data showed that the clustering technique successfully outlines causative bodies more accurate than other methods of discriminating Euler solutions. In complicated field cases such as the magnetic field in the Gulf of Saint Malo region (Brittany, France), the method provides geologically insightful solutions. Other advantages of the clustering method application are: - Clusters provide solutions associated with particular bodies or parts of bodies permitting the analysis of different clusters of Euler solutions separately. This may allow computation of average param- eters for individual causative bodies. - Those measurements of the anomalous field that yield clusters also form dense clusters themselves. The application of cluster- ing technique thus outlines areas where the influence of different causative sources is more prominent. This allows one to focus on areas for reinterpretation, using different window sizes, structural indices and so on.
Research of Euler free nutation of the earth
Directory of Open Access Journals (Sweden)
Игорь Иванович Гладких
2015-06-01
Full Text Available Geometric center of the Earth is forcedly identified to the center of its mass using geocentric coordinate system including the WGS-84. Euler free nutation is revealed in result of data comparison on change of the form of the geoid using satellite technologies and corresponding measurements on the coastal areas. Periodic and episodic displacement of the center of mass relative to the geometric center of the Earth is investigated
Higher recurrences for Apostol-Bernoulli-Euler numbers
Bayad, A.; Kim, T.
2012-03-01
We present explicit formulas for sums of products of Apostol-Bernoulli and Apostol-Euler numbers of the form sumlimits_{_{m_1 , \\cdots ,m_N ≥slant n}^{m_1 + \\cdots + m_N = n} } {left( {_{m_1 , \\cdots m_N }^n } right)B_{m_1 } (q) \\cdots B_{m_N } (q),} sumlimits_{_{m_1 , \\cdots ,m_N ≥slant n}^{m_1 + \\cdots + m_N = n} } {left( {_{m_1 , \\cdots m_N }^n } right)E_{m_1 } (q) \\cdots E_{m_N } (q),} where N and n are positive integers, B m ( q) n stand for the Apostol-Bernoulli numbers, E m ( q) for the Apostol-Euler numbers, and left( {begin{array}{*{20}c} n \\ {m_1 , \\cdots ,m_N } \\ } right) = frac{{n!}} {{m_1 ! \\cdots m_N !}}. Our formulas involve Stirling numbers of the first kind. We also derive results for Apostol-Bernoulli and Apostol-Euler polynomials. As an application, for q = 1 we recover results of Dilcher, and our paper can be regarded as a q-extension of that of Dilcher.
Niceno, B.; Dhotre, M.T.; Deen, N.G.
2008-01-01
In this work, we have presented a one-equation model for sub-grid scale (SGS) kinetic energy and applied it for an Euler-Euler large eddy simulation (EELES) of a bubble column reactor. The one-equation model for SGS kinetic energy shows improved predictions over the state-of-the-art dynamic
Institute of Scientific and Technical Information of China (English)
2012-01-01
We select 204 panel data samples from fixed observation spots in China’s rural areas(Nagqu County,Duilongdeqing County and Xigaze City in Tibet),and conduct systematic analysis of factors influencing farmer and herdsman’s operating behavior in crop production,using regression estimation method of the linear model,mixed OLS model and the random effects model.The research shows that "the number of migrant workers","the amount of household labor forces","original value of fixed assets for production purpose at the end of year","whether having agricultural machinery or not" and other household endowment factors,have a positive impact on total planting area of households,and theoretically,the endowment effect of internal factors predicted is valid;the product of "average food price" and "whether selling or not" has conspicuous impact,and the empirical results confirm that in external factors,the substitution effect of price is greater than the income effect.
Biotechnology Towards Energy Crops.
Margaritopoulou, Theoni; Roka, Loukia; Alexopoulou, Efi; Christou, Myrsini; Rigas, Stamatis; Haralampidis, Kosmas; Milioni, Dimitra
2016-03-01
New crops are gradually establishing along with cultivation systems to reduce reliance on depleting fossil fuel reserves and sustain better adaptation to climate change. These biological assets could be efficiently exploited as bioenergy feedstocks. Bioenergy crops are versatile renewable sources with the potential to alternatively contribute on a daily basis towards the coverage of modern society's energy demands. Biotechnology may facilitate the breeding of elite energy crop genotypes, better suited for bio-processing and subsequent use that will improve efficiency, further reduce costs, and enhance the environmental benefits of biofuels. Innovative molecular techniques may improve a broad range of important features including biomass yield, product quality and resistance to biotic factors like pests or microbial diseases or environmental cues such as drought, salinity, freezing injury or heat shock. The current review intends to assess the capacity of biotechnological applications to develop a beneficial bioenergy pipeline extending from feedstock development to sustainable biofuel production and provide examples of the current state of the art on future energy crops.
Impact of cash cropping and perennial crops on food crop ...
African Journals Online (AJOL)
, ... Moreover, more intensive coffee production is associated with more intensive enset ... Keywords: Ethiopia, Cash crops, Food crops, Productivity, Enset. ... household food security at the household level is often based on the income cash.
Plant senescence and crop productivity
DEFF Research Database (Denmark)
Gregersen, Per L.; Culetic, Andrea; Boschian, Luca
2013-01-01
Senescence is a developmental process which in annual crop plants overlaps with the reproductive phase. Senescence might reduce crop yield when it is induced prematurely under adverse environmental conditions. This review covers the role of senescence for the productivity of crop plants....... With the aim to enhance productivity, a number of functional stay-green cultivars have been selected by conventional breeding, in particular of sorghum and maize. In many cases, a positive correlation between leaf area duration and yield has been observed, although in a number of other cases, stay...... plants, the expression of the IPT gene under control of senescence-associated promoters has been the most successful. The promoters employed for senescence-regulated expression contain cis-elements for binding of WRKY transcription factors and factors controlled by abscisic acid. In most crops...
Interpolation Functions of q-Extensions of Apostol's Type Euler Polynomials
Directory of Open Access Journals (Sweden)
Kyung-Won Hwang
2009-01-01
Full Text Available The main purpose of this paper is to present new q-extensions of Apostol's type Euler polynomials using the fermionic p-adic integral on ℤp. We define the q-λ-Euler polynomials and obtain the interpolation functions and the Hurwitz type zeta functions of these polynomials. We define q-extensions of Apostol type's Euler polynomials of higher order using the multivariate fermionic p-adic integral on ℤp. We have the interpolation functions of these q-λ-Euler polynomials. We also give (h,q-extensions of Apostol's type Euler polynomials of higher order and have the multiple Hurwitz type zeta functions of these (h,q-λ-Euler polynomials.
Measurement of the Euler Angles of Wurtzitic ZnO by Raman Spectroscopy
Directory of Open Access Journals (Sweden)
Wu Liu
2017-01-01
Full Text Available A Raman spectroscopy-based step-by-step measuring method of Euler angles φ,θ,and ψ was presented for the wurtzitic crystal orientation on a microscopic scale. Based on the polarization selection rule and coordinate transformation theory, a series of analytic expressions for the Euler angle measurement using Raman spectroscopy were derived. Specific experimental measurement processes were presented, and the measurement of Raman tensor elements and Euler angles of the ZnO crystal were implemented. It is deduced that there is a trigonometric functional relationship between the intensity of each Raman bands of wurtzite crystal and Euler angle ψ, the polarization direction of incident light under different polarization configurations, which can be used to measure the Euler angles. The experimental results show that the proposed method can realize the measurement of Euler angles for wurtzite crystal effectively.
Versteeg, M.N.
1985-01-01
The objective of the study was to determine the growth potential of alfalfa, potato, Rhodes grass and maize in the irrigated desert of S. Peru, as at that production level the highest utilization efficiency of irrigation water is usually obtained. Important growth- influencing factors were identifie
Versteeg, M.N.
1985-01-01
The objective of the study was to determine the growth potential of alfalfa, potato, Rhodes grass and maize in the irrigated desert of S. Peru, as at that production level the highest utilization efficiency of irrigation water is usually obtained. Important growth- influencing factors were identifie
Institute of Scientific and Technical Information of China (English)
Gan YIN; Wancheng SHENG
2008-01-01
The Riemann problems for the Euler system of conservation laws of energy and momentum in special relativity as pressure vanishes are considered. The Riemann solutions for the pressureless relativistic Euler equations are obtained constructively. There are two kinds of solutions, the one involves delta shock wave and the other involves vacuum. The authors prove that these two kinds of solutions are the limits of the solutions as pressure vanishes in the Euler system of conservation laws of energy and momentum in special relativity.
Exploration of POD-Galerkin Techniques for Developing Reduced Order Models of the Euler Equations
2015-07-01
Models of the Euler Equations 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Mundis, N., Edoh, A. and Sankaran...for describing combustion response to specific excitations using Euler equations as a continued work from a previous studies using a reaction...eigen-bases. For purposes of this study, a linearized version of the Euler equations is employed. The knowledge obtained from previous scalar equation
Stability properties of the Euler-Korteweg system with nonmonotone pressures
Giesselmann, Jan
2016-12-21
We establish a relative energy framework for the Euler-Korteweg system with non-convex energy. This allows us to prove weak-strong uniqueness and to show convergence to a Cahn-Hilliard system in the large friction limit. We also use relative energy to show that solutions of Euler-Korteweg with convex energy converge to solutions of the Euler system in the vanishing capillarity limit, as long as the latter admits sufficiently regular strong solutions.
Études combinatoires du tableau d’Euler sur les produits en couronne
Faliharimalala, Hilarion
2010-01-01
In the last two decades, much effort has been made to extend various enumerative results on symmetric groups to other more general groups. The main objective of this thesis is to extend to wreath products the results that concern the Euler's difference table. It is divided into five chapters. Euler's difference table associated to the sequence {n!} leads naturally to the counting formula for the derangements. In the first two chapters, we study Euler's difference table associated to the seque...
Non-uniqueness of Admissible Weak Solutions to Compressible Euler Systems with Source Terms
Luo, Tianwen; Xie, Chunjing; Xin, Zhouping
2015-01-01
We consider admissible weak solutions to the compressible Euler system with source terms, which include rotating shallow water system and the Euler system with damping as special examples. In the case of anti-symmetric sources such as rotations, for general piecewise Lipschitz initial densities and some suitably constructed initial momentum, we obtain infinitely many global admissible weak solutions. Furthermore, we construct a class of finite-states admissible weak solutions to the Euler sys...
Kim, Gil Won; Jeong, Seung Tak; Kim, Gun Yeob; Kim, Pil Joo; Kim, Sang Yoon
2016-08-01
Fertilization with urea can lead to a loss of carbon dioxide (CO2) that was fixed during the industrial production process. The extent of atmospheric CO2 removal from urea manufacturing was estimated by the Industrial Processes and Product Use sector (IPPU sector). On its basis, the Intergovernmental Panel on Climate Change (IPCC) has proposed a value of 0.2 Mg C per Mg urea (available in 2006 revised IPCC guidelines for greenhouse gas inventories), which is the mass fractions of C in urea, as the CO2 emission coefficient from urea for the agricultural sector. Notably, due to the possibility of bicarbonate leaching to waters, all C in urea might not get released as CO2 to the atmosphere. Hence, in order to provide an accurate value of the CO2 emission coefficient from applied urea in the rice ecosystem, the CO2 emission factors were characterized under different levels of 13C-urea applied paddy field in the current study. The total CO2 fluxes and rice grain yields increased significantly with increasing urea application (110-130 kg N ha-1) and thereafter, decreased. However, with increasing 13C-urea application, a significant and proportional increase of the 13CO2sbnd C emissions from 13C-urea was also observed. From the relationships between urea application levels and 13CO2sbnd C fluxes from 13C-urea, the CO2sbnd C emission factor from urea was estimated to range between 0.0143 and 0.0156 Mg C per Mg urea. Thus, the CO2sbnd C emission factor of this study is less than that of the value proposed by IPCC. Therefore, for the first time, we propose to revise the current IPCC guideline value of CO2sbnd C emission factor from urea as 0.0143-0.0156 Mg C per Mg urea for Korean paddy soils.
Euler vector for search and retrieval of gray-tone images.
Bishnu, Arijit; Bhattacharya, Bhargab B; Kundu, Malay K; Murthy, C A; Acharya, Tinku
2005-08-01
A new combinatorial characterization of a gray-tone image called Euler Vector is proposed. The Euler number of a binary image is a well-known topological feature, which remains invariant under translation, rotation, scaling, and rubber-sheet transformation of the image. The Euler vector comprises a 4-tuple, where each element is an integer representing the Euler number of the partial binary image formed by the gray-code representation of the four most significant bit planes of the gray-tone image. Computation of Euler vector requires only integer and Boolean operations. The Euler vector is experimentally observed to be robust against noise and compression. For efficient image indexing, storage and retrieval from an image database using this vector, a bucket searching technique based on a simple modification of Kd-tree, is employed successfully. The Euler vector can also be used to perform an efficient four-dimensional range query. The set of retrieved images are finally ranked on the basis of Mahalanobis distance measure. Experiments are performed on the COIL database and results are reported. The retrieval success can be improved significantly by augmentiong the Euler vector by a few additional simple shape features. Since Euler vector can be computed very fast, the proposed technique is likely to find many applications to content-based image retrieval.
Euler/Navier-Stokes Solvers Applied to Ducted Fan Configurations
Keith, Theo G., Jr.; Srivastava, Rakesh
1997-01-01
Due to noise considerations, ultra high bypass ducted fans have become a more viable design. These ducted fans typically consist of a rotor stage containing a wide chord fan and a stator stage. One of the concerns for this design is the classical flutter that keeps occurring in various unducted fan blade designs. These flutter are catastrophic and are to be avoided in the flight envelope of the engine. Some numerical investigations by Williams, Cho and Dalton, have suggested that a duct around a propeller makes it more unstable. This needs to be further investigated. In order to design an engine to safely perform a set of desired tasks, accurate information of the stresses on the blade during the entire cycle of blade motion is required. This requirement in turn demands that accurate knowledge of steady and unsteady blade loading be available. Aerodynamic solvers based on unsteady three-dimensional analysis will provide accurate and fast solutions and are best suited for aeroelastic analysis. The Euler solvers capture significant physics of the flowfield and are reasonably fast. An aerodynamic solver Ref. based on Euler equations had been developed under a separate grant from NASA Lewis in the past. Under the current grant, this solver has been modified to calculate the aeroelastic characteristics of unducted and ducted rotors. Even though, the aeroelastic solver based on three-dimensional Euler equations is computationally efficient, it is still very expensive to investigate the effects of multiple stages on the aeroelastic characteristics. In order to investigate the effects of multiple stages, a two-dimensional multi stage aeroelastic solver was also developed under this task, in collaboration with Dr. T. S. R. Reddy of the University of Toledo. Both of these solvers were applied to several test cases and validated against experimental data, where available.
Ahmad, Zeeshan; Khan, Shujaul Mulk; Abd Allah, Elsayed Fathi; Alqarawi, Abdulaziz Abdullah; Hashem, Abeer
2016-11-01
Weeds are unwanted plant species growing in ordinary environment. In nature there are a total of 8000 weed species out of which 250 are important for agriculture world. The present study was carried out on weed species composition and distribution pattern with special reference to edaphic factor and farming practices in maize crop of District Mardan during the months of August and September, 2014. Quadrates methods were used to assess weed species distribution in relation to edaphic factor and farming practices. Phytosociological attributes such as frequency, relative frequency, density, relative density and Importance Values were measured by placing 9 quadrates (1 × 1 m(2)) randomly in each field. Initial results showed that the study area has 29 diverse weed species belonging to 27 genera and 15 families distributed in 585 quadrats. Presence and absence data sheet of 29 weed species and 65 fields were analyzed through PC-ORD version 5. Cluster and Two Way Cluster Analyses initiated four different weed communities with significant indicator species and with respect to underlying environmental variables using data attribute plots. Canonical Correspondence Analyses (CCA) of CANOCO software version 4.5 was used to assess the environmental gradients of weed species. It is concluded that among all the edaphic factors the strongest variables were higher concentration of potassium, organic matter and sandy nature of soil. CCA plots of both weed species and sampled fields based on questionnaire data concluded the farming practices such as application of fertilizers, irrigation and chemical spray were the main factors in determination of weed communities.
Optimum Transonic Airfoils Based on the Euler Equations
Iollo, Angelo; Salas, Manuel, D.
1996-01-01
We solve the problem of determining airfoils that approximate, in a least square sense, given surface pressure distributions in transonic flight regimes. The flow is modeled by means of the Euler equations and the solution procedure is an adjoint- based minimization algorithm that makes use of the inverse Theodorsen transform in order to parameterize the airfoil. Fast convergence to the optimal solution is obtained by means of the pseudo-time method. Results are obtained using three different pressure distributions for several free stream conditions. The airfoils obtained have given a trailing edge angle.
Towards Perfectly Absorbing Boundary Conditions for Euler Equations
Hayder, M. Ehtesham; Hu, Fang Q.; Hussaini, M. Yousuff
1997-01-01
In this paper, we examine the effectiveness of absorbing layers as non-reflecting computational boundaries for the Euler equations. The absorbing-layer equations are simply obtained by splitting the governing equations in the coordinate directions and introducing absorption coefficients in each split equation. This methodology is similar to that used by Berenger for the numerical solutions of Maxwell's equations. Specifically, we apply this methodology to three physical problems shock-vortex interactions, a plane free shear flow and an axisymmetric jet- with emphasis on acoustic wave propagation. Our numerical results indicate that the use of absorbing layers effectively minimizes numerical reflection in all three problems considered.
Large Scale Simulations of the Euler Equations on GPU Clusters
Liebmann, Manfred
2010-08-01
The paper investigates the scalability of a parallel Euler solver, using the Vijayasundaram method, on a GPU cluster with 32 Nvidia Geforce GTX 295 boards. The aim of this research is to enable large scale fluid dynamics simulations with up to one billion elements. We investigate communication protocols for the GPU cluster to compensate for the slow Gigabit Ethernet network between the GPU compute nodes and to maintain overall efficiency. A diesel engine intake-port and a nozzle, meshed in different resolutions, give good real world examples for the scalability tests on the GPU cluster. © 2010 IEEE.
NURBS-enhanced finite element method for Euler equations
Sevilla Cárdenas, Rubén; Fernandez Mendez, Sonia; Huerta, Antonio , coaut.
2008-01-01
This is the pre-peer reviewed version of the following article: Sevilla, R.; Fernandez, S.; Huerta, A. NURBS-enhanced finite element method for Euler equations. "International journal for numerical methods in fluids", Juliol 2008, vol. 57, núm. 9, p. 1051-1069., which has been published in final form at http://www3.interscience.wiley.com/journal/117905455/abstract In this work, the NURBS-enhanced finite element method (NEFEM) is combined with a discontinuous Galerkin (DG) formulation for t...
Remarks on the Einstein-Euler-Entropy system
Disconzi, Marcelo M
2013-01-01
We prove short-time existence for the Einstein-Euler-Entropy system for non-isentropic fluids with data in uniformly local Sobolev spaces. The cases of compact as well as non-compact Cauchy surfaces are covered. The method employed uses a Lagrangian description of the fluid flow which is based on techniques developed by Friedrich, hence providing a completely different proof of earlier results of Choquet-Bruhat and Lichnerowicz. This new proof is specially suited for applications to self-gravitating fluid bodies.
Euler-Lagrange formulas for pseudo-Kähler manifolds
Park, JeongHyeong
2016-01-01
Let c be a characteristic form of degree k which is defined on a Kähler manifold of real dimension m > 2 k. Taking the inner product with the Kähler form Ωk gives a scalar invariant which can be considered as a generalized Lovelock functional. The associated Euler-Lagrange equations are a generalized Einstein-Gauss-Bonnet gravity theory; this theory restricts to the canonical formalism if c =c2 is the second Chern form. We extend previous work studying these equations from the Kähler to the pseudo-Kähler setting.
Level Set interface treatment and its application in Euler method
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
Level Set interface treatment method is introduced into Euler method,which is employed for interface treatment method for multi-materials. Combined with the ghost fluid method,the moving interface is tracked. Fifth-order WENO spatial discretization and third-order TVD Runge-Kutta time discretization methods are used. Shock-wave action on bubble,implosion and velocity field Shock effect bubbles; implosion and velocity field are simulated by means of LS-MMIC3D programmed by C++. Nu-merical results show that the Level Set interface treatment method is effective and feasible for multi-material interface treatment in comparison with the WENO method.
Computation of hypersonic vortex flows with an Euler model
Bruneau, Charles-Henri; Laminie, Jacques; Chattot, Jean-Jacques
The variational approach of the steady Euler equations presented at the loth ICNMFD [1] is extended to the treatment of supersonic and hypersonic flows by introducing the energy equation inthe least-squares formulation. The approximation is made with cubic or prismatic linear finite elements and the results are presented for flows around a rectangular flat plate or a thin delta wing for various Mach numbers and angles of attack. They show the occurrence of vortical flows on the upper surface of the wings due to the sharp edges.
Euler Top Dynamics of Nambu-Goto P-Branes
Axenides, Minos; Floratos, Emmanuel
2006-01-01
We propose a method to obtain new exact solutions of spinning p-branes in flat space-times for any p, which manifest themselves as higher dimensional Euler Tops and minimize their energy functional. We provide concrete examples for the case of spherical topology S^{2}, S^{3} and rotational symmetry \\prod_{i}SO(q_{i}). In the case of toroidal topology T^{2}, T^{3} the rotational symmetry is \\prod SU(q_{i}) and m target dimensions are compactified on the torus T^{m} . By double dimensional redu...
Dynamic Response of Axially Loaded Euler-Bernoulli Beams
DEFF Research Database (Denmark)
Bayat, M.; Barari, Amin; Shahidi, M.
2011-01-01
expressions for geometrically nonlinear vibration of beams are provided. The effect of vibration amplitude on the nonlinear frequency is discussed. Comparison between Energy Balance Method results and those available in literature demonstrates the accuracy of this method. In Energy Balance Method contrary...... to the conventional methods, only one iteration leads to high accuracy of the solutions which are valid for a wide range of vibration amplitudes.......The current research deals with application of a new analytical technique called Energy Balance Method (EBM) for a nonlinear problem. Energy Balance Method is used to obtain the analytical solution for nonlinear vibration behavior of Euler-Bernoulli beams subjected to axial loads. Analytical...
Energy equation, the dissipation function and the Euler turbine equation
Energy Technology Data Exchange (ETDEWEB)
Mobarak, A. (Cairo Univ. (Egypt). Faculty of Engineering)
1978-01-01
The derivation of the energy equation for a rotating frame of coordinates is presented. The link between the thermodynamics and the fluid dynamics of viscous flow and which is generally given by the dissipation function is discussed in more detail. This work shows, that the published definition of the dissipation function is an improper one, and leads in connection with the energy equation to contradictory results when considering the principle of energy conservation. Further, the Euler turbine equation is discussed, and it is shown that the present form is only valid, if the flow condition in the rotor (the relative system) is steady.
A major latex-like protein is a key factor in crop contamination by persistent organic pollutants.
Inui, Hideyuki; Sawada, Mami; Goto, Junya; Yamazaki, Kiyoshi; Kodama, Noriko; Tsuruta, Hiroki; Eun, Heesoo
2013-04-01
This is the first report, to our knowledge, to reveal important factors by which members of the Cucurbitaceae family, such as cucumber (Cucumis sativus), watermelon (Citrullus lanatus), melon (Cucumis melo), pumpkin (Cucurbita pepo), squash (C. pepo), and zucchini (C. pepo), are selectively polluted with highly toxic hydrophobic contaminants, including organochlorine insecticides and dioxins. Xylem sap of C. pepo ssp. pepo, which is a high accumulator of hydrophobic compounds, solubilized the hydrophobic compound pyrene into the aqueous phase via some protein(s). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of xylem sap of two C. pepo subspecies revealed that the amount of 17-kD proteins in C. pepo ssp. pepo was larger than that in C. pepo ssp. ovifera, a low accumulator, suggesting that these proteins may be related to the translocation of hydrophobic compounds. The protein bands at 17 kD contained major latex-like proteins (MLPs), and the corresponding genes MLP-PG1, MLP-GR1, and MLP-GR3 were cloned from the C. pepo cultivars Patty Green and Gold Rush. Expression of the MLP-GR3 gene in C. pepo cultivars was positively correlated with the band intensity of 17-kD proteins and bioconcentration factors toward dioxins and dioxin-like compounds. Recombinant MLP-GR3 bound polychlorinated biphenyls immobilized on magnetic beads, whereas recombinant MLP-PG1 and MLP-GR1 did not. These results indicate that the high expression of MLP-GR3 in C. pepo ssp. pepo plants and the existence of MLP-GR3 in their xylem sap are related to the efficient translocation of hydrophobic contaminants. These findings should be useful for decreasing the contamination of fruit of the Cucurbitaceae family as well as the phytoremediation of hydrophobic contaminants.
Feddes, R.A.
1971-01-01
To a large extent the results of a farmer's efforts to get higher crop yields will be determined by the prevailing environmental conditions, i.e. by the existing complex of physical, chemical and biological factors. The possibilities of an efficient use of these factors are enlarged by our
Crop responses to climatic variation
DEFF Research Database (Denmark)
Porter, John R.; Semenov, Mikhail A.
2005-01-01
The yield and quality of food crops is central to the well being of humans and is directly affected by climate and weather. Initial studies of climate change on crops focussed on effects of increased carbon dioxide (CO2) level and/or global mean temperature and/or rainfall and nutrition on crop...... production. However, crops can respond nonlinearly to changes in their growing conditions, exhibit threshold responses and are subject to combinations of stress factors that affect their growth, development and yield. Thus, climate variability and changes in the frequency of extreme events are important...... sufficient importance when assessing the impact of climate change for food and this is addressed. Using simulation models of wheat, the concentration of grain protein is shown to respond to changes in the mean and variability of temperature and precipitation events. The paper concludes with discussion...
GPU Accelerated Spectral Element Methods: 3D Euler equations
Abdi, D. S.; Wilcox, L.; Giraldo, F.; Warburton, T.
2015-12-01
A GPU accelerated nodal discontinuous Galerkin method for the solution of three dimensional Euler equations is presented. The Euler equations are nonlinear hyperbolic equations that are widely used in Numerical Weather Prediction (NWP). Therefore, acceleration of the method plays an important practical role in not only getting daily forecasts faster but also in obtaining more accurate (high resolution) results. The equation sets used in our atomospheric model NUMA (non-hydrostatic unified model of the atmosphere) take into consideration non-hydrostatic effects that become more important with high resolution. We use algorithms suitable for the single instruction multiple thread (SIMT) architecture of GPUs to accelerate solution by an order of magnitude (20x) relative to CPU implementation. For portability to heterogeneous computing environment, we use a new programming language OCCA, which can be cross-compiled to either OpenCL, CUDA or OpenMP at runtime. Finally, the accuracy and performance of our GPU implementations are veried using several benchmark problems representative of different scales of atmospheric dynamics.
Potentially Singular Solutions of the 3D Incompressible Euler Equations
Luo, Guo
2013-01-01
Whether the 3D incompressible Euler equations can develop a singularity in finite time from smooth initial data is one of the most challenging problems in mathematical fluid dynamics. This work attempts to provide an affirmative answer to this long-standing open question from a numerical point of view, by presenting a class of potentially singular solutions to the Euler equations computed in axisymmetric geometries. The solutions satisfy a periodic boundary condition along the axial direction and no-flow boundary condition on the solid wall. The equations are discretized in space using a hybrid 6th-order Galerkin and 6th-order finite difference method, on specially designed adaptive (moving) meshes that are dynamically adjusted to the evolving solutions. With a maximum effective resolution of over $(3 \\times 10^{12})^{2}$ near the point of the singularity, we are able to advance the solution up to $\\tau_{2} = 0.003505$ and predict a singularity time of $t_{s} \\approx 0.0035056$, while achieving a \\emph{pointw...
Wellformedness properties in Euler diagrams: which should be used?
Rodgers, Peter; Zhang, Leishi; Purchase, Helen
2012-07-01
Euler diagrams are often used to visualize intersecting data sets in applications such as criminology; genetics, medicine, and computer file systems. One interesting aspect of these diagrams is that some data sets cannot be drawn without breaking one or more "wellformedness properties," which are considered to reduce the user comprehension of the diagrams. However, it is possible to draw the same data with different diagrams, each of which breaks different wellformedness properties. Hence, some properties are "swappable," so motivating the study of which of the alternatives would be best to use. This paper reports on the two empirical studies to determine how wellformedness properties affect comprehension. One study was with abstract data, the other was with concrete data that visualized students' enrollment on university modules. We have results from both studies that imply that diagrams with concurrency or disconnected zones perform less well than other some other properties. Further, we have no results that imply that diagrams with brushing points adversely affect performance. Our data also indicate that nonsimple curves are preferred less than diagrams with other properties. These results will inform both human diagram designers and the developers of automated drawing systems on the best way to visualize data using Euler diagrams.
Dynamic Stability of Euler Beams under Axial Unsteady Wind Force
Directory of Open Access Journals (Sweden)
You-Qin Huang
2014-01-01
Full Text Available Dynamic instability of beams in complex structures caused by unsteady wind load has occurred more frequently. However, studies on the parametric resonance of beams are generally limited to harmonic loads, while arbitrary dynamic load is rarely involved. The critical frequency equation for simply supported Euler beams with uniform section under arbitrary axial dynamic forces is firstly derived in this paper based on the Mathieu-Hill equation. Dynamic instability regions with high precision are then calculated by a presented eigenvalue method. Further, the dynamically unstable state of beams under the wind force with any mean or fluctuating component is determined by load normalization, and the wind-induced parametric resonant response is computed by the Runge-Kutta approach. Finally, a measured wind load time-history is input into the dynamic system to indicate that the proposed methods are effective. This study presents a new method to determine the wind-induced dynamic stability of Euler beams. The beam would become dynamically unstable provided that the parametric point, denoting the relation between load properties and structural frequency, is located in the instability region, no matter whether the wind load component is large or not.
Euler: programa didáctico de elementos finitos
Directory of Open Access Journals (Sweden)
Dorian Luis Linero Segrera
2011-02-01
Full Text Available This article explains the characteristics of the Euler software, which was used as a learning tool on finite element method with emphasis on structural analysis. Euler can solve the following problems, among others: static matríx analysis of truss and plane frames; stability analysis, evaluation of frequencies and vibration modes in plane frames, displacement in beams and in elements subjected to axial force and other problems controlled by the one-dimensional field differential equation that is shown in the article. Furthermore, the program can solve: torsion ofnoncircular sections, irrotational flow, heat transfer, and other problems controlled by two-dimensional field differential equation that is shown in the article. The program also allows for solutions to problems of twodimensional elasticity: plane stress or plane strain. In order to operate the program, the user should write, one by one, the necessary instructions to obtain the quantities of interest. The available instructions are classified as follows: matrix edition, basic matrix operations, simultaneous equation systems, matrix and vector assemblage, numeration of freedom degrees, eigenvalues and eigenvectors. Futhermore, the creation of matrix elements as shape functions, gradient vector, stiffness matrix, force vector, interelement contribution, transformation matrix and constant elastic matrix.
SOME EULER SPACES OF DIFFERENCE SEQUENCES OF ORDER m
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Kizmaz [13] studied the difference sequence spaces e∞(△), c(△), and c0(△).Several article dealt with the sets of sequences of m-th order difference of which are bounded, convergent, or convergent to zero. Altay and Basar [5] and Altay, Basar, and Mursaleen [7] introduced the Euler sequence spaces eτ0, eτ0, andeτ∞, respectively. The main purpose of this article is to introduce the spaces eτ0(△(m)), eτc(△(m)), and eτ∞(△(m)) consisting of all sequences whose mth order differences are in the Euler spaces eτ0, eτc, and eτ∞, respectively. Moreover, the authors give some topological properties and inclusion relations, and determine the α-, β-, and γ-duals of the spaces eτ0(△(m)), eτc(△(m)), and eτ∞(△(m)), and the Schauder basis of the spaces eτ0(△(m)), eτc(△(m)). The last section of the article is devoted to the characterization of some matrix mappings on the sequence space eτc(△(m)).
Wing flutter boundary prediction using unsteady Euler aerodynamic method
Lee-Rausch, Elizabeth M.; Batina, John T.
1993-01-01
Modifications to an existing 3D implicit upwind Euler/Navier-Stokes code for the aeroelastic analysis of wings are described. These modifications include the incorporation of a deforming mesh algorithm and the addition of the structural equations of motion for their simultaneous time-integration with the governing flow equations. The paper gives a brief description of these modifications and presents unsteady calculations which check the modifications to the code. Euler flutter results for an isolated 45 deg swept-back wing are compared with experimental data for seven freestream Mach numbers which define the flutter boundary over a range of Mach number from 0.499 to 1.14. These comparisons show good agreement in flutter characteristics for freestream Mach numbers below unity. For freestream Mach numbers above unity, the computed aeroelastic results predict a premature rise in the flutter boundary as compared with the experimental boundary. Steady and unsteady contours of surface Mach number and pressure are included to illustrate the basic flow characteristics of the time-marching flutter calculations and to aid in identifying possible causes for the premature rise in the computational flutter boundary.
Directory of Open Access Journals (Sweden)
Joan Caliz
Full Text Available The microbial ecology of the nitrogen cycle in agricultural soils is an issue of major interest. We hypothesized a major effect by farm management systems (mineral versus organic fertilizers and a minor influence of soil texture and plant variety on the composition and abundance of microbial nitrifiers. We explored changes in composition (16S rRNA gene of ammonia-oxidizing archaea (AOA, bacteria (AOB, and nitrite-oxidizing bacteria (NOB, and in abundance of AOA and AOB (qPCR of amoA genes in the rhizosphere of 96 olive orchards differing in climatic conditions, agricultural practices, soil properties, and olive variety. Majority of archaea were 1.1b thaumarchaeota (soil crenarchaeotic group, SCG closely related to the AOA genus Nitrososphaera. Most AOB (97% were identical to Nitrosospira tenuis and most NOB (76% were closely related to Nitrospira sp. Common factors shaping nitrifiers assemblage composition were pH, soil texture, and olive variety. AOB abundance was positively correlated with altitude, pH, and clay content, whereas AOA abundances showed significant relationships with organic nitrogen content and exchangeable K. The abundances of AOA differed significantly among soil textures and olive varieties, and those of AOB among soil management systems and olive varieties. Overall, we observed minor effects by orchard management system, soil cover crop practices, plantation age, or soil organic matter content, and major influence of soil texture, pH, and olive tree variety.
Caliz, Joan; Montes-Borrego, Miguel; Triadó-Margarit, Xavier; Metsis, Madis; Landa, Blanca B; Casamayor, Emilio O
2015-01-01
The microbial ecology of the nitrogen cycle in agricultural soils is an issue of major interest. We hypothesized a major effect by farm management systems (mineral versus organic fertilizers) and a minor influence of soil texture and plant variety on the composition and abundance of microbial nitrifiers. We explored changes in composition (16S rRNA gene) of ammonia-oxidizing archaea (AOA), bacteria (AOB), and nitrite-oxidizing bacteria (NOB), and in abundance of AOA and AOB (qPCR of amoA genes) in the rhizosphere of 96 olive orchards differing in climatic conditions, agricultural practices, soil properties, and olive variety. Majority of archaea were 1.1b thaumarchaeota (soil crenarchaeotic group, SCG) closely related to the AOA genus Nitrososphaera. Most AOB (97%) were identical to Nitrosospira tenuis and most NOB (76%) were closely related to Nitrospira sp. Common factors shaping nitrifiers assemblage composition were pH, soil texture, and olive variety. AOB abundance was positively correlated with altitude, pH, and clay content, whereas AOA abundances showed significant relationships with organic nitrogen content and exchangeable K. The abundances of AOA differed significantly among soil textures and olive varieties, and those of AOB among soil management systems and olive varieties. Overall, we observed minor effects by orchard management system, soil cover crop practices, plantation age, or soil organic matter content, and major influence of soil texture, pH, and olive tree variety.
Luo, Qiu-Ming
2009-12-01
We investigate Fourier expansions for the Apostol-Bernoulli and Apostol-Euler polynomials using the Lipschitz summation formula and obtain their integral representations. We give some explicit formulas at rational arguments for these polynomials in terms of the Hurwitz zeta function. We also derive the integral representations for the classical Bernoulli and Euler polynomials and related known results.
Beyond Euler's Method: Implicit Finite Differences in an Introductory ODE Course
Kull, Trent C.
2011-01-01
A typical introductory course in ordinary differential equations (ODEs) exposes students to exact solution methods. However, many differential equations must be approximated with numerical methods. Textbooks commonly include explicit methods such as Euler's and Improved Euler's. Implicit methods are typically introduced in more advanced courses…
Convergence of the Vlasov-Poisson-Fokker- Planck system to the incompressible Euler equations
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
We establish the convergence of the Vlasov-Poisson-Fokker-Planck system to the incompressible Euler equations in this paper. The convergence is rigorously proved on the time interval where the smooth solution to the incompressible Euler equations exists. The proof relies on the compactness argument and the so-called relative-entropy method.
Generalized q-Euler Numbers and Polynomials of Higher Order and Some Theoretic Identities
Directory of Open Access Journals (Sweden)
T. Kim
2010-01-01
Full Text Available We give a new construction of the q-Euler numbers and polynomials of higher order attached to Dirichlet's character χ. We derive some theoretic identities involving the generalized q-Euler numbers and polynomials of higher order.
Note on q-Extensions of Euler Numbers and Polynomials of Higher Order
Directory of Open Access Journals (Sweden)
Taekyun Kim
2008-02-01
Full Text Available In 2007, Ozden et al. constructed generating functions of higher-order twisted (h,q-extension of Euler polynomials and numbers, by using p-adic, q-deformed fermionic integral on Ã¢Â„Â¤p. By applying their generating functions, they derived the complete sums of products of the twisted (h,q-extension of Euler polynomials and numbers. In this paper, we consider the new q-extension of Euler numbers and polynomials to be different which is treated by Ozden et al. From our q-Euler numbers and polynomials, we derive some interesting identities and we construct q-Euler zeta functions which interpolate the new q-Euler numbers and polynomials at a negative integer. Furthermore, we study Barnes-type q-Euler zeta functions. Finally, we will derive the new formula for Ã¢Â€Âœsums of products of q-Euler numbers and polynomialsÃ¢Â€Â by using fermionic p-adic, q-integral on Ã¢Â„Â¤p.
Directory of Open Access Journals (Sweden)
D. Vivek
2016-11-01
Full Text Available In this paper, the improved Euler method is used for solving hybrid fuzzy fractional differential equations (HFFDE of order $q \\in (0, 1 $ under Caputo-type fuzzy fractional derivatives. This method is based on the fractional Euler method and generalized Taylor's formula. The accuracy and efficiency of the proposed method is demonstrated by solving numerical examples.
Euler-Poincaré Reduction of Externally Forced Rigid Body Motion
DEFF Research Database (Denmark)
Wisniewski, Rafal; Kulczycki, P.
2004-01-01
. Assuming that the system possesses symmetry and the configuration manifold corresponds to a Lie group, the Euler-Poincaré reduction breaks up the motion into separate equations of dynamics and kinematics. This becomes of particular interest for modelling, estimation and control of mechanical systems......-known Euler-Poincaré reduction to a rigid body motion with forcing....
Euler Strut: A Mechanical Analogy for Dynamics in the Vicinity of a Critical Point
Bobnar, Jaka; Susman, Katarina; Parsegian, V. Adrian; Rand, Peter R.; Cepic, Mojca; Podgornik, Rudolf
2011-01-01
An anchored elastic filament (Euler strut) under an external point load applied to its free end is a simple model for a second-order phase transition. In the static case, a load greater than the critical load causes a Euler buckling instability, leading to a change in the filament's shape. The analysis of filament dynamics with an external point…
Euler-Lagrange Equations of Networks with Higher-Order Elements
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Z. Biolek
2017-06-01
Full Text Available The paper suggests a generalization of the classic Euler-Lagrange equation for circuits compounded of arbitrary elements from Chua’s periodic table. Newly defined potential functions for general (α, β elements are used for the construction of generalized Lagrangians and generalized dissipative functions. Also procedures of drawing the Euler-Lagrange equations are demonstrated.
Euler Strut: A Mechanical Analogy for Dynamics in the Vicinity of a Critical Point
Bobnar, Jaka; Susman, Katarina; Parsegian, V. Adrian; Rand, Peter R.; Cepic, Mojca; Podgornik, Rudolf
2011-01-01
An anchored elastic filament (Euler strut) under an external point load applied to its free end is a simple model for a second-order phase transition. In the static case, a load greater than the critical load causes a Euler buckling instability, leading to a change in the filament's shape. The analysis of filament dynamics with an external point…
Generalizations of Euler Inequality in the n-dimensional Euclidean Space
Institute of Scientific and Technical Information of China (English)
WANG Wen; YANG Shi-guo
2012-01-01
The relation between the circum-radius and the in-radius of an n-dimensional simplex in En is studied.Two new generalizations of Euler inequality for the n-dimensional simplex are established.Besides,we obtain some stronger generalizations of Euler inequality for the n-dimensional simplex than previously known results.
Ill-Posedness of the Hydrostatic Euler and Singular Vlasov Equations
Han-Kwan, Daniel; Nguyen, Toan T.
2016-09-01
In this paper, we develop an abstract framework to establish ill-posedness, in the sense of Hadamard, for some nonlocal PDEs displaying unbounded unstable spectra. We apply this to prove the ill-posedness for the hydrostatic Euler equations as well as for the kinetic incompressible Euler equations and the Vlasov-Dirac-Benney system.
TWO-DIMENSIONAL RIEMANN PROBLEMS:FROM SCALAR CONSERVATION LAWS TO COMPRESSIBLE EULER EQUATIONS
Institute of Scientific and Technical Information of China (English)
Li Jiequan; Sheng Wancheng; Zhang Tong; Zheng Yuxi
2009-01-01
In this paper we survey the authors' and related work on two-dimensional Rie-mann problems for hyperbolic conservation laws, mainly those related to the compressible Euler equations in gas dynamics. It contains four sections: 1. Historical review. 2. Scalar conservation laws. 3. Euler equations. 4. Simplified models.
T. Kim; Choi, J.; Kim, Y. H.; C. S. Ryoo
2010-01-01
In this paper, we give a fermionic p-adic integral representions of Benstein polynomials associated with Euler numbers and polynomials. Finally, we give some interesting identities for the Euler numbers by using the properties of our integral represention.
Institute of Scientific and Technical Information of China (English)
郝旺林; 梁银丽; 吴兴; 林兴军; 朱艳丽; 罗安荣
2011-01-01
This study was to define the Variations of soil respiration,the response of influence factors to soil respiration and carbon sink in the total growing season,in winter wheat field of different previous crops.The results showed that： ①as soil depth increases,the response of temperature to soil respiration rate also increased with a lag;②the soil respiration rate was quadric to soil moisture,phosphorus,potassium,soil urease activity,soil temperature,soil moisture as the main factors had an effect on soil respiration rate;soil temperature had the stronger effect on soil respiration rate when potassium had the weaker effect on soil respiration rate;③the average carbon emission rate in wheat filed of different previous crops showed as follow： Pepper of previous crops celery of previous crops corn of previous crops eggplant of previous crops.The intensity of carbon ＂sink＂ displayed as follow： eggplant of previous crops celery of previous crops corn of previous crops pepper of previous crops.As for the trials of this study,although the soil respiration rate is highest in the winter wheat filed of previous pepper,the amount of carbon fixed is the most.Its ratio of net primary productivity（NPP） and soil carbon release quantity was highest,so carbon sink was the strongest.If rotation planting was arranged according to the purpose of increasing carbon sink and reducing carbon emissions,pepper was relatively appropriate stubbles crop,followed by corn crop,celery and eggplant.%以不同蔬菜前茬处理的冬小麦田为对象,研究土壤呼吸变化特征、各影响因子对土壤呼吸的响应的通径分析以及计算全生长季农田碳汇强度.结果表明：①温度对土壤呼吸速率的响应随深度增加具有滞后性;土壤呼吸与土壤水分呈显著二次相关.②有效磷、速效钾、土壤脲酶、土壤温度、土壤水分对土壤呼吸变化的贡献较大,为主要影响因子.5种主要因子中土壤温
Ill posedness of force-free electrodynamics in Euler potentials
Reula, Oscar A.; Rubio, Marcelo E.
2017-03-01
We prove that the initial value problem for force-free electrodynamics in Euler variables is not well posed. We establish this result by showing that a well-posedness criterion provided by Kreiss fails to hold for this theory, and using a theorem provided by Strang. To show the nature of the problem we display a particular bounded (in Sobolev norms) sequence of initial data for the force-free equations such that at any given time as close to zero as one wishes, the corresponding evolution sequence is not bounded. Thus, the force-free evolution is noncontinuous in that norm with respect to the initial data. We furthermore prove that this problem is also ill-posed in the Leray-Ohya sense.
Potentially singular solutions of the 3D axisymmetric Euler equations.
Luo, Guo; Hou, Thomas Y
2014-09-09
The question of finite-time blowup of the 3D incompressible Euler equations is numerically investigated in a periodic cylinder with solid boundaries. Using rotational symmetry, the equations are discretized in the (2D) meridian plane on an adaptive (moving) mesh and is integrated in time with adaptively chosen time steps. The vorticity is observed to develop a ring-singularity on the solid boundary with a growth proportional to ∼(ts - t)(-2.46), where ts ∼ 0.0035056 is the estimated singularity time. A local analysis also suggests the existence of a self-similar blowup. The simulations stop at τ(2) = 0.003505 at which time the vorticity amplifies by more than (3 × 10(8))-fold and the maximum mesh resolution exceeds (3 × 10(12))(2). The vorticity vector is observed to maintain four significant digits throughout the computations.
Equation for self-similar singularity of Euler 3D
Pomeau, Yves
2016-01-01
The equations for a self-similar solution of an inviscid incompressible fluid are mapped into an integral equation which hopefully can be solved by iteration. It is argued that the exponent of the similarity are ruled by Kelvin's theorem of conservation of circulation. The end result is an iteration with a nonlinear term entering in a kernel given by a 3D integral (in general 3D flow) or 2D (for swirling flows), which seems to be within reach of present day computational power. Because of the slow decay of the similarity solution at large distances the total energy is diverging and recent mathematical results excluding a solution of the self-similar solution of Euler equation do not apply.
Monte Carlo Euler approximations of HJM term structure financial models
Björk, Tomas
2012-11-22
We present Monte Carlo-Euler methods for a weak approximation problem related to the Heath-Jarrow-Morton (HJM) term structure model, based on Itô stochastic differential equations in infinite dimensional spaces, and prove strong and weak error convergence estimates. The weak error estimates are based on stochastic flows and discrete dual backward problems, and they can be used to identify different error contributions arising from time and maturity discretization as well as the classical statistical error due to finite sampling. Explicit formulas for efficient computation of sharp error approximation are included. Due to the structure of the HJM models considered here, the computational effort devoted to the error estimates is low compared to the work to compute Monte Carlo solutions to the HJM model. Numerical examples with known exact solution are included in order to show the behavior of the estimates. © 2012 Springer Science+Business Media Dordrecht.
Stability analysis of the Euler discretization for SIR epidemic model
Energy Technology Data Exchange (ETDEWEB)
Suryanto, Agus [Department of Mathematics, Faculty of Sciences, Brawijaya University, Jl. Veteran Malang 65145 (Indonesia)
2014-06-19
In this paper we consider a discrete SIR epidemic model obtained by the Euler method. For that discrete model, existence of disease free equilibrium and endemic equilibrium is established. Sufficient conditions on the local asymptotical stability of both disease free equilibrium and endemic equilibrium are also derived. It is found that the local asymptotical stability of the existing equilibrium is achieved only for a small time step size h. If h is further increased and passes the critical value, then both equilibriums will lose their stability. Our numerical simulations show that a complex dynamical behavior such as bifurcation or chaos phenomenon will appear for relatively large h. Both analytical and numerical results show that the discrete SIR model has a richer dynamical behavior than its continuous counterpart.
Euler Deconvolution with Improved Accuracy and Multiple Different Structural Indices
Institute of Scientific and Technical Information of China (English)
G R J Cooper
2008-01-01
Euler deconvolution is a semi-automatic interpretation method that is frequently used with magnetic and gravity data. For a given source type, which is specified by its structural index (SI), it provides an estimate of the source location. It is demonstrated here that by computing the solution space of individual data points and selecting common source locations the accuracy of the result can be improved. Furthermore, only a slight modification of the method is necessary to allow solutions for any number of different Sis to be obtained simultaneously. The method is applicable to both evenly and unevenly sampled geophysical data and is demonstrated on gravity and magnetic data. Source code (in Matlab format) is available from www.iamg.org.
Emerging Viral Diseases of Tomato Crops
Hanssen, I.M.; Lapidot, M.; Thomma, B.P.H.J.
2010-01-01
Viral diseases are an important limiting factor in many crop production systems. Because antiviral products are not available, control strategies rely on genetic resistance or hygienic measures to prevent viral diseases, or on eradication of diseased crops to control such diseases. Increasing intern
Determination of Euler parameters of Philippine Sea plate and the inferences
Institute of Scientific and Technical Information of China (English)
臧绍先; 陈起永; 宁杰远; 沈正康; 刘永刚
2002-01-01
Euler vectors of 12 plates, including Philippine Sea plate (PH), relative to a randomly fixed Pacific plate(PA) were determined by inverting the 1122 data from NUVEL-1 global plate motion model, earthquake slip vectors along Philippine Sea plate boundary, and GPS observed velocities. Euler vectors of Philippine Sea plate relative to adjacent plates are also gained. Our results are well consistent with observed data and can satisfy the geological and geophysical constraints along the Caroline(CR)-PH and PA-CR boundaries. Deformation of Philippine Sea plate is also discussed by using the plate motion Euler parameters.
Euler number of Instanton Moduli space and Seiberg-Witten invariants
Sako, A; Sako, Akifumi; Sasaki, Toru
2001-01-01
We show that a partition function of topological twisted N=4 Yang-Mills theory is given by Seiberg-Witten invariants on a Riemannian four manifolds under the condition that the sum of Euler number and signature of the four manifolds vanish. The partition function is the sum of Euler number of instanton moduli space when it is possible to apply the vanishing theorem. And we get a relation of Euler number labeled by the instanton number $k$ with Seiberg-Witten invariants, too. All calculation in this paper is done without assuming duality.
Blow-up conditions for two dimensional modified Euler-Poisson equations
Lee, Yongki
2016-09-01
The multi-dimensional Euler-Poisson system describes the dynamic behavior of many important physical flows, yet as a hyperbolic system its solution can blow-up for some initial configurations. This article strives to advance our understanding on the critical threshold phenomena through the study of a two-dimensional modified Euler-Poisson system with a modified Riesz transform where the singularity at the origin is removed. We identify upper-thresholds for finite time blow-up of solutions for the modified Euler-Poisson equations with attractive/repulsive forcing.
Rainfed intensive crop systems
DEFF Research Database (Denmark)
Olesen, Jørgen E
2014-01-01
This chapter focuses on the importance of intensive cropping systems in contributing to the world supply of food and feed. The impact of climate change on intensive crop production systems is also discussed.......This chapter focuses on the importance of intensive cropping systems in contributing to the world supply of food and feed. The impact of climate change on intensive crop production systems is also discussed....
Micronutrients in cereal crops
Hamnér, Karin
2016-01-01
Seven elements essential for plants are defined as micronutrients: boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni) and zinc (Zn). Deficiency of these nutrients can cause yield losses in crops and impaired crop quality. The overall aim of this thesis work was to increase the knowledge how micronutrients in Swedish cereal crops are affected by nutrient management and soil properties in order to improve crop status and avoid yield losses. Data from long term and s...
Energy Technology Data Exchange (ETDEWEB)
Lipinsky, E. S.; Kresovich, S.
1980-01-01
The botanical, physiological, and agronomic characteristics of sorghum are described. Integration concepts to improve sorghum prospects are discussed as follows: multiple sweet sorghum crops each year, integration with sugarcane, integration with sugar beets, integration with starch crops, sweet stemmed grain sorghum, and integration with lignocellulosic crops. (MHR)
Gerssen-Gondelach, Sarah|info:eu-repo/dai/nl/355262436; Wicke, Birka|info:eu-repo/dai/nl/306645955; Faaij, Andre
The sustainable production potential of biomass for energy and material purposes largely depends on the future availability of surplus agricultural lands made available through yield improvements in crop and livestock production. However, the rates at which yields may develop, and the influence of
Gerssen-Gondelach, Sarah; Wicke, Birka; Faaij, Andre
2015-01-01
The sustainable production potential of biomass for energy and material purposes largely depends on the future availability of surplus agricultural lands made available through yield improvements in crop and livestock production. However, the rates at which yields may develop, and the influence of t
Some Formulae of Products of the Apostol-Bernoulli and Apostol-Euler Polynomials
Directory of Open Access Journals (Sweden)
Yuan He
2012-01-01
Full Text Available Some formulae of products of the Apostol-Bernoulli and Apostol-Euler polynomials are established by applying the generating function methods and some summation transform techniques, and various known results are derived as special cases.
Some Formulae of Products of the Apostol-Bernoulli and Apostol-Euler Polynomials
2012-01-01
Some formulae of products of the Apostol-Bernoulli and Apostol-Euler polynomials are established by applying the generating function methods and some summation transform techniques, and various known results are derived as special cases.
Directory of Open Access Journals (Sweden)
Ryoo CS
2010-01-01
Full Text Available The purpose of this paper is to give some properties of several Bernstein type polynomials to represent the fermionic -adic integral on . From these properties, we derive some interesting identities on the Euler numbers and polynomials.
Directory of Open Access Journals (Sweden)
Heejeong Koh
2013-01-01
Full Text Available We obtain the general solution of Euler-Lagrange-Rassias quartic functional equation of the following . We also prove the Hyers-Ulam-Rassias stability in various quasinormed spaces when .
Accuracy of AFM force distance curves via direct solution of the Euler-Bernoulli equation
National Research Council Canada - National Science Library
Eppell, Steven J; Liu, Yehe; Zypman, Fredy R
2016-01-01
In an effort to improve the accuracy of force-separation curves obtained from atomic force microscope data, we compare force-separation curves computed using two methods to solve the Euler-Bernoulli equation...
Some New Formulae for Genocchi Numbers and Polynomials Involving Bernoulli and Euler Polynomials
Directory of Open Access Journals (Sweden)
Serkan Araci
2014-01-01
Full Text Available We give some new formulae for product of two Genocchi polynomials including Euler polynomials and Bernoulli polynomials. Moreover, we derive some applications for Genocchi polynomials to study a matrix formulation.
Institute of Scientific and Technical Information of China (English)
ZHANG; Shuqing; ZHANG; Junyan; ZHANG; Bai
2004-01-01
By combining geographic information system (GIS), a new conception of "group" in which covers the complex connected region is introduced in the paper. Based on the conception of group, a generalized Euler formula and its properties are deduced and proved. The paper also describes the mathematical principles of generating topological information of polygon in GIS maps and the methods for checking up the veracity of topological relations of the map with Euler formula and general Euler formula. We have also obtained the quantitative relations among real nodes, chains, islands and groups with the formulas. At the same time, the paper introduces Whole Sphere Stereographic (WSS) projection into the GIS, and defines a new conception of "sea". The deduction of general Euler formula and the introduction of WSS projection to GIS have developed new ways of delineating GIS topological models from plane to sphere and even constructing three dimensional (3-D) topological models.
The symplectic structure of Euler-Lagrange superequations and Batalin-Vilkoviski formalism
Energy Technology Data Exchange (ETDEWEB)
Monterde, J; Vallejo, J A [Departament de Geometria i Topologia, Universitat de Valencia, Avda V A Estelles 1, 46100, Burjassot (Spain)
2003-05-09
We study the graded Euler-Lagrange equations from the viewpoint of graded Poincare-Cartan forms. An application to a certain class of solutions of the Batalin-Vilkoviski master equation is also given.
Ford, Kevin; Moree, Pieter
2011-01-01
For a fixed odd prime q we investigate the first and second order terms of the asymptotic series expansion for the number of n\\le x such that q does not divide phi(n). Part of the analysis involves a careful study of the Euler-Kronecker constants for cyclotomic fields. In particular, we show that the Extended Riemann Hypothesis, the prime k-tuples conjecture and a conjecture of Ihara about the distribution of these Euler-Kronecker constants cannot be all true.
Generating Functions for q-Apostol Type Frobenius–Euler Numbers and Polynomials
Directory of Open Access Journals (Sweden)
Yilmaz Simsek
2012-12-01
Full Text Available The aim of this paper is to construct generating functions, related to nonnegative real parameters, for q-Eulerian type polynomials and numbers (or q-Apostol type Frobenius–Euler polynomials and numbers. We derive some identities for these polynomials and numbers based on the generating functions and functional equations. We also give multiplication formula for the generalized Apostol type Frobenius–Euler polynomials.
Yoneda, Tsuyoshi
2016-01-01
The dynamics along the particle trajectories for the 3D axisymmetric Euler equations in an infinite cylinder are considered. It is shown that if the inflow-outflow is rapidly increasing in time, the corresponding laminar profile of the Euler flow is not (in some sense) stable provided that the swirling component is not small. This exhibits an instability mechanism of pulsatile flow. In the proof, Frenet-Serret formulas and orthonormal moving frame are essentially used.
WELL-POSEDNESS OF INITIAL VALUE PROBLEM FOR EULER EQUATIONS OF INVISCID COMPRESSIBLE ADIABATIC FLUID
Institute of Scientific and Technical Information of China (English)
WANG Yue-peng
2005-01-01
The well-posedness of the initial value problem of the Euler equations was mainly discussed based on the stratification theory, and the necessary and sufficient conditions of well-posedness are presented for some representative initial or boundary value problem, thus the structure of solution space for local (exact) solution of the Euler equations is determined. Moreover the computation formulas of the analytical solution of the well-posed problem are also given.
Khan, Waseem A; Haroon, Hiba
2016-01-01
In 2008, Liu and Wang established various symmetric identities for Bernoulli, Euler and Genocchi polynomials. In this paper, we extend these identities in a unified and generalized form to families of Hermite-Bernoulli, Euler and Genocchi polynomials. The procedure followed is that of generating functions. Some relevant connections of the general theory developed here with the results obtained earlier by Pathan and Khan are also pointed out.
Buckling of Euler Columns with a Continuous Elastic Restraint via Homotopy Analysis Method
Directory of Open Access Journals (Sweden)
Aytekin Eryılmaz
2013-01-01
Full Text Available Homotopy Analysis Method (HAM is applied to find the critical buckling load of the Euler columns with continuous elastic restraints. HAM has been successfully applied to many linear and nonlinear, ordinary and partial, differential equations, integral equations, and difference equations. In this study, we presented the application of HAM to the critical buckling loads for Euler columns with five different support cases continuous elastic restraints. The results are compared with the analytic solutions.
Global Existence of Smooth Solutions of Compressible Bipolar Euler-Maxwell Equations
Institute of Scientific and Technical Information of China (English)
XU Qian-jin; LI Xin; FENG Yue-hong
2013-01-01
The bipolar compressible Euler-Maxwell equations as a fluid dynamic model arising from plasma physics to describe the dynamics of the compressible electrons and ions is investigated.This work is concerned with three-dimensional Euler-Maxwell equations with smooth periodic solutions.With the help of the symmetry operator techniques and energy method,the global smooth solution with small amplitude is constructed around a constant equilibrium solution with asymptotic stability property.
Dynamic Euler-Bernoulli Beam Equation: Classification and Reductions
Directory of Open Access Journals (Sweden)
R. Naz
2015-01-01
Full Text Available We study a dynamic fourth-order Euler-Bernoulli partial differential equation having a constant elastic modulus and area moment of inertia, a variable lineal mass density g(x, and the applied load denoted by f(u, a function of transverse displacement u(t,x. The complete Lie group classification is obtained for different forms of the variable lineal mass density g(x and applied load f(u. The equivalence transformations are constructed to simplify the determining equations for the symmetries. The principal algebra is one-dimensional and it extends to two- and three-dimensional algebras for an arbitrary applied load, general power-law, exponential, and log type of applied loads for different forms of g(x. For the linear applied load case, we obtain an infinite-dimensional Lie algebra. We recover the Lie symmetry classification results discussed in the literature when g(x is constant with variable applied load f(u. For the general power-law and exponential case the group invariant solutions are derived. The similarity transformations reduce the fourth-order partial differential equation to a fourth-order ordinary differential equation. For the power-law applied load case a compatible initial-boundary value problem for the clamped and free end beam cases is formulated. We deduce the fourth-order ordinary differential equation with appropriate initial and boundary conditions.
Euler buckling and nonlinear kinking of double-stranded DNA.
Fields, Alexander P; Meyer, Elisabeth A; Cohen, Adam E
2013-11-01
The bending stiffness of double-stranded DNA (dsDNA) at high curvatures is fundamental to its biological activity, yet this regime has been difficult to probe experimentally, and literature results have not been consistent. We created a 'molecular vise' in which base-pairing interactions generated a compressive force on sub-persistence length segments of dsDNA. Short dsDNA strands (Euler buckling'. We monitored the buckling transition via Förster Resonance Energy Transfer (FRET) between appended fluorophores. For low-to-moderate concentrations of monovalent salt (up to ∼150 mM), our results are in quantitative agreement with the worm-like chain (WLC) model of DNA elasticity, without the need to invoke any 'kinked' states. Greater concentrations of monovalent salts or 1 mM Mg(2+) induced an apparent softening of the dsDNA, which was best accounted for by a kink in the region of highest curvature. We tested the effects of all single-nucleotide mismatches on the DNA bending. Remarkably, the propensity to kink correlated with the thermodynamic destabilization of the mismatched DNA relative the perfectly complementary strand, suggesting that the kinked state is locally melted. The molecular vise is exquisitely sensitive to the sequence-dependent linear and nonlinear elastic properties of dsDNA.
Aeroelastic Calculations Based on Three-Dimensional Euler Analysis
Bakhle, Milind A.; Srivastava, Rakesh; Keith, Theo G., Jr.; Stefko, George L.
1998-01-01
This paper presents representative results from an aeroelastic code (TURBO-AE) based on an Euler/Navier-Stokes unsteady aerodynamic code (TURBO). Unsteady pressure, lift, and moment distributions are presented for a helical fan test configuration which is used to verify the code by comparison to two-dimensional linear potential (flat plate) theory. The results are for pitching and plunging motions over a range of phase angles, Good agreement with linear theory is seen for all phase angles except those near acoustic resonances. The agreement is better for pitching motions than for plunging motions. The reason for this difference is not understood at present. Numerical checks have been performed to ensure that solutions are independent of time step, converged to periodicity, and linearly dependent on amplitude of blade motion. The paper concludes with an evaluation of the current state of development of the TURBO-AE code and presents some plans for further development and validation of the TURBO-AE code.
Advanced mechanics from Euler's determinism to Arnold's chaos
Rajeev, S G
2013-01-01
Classical Mechanics is the oldest and best understood part of physics. This does not mean that it is cast in marble yet, a museum piece to be admired from a distance. Instead, mechanics continues to be an active area of research by physicists and mathematicians. Every few years, we need to re-evaluate the purpose of learning mechanics and look at old material in the light of modern developments. Once you have learned basic mechanics (Newton's laws, the solution of the Kepler problem) and quantum mechanics (the Schrodinger equation, hydrogen atom) it is time to go back and relearn classical mechanics in greater depth. It is the intent of this book to take you through the ancient (the original meaning of "classical") parts of the subject quickly: the ideas started by Euler and ending roughly with Poincare. We then take up the developments of twentieth century physics that have largely to do with chaos and discrete time evolution (the basis of numerical solutions).
Euler-Lagrange Elasticity: elasticity without stress or strain
Hardy, Humphrey
2014-03-01
A Euler-Lagrange (E-L) approach to elasticity is proposed that produces differential equations of elasticity without the need to define stress or strain tensors. The positions of the points within the body are the independent parameters instead of strain. Force replaces stress. The advantage of this approach is that the E-L differential equations are the same for both infinitesimal and finite deformations. Material properties are expressed in terms of the energy of deformation. The energy is expressed as a function of the principal invariants of the deformation gradient tensor. This scalar invariant representation of the energy of deformation enters directly into the E-L differential equations so that there is no need to define fourth order tensor material properties. By experimentally measuring the force and displacement of materials the functional form of the energy of deformation can be determined. The E-L differential equations can be input directly into finite element, finite difference, or other numerical models. If desired, stress and stain can be calculated as dependent parameters.
Generalized Burgers equations and Euler-Painlevé transcendents. I
Sachdev, P. L.; Nair, K. R. C.; Tikekar, V. G.
1986-06-01
Initial-value problems for the generalized Burgers equation (GBE) ut+u βux+λuα =(δ/2)uxx are discussed for the single hump type of initial data—both continuous and discontinuous. The numerical solution is carried to the self-similar ``intermediate asymptotic'' regime when the solution is given analytically by the self-similar form. The nonlinear (transformed) ordinary differential equations (ODE's) describing the self-similar form are generalizations of a class discussed by Euler and Painlevé and quoted by Kamke. These ODE's are new, and it is postulated that they characterize GBE's in the same manner as the Painlevé equations categorize the Kortweg-de Vries (KdV) type. A connection problem for some related ODE's satisfying proper asymptotic conditions at x=±∞, is solved. The range of amplitude parameter is found for which the solution of the connection problem exists. The other solutions of the above GBE, which display several interesting features such as peaking, breaking, and a long shelf on the left for negative values of the damping coefficient λ, are also discussed. The results are compared with those holding for the modified KdV equation with damping.
Directory of Open Access Journals (Sweden)
Hiel, MP.
2016-01-01
Full Text Available Introduction. Residues of previous crops provide a valuable amount of organic matter that can be used either to restore soil fertility or for external use. A better understanding of the impact of crop residue management on the soil-water-plant system is needed in order to manage agricultural land sustainably. This review focuses on soil physical aspects related to crop residue management, and specifically on the link between soil structure and hydraulic properties and its impact on crop production. Literature. Conservation practices, including crop residue retention and non-conventional tillage, can enhance soil health by improving aggregate stability. In this case, water infiltration is facilitated, resulting in an increase in plant water availability. Conservation practices, however, do not systematically lead to higher water availability for the plant. The influence of crop residue management on crop production is still unclear; in some cases, crop production is enhanced by residue retention, but in others crop residues can reduce crop yield. Conclusions. In this review we discuss the diverse and contrasting effects of crop residue management on soil physical properties and crop production under a temperate climate. The review highlights the importance of environmental factors such as soil type and local climatic conditions, highlighting the need to perform field studies on crop residue management and relate them to specific pedo-climatic contexts.
Crop systems biology : an approach to connect functional genomics with crop modelling
Yin, X.; Struik, P.C.
2007-01-01
The response of the whole crop to environmental conditions is a critical factor in agriculture. It can only be understood if the organization of the crop system is taken into account. A popular view in modern science is that genomics (and other `omics¿) will provide knowledge and tools to allow the
Automated Euler and Navier-Stokes Database Generation for a Glide-Back Booster
Chaderjian, Neal M.; Rogers, Stuart E.; Aftosmis, Mike J.; Pandya, Shishir A.; Ahmad, Jasim U.; Tejnil, Edward
2004-01-01
The past two decades have seen a sustained increase in the use of high fidelity Computational Fluid Dynamics (CFD) in basic research, aircraft design, and the analysis of post-design issues. As the fidelity of a CFD method increases, the number of cases that can be readily and affordably computed greatly diminishes. However, computer speeds now exceed 2 GHz, hundreds of processors are currently available and more affordable, and advances in parallel CFD algorithms scale more readily with large numbers of processors. All of these factors make it feasible to compute thousands of high fidelity cases. However, there still remains the overwhelming task of monitoring the solution process. This paper presents an approach to automate the CFD solution process. A new software tool, AeroDB, is used to compute thousands of Euler and Navier-Stokes solutions for a 2nd generation glide-back booster in one week. The solution process exploits a common job-submission grid environment, the NASA Information Power Grid (IPG), using 13 computers located at 4 different geographical sites. Process automation and web-based access to a MySql database greatly reduces the user workload, removing much of the tedium and tendency for user input errors. The AeroDB framework is shown. The user submits/deletes jobs, monitors AeroDB's progress, and retrieves data and plots via a web portal. Once a job is in the database, a job launcher uses an IPG resource broker to decide which computers are best suited to run the job. Job/code requirements, the number of CPUs free on a remote system, and queue lengths are some of the parameters the broker takes into account. The Globus software provides secure services for user authentication, remote shell execution, and secure file transfers over an open network. AeroDB automatically decides when a job is completed. Currently, the Cart3D unstructured flow solver is used for the Euler equations, and the Overflow structured overset flow solver is used for the
Institute of Scientific and Technical Information of China (English)
刘国栋
1999-01-01
利用递归序列建立了高阶多元Euler-Bernoulli多项式的一个递归关系.得到了高阶多元Euler多项式和高阶多元Bernoulli多项式的一种关系式,推广了Byrd,Kelisky和Zhang Zhizheng的结果.
A comparison of SPH schemes for the compressible Euler equations
Puri, Kunal; Ramachandran, Prabhu
2014-01-01
We review the current state-of-the-art Smoothed Particle Hydrodynamics (SPH) schemes for the compressible Euler equations. We identify three prototypical schemes and apply them to a suite of test problems in one and two dimensions. The schemes are in order, standard SPH with an adaptive density kernel estimation (ADKE) technique introduced Sigalotti et al. (2008) [44], the variational SPH formulation of Price (2012) [33] (referred herein as the MPM scheme) and the Godunov type SPH (GSPH) scheme of Inutsuka (2002) [12]. The tests investigate the accuracy of the inviscid discretizations, shock capturing ability and the particle settling behavior. The schemes are found to produce nearly identical results for the 1D shock tube problems with the MPM and GSPH schemes being the most robust. The ADKE scheme requires parameter values which must be tuned to the problem at hand. We propose an addition of an artificial heating term to the GSPH scheme to eliminate unphysical spikes in the thermal energy at the contact discontinuity. The resulting modification is simple and can be readily incorporated in existing codes. In two dimensions, the differences between the schemes is more evident with the quality of results determined by the particle distribution. In particular, the ADKE scheme shows signs of particle clumping and irregular motion for the 2D strong shock and Sedov point explosion tests. The noise in particle data is linked with the particle distribution which remains regular for the Hamiltonian formulations (MPM and GSPH) and becomes irregular for the ADKE scheme. In the interest of reproducibility, we make available our implementation of the algorithms and test problems discussed in this work.
Ravi Kannan, Ravishekar; Przekwas, A J; Singh, Narender; Delvadia, Renishkumar; Tian, Geng; Walenga, Ross
2017-04-01
This study uses Computational Fluid Dynamics (CFD) to predict, analyze and validate the deposition patterns in a human lung for a Budesonide drug delivered from the Novolizer Dry Powder Inhaler device. We used a test case of known deposition patterns to validate our computational Euler Lagrangian-based deposition predictions. Two different lung models are used: (i) a basic ring-less trachea model and (ii) an advanced Human Zygote5 model. Unlike earlier attempts, the current simulations do not include the device in the computational domain. This greatly reduces the computational effort. To mimic the device, we model the inlet particle jet stream from the device as a spray entering the mouth in a conical fashion. Deposition studies in the various lung regions were performed. We were able to computationally predict and then demonstrate the enhanced deposition in the tracheal and first generation rings/ridges. The enhanced vorticity creation due to the ring structure and the geometrical design contributes to larger deposition in the Zygote5 model. These are in accord with existing data, unlike the ring-less model. Our validated results indicate the need to (i) introduce the ridges in the experimental casts and the CFD surface meshes to be anatomically consistent and obtain physiologically consistent depositions; (ii) introduce a factor to account for the recirculating lighter particles in empirical models.
A 3-dimensional Navier-Stokes-Euler code for blunt-body flow computations
Li, C. P.
1985-01-01
The shock-layer flowfield is obtained with or without viscous and heat-conducting dissipations from the conservative laws of fluid dynamics equations using a shock-fitting implicity finite-difference technique. The governing equations are cast in curvilinear-orthogonal coordinates and transformed to the domain between the shock and the body. Another set of equations is used for the singular coordinate axis, which, together with a cone generator away from the stagnation point, encloses the computation domain. A time-dependent alternating direction implicit factorization technique is applied to integrate the equations with local-time increment until a steady solution is reached. The shock location is updated after the flowfield computation, but the wall conditions are implemented into the implicit procedure. Innovative procedures are introduced to define the initial flowfield, to treat both perfect and equilibrium gases, to advance the solution on a coarse-to-fine grid sequence, and to start viscous flow computations from their corresponding inviscid solutions. The results are obtained from a grid no greater than 28 by 18 by 7 and converged within 300 integration steps. They are of sufficient accuracy to start parabolized Navier-Stokes or Euler calculations beyond the nose region, to compare with flight and wind-tunnel data, and to evaluate conceptual designs of reentry spacecraft.
The Euler characteristic correction to the Kähler potential — revisited
Bonetti, Federico; Weissenbacher, Matthias
2017-01-01
We confirm the leading α '3 correction to the 4d, N=1 Kähler potential of type IIB orientifold compactifications, proportional to the Euler characteristic of the Calabi-Yau threefold (BBHL correction). We present the explicit solution for the α '3-modified internal background metric in terms of the non-harmonic part of the third Chern form of the leading order Calabi-Yau manifold. The corrected internal manifold is almost Calabi-Yau and admits an SU(3) structure with non-vanishing torsion. We also find that the full ten-dimensional Einstein frame background metric is multiplied by a non-trivial Weyl factor. Performing a Kaluza-Klein reduction on the modified background we derive the α '3-corrected kinetic terms for the dilaton and the Kähler deformations of the internal Calabi-Yau threefold for arbitrary h 1,1. We analyze these kinetic terms in the 4d, N=2 un-orientifolded theory, confirming the expected correction to the Kähler moduli space pre-potential, as well as in the 4d, N=1 orientifolded theory, thus determining the corrections to the Kähler potential and Kähler coordinates.
2014-06-01
3D Euler Equations of Moist Atmospheric Convection 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER...STABILIZATION OF SPECTRAL ELEMENTS FOR THE 3D EULER EQUATIONS OF MOIST ATMOSPHERIC CONVECTION SIMONE MARRAS, ANDREAS MÜLLER, FRANCIS X. GIRALDO Dept. Appl...spectral elements, we introduce a dissipative scheme based on the solution of the compressible Euler equations that are regularized through the addi
Institute of Scientific and Technical Information of China (English)
柴强; 于爱忠; 陈桂平; 黄鹏
2011-01-01
Several studies have shown that compared to sole cropping, well managed intercropping improves agricultural resources utilization efficiency, include radiation, nutrient, water and land. However, high productivity of traditional intercropping system has mainly depended on high input of agricultural resources. With severe water shortages in recent years (especially in mainland China), intercropping system of farming has continuously declined. The scientific challenge therefore is the determination of water consumption characteristics and systematic development of high-efficiency water-saving theories and technologies of intercropping system. In this study, a field experiment (comprising of wheat or maize sole cropping and wheat-maize intercropping systems under three different irrigation schemes) was conducted in 2008 in the Hexi Corridor oasis region. The study investigated soil evaporation characteristics and associated driving factors under the different cropping systems and treatments with the aim of laying the scientific basis for developing optimized irrigation techniques. The study showed that evapotranspiration (ET) under wheat-maize intercropping was 41.44%～47.15% higher than the average ET under wheat and maize sole cropping systems. Total soil evaporation (E) of intercropping system was significantly higher than that of sole cropping systems. However, daily E of intercropping system was significantly lower than that of maize sole cropping system. Also compared with sole cropping system of maize, wheat-maize intercropping system enhanced E/ET ratio. With increasing irrigation, total water consumption increased significantly under intercropping. However, the difference in water consumption between two adjacent irrigation treatments under sole cropping systems of wheat and maize was insignificant. The difference in E of sole cropping maize and intercropping wheat-maize was insignificant for different irrigation schemes. It then implied that high water
Ecophysiology of horticultural crops: an overview
Directory of Open Access Journals (Sweden)
Restrepo-Díaz Hermann
2010-04-01
Full Text Available
Horticultural crops include a wide range of commodities, such as fruits and vegetables that are highly valuable for humanity. They are extensively grown worldwide, and their production can be described as an open and highly complex system affected by many factors, among which we can count weather, soil and cropping system, as well as the interaction between these factors. The aim of environmental physiology is to characterize the interaction between environmental stress and crop response, in order to maximize both yield quantity and quality. This review presents the most recent findings about the effects of the main abiotic environmental factors (light, temperature, and water on whole plant physiology of horticultural crops. Environmental stresses can cause morpho-anatomical, physiological and biochemical changes in crops, resulting in a strong profit reduction. A clear understanding of environmental factors and their interaction with physiological processes is extremely important for improving horticultural practices (irrigation, light management, mineral nutrition, greenhouse design, etc., optimizing photosynthetic carbon assimilation and increasing fruit productivity and crop quality. In addition, the information obtained by ecophysiological studies can be incorporated into breeding programs or agricultural zoning strategies.
Euler force actuation mechanism for siphon valving in compact disk-like microfluidic chips.
Deng, Yongbo; Fan, Jianhua; Zhou, Song; Zhou, Teng; Wu, Junfeng; Li, Yin; Liu, Zhenyu; Xuan, Ming; Wu, Yihui
2014-03-01
Based on the Euler force induced by the acceleration of compact disk (CD)-like microfluidic chip, this paper presents a novel actuation mechanism for siphon valving. At the preliminary stage of acceleration, the Euler force in the tangential direction of CD-like chip takes the primary place compared with the centrifugal force to function as the actuation of the flow, which fills the siphon and actuates the siphon valving. The Euler force actuation mechanism is demonstrated by the numerical solution of the phase-field based mathematical model for the flow in siphon valve. In addition, experimental validation is implemented in the polymethylmethacrylate-based CD-like microfluidic chip manufactured using CO2 laser engraving technique. To prove the application of the proposed Euler force actuation mechanism, whole blood separation and plasma extraction has been conducted using the Euler force actuated siphon valving. The newly introduced actuation mechanism overcomes the dependence on hydrophilic capillary filling of siphon by avoiding external manipulation or surface treatments of polymeric material. The sacrifice for highly integrated processing in pneumatic pumping technique is also prevented by excluding the volume-occupied compressed air chamber.
基于格式塔心理学和Euler spiral的轮廓修复算法%Gestalt psychology and Euler spiral for contour completion
Institute of Scientific and Technical Information of China (English)
张桂梅; 刘丕玉
2013-01-01
现有的轮廓修复方法假设已知遮挡发生的位置,且未考虑人类认知特性.针对该问题,提出一种结构较完整的轮廓修复方法.算法首先检测T型节点确定遮挡发生的位置；根据格式塔心理学的完形法则提出组合约束条件,据此将T型节点进行组合.对平滑轮廓遮挡,基于Euler spiral,并以曲率变化最小作为能量最小化准则,修复局部缺失的轮廓；对角点轮廓遮挡,利用过角点的两条曲线的可见部分构造两条Euler spiral,根据Euler spiral的扩展性对构造的两条Euler spiral进行延拓并求交,从而修复角点遮挡轮廓.方法能自动确定遮挡发生的位置,能够对T型节点进行正确组合,使轮廓修复更符合人类视觉感知；对角点轮廓遮挡采用Euler spiral的扩展性进行修复,能克服角点轮廓修复仅适合于修复轮廓为直线或圆弧的规则物体.应用模拟图像和真实图像验证了方法的有效性.%The existing contour completion methods assume known the positions of occlusion,and do not consider the human cognitive characteristics.To solve these problems,this paper proposed a more complete contour completion method.The algorithm firstly detected T-junctions to locate the occlusion; then proposed the combined constraint conditions based on laws of organization in Gestalt psychology,combined T-junctions using the above conditions.Finally,it investigated the contour completion in two kinds.For smooth contour,it completed by Euler spiral.It considered curvature variation minimum as energy minimization criterion.For occluded comer contour,it constructed two Euler spiral using the visible part of the two curves which composed the comer point.The constructed two Euler spirals extended and intersected with each other according to the extensible of Euler spiral.This method can automatically locate the occlusion by detecting T-junctions; the contour completion can more correspond with human visual perception
作物资源伦理观念的调查及决定性因素分析%Investigation on crop resources ethical ideas and the decisive factors analysis
Institute of Scientific and Technical Information of China (English)
王晓为; 王晶宇; 丁广洲
2012-01-01
In order to study the situation of future jobholders＇ crop resources ethical ideas and the concerning decisive factors, tests and ques-tionnaires are used to investigate, evaluate, and analyze the investigated groups＇ crop resources ethical ideas and the decisive factors. SPSS data processing software is used to analyze the 708 samples from relevant groups, and the studies show that meta cognitive awareness, meta cogni-tive initiation, deep technology motivation, agricultural culture cognition and crop production and development cognition, the 5 factors, decide an individual＇s crop resources ethical ideas. The mains problems reflected in the investigation are departmental and self-centered thinking mod-el, ubiquitous and strong benefit pursuing ideas in technology motivation, and lack of native traditional agricultural thought and understanding.%为研究未来从业人员的作物资源伦理观念状况及其决定性因素,采用测试和调查问卷的方法,对被调查群体的作物资源伦理观状况和伦理观念的决定性因素进行了评价和意识寻踪。运用SPSS数据处理软件对相关群体的708份调研样本进行了分析,研究结果表明：元认知意识、元认知引发、深层技术动机等5种因素决定个体的作物资源伦理观念;本位与自我的思维模式、技术动机中普遍而浓重的逐利思想以及缺乏对本土传统农业思想认知的意识与动力,是本次调查反映出的作物资源伦理观念的主要问题。
Yin, Xinyou; Struik, P.C.
2015-01-01
The sequencing of genomes has been completed for an increasing number of crop species, and researchers have now succeeded in isolating and characterising many important QTLs/genes. High expectations from genomics, however, are waving back toward the recognition that crop physiology is also
Doses and application seasons of potassium on soybean crop in succession the cover crops
Directory of Open Access Journals (Sweden)
Amilton Ferreira Silva
2014-02-01
Full Text Available Potassium (K is the second nutrient that is required in larger amounts by soybean crop. With the use of high doses of that nutrient and increase of no-tillage areas in last years, some changes occurred in ways of this nutrient application, as well as the introduction of cover crops in the system for straw formation. Due those facts, the aim with this work was to study doses and times of potassium application for soybean sowed as succession for cover crops in no-tillage system, in a clayey Distrofic Red Latosol, in cerrado region. The experimental design was a randomized block with treatments arranged in 3x3x5 factorial scheme, with the following factors, cover crops: Pearl millet (Pennisetum glaucum and Proso millet (Panicum miliaceum and a control (fallow area, rates of K2O (0, 50 e 100 kg ha-1 and K2O application forms (100% in the cover crops; 100% at sowing of soybean; 100% in topdressing in soybean; 50% at sowing cover crops + 50% at soybean sowing; 50% at soybean sowing + 50% in topdressing in the soybean with four replicates. The Pennisetum glaucum as soybean predecessor crop yields higher dry matter content than the Panicum miliaceum in a short period of time. In clay soil with high content of potassium there was no response to the applied potassium levels. Full doses of potassium maintenance fertilization can be applied in the predecessor cover crop, at sowing or topdressing in soybean crop.
Simulation of crop evapotranspiration and crop coefficient in weighing lysimeters
Accurate quantification of crop evapotranspiration (ET) is critical in optimizing irrigation water productivity, especially, in the semiarid regions of the world where limited rainfall is supplemented by irrigation for profitable crop production. In this context, cropping system models are potential...
Directory of Open Access Journals (Sweden)
Hamdia, M. A
2010-09-01
Full Text Available Several environmental factors adversely affect plant growth and development and final yield performance of a crop. Drought, salinity, nutrient imbalances (including mineral toxicities and deficiencies and extremes of temperature are among the major environmental constraints to crop productivity worldwide. Development of crop plants with stress tolerance, however, requires, among others, knowledge of the physiological mechanisms and genetic controls of the contributing traits at different plant developmental stages. In the past 2 decades, biotechnology research has provided considerable insights into the mechanism of biotic stress tolerance in plants at the molecular level. Furthermore, different abiotic stress factors may provoke osmotic stress, oxidative stress and protein denaturation in plants, which lead to similar cellular adaptive responses such as accumulation of compatible solutes, induction of stress proteins, and acceleration of reactive oxygen species scavenging systems. Recently, the authores try to improve plant tolerance to salinity injury through either chemical treatments (plant hormones, minerals, amino acids, quaternary ammonium compounds, polyamines and vitamins or biofertilizers treatments (Asymbiotic nitrogen-fixing bacteria, symbiotic nitrogen-fixing bacteria and mycorrhiza or enhanced a process used naturally by plants to minimise the movement of Na+ to the shoot, using genetic modification to amplify the process, helping plants to do what they already do - but to do it much better."
An Algorithm for Connected-Component Labeling, Hole Labeling and Euler Number Computing
Institute of Scientific and Technical Information of China (English)
Li-Feng He; Yu-Yan Chao; Kenji Suzuki
2013-01-01
Labeling connected components and holes and computing the Euler number in a binary image are necessary for image analysis,pattern recognition,and computer (robot) vision,and are usually made independently of each other in conventional methods.This paper proposes a two-scan algorithm for labeling connected components and holes simultaneously in a binary image by use of the same data structure.With our algorithm,besides labeling,we can also easily calculate the number and the area of connected components and holes,as well as the Euler number.Our method is very simple in principle,and experimental results demonstrate that our method is much more efficient than conventional methods for various kinds of images in cases where both labeling and Euler number computing are necessary.
On the rotational equations of motion in rigid body dynamics when using Euler parameters.
Sherif, Karim; Nachbagauer, Karin; Steiner, Wolfgang
Many models of three-dimensional rigid body dynamics employ Euler parameters as rotational coordinates. Since the four Euler parameters are not independent, one has to consider the quaternion constraint in the equations of motion. This is usually done by the Lagrange multiplier technique. In the present paper, various forms of the rotational equations of motion will be derived, and it will be shown that they can be transformed into each other. Special attention is hereby given to the value of the Lagrange multiplier and the complexity of terms representing the inertia forces. Particular attention is also paid to the rotational generalized external force vector, which is not unique when using Euler parameters as rotational coordinates.
Exact and approximate area-proportional circular Venn and Euler diagrams.
Wilkinson, Leland
2012-02-01
Scientists conducting microarray and other experiments use circular Venn and Euler diagrams to analyze and illustrate their results. As one solution to this problem, this paper introduces a statistical model for fitting area-proportional Venn and Euler diagrams to observed data. The statistical model outlined in this paper includes a statistical loss function and a minimization procedure that enables formal estimation of the Venn/Euler area-proportional model for the first time. A significance test of the null hypothesis is computed for the solution. Residuals from the model are available for inspection. As a result, this algorithm can be used for both exploration and inference on real data sets. A Java program implementing this algorithm is available under the Mozilla Public License. An R function venneuler() is available as a package in CRAN and a plugin is available in Cytoscape.
Novel Euler-LaCoste linkage as a very low frequency vertical vibration isolator.
Hosain, M A; Sirr, A; Ju, L; Blair, D G
2012-08-01
LaCoste linkage vibration isolators have shown excellent performance for ultra-low frequency vertical vibration isolation. However, such isolators depend on the use of conventional pre-stressed coil springs, which suffer from creep. Here, we show that compressional Euler springs can be configured to create a stable tension unit for use in a LaCoste structure. In a proof of concept experiment, we demonstrate a vertical resonance frequency of 0.15 Hz in an Euler-LaCoste configuration with 200 mm height. The system enables the use of very low creep maraging steel as spring elements to eliminate the creep while minimising spring mass and reducing the effect of parasitic resonances. Larger scale systems with optimized Euler spring boundary conditions should achieve performance suitable for applications on third generation gravitational wave detectors such as the proposed Einstein telescope.
Correction to Euler's equations and elimination of the closure problem in turbulence
Zak, Michail
2012-01-01
It has been demonstrated that the Euler equations of inviscid fluid are incomplete: according to the principle of release of constraints, absence of shear stresses must be compensated by additional degrees of freedom, and leads to Reynolds-type multivalued velocity field. however unlike the Reynolds equations, the enlarged Euler's (EE) model provides additional equations for fluctuations, and that eliminates the closure problem. Therefore the (EE) equations are applicable to fully developed turbulent motions where the physical viscosity is vanishingly small compare to the turbulent viscosity, as well as to superfluids and atomized fluids.Analysis of coupled mean/fluctuation EE equations shows that fluctuations stabilize the whole system generating elastic shear waves and increasing speed of sound. Those turbulent motions that originated from instability of underlying laminar motions can be described by the modified Euler's equation with the closure provided by the stabilization principle: driven by instabilit...
On the invariant motions of rigid body rotation over the fixed point, via Euler angles
Ershkov, Sergey V
2016-01-01
The generalized Euler case (rigid body rotation over the fixed point) is discussed here: - the center of masses of non-symmetric rigid body is assumed to be located at the equatorial plane on axis Oy which is perpendicular to the main principal axis Ox of inertia at the fixed point. Such a case was presented in the rotating coordinate system, in a frame of reference fixed in the rotating body for the case of rotation over the fixed point (at given initial conditions). In our derivation, we have represented the generalized Euler case in the fixed Cartesian coordinate system; so, the motivation of our ansatz is to elegantly transform the proper components of the previously presented solution from one (rotating) coordinate system to another (fixed) Cartesian coordinates. Besides, we have obtained an elegantly analytical case of general type of rotations; also, we have presented it in the fixed Cartesian coordinate system via Euler angles.
Analysis of Lagrange's original derivation of the Euler-Lagrange Differential Equation
Laughlin, Ryan; Close, Hunter
2012-03-01
The Euler-Lagrange differential equation provides the Lagrangian equations of motion, and thus allows the exact trajectory of an object in a potential to be found. We analyze the original derivation of the Euler-Lagrange differential equation via a translation of the third edition of Lagrange's Mecanique Analytique (1811). We compare and contrast this derivation with the derivation commonly done in a junior-level classical mechanics course. Lagrange uses several founding concepts to produce a generalized equation of motion for all dynamics. These concepts are, in the order addressed by Lagrange, the Principle of Virtual Velocities, the Conservation des Forces Vives, and the Principle of Least Action. Lagrange then employs what he calls the Method of Variations to the general equation of motion for dynamics to ultimately resolve something similar to the Euler-Lagrange Differential equation we use today. We also compare modern notation with Lagrange's notation.
Euler Characteristic and Topological Phase Transition of NUT-Kerr-Newman Black Hole
Institute of Scientific and Technical Information of China (English)
FAN Hong-Yi; YUE Jing-Hua; YANG Guo-Hong; TIAN Li-Jun; ZHU Shu
2008-01-01
From the Causs-Bonnet-Chern theorem, the Euler characteristic of NUT-Kerr-Newman black hole is calculated to be some discrete numbers from 0 to 2. We find that the Bekenstein-Hawking entropy is the largest entropy in topology by taking into account of the relationship between the entropy and the Euler characteristic. The NUT-Kerr-Newman black hole evolves from the torus-like topological structure to the spherical structure with the changes of mass, angular momentum, electric and NUT charges. In this process, the Euler characteristic and the entropy are changed discontinuously, which give the topological aspect of the first-order phase transition of NUT-Kerr-Newman black hole. The corresponding latent heat of the topologicaJ phase transition is also obtained. The estimated latent heat of the black hole evolving from the star just lies in the range of the energy of gamma ray bursts.
A novel numerical flux for the 3D Euler equations with general equation of state
Toro, Eleuterio F.
2015-09-30
Here we extend the flux vector splitting approach recently proposed in (E F Toro and M E Vázquez-Cendón. Flux splitting schemes for the Euler equations. Computers and Fluids. Vol. 70, Pages 1-12, 2012). The scheme was originally presented for the 1D Euler equations for ideal gases and its extension presented in this paper is threefold: (i) we solve the three-dimensional Euler equations on general meshes; (ii) we use a general equation of state; and (iii) we achieve high order of accuracy in both space and time through application of the semi-discrete ADER methodology on general meshes. The resulting methods are systematically assessed for accuracy, robustness and efficiency on a carefully selected suite of test problems. Formal high accuracy is assessed through convergence rates studies for schemes of up to 4th order of accuracy in both space and time on unstructured meshes.
DEFF Research Database (Denmark)
Jensen, E.S.
1996-01-01
using N-15-labelled residues. Field pea fixed 75% of its N requirement and the N-2 fixation almost balanced the N removed with the seeds. The barley crop recovered 80% of the N-15-labelled fertilizer N supplied and the N in the barley grain corresponded to 80% of the fertilizer N taken up by the crop....... In the short term, the incorporation of crop residues was not important in terms of contributing N to the subsequent crop compared to soil and fertilizer N sources, but residues improved the conservation of soil N in the autumn. In the long-term, crop residues are an important factor in maintaining soil...
The role and status of Euler solvers in impulsive rotor noise computations
Baeder, James D.
1995-01-01
Several recent applications (in the last five years) of Euler solvers in the computation of impulsive noise from rotor blades emphasize their emerging role in complementing other methods and experimental work. In the area of high-speed impulsive noise the use of Euler solvers as research tools has become fairly mature with very favorable comparisons with experimental data, especially in hover. The grid sizes and resulting computational times are reasonable when compared to those required for accurate surface aerodynamics alone. Furthermore, Euler solvers have provided a rich database with the resolution and accuracy needed for input to Kirchhoff and acoustic analogy methods for predicting the far-field noise. On the other hand, the application of Euler solvers to calculate blade-vortex interaction noise is still far from mature. The computational resources required for accurate calculations away from the blade are much larger than for high-speed impulsive noise. Current calculations help improve the basic understanding of the phenomena involved, but to date no comparisons with experiment have been made. Fortunately, the use of coupled Euler solver/Kirchhoff methods seems to offer promise for a robust and efficient technique for predicting both high-speed impulsive noise and blade-vortex interaction noise. Finally, a simple model problem of an isolated vortex interacting with an arbitrarily prescribed pitching airfoil demonstrates the feasibility of using Euler solvers to examine noise reduction techniques. The use of simple aerodynamic quasi-static theory and the computed lift time history as feedback to determine the required pitching motion appears sufficient to significantly dampen the unsteady loading and subsequent acoustics by an order of magnitude within a few blade passages.
Gene flow from glyphosate-resistant crops.
Mallory-Smith, Carol; Zapiola, Maria
2008-04-01
Gene flow from transgenic glyphosate-resistant crops can result in the adventitious presence of the transgene, which may negatively impact markets. Gene flow can also produce glyphosate-resistant plants that may interfere with weed management systems. The objective of this article is to review the gene flow literature as it pertains to glyphosate-resistant crops. Gene flow is a natural phenomenon not unique to transgenic crops and can occur via pollen, seed and, in some cases, vegetative propagules. Gene flow via pollen can occur in all crops, even those that are considered to be self-pollinated, because all have low levels of outcrossing. Gene flow via seed or vegetative propagules occurs when they are moved naturally or by humans during crop production and commercialization. There are many factors that influence gene flow; therefore, it is difficult to prevent or predict. Gene flow via pollen and seed from glyphosate-resistant canola and creeping bentgrass fields has been documented. The adventitious presence of the transgene responsible for glyphosate resistance has been found in commercial seed lots of canola, corn and soybeans. In general, the glyphosate-resistant trait is not considered to provide an ecological advantage. However, regulators should consider the examples of gene flow from glyphosate-resistant crops when formulating rules for the release of crops with traits that could negatively impact the environment or human health.
Directory of Open Access Journals (Sweden)
Marco CAMARDO LEGGIERI
2015-09-01
Full Text Available The occurrence of mycotoxins associated with Fusarium spp. and Aspergillus flavus in Northern Italy, and the role of cropping systems, were investigated on 140 field samples collected over the years 2009–2011. Samples were analysed for fumonisins B1 and B2 (FBs, aflatoxins B1, B2, G1 and G2 (AFs, deoxynivalenol (DON and zearalenone (ZEN using validated analytical methods. Information on: maize hybrid, preceding crop, tillage applied, mineral nutrition, pest and disease control, severity of European Corn Borer (ECB attack, sowing and harvesting dates, kernel moisture at harvesting and longitude of the sampled province, were also collected. During this period there were distinct differences in FBs and AFs concentrations between years and geographic origins, and very low contamination with DON and ZEN was always found. The incidence of AFs exceeded 75% across all samples, and was almost 100% for FBs. The meteorological trends were quite different in the 3 years surveyed. 2009 was the coldest in June and the warmest in August, 2010 the most humid, and in 2011 cold weather occurred during flowering and dry conditions during ripening. The run of a logistic equation with the backward stepwise approach selected three parameters, (seeding week, ECB severity and longitude of sampling province to predict AFB1 contamination and four parameters (year, sowing week, ECB severity and longitude of sampling province to predict FB contamination. The internal validation gave good results, with 76% correct predictions. The probability of harvesting maize with more than 5 µg kg-1 of AFB1 varied between 86 and 5%, and the probability of harvesting maize with more than 4,000 µg kg-1 of FBs varied between 81 and 2%, respectively, for conducive and non-conducive environments. Therefore, considerable variability was found even if a limited area and only 3 years were considered.
Chen, Gujun; He, Shengping; Li, Yugang; Guo, Yintao; Wang, Qian
2016-08-01
In the present work, a mathematical model was developed to understand the multiphase flow behavior in a Rheinsahl-Heraeus (RH) reactor by using the Euler-Euler approach, and the effects of initial bubble diameter, nonequilibrium expansion of bubble caused by sudden thermal effect and sharp pressure drop, and various interphase forces were considered and clarified. The simulation results of mixing time, liquid circulation rate, and local liquid velocity in RH agree well with the measured results. The result indicates that the initial bubble diameter has a weak impact on the multiphase flow but that the bubble expansion has a tremendous impact on it for an actual RH. Meanwhile, the drag force and turbulent dispersion force strongly influence the multiphase flow, whereas the lift force and virtual mass force only have negligible influence on it. Furthermore, the turbulent dispersion force should be responsible for reasonable prediction of multiphase flow behavior in the RH reactor.
Ostrowski, Z.; Melka, B.; Adamczyk, W.; Rojczyk, M.; Golda, A.; Nowak, A. J.
2016-09-01
In the research a numerical Computational Fluid Dynamics (CFD) model of the pulsatile blood flow was created and analyzed. A real geometry of aorta and its thoracic branches of 8-year old patient diagnosed with a congenital heart defect - coarctation of aorta was used. The inlet boundary condition were implemented as the User Define Function according to measured values of volumetric blood flow. The blood flow was treated as multiphase: plasma, set as the primary fluid phase, was dominant with volume fraction of 0.585 and morphological elements of blood were treated in Euler-Euler approach as dispersed phases (with 90% Red Blood Cells and White Blood Cells as remaining solid volume fraction).
Some New Classes of Generalized Apostol-Euler and Apostol-Genocchi Polynomials
Directory of Open Access Journals (Sweden)
R. Tremblay
2012-01-01
Full Text Available The main object of this paper is to introduce and investigate two new classes of generalized Apostol-Euler and Apostol-Genocchi polynomials. In particular, we obtain a new addition formula for the new class of the generalized Apostol-Euler polynomials. We also give an extension and some analogues of the Srivastava-Pintér addition theorem obtained in the works by Srivastava and Pintér (2004 and R. Tremblay, S. Gaboury, B.-J. Fugère, and Tremblay et al. (2011. for both classes.
Some New Classes of Generalized Apostol-Euler and Apostol-Genocchi Polynomials
2012-01-01
The main object of this paper is to introduce and investigate two new classes of generalized Apostol-Euler and Apostol-Genocchi polynomials. In particular, we obtain a new addition formula for the new class of the generalized Apostol-Euler polynomials. We also give an extension and some analogues of the Srivastava-Pintér addition theorem obtained in the works by Srivastava and Pintér (2004) and R. Tremblay, S. Gaboury, B.-J. Fugère, and Tremblay et al. (2011). for both classes.
Institute of Scientific and Technical Information of China (English)
D.C. Wan; G.W. Wei
2000-01-01
An efficient discrete singular convolution (DSC) method is introduced to the numerical solutions of incompressible Euler and Navier-Stokes equations with periodic boundary conditions. Two numerical tests of two-dimensional NavierStokes equations with periodic boundary conditions and Euler equations for doubly periodic shear layer flows are carried out by using the DSC method for spatial derivatives and fourth-order Runge-Kutta method for time advancement, respectively. The computational results show that the DSC method is efficient and robust for solving the problems of incompressible flows, and has the potential of being extended to numerically solve much broader problems in fluid dynamics.
Asymptotic solution for high vorticity regions in incompressible 3D Euler equations
Agafontsev, D S; Mailybaev, A A
2016-01-01
Incompressible 3D Euler equations develop high vorticity in very thin pancake-like regions from generic large-scale initial conditions. In this work we propose an exact solution of the Euler equations for the asymptotic pancake evolution. This solution combines a shear flow aligned with an asymmetric straining flow, and is characterized by a single asymmetry parameter and an arbitrary transversal vorticity profile. The analysis is based on detailed comparison with numerical simulations performed using a pseudo-spectral method in anisotropic grids of up to 972 x 2048 x 4096.
High-order Finite Difference Solution of Euler Equations for Nonlinear Water Waves
DEFF Research Database (Denmark)
Christiansen, Torben Robert Bilgrav; Bingham, Harry B.; Engsig-Karup, Allan Peter
2012-01-01
The incompressible Euler equations are solved with a free surface, the position of which is captured by applying an Eulerian kinematic boundary condition. The solution strategy follows that of [1, 2], applying a coordinate-transformation to obtain a time-constant spatial computational domain which...... with a two-dimensional implementation of the model are compared with highly accurate stream function solutions to the nonlinear wave problem, which show the approximately expected convergence rates and a clear advantage of using high-order finite difference schemes in combination with the Euler equations....
Admissibility of weak solutions for the compressible Euler equations, n ≥ 2.
Slemrod, Marshall
2013-12-28
This paper compares three popular notions of admissibility for weak solutions of the compressible isentropic Euler equations of gas dynamics: (i) the viscosity criterion, (ii) the entropy inequality (the thermodynamically admissible isentropic solutions), and (iii) the viscosity-capillarity criterion. An exact summation of the Chapman-Enskog expansion for Grad's moment system suggests that it is the third criterion that is representing the kinetic theory of gases. This, in turn, may shed some light on the ability to recover weak solutions of the Euler equations via a hydrodynamic limit.
Pseudo-time method for optimal shape design using the Euler equations
Iollo, Angelo; Kuruvila, Geojoe; Ta'asan, Shlomo
1995-01-01
We exploit a novel idea for the optimization of flows governed by the Euler equations. The algorithm consists of marching on the design hypersurface while improving the distance to the state and costate hypersurfaces. We consider the problem of matching the pressure distribution to a desired one, subject to the euler equations, both for subsonic and supersonic flows. The rate of convergence to the minimum for the cases considered is 3 to 4 times slower than that of the analysis problem. Results are given for Ringleb flow and a shockless recompression case.
Eigenmode Analysis of Boundary Conditions for One-Dimensional Preconditioned Euler Equations
Darmofal, David L.
1998-01-01
An analysis of the effect of local preconditioning on boundary conditions for the subsonic, one-dimensional Euler equations is presented. Decay rates for the eigenmodes of the initial boundary value problem are determined for different boundary conditions. Riemann invariant boundary conditions based on the unpreconditioned Euler equations are shown to be reflective with preconditioning, and, at low Mach numbers, disturbances do not decay. Other boundary conditions are investigated which are non-reflective with preconditioning and numerical results are presented confirming the analysis.
Euler-like modelling of dense granular flows: application to a rotating drum
Bonamy, D.; Chavanis, P.-H.; Cortet, P.-P.; Daviaud, F.; Dubrulle, B.; Renouf, M.
2009-04-01
General conservation equations are derived for 2D dense granular flows from the Euler equation within the Boussinesq approximation. In steady flows, the 2D fields of granular temperature, vorticity and stream function are shown to be encoded in two scalar functions only. We checked such prediction on steady surface flows in a rotating drum simulated through the Non-Smooth Contact Dynamics method even though granular flows are dissipative and therefore not necessarily compatible with Euler equation. Finally, we briefly discuss some possible ways to predict theoretically these two functions using statistical mechanics.
The periodic b-equation and Euler equations on the circle
Escher, J
2010-01-01
In this note we show that the periodic b-equation can only be realized as an Euler equation on the Lie group Diff(S^1) of all smooth and orientiation preserving diffeomorphisms on the cirlce if b=2, i.e. for the Camassa-Holm equation. In this case the inertia operator generating the metric on Diff(S^1) is given by A=1-d^2/dx^2. In contrast, the Degasperis-Procesi equation, for which b=3, is not an Euler equation on Diff(S^1) for any inertia operator. Our result generalizes a recent result of B. Kolev.
Symmetries of the Euler compressible flow equations for general equation of state
Energy Technology Data Exchange (ETDEWEB)
Boyd, Zachary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ramsey, Scott D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Baty, Roy S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-10-15
The Euler compressible flow equations exhibit different Lie symmetries depending on the equation of state (EOS) of the medium in which the flow occurs. This means that, in general, different types of similarity solution will be available in different flow media. We present a comprehensive classification of all EOS’s to which the Euler equations apply, based on the Lie symmetries admitted by the corresponding flow equations, restricting to the case of 1-D planar, cylindrical, or spherical geometry. The results are conveniently summarized in tables. This analysis also clarifies past work by Axford and Ovsiannikov on symmetry classification.
A two-dimensional Euler solution for an unbladed jet engine configuration
Stewart, Mark E. M.
1992-01-01
A two dimensional, nonaxisymmetric Euler solution in a geometry representative of a jet engine configuration without blades is presented. The domain, including internal and external flow, is covered with a multiblock grid. In order to construct this grid, a domain decomposition technique is used to subdivide the domain, and smooth grids are dimensioned and placed in each block. The Euler solution is verified by examining five theoretical properties. The result demonstrates techniques for performing numerical solutions in complex geometries and provides a foundation for complete engine throughflow calculations.
Self-Duality Helicity and Higher-Loop Euler-Heisenberg Effective Actions
Dunne, Gerald V.; Schubert, Christian
2004-10-01
The Euler-Heisenberg effective action in a self-dual background is remarkably simple at two-loop. This simplicity is due to the inter-relationship between self-duality, helicity and supersymmetry. Applications include two-loop helicity amplitudes, beta-functions and nonperturbative effects. The two-loop Euler-Heisenberg effective Lagrangian for QED in a self-dual background field is naturally expressed in terms of one-loop quantities. This mirrors similar behavior recently found in two-loop amplitudes in N=4 SUSY Yang-Mills theory.
Euler-like method for the simultaneous inclusion of polynomial zeros with Weierstass' correction
2001-01-01
An improved iterative method of Euler's type for the simultaneous inclusion of polynomial zeros is considered. To accelerate the convergence of the basic method of fourth order, Carstensen-Petkovi c's approach [7]using Weierstrass' correction is applied. It is proved that the R-order of convergence of the improved Euler-like method is (asymptotically)2 + V7 = 4.646 or 5, depending of the type of applied inversion of a disk. The proposed algorithm possesses great computational e ciency since t...
Kushwaha, Jitendra Kumar
2013-01-01
Approximation theory is a very important field which has various applications in pure and applied mathematics. The present study deals with a new theorem on the approximation of functions of Lipschitz class by using Euler's mean of conjugate series of Fourier series. In this paper, the degree of approximation by using Euler's means of conjugate of functions belonging to Lip (ξ(t), p) class has been obtained. Lipα and Lip (α, p) classes are the particular cases of Lip (ξ(t), p) class. The main result of this paper generalizes some well-known results in this direction.
Site-specific crop management using geophysical proximal sensors
Key components of site-specific crop management are (i) identifying the site-specific factors that influence within-field crop yield variation and (ii) spatially characterizing those factors. Geo-referenced measurements of apparent soil electrical conductivity (ECa) provide a potential means of cha...
Bayad, A.; Kim, T.
2016-04-01
We introduce a special nonlinear differential operator and, using its properties, reduce higher-order Frobenius-Euler Apostol-type polynomials to a finite series of first-order Apostol-type Frobenius-Euler polynomials and Stirling numbers. Interesting identities are established.
Parameterization models for pesticide exposure via crop consumption.
Fantke, Peter; Wieland, Peter; Juraske, Ronnie; Shaddick, Gavin; Itoiz, Eva Sevigné; Friedrich, Rainer; Jolliet, Olivier
2012-12-04
An approach for estimating human exposure to pesticides via consumption of six important food crops is presented that can be used to extend multimedia models applied in health risk and life cycle impact assessment. We first assessed the variation of model output (pesticide residues per kg applied) as a function of model input variables (substance, crop, and environmental properties) including their possible correlations using matrix algebra. We identified five key parameters responsible for between 80% and 93% of the variation in pesticide residues, namely time between substance application and crop harvest, degradation half-lives in crops and on crop surfaces, overall residence times in soil, and substance molecular weight. Partition coefficients also play an important role for fruit trees and tomato (Kow), potato (Koc), and lettuce (Kaw, Kow). Focusing on these parameters, we develop crop-specific models by parametrizing a complex fate and exposure assessment framework. The parametric models thereby reflect the framework's physical and chemical mechanisms and predict pesticide residues in harvest using linear combinations of crop, crop surface, and soil compartments. Parametric model results correspond well with results from the complex framework for 1540 substance-crop combinations with total deviations between a factor 4 (potato) and a factor 66 (lettuce). Predicted residues also correspond well with experimental data previously used to evaluate the complex framework. Pesticide mass in harvest can finally be combined with reduction factors accounting for food processing to estimate human exposure from crop consumption. All parametric models can be easily implemented into existing assessment frameworks.
ENUMERATION OF LABELED EULER GRAPHS WITH CUT VERTICES%具有割点的标号Euler图的计数
Institute of Scientific and Technical Information of China (English)
金应烈; 金昌录
2000-01-01
This paper discusses the enumeration of labeled Euler graphs with k(k≥2) cut vertices distributed only on one 2-connected Euler graph. In this paper we give the exponential generating function for labeled Euler graphs having exactly n 2-connected Euler graphs and the k(k≥2) cut vertices distributed only on one 2-connected Euler graph.%本文讨论了具有k(k≥2)个割点,并且所有割点均分布在一个2-连通Euler图的标号Euler图的计数.在这里给出了含有n个2-连通Euler图和k(k≥2)个割点,并且所有割点均分布在其中一个2-连通Euler图的标号Euler图的指数型生成函数.
Numerical simulation of cropping
DEFF Research Database (Denmark)
Tvergaard, Viggo; Hutchinson, John W.
2014-01-01
Cropping is a cutting process whereby opposing aligned blades create a shearing failure by exerting opposing forces normal to the surfaces of a metal sheet or plate. Building on recent efforts to quantify cropping, this paper formulates a plane strain elastic-plastic model of a plate subject...... to shearing action by opposing rigid platens. Shear failure at the local level is modeled by a cohesive zone characterized by the peak shear traction and the energy dissipated by shear failure process at the microscopic level. The model reveals the interplay between shear cracking and the extensive plastic...... shearing accompanying the cutting process. Specifically, it provides insight into the influence of the material's microscopic shear strength and toughness on the total work of cropping. The computational model does not account for deformation of the cropping tool, friction between sliding surfaces...
Federal Laboratory Consortium — The mission of the Cereal Crops Research Unit is to 1) conduct basic research to identify and understand the biological processes affecting the growth, development...
Federal Laboratory Consortium — The mission of the Cereal Crops Research Unit is to 1) conduct basic research to identify and understand the biological processes affecting the growth, development...
Institute of Scientific and Technical Information of China (English)
徐雪风; 回振龙; 李自龙; 张俊莲; 李朝周
2015-01-01
This study aims to investigate the effect of potato continuous cropping on soil properties ,thus clarifying factors contributing to continuous cropping obstacles ,using pot culture experiments .We analyzed soil properties includ-ing microbiological compositions ,fertility ,physicochemical properties and contents of phenolic acid and allelochemicals of potato continuous cropping soil ,and performance of potato seedlings .The results indicated that soil salinity ,alkaline hydrolysis nitrogen content and soil bulk density increased ,as the continuous cropping prolonged .Activities of urease , catalase ,alkaline phosphatase and invertase decreased markedly when continuous cropping lasted for 5 and 7 years ,while the quantity of soil’s bacteria and actinomycetes decreased .The content of chlorophyll ,activities of antioxidase ,root ac-tivity and net photosynthetic rate decreased significantly when the continuous cropping lasted for 5 and 7 years .As a whole ,continuous cropping obstacle was not obvious when continuous cropping lasted for 3 years .But potato continuously cropping lasted for 5 and 7 years ,a series of biotic and abiotic stresses were triggered due to increasing of compositions of soil fungi ,and the activity of key enzyme ,the changes of physicochemical properties ,and phenolic acid and allelochemi-cals contents ,resulting in continuous cropping obstacle .%取不同连作年限（连作0、3、5、7年）的土壤测定其生物和非生物环境因子，并采用盆栽的方法获取不同连作年限的马铃薯幼苗，测定其生长发育指标及抗性生理指标，以探究马铃薯不同连作年限土壤生物和非生物环境因子的变化。结果表明：随着连作年限的增加，土壤含盐量、碱解氮含量和土壤容重逐年上升，在连作7年时分别比对照高348．31％、228．57％和5．39％；在连作5年和7年时，速效磷、速效钾和有机质含量显著下降，连作7年时比对照下降27．43
Cover crop biomass harvest for bioenergy: implications for crop productivity
Winter cover crops, such as rye (Secale cereale), are usually used in conservation agriculture systems in the Southeast. Typically, the cover crop is terminated two to three weeks before planting the summer crop, with the cover biomass left on the soil surface as a mulch. However, these cover crops ...
Shahab, S.; Erturk, A.
2016-10-01
Bio-inspired hydrodynamic thrust generation using smart materials has received growing attention over the past few years to enable improved maneuverability and agility, small form factor, reduced power consumption, and ease of fabrication in next-generation aquatic swimmers. In order to develop a high-fidelity model to predict the electrohydroelastic dynamics of macro-fiber composite (MFC) piezoelectric structures, in this work, mixing rules-based (i.e. rule of mixtures) electroelastic mechanics formulation is coupled with the global electroelastic dynamics based on the Euler-Bernoulli kinematics and nonlinear fluid loading based on Morison’s semi-empirical model. The focus is placed on the dynamic actuation problem for the first two bending vibration modes under geometrically and materially linear, hydrodynamically nonlinear behavior. The electroelastic and dielectric properties of a representative volume element (piezoelectric fiber and epoxy matrix) between two subsequent interdigitated electrodes are correlated to homogenized parameters of MFC bimorphs and validated for a set of MFCs that have the same overhang length but different widths. Following this process of electroelastic model development and validation, underwater actuation experiments are conducted for different length-to-width aspect ratios (L/b) in quiescent water, and the empirical drag and inertia coefficients are extracted from Morison’s equation to establish the electrohydroelastic model. The repeatability of these empirical coefficients is demonstrated for experiments conducted using aluminum cantilevers of different aspect ratios with a focus on the first two bending modes. The convergence of the nonlinear electrohydroelastic Euler-Bernoulli-Morison model to its hydrodynamically linear counterpart for increased L/b values is also reported. The proposed model, its harmonic balance analysis, and experimental results can be used not only for underwater piezoelectric actuation, but also for
Energy Technology Data Exchange (ETDEWEB)
Drury, J.S.; Baldauf, M.F.; Daniel, E.W.; Fore, C.S.; Uziel, M.S.
1983-05-01
Published levels of radioactivity in food crops from 21 countries and 4 island chains of Oceania are listed. The tabulation includes more than 3000 examples of 100 different crops. Data are arranged alphabetically by food crop and geographical origin. The sampling date, nuclide measured, mean radioactivity, range of radioactivities, sample basis, number of samples analyzed, and bibliographic citation are given for each entry, when available. Analyses were reported most frequently for /sup 137/Cs, /sup 40/K, /sup 90/Sr, /sup 226/Ra, /sup 228/Ra, plutonium, uranium, total alpha, and total beta, but a few authors also reported data for /sup 241/Am, /sup 7/Be, /sup 60/Co, /sup 55/Fe, /sup 3/H, /sup 131/I, /sup 54/Mn, /sup 95/Nb, /sup 210/Pb, /sup 210/Po, /sup 106/Ru, /sup 125/Sb, /sup 228/Th, /sup 232/Th, and /sup 95/Zr. Based on the reported data it appears that radioactivity from alpha emitters in food crops is usually low, on the order of 0.1 Bq.g/sup -1/ (wet weight) or less. Reported values of beta radiation in a given crop generally appear to be several orders of magnitude greater than those of alpha emitters. The most striking aspect of the data is the great range of radioactivity reported for a given nuclide in similar food crops with different geographical origins.
Frobenious-Euler Type Polynomials Related to Hermite-Bernoulli Polynomials
Kurt, Burak; Simsek, Yilmaz
2011-09-01
The aim of this paper is to define and investigate a new generating functions of the Frobenious-Euler polynomials and numbers. We establish some fundamental properties of these numbers and polynomials. We also derive relationship between these polynomials and Hermite-Apostol-Bernoulli polynomials and numbers. We also give some remarks and applications.
Unification of Generating Function of the Bernoulli, Euler and Genocchi Numbers and Polynomials
Özden, Hacer
2010-09-01
The aim of this paper is to unify generating functions of the some special numbers and polynomials. By using these generating functions, we modify Apostol-Bernoulli and Apostol-Euler polynomials. We also give some new relations on these numbers and polynomials.
Improving the Precision and Speed of Euler Angles Computation from Low-Cost Rotation Sensor Data
Directory of Open Access Journals (Sweden)
Aleš Janota
2015-03-01
Full Text Available This article compares three different algorithms used to compute Euler angles from data obtained by the angular rate sensor (e.g., MEMS gyroscope—the algorithms based on a rotational matrix, on transforming angular velocity to time derivations of the Euler angles and on unit quaternion expressing rotation. Algorithms are compared by their computational efficiency and accuracy of Euler angles estimation. If attitude of the object is computed only from data obtained by the gyroscope, the quaternion-based algorithm seems to be most suitable (having similar accuracy as the matrix-based algorithm, but taking approx. 30% less clock cycles on the 8-bit microcomputer. Integration of the Euler angles’ time derivations has a singularity, therefore is not accurate at full range of object’s attitude. Since the error in every real gyroscope system tends to increase with time due to its offset and thermal drift, we also propose some measures based on compensation by additional sensors (a magnetic compass and accelerometer. Vector data of mentioned secondary sensors has to be transformed into the inertial frame of reference. While transformation of the vector by the matrix is slightly faster than doing the same by quaternion, the compensated sensor system utilizing a matrix-based algorithm can be approximately 10% faster than the system utilizing quaternions (depending on implementation and hardware.
A Note on Residue Formulas for the Euler Class of Sphere Fibrations
Institute of Scientific and Technical Information of China (English)
Francisco Gómez RUIZ
2011-01-01
This paper presents a definition of residue formulas for the Euler class of cohomology-oriented sphere fibrations §. If the base of § is a topological manifold, a Hopf index theorem can be obtained and, for the smooth category, a generalization of a residue formula is derived for real vector bundles given in [2].
Debnath, Lokenath
2010-01-01
This article is essentially devoted to a brief historical introduction to Euler's formula for polyhedra, topology, theory of graphs and networks with many examples from the real-world. Celebrated Konigsberg seven-bridge problem and some of the basic properties of graphs and networks for some understanding of the macroscopic behaviour of real…
Simulation of free surfaces in 3-D with the arbitrary Lagrange-Euler method
DEFF Research Database (Denmark)
Szabo, Peter; Hassager, Ole
1995-01-01
The arbitrary Lagrange-Euler (ALE) kinematic description has been implemented in a 3-D transient finite element program so as to simulate multiple fluid flows with Surfaces and interfaces of general shapes. The description of fluid interfaces includes continuity of velocity and a discontinuous...
EVALUATING THE EULER-POINCARÉ CHARACTERISTIC OF A SET USING A SPATIAL TESSELLATION
Directory of Open Access Journals (Sweden)
Jean-Paul Jernot
2011-05-01
Full Text Available A new formula is established to evaluate the Euler-Poincaré characteristic of a polyconvex subset X in Rd starting only from measurements of X in the cells of a tessellation. Simplifications occur when X is a union of cells of the tessellation, leading to another formula that unifies and extends several classical digitization results.
Field theory and weak Euler-Lagrange equation for classical particle-field systems.
Qin, Hong; Burby, Joshua W; Davidson, Ronald C
2014-10-01
It is commonly believed as a fundamental principle that energy-momentum conservation of a physical system is the result of space-time symmetry. However, for classical particle-field systems, e.g., charged particles interacting through self-consistent electromagnetic or electrostatic fields, such a connection has only been cautiously suggested. It has not been formally established. The difficulty is due to the fact that the dynamics of particles and the electromagnetic fields reside on different manifolds. We show how to overcome this difficulty and establish the connection by generalizing the Euler-Lagrange equation, the central component of a field theory, to a so-called weak form. The weak Euler-Lagrange equation induces a new type of flux, called the weak Euler-Lagrange current, which enters conservation laws. Using field theory together with the weak Euler-Lagrange equation developed here, energy-momentum conservation laws that are difficult to find otherwise can be systematically derived from the underlying space-time symmetry.
Entropy Analysis of Kinetic Flux Vector Splitting Schemes for the Compressible Euler Equations
Shiuhong, Lui; Xu, Jun
1999-01-01
Flux Vector Splitting (FVS) scheme is one group of approximate Riemann solvers for the compressible Euler equations. In this paper, the discretized entropy condition of the Kinetic Flux Vector Splitting (KFVS) scheme based on the gas-kinetic theory is proved. The proof of the entropy condition involves the entropy definition difference between the distinguishable and indistinguishable particles.
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
In this paper we investigate the two-dimensional compressible isentropic Euler equations for Chaplygin gases. Under the assumption that the initial data is close to a constant state and the vorticity of the initial velocity vanishes, we prove the global existence of the smooth solution to the Cauchy problem for twodimensional flow of Chaplygin gases.
The First-Order Euler-Lagrange equations and some of their uses
Adam, C
2016-01-01
In many nonlinear field theories, relevant solutions may be found by reducing the order of the original Euler-Lagrange equations, e.g., to first order equations (Bogomolnyi equations, self-duality equations, etc.). Here we generalise, further develop and apply one particular method for the order reduction of nonlinear field equations which, despite its systematic and versatile character, is not widely known.
Karbstein, Felix
2016-01-01
The focus of these lectures is on the quantum vacuum subjected to classical electromagnetic fields. To this end we explicitly derive the renowned Heisenberg-Euler effective action in constant electromagnetic fields in a rather pedagogical and easy to conceive way. As an application, we use it to study vacuum birefringence constituting one of the most promising optical signatures of quantum vacuum nonlinearity.
Risk of Rare Disasters, Euler Equation Errors and the Performance of the C-CAPM
DEFF Research Database (Denmark)
Posch, Olaf; Schrimpf, Andreas
This paper shows that the consumption-based asset pricing model (C-CAPM) with low-probability disaster risk rationalizes large pricing errors, i.e. Euler equation errors. This result is remarkable, since Lettau and Ludvigson (2009) show that leading asset pricing models cannot explain sizeable...
Ravat, Dhananjay
1996-01-01
The applicability of the Euler method of source location determination was investigated on several model situations pertinent to satellite-data scale situations as well as Magsat data of Europe. Our investigations enabled us to understand the end-member cases for which the Euler method will work with the present satellite magnetic data and also the cases for which the assumptions implicit in the Euler method will not be met by the present satellite magnetic data. These results have been presented in one invited lecture at the Indo-US workshop on Geomagnetism in Studies of the Earth's Interior in August 1994 in Pune, India, and at one presentation at the 21st General Assembly of the IUGG in July 1995 in Boulder, CO. A new method, called Anomaly Attenuation Rate (AAR) Method (based on the Euler method), was developed during this study. This method is scale-independent and is appropriate to locate centroids of semi-compact three dimensional sources of gravity and magnetic anomalies. The method was presented during 1996 Spring AGU meeting and a manuscript describing this method is being prepared for its submission to a high-ranking journal. The grant has resulted in 3 papers and presentations at national and international meetings and one manuscript of a paper (to be submitted shortly to a reputable journal).
Total coloring of graphs embedded in surfaces of nonnegative Euler characteristic
Institute of Scientific and Technical Information of China (English)
WANG HuiJuan; LIU Bin; WU JianLiang; WANG Bing
2014-01-01
Let G be a graph which can be embedded in a surface of nonnegative Euler characteristic.In this paper,it is proved that the total chromatic number of G is △（G）＋1 if △（G）9,where △（G）is the maximum degree of G.
Improving the precision and speed of Euler angles computation from low-cost rotation sensor data.
Janota, Aleš; Šimák, Vojtech; Nemec, Dušan; Hrbček, Jozef
2015-03-23
This article compares three different algorithms used to compute Euler angles from data obtained by the angular rate sensor (e.g., MEMS gyroscope)-the algorithms based on a rotational matrix, on transforming angular velocity to time derivations of the Euler angles and on unit quaternion expressing rotation. Algorithms are compared by their computational efficiency and accuracy of Euler angles estimation. If attitude of the object is computed only from data obtained by the gyroscope, the quaternion-based algorithm seems to be most suitable (having similar accuracy as the matrix-based algorithm, but taking approx. 30% less clock cycles on the 8-bit microcomputer). Integration of the Euler angles' time derivations has a singularity, therefore is not accurate at full range of object's attitude. Since the error in every real gyroscope system tends to increase with time due to its offset and thermal drift, we also propose some measures based on compensation by additional sensors (a magnetic compass and accelerometer). Vector data of mentioned secondary sensors has to be transformed into the inertial frame of reference. While transformation of the vector by the matrix is slightly faster than doing the same by quaternion, the compensated sensor system utilizing a matrix-based algorithm can be approximately 10% faster than the system utilizing quaternions (depending on implementation and hardware).
KINETIC FLUX VECTOR SPLITTING FOR THE EULER EQUATIONS WITH GENERAL PRESSURE LAWS
Institute of Scientific and Technical Information of China (English)
Hua-zhong Tang
2004-01-01
This paper attempts to develop kinetic flux vector splitting (KFVS) for the Euler equations with general pressure laws. It is well known that the gas distribution function for the local equilibrium state plays an important role in the construction of the gas-kinetic schemes. To recover the Euler equations with a general equation of state (EOS), a new local equilibrium distribution is introduced with two parameters of temperature approximation decided uniquely by macroscopic variables. Utilizing the well-known connection that the Euler equations of motion are the moments of the Boltzmann equation whenever the velocity distribution function is a local equilibrium state, a class of high resolution MUSCL-type KFVS schemes are presented to approximate the Euler equations of gas dynamics with a general EOS. The schemes are finally applied to several test problems for a general EOS. In comparison with the exact solutions, our schemes give correct location and more accurate resolution of discontinuities. The extension of our idea to multidimensional case is natural.
Ran, Changyan; Cheng, Xianghong
2016-09-02
This paper presents a direct and non-singular approach based on an unscented Kalman filter (UKF) for the integration of strapdown inertial navigation systems (SINSs) with the aid of velocity. The state vector includes velocity and Euler angles, and the system model contains Euler angle kinematics equations. The measured velocity in the body frame is used as the filter measurement. The quaternion nonlinear equality constraint is eliminated, and the cross-noise problem is overcome. The filter model is simple and easy to apply without linearization. Data fusion is performed by an UKF, which directly estimates and outputs the navigation information. There is no need to process navigation computation and error correction separately because the navigation computation is completed synchronously during the filter time updating. In addition, the singularities are avoided with the help of the dual-Euler method. The performance of the proposed approach is verified by road test data from a land vehicle equipped with an odometer aided SINS, and a singularity turntable test is conducted using three-axis turntable test data. The results show that the proposed approach can achieve higher navigation accuracy than the commonly-used indirect approach, and the singularities can be efficiently removed as the result of dual-Euler method.
Gaia17aub and Gaia17awk transients confirmed by Euler imaging
Blanco-Cuaresma, S.; Barblan, F.; Saesen, S.; Roelens, M.; Semaan, T.; Palaversa, L.; Mowlavi, N.; Eyer, L.
2017-04-01
We report confirmation of Gaia Science Alerts transients Gaia17aub and Gaia17awk. Images were obtained through modified Gunn R band filter of the ECAM instrument installed on the Swiss 1.2m Euler telescope at La Silla, on 2017 March 30th - 3rd April.
Supernovae candidates Gaia17aty, Gaia17atz and Gaia17aud confirmed by Euler imaging
Blanco-Cuaresma, S.; Saesen, S.; Roelens, M.; Semaan, T.; Palaversa, L.; Mowlavi, N.; Eyer, L.
2017-04-01
We report confirmation of Gaia Science Alerts supernovae candidates Gaia17aty, Gaia17atz and Gaia17aud. Images were obtained through modified Gunn R band filter of the ECAM instrument installed on the Swiss 1.2m Euler telescope at La Silla, on 2017 March 29th - 30th.
Ran, Changyan; Cheng, Xianghong
2016-01-01
This paper presents a direct and non-singular approach based on an unscented Kalman filter (UKF) for the integration of strapdown inertial navigation systems (SINSs) with the aid of velocity. The state vector includes velocity and Euler angles, and the system model contains Euler angle kinematics equations. The measured velocity in the body frame is used as the filter measurement. The quaternion nonlinear equality constraint is eliminated, and the cross-noise problem is overcome. The filter model is simple and easy to apply without linearization. Data fusion is performed by an UKF, which directly estimates and outputs the navigation information. There is no need to process navigation computation and error correction separately because the navigation computation is completed synchronously during the filter time updating. In addition, the singularities are avoided with the help of the dual-Euler method. The performance of the proposed approach is verified by road test data from a land vehicle equipped with an odometer aided SINS, and a singularity turntable test is conducted using three-axis turntable test data. The results show that the proposed approach can achieve higher navigation accuracy than the commonly-used indirect approach, and the singularities can be efficiently removed as the result of dual-Euler method. PMID:27598169
Euler-Poincaré Reduction of Externally Forced Rigid Body Motion
DEFF Research Database (Denmark)
Wisniewski, Rafal; Kulczycki, P.
2004-01-01
. Assuming that the system possesses symmetry and the configuration manifold corresponds to a Lie group, the Euler-Poincaré reduction breaks up the motion into separate equations of dynamics and kinematics. This becomes of particular interest for modelling, estimation and control of mechanical systems...
Euler-Lagrange Equations for the Gribov Reggeon Calculus in QCD and in Gravity
Lipatov, L. N.
The theory of the high energy scattering in QCD and gravity is based on the reggeization of gluons and gravitons, respectively. We discuss the corresponding effective actions for reggeized particle interactions. The Euler-Lagrange equations in these theories are constructed with a variational approach for the effective actions and by using their invariance under the gauge and general coordinate transformations.
Scherpen, Jacquelien M.A.; Ortega, Romeo; Escobar, Gerardo
1997-01-01
In this paper we analyse and experimentally verify the (local) disturbance attenuation properties of some asymptotically stabilizing nonlinear controllers for Euler-Lagrange systems reported in the literature. Our objective with this study is twofold: first, to compare the performance of these schem
Asymptotic Behavior of Global Solution for Nonlinear Generalized Euler-Possion-Darboux Equation
Institute of Scientific and Technical Information of China (English)
LIANGBao-song; CHENZhen
2004-01-01
J. L Lions and W. A. Stranss [1] have proved the existence of a global solution of the initial boundary value problem for nonlinear generalized Euler-Possion-Darboux equation. In this paper we are going to investigate the asymptotic behavior of the global solution by a difference inequality.
Directory of Open Access Journals (Sweden)
Ondřej Došlý
2012-01-01
Full Text Available We investigate transformations of the modified Riccati differential equation and the obtained results we apply in the investigation of oscillatory properties of perturbed half-linear Euler differential equation. A perturbation is also allowed in the differential term.
Pesch, L.; van der Vegt, Jacobus J.W.
2008-01-01
Using the generalized variable formulation of the Euler equations of fluid dynamics, we develop a numerical method that is capable of simulating the flow of fluids with widely differing thermodynamic behavior: ideal and real gases can be treated with the same method as an incompressible fluid. The
A dynamic multiblock approach to solving the unsteady Euler equations about complex configurations
Arabshahi, Abdollah
The objective is the development of a numerical method which can accurately and economically solve the unsteady Euler equations for three-dimensional flow fields around complex configurations, particularly a generic aircraft with a store in the captive and vertical launch position. A cell centered finite volume spatial discretization is applied to the three-dimensional, time-dependent, Euler equations written in general time-dependent curvilinear coordinates. Two algorithms are presented for solving the system of Euler equations. The first algorithm is based on flux-vector splitting while the second algorithm is based on flux-difference splitting using Roe averaged variables. For both algorithms, an implicit upwind biased approach is employed to integrate the spatially discretized equations in time. The multiblock technique utilizes the concept of decomposing the flow field between the surfaces of the configuration and some outer far field boundary into a set of blocks. Calculated results compared with experimental data indicate that the present Euler solver can calculate transonic flow fields efficiently and accurately over complex geometries. Furthermore, the results demonstrate how computational fluid dynamics (CFD) can be used to accurately simulate steady and, for the first time, unsteady fluid flow over a complete wing-pylon-store configuration with the store in the captive and vertical launch positions.
Directory of Open Access Journals (Sweden)
Fengyan Yang
2016-09-01
Full Text Available This article studies the exact controllability of an Euler-Bernoulli plate equation with variable coefficients, subject to the simply supported boundary condition. By the Riemannian geometry approach, the duality method, the multiplier technique, and the compactness-uniqueness argument, we establish the corresponding observability inequality and obtain the exact controllability results.
A meshless front tracking method for the Euler equations of fluid dynamics
Witteveen, J.A.S.
2009-01-01
A second order front tracking method is developed for solving the Euler equations of inviscid fluid dynamics numerically. Front tracking methods are usually limited to first order accuracy, since they are based on a piecewise constant approximation of the solution. Here the second order convergence
NEW OSCILLATION CRITERIA RELATED TO EULER S INTEGRAL FOR CERTAIN NONLINEAR DIFFERENTIAL EQUATION
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
Using the integral average technique and a new function,some new oscillation criteria related to Euler integral are obtained for second order nonlinear differential equations with damping and forcing. Our results are of a higher degree of generality than some previous results. Information about the distribution of the zeros of solutions to the system is also obtained.
Pesch, L.; Vegt, van der J.J.W.
2008-01-01
Using the generalized variable formulation of the Euler equations of fluid dynamics, we develop a numerical method that is capable of simulating the flow of fluids with widely differing thermodynamic behavior: ideal and real gases can be treated with the same method as an incompressible fluid. The w
Formation control of multiple Euler-Lagrange systems via null-space-based behavioral control
Chen, Jie; Huang, Jie; Dou, Lihua; Fang, Hao
2016-01-01
This paper addresses the formation control problem of multiple Euler-Lagrange systems with model uncertainties in the environment containing obstacles. Utilizing the null-space-based (NSB) behavioral control architecture, the proposed problem can be decomposed into elementary missions (behaviors) wi
The first-order Euler-Lagrange equations and some of their uses
Energy Technology Data Exchange (ETDEWEB)
Adam, C.; Santamaria, F. [Departamento de Física de Partículas and Instituto Galego de Física de Altas Enerxias (IGFAE),Campus Vida, E-15782 Santiago de Compostela (Spain)
2016-12-13
In many nonlinear field theories, relevant solutions may be found by reducing the order of the original Euler-Lagrange equations, e.g., to first order equations (Bogomolnyi equations, self-duality equations, etc.). Here we generalise, further develop and apply one particular method for the order reduction of nonlinear field equations which, despite its systematic and versatile character, is not widely known.
A note on Rubin’s methods of the use of two Euler systems
Institute of Scientific and Technical Information of China (English)
印林生
2000-01-01
Here we show that Rubin’ s method of the use of two Euler systems to the proofs of lwa-sawa main conjectures of the rational number field and of an imaginary quadratic field is only proper to these two kinds of number fields. We mainly use the properties of adele ring and idele group in class field theory to get the result.
ASYMPTOTIC BEHAVIOR OF GLOBAL SMOOTH SOLUTIONS TO THE EULER-POISSON SYSTEM IN SEMICONDUCTORS
Institute of Scientific and Technical Information of China (English)
琚强昌
2002-01-01
In this paper, we establish the global existence and the asymptotic behavior of smooth solution to the initial-boundary value problem of Euler-Poisson system which is used as the bipolar hydrodynamic model for semiconductors with the nonnegative constant doping profile.
Biotechnology: herbicide-resistant crops
Transgenic, herbicide-resistant (HR) crops are planted on about 80% of the land covered by transgenic crops. More than 90% of HR crios are glyphosate-resistant (GR) crops, the others being resistant to glufosinate. The wide-scale adoption of HR crops, largely for economic reasons, has been the mos...
Cover crops often provide many short- and long-term benefits to cropping systems. Legume cover crops can significantly reduce the N fertilizer requirement of non-legume cash crops that follow. The objectives of this presentation were to: I) educate stakeholders about the potential benefits of cover ...
Rice crop risk map in Babahoyo canton (Ecuador)
Valverde Arias, Omar; Tarquis, Ana; Garrido, Alberto
2016-04-01
It is widely known that extreme climatic phenomena occur with more intensity and frequency. This fact has put more pressure over farming, making agricultural and livestock production riskier. In order to reduce hazards and economic loses that could jeopardize farmer's incomes and even its business continuity, it is very important to implement agriculture risk management plans by governments and institutions. One of the main strategies is transfer risk by agriculture insurance. Agriculture insurance based in indexes has a significant growth in the last decade. And consist in a comparison between measured index values with a defined threshold that triggers damage losses. However, based index insurance could not be based on an isolated measurement. It is necessary to be integrated in a complete monitoring system that uses many sources of information and tools. For example, index influence areas, crop production risk maps, crop yields, claim statistics, and so on. Crop production risk is related with yield variation of crops and livestock, due to weather, pests, diseases, and other factors that affect both the quantity and quality of commodities produced. This is the risk which farmers invest more time managing, and it is completely under their control. The aim of this study is generate a crop risk map of rice that can provide risk manager important information about the status of crop facing production risks. Then, based on this information, it will be possible to make best decisions to deal with production risk. The rice crop risk map was generated qualifying a 1:25000 scale soil and climatic map of Babahoyo canton, which is located in coast region of Ecuador, where rice is one of the main crops. The methodology to obtain crop risk map starts by establishing rice crop requirements and indentifying the risks associated with this crop. A second step is to evaluate soil and climatic conditions of the study area related to optimal crop requirements. Based on it, we can
Noah-MP-Crop: Introducing dynamic crop growth in the Noah-MP land surface model
Liu, Xing; Chen, Fei; Barlage, Michael; Zhou, Guangsheng; Niyogi, Dev
2016-12-01
Croplands are important in land-atmosphere interactions and in the modification of local and regional weather and climate; however, they are poorly represented in the current version of the coupled Weather Research and Forecasting/Noah with multiparameterization (Noah-MP) land surface modeling system. This study introduced dynamic corn (Zea mays) and soybean (Glycine max) growth simulations and field management (e.g., planting date) into Noah-MP and evaluated the enhanced model (Noah-MP-Crop) at field scales using crop biomass data sets, surface heat fluxes, and soil moisture observations. Compared to the generic dynamic vegetation and prescribed-leaf area index (LAI)-driven methods in Noah-MP, the Noah-MP-Crop showed improved performance in simulating leaf area index (LAI) and crop biomass. This model is able to capture the seasonal and annual variability of LAI and to differentiate corn and soybean in peak values of LAI as well as the length of growing seasons. Improved simulations of crop phenology in Noah-MP-Crop led to better surface heat flux simulations, especially in the early period of growing season where current Noah-MP significantly overestimated LAI. The addition of crop yields as model outputs expand the application of Noah-MP-Crop to regional agriculture studies. There are limitations in the use of current growing degree days (GDD) criteria to predict growth stages, and it is necessary to develop a new method that combines GDD with other environmental factors, to more accurately define crop growth stages. The capability introduced in Noah-MP allows further crop-related studies and development.
Directory of Open Access Journals (Sweden)
Zhevandrov Petr
2011-05-01
Full Text Available
En el presente trabajo se estudia el problema de frecuencias propias de la viga Euler-Bernoulli de sección no uniforme; se comparan las soluciones del problema obtenidas numéricamente con la solución asintótica lograda mediante el método Wentzel-Kramers-Brillouin (WKB. Se establece que la precisión de las fórmulas WKB es mayor del 3% para frecuencias altas (número de modo ≥ 4.
This paper has studied the problem of natural frequencies for Euler-Bernoulli beams having non-uniform cross-section. The numerically-obtained solutions were compared to asymptotic solutions obtained by the Wentzel-Kramers-Brillouin (WKB method. It was established that WKB formula precision was higher than 3% for high frequencies (Factors affecting farmers’ coping and adaptation strategies to perceived trends of declining rainfall and crop productivity in the central Rift valley of Ethiopia
National Research Council Canada - National Science Library
Adimassu, Zenebe; Kessler, Aad
2016-01-01
.... A better understanding of the factors affecting farmers’ coping and adaptation strategies to counteract both trends is crucial for policies and programs that aim at promoting successful rainfed agriculture in Ethiopia...
Wren, Tishya A L; Mitiguy, Paul C
2007-08-01
Clinical gait analysis usually describes joint kinematics using Euler angles, which depend on the sequence of rotation. Studies have shown that pelvic obliquity angles from the traditional tilt-obliquity-rotation (TOR) Euler angle sequence can deviate considerably from clinical expectations and have suggested that a rotation-obliquity-tilt (ROT) Euler angle sequence be used instead. We propose a simple alternate approach in which clinical joint angles are defined and exactly calculated in terms of Euler angles from any rotation sequence. Equations were derived to calculate clinical pelvic elevation, progression, and lean angles from TOR and ROT Euler angles. For the ROT Euler angles, obliquity was exactly the same as the clinical elevation angle, rotation was similar to the clinical progression angle, and tilt was similar to the clinical lean angle. Greater differences were observed for TOR. These results support previous findings that ROT is preferable to TOR for calculating pelvic Euler angles for clinical interpretation. However, we suggest that exact clinical angles can and should be obtained through a few extra calculations as demonstrated in this technical note.
Zhang, Tianran; Wooster, Martin J.; Green, David C.; Main, Bruce
2015-11-01
Despite policy attempts to limit or prevent agricultural burning, its use to remove crop residues either immediately after harvest (e.g. field burning of wheat stubble) or after subsequent crop processing (e.g. "bonfires" of rice straw and rapeseed residues) appears to remain widespread across parts of China. Emission factors for these types of small but highly numerous fire are therefore required to fully assess their impact on atmospheric composition and air pollution. Here we describe the design and deployment of a new smoke measurement system for the close-range sampling of key gases and particles within smoke from crop residue fires, using it to assess instantaneous mixing ratios of CO and CO2 and mass concentrations of black carbon (BC) and PM2.5 from wheat stubble, rice straw, and rapeseed residue fires. Using data of our new smoke sampling system, we find a strong linear correlation between the PM2.5 mass and BC, with very high PM2.5 to BC emission ratios found in the smouldering phase (up to 80.7 mg m-3.(mg m-3)-1) compared to the flaming phase (2.0 mg m-3.(mg m-3)-1). We conclude that the contribution of BC to PM2.5 mass was as high as 50% in the flaming phase of some burns, whilst during smouldering it sometimes decreased to little over one percent. A linear mixing model is used to quantify the relative contribution of each combustion phase to the overall measured smoke composition, and we find that flaming combustion dominated the total emission of most species assessed. Using time series of trace gas concentrations from different fire cases, we calculated 'fire integrated' trace gas emission factors (EFs) for wheat, rice and rapeseed residue burns as 1739 ± 19 g kg-1, 1761 ± 30 g kg-1and 1704 ± 27 g kg-1 respectively for CO2, and 60 ± 12 g kg-1, 47 ± 19 g kg-1 and 82 ± 17 g kg-1 respectively for CO. Where comparisons were possible, our EFs agreed well with those derived via a simultaneously-deployed open path Fourier transform infrared (OP
Vanishing viscosity as a selection principle for the Euler equations: The case of 3D shear flow
Bardos, Claude; Wiedemann, Emil
2012-01-01
We show that for a certain family of initial data, there exist non-unique weak solutions to the 3D incompressible Euler equations satisfying the weak energy inequality, whereas the weak limit of every sequence of Leray-Hopf weak solutions for the Navier-Stokes equations, with the same initial data, and as the viscosity tends to zero, is uniquely determined and equals the shear flow solution of the Euler equations. This simple example suggests that, also in more general situations, the vanishing viscosity limit of the Navier-Stokes equations could serve as a uniqueness criterion for weak solutions of the Euler equations.
A Note on the Bernoulli and Euler Polynomials%关于Bernoulli和Euler多项式的一个注记
Institute of Scientific and Technical Information of China (English)
巫朝霞; 何圆
2012-01-01
研究了Bernoulli多项式和Euler多项式的循环关系.运用Bernoulli多项式、Euler多项式和第二类Stirling数的基本性质及初等方法,给出了Bernoulli多项式和Euler多项式的两个封闭公式.%Some recurrence relationships between Bernoulli polynomials and Euler polynomials are studied. By using some basic properties for the Bernoulli polynomials,the Euler polynomials and the second kind of Stirling numbers and elementary techniques,two closed formulae involving the Bernoulli and Euler polynomials are obtained.
DEFF Research Database (Denmark)
Simonsen, Maria; Schiøler, Henrik; Leth, John-Josef
2014-01-01
The Euler-Maruyama method is applied to a simple stochastic differential equation (SDE) with discontinuous drift. Convergence aspects are investigated in the case, where the Euler-Maruyama method is simulated in dyadic points. A strong rate of convergence is presented for the numerical simulations...... and it is shown that the produced sequences converge almost surely. This is an improvement of the general result for SDEs with discontinuous drift, i.e. that the Euler-Maruyama approximations converge in probability to a strong solution of the SDE. A numerical example is presented together with a confidence...
Euler integral symmetries for a deformed Heun equation and symmetries of the Painlevé PVI equation
Kazakov, A. Ya.; Slavyanov, S. Yu.
2008-05-01
Euler integral transformations relate solutions of ordinary linear differential equations and generate integral representations of the solutions in a number of cases or relations between solutions of constrained equations (Euler symmetries) in some other cases. These relations lead to the corresponding symmetries of the monodromy matrices. We discuss Euler symmetries in the case of the simplest Fuchsian system that is equivalent to a deformed Heun equation, which is in turn related to the Painlevé PVI equation. The existence of integral symmetries of the deformed Heun equation leads to the corresponding symmetries of the PVI equation.
Institute of Scientific and Technical Information of China (English)
闫庆旭; 侯瑞鸿; 冯德兴; 齐剑冷
2005-01-01
In this article, we study the locally distributed feedback stabilization problem of a nonuniform Euler-Bernoulli beam. Firstly, using the semi-group theory, we establish the wellposedness of the associated closed loop system. Then by proving the uniqueness of the solution to a related ordinary differential equation, we derive the asymptotic stability of the closed loop system. Finally, by means of the piecewise multiplier method, we prove that, by either one distributed force feedback or a distributed moment feedback control, the closed loop system can be exponentially stabilized.
Modelling of soil salinity and halophyte crop production
Vermue, E.; Metselaar, K.; Zee, van der S.E.A.T.M.
2013-01-01
In crop modelling the soil, plant and atmosphere system is regarded as a continuum with regard to root water uptake and transpiration. Crop production, often assumed to be linearly related with transpiration, depends on several factors, including water and nutrient availability and salinity. The
Control and modelling of vertical temperature distribution in greenhouse crops
Kempkes, F.L.K.; Bakker, J.C.; Braak, van de N.J.
1998-01-01
Based on physical transport processes (radiation, convection and latent heat transfer) a model has been developed to describe the vertical temperature distribution of a greenhouse crop. The radiation exchange factors between heating pipes, crop layers, soil and roof were determined as a function of
Estimating winter wheat phenological parameters: Implications for crop modeling
Crop parameters, such as the timing of developmental events, are critical for accurate simulation results in crop simulation models, yet uncertainty often exists in determining the parameters. Factors contributing to the uncertainty include: a) sources of variation within a plant (i.e., within diffe...
Institute of Scientific and Technical Information of China (English)
张焕雪; 李强子; 文宁; 杜鑫; 陶青山; 董泰锋
2014-01-01
空间抽样技术在农作物种植面积调查中具有不可替代的作用，各抽样要素（抽样率、抽样调查单元尺寸及布局）对于抽样精度的影响至关重要。该文以湖南省晚稻为研究对象，设计了9种抽样调查单元和31种抽样率水平，以晚稻面积百分比为分层标志进行空间分层抽样，分析抽样格网大小、抽样率及样本空间分布格局对面积估算精度的敏感性及控制途径，并建立3种影响因素对面积估算的综合评估模型。结果表明：1）作物面积估计的平均抽样误差随抽样格网尺寸的增加而增加（R2=0.92），当抽样格网控制在5 km以内时，平均误差基本限制在5%以下，标准差变幅稳定在0.12以内；2）作物面积估计的平均抽样误差随抽样率的增加而逐渐降低（R2=0.82），当抽样率达到0.4%时，平均误差基本限制在5%以内，标准差变幅稳定在0.12以内；3）在抽样率确定的情况下，样本的空间分布是影响抽样精度的重要因素，随着样本空间分布由近似均匀分布向随机分布再向集群分布变化，作物面积估计量的平均抽样误差逐渐增大，当样本空间分布的方差均值比指标＜0.7时，平均误差控制在5%以内，标准差变幅稳定在0.1以内；4）得到3种影响因素对面积估算精度的定量评估模型。该成果揭示了农作物种植面积抽样过程中样方尺寸、抽样率和样本空间分布对精度影响的敏感性，为农作物种植面积监测空间抽样方案的选取以及确定特定的抽样方案可以达到的面积估算水平提供了理论基础。%Crop acreage estimation is important for the assurance of food security and establishment of national socio-economic development planning. During the current development period, rapid, accurate and reliable estimation for crop acreage is particularly significant in China since the estimation can be affected by many factors
Kissoudis, Christos; Wiel, van de Clemens; Visser, R.G.F.; Linden, van der Gerard
2016-01-01
Breeding for stress-resilient crops strongly depends on technological and biological advancements that have provided a wealth of information on genetic variants and their contribution to stress tolerance. In the context of the upcoming challenges for agriculture due to climate change, such as
Mycorrhiza and crop production
Energy Technology Data Exchange (ETDEWEB)
Hayman, D.S.
1980-10-09
This article describes recent research with vesicular-arbuscular mycorrhiza, a symbiotic fungus-root association. The suggestion that the symbiotic association may be harnessed to achieve more economical use of phosphate fertilizers is discussed and the results from various test crops are given.
Kissoudis, Christos; Wiel, van de Clemens; Visser, R.G.F.; Linden, van der Gerard
2016-01-01
Breeding for stress-resilient crops strongly depends on technological and biological advancements that have provided a wealth of information on genetic variants and their contribution to stress tolerance. In the context of the upcoming challenges for agriculture due to climate change, such as pro
Yu, Y.
2016-01-01
Yu, Y.
2016-01-01
Directory of Open Access Journals (Sweden)
Aline G Lemos
2011-06-01
modo geral, as perdas avaliadas pelo FC estão mais relacionadas ao manipulador das folhosas e ao estado de conservação das hortaliças do que ao período de safra. Desta forma, para as hortaliças que apresentaram diferenças com relação à época de amostragem, recomenda-se observância quanto ao período de planejamento dos cardápios visando a obtenção do aproveitamento eficiente do produto.Brazil has high indexes of food waste, which affects regional economy and increases social problems. Inadequate planning of food processing, from postharvest to consumption, is one of the reasons of loss. Vegetable crops are live organisms and their durability is affected by the processes of subdivision and cooking. To reduce losses, the determination of the Correction Factor is essential in order to evaluate the losses and the factors which interfere on these losses. This work consists on determining the Correction Factor of the following vegetable crops: Crisphead Lettuce, Unheaded Lettuce, Lettuce, Purple Leafs, Chard, Endive, Watercress, Common Chicory, Borecole Green Collard, Escarole, Spinach, Mustard, Cabbage, Red Cabbage and Rocket Crop. Three sale units of each vegetable crop were acquired at the CEASA in Brasília (Federal District, Brazil, from three different suppliers, with four replicates, a total of 36 samples of each vegetable crop. Aiming to detect the influence of the gathering month on the Partial Correction Factor (CF 1 and Final Correction Factor (CF 2 analysis of variance (ANOVA and Tukey test were carried out. In all tests a level of 5% of statistical significance was considered. The results showed that for the majority of the vegetables, harvest does not influence loss. However for chard, the lower CF occurred at harvest. On the other hand for cabbage, the lower CF occurred at harvest. This way for the majority of the vegetables, the losses evaluated by the CF are more related to handling procedures and conservation. For cabbage, it is recommended
MICROELEMENTS IN SUNFLOWER CROPS
Directory of Open Access Journals (Sweden)
Buldykova I. A.
2015-03-01
Full Text Available The obtained experimental data show that the incorporation of trace elements into the system of the sunflower crop has a positive impact on the mineral nutrition of plants, the number and quality of the crop. Foliar feeding of sunflower crops with micronutrients improves nutrition of plants with nitrogen, phosphorus and potassium, thus creating the preconditions for the formation of highly agrocenosis. The seed yield of sunflower increased by variants with application of micronutrients 1.2-3.5 t/ha or 4.4-12.9 percent. The greatest impact of treatment with boron and copper, exceeding the background option 3.1-3.5 t/ha or 11.5-12.9% respectively. The crop is least influenced by manganese and molybdenum. The examined elements positively influenced the structure of the sunflower crop. The greatest influence on the diameter of the basket, the number of seeds, weight of seeds in the basket, the weight of 1000 seeds was provided by the zinc and copper. Trace elements contributed to the improvement of quality indicators of sunflower. For husk content, the greatest positive effect was cobalt, zinc, manganese and copper, increasing the background option 10.1, 10.4, 10.5 and 10, and 6%, respectively, on the oil content of sunflower seeds had cobalt, copper and zinc. The oil content on these options amounted 55,0, with 55.1 and 55.2%, respectively, increasing this figure by 1.5 to 1.7 %. The acid number at variants with boron, manganese and zinc was the same with the background option and amounted to 1.8. The greatest influence on iodine number provided molybdenum, zinc and copper, which accounted for 170,5, 171,2 and 171,4, exceeding the background option 10.2 and 11.1
Institute of Scientific and Technical Information of China (English)
武洁琼; 陈发师
2003-01-01
讨论变系数Euler-Bernoulli梁振动系统utt(x,t)+η(t)uxxxx(x,t)=0,0＜x＜1,0≤t≤T{ u(0,t)=ux(0,t)=0,0≤t≤T-uxxx(1,t)+mutt(1,t)=-αut(1,t)+βuxxxt(1,t),0≤t≤T (1)uxt(1,t)=-γuxx(1,t),0≤t≤Tu(x,0)=u1(x),ut(x,0)=u2(x),0≤x≤1证明了该系统产生一个发展系统.%A flexible structure consisting of Euler-Bernoulli beam with a variable coefficient described by utt(x,t) +-η(t)uxxxx (x,t)=0, 0＜x＜1, 0≤t≤T u(0,t) = ux(0,t) = 0, 0 ≤ t ≤ T { - uxxx(1,t) +mutt(1,t) =- aut(1,t) + βuxxxt(1,t), 0≤t≤T (1) uxt(1,t) =-γuxx(1,t), 0≤t≤T u(x,0) =u1(x), ut(x,0) =u2(x), 0≤x≤ 1 is considered. We prove that the system generate an evolution system when η(t) is a continuous function and η(t) ∈∨ [0,T], 0＜η0≤η(t)≤M.
Quantum distance and the Euler number index of the Bloch band in a one-dimensional spin model.
Ma, Yu-Quan
2014-10-01
We study the Riemannian metric and the Euler characteristic number of the Bloch band in a one-dimensional spin model with multisite spins exchange interactions. The Euler number of the Bloch band originates from the Gauss-Bonnet theorem on the topological characterization of the closed Bloch states manifold in the first Brillouin zone. We study this approach analytically in a transverse field XY spin chain with three-site spin coupled interactions. We define a class of cyclic quantum distance on the Bloch band and on the ground state, respectively, as a local characterization for quantum phase transitions. Specifically, we give a general formula for the Euler number by means of the Berry curvature in the case of two-band models, which reveals its essential relation to the first Chern number of the band insulators. Finally, we show that the ferromagnetic-paramagnetic phase transition in zero temperature can be distinguished by the Euler number of the Bloch band.
A influência dos tratados de cálculo infinitesimal de Euler no séc. XVIII
João Caramalho Domingues, João
2012-01-01
Leonhard Euler (1701–1783) foi provavelmente o mais influente matemático do séc. XVIII. Entre as suas obras clássicas contam-se três tratados que, no seu conjunto (perfazendo seis volumes), fornecem uma apresentação «completa» do cálculo infinitesimal: uma introdução à análise infinitesimal [Euler 1748 ]; um tratado de cálculo diferencial [Euler 1755 ]; e um tratado de cálculo integral [Euler 1768–1770 ]. Estes tratados são muito mais avançados do que quaisquer outros publicados anteriormente...
Fundamental Group and Euler Characteristic of Permutation Products and Fat Diagonals
Kallel, Sadok
2010-01-01
Permutation products and their various "fat diagonal" subspaces are studied from the topological and geometric point of view. We first write down an expression for the fundamental group of any permutation product of a connected space $X$, having the homotopy type of a simplicial complex, in terms of $\\pi_1(X)$ and $H_1(X;{\\mathbb Z})$. We then prove that the fundamental group of the configuration space of $n$-points on $X$ of which multiplicities do not exceed $n/2$ coincides with $H_1(X;{\\mathbb Z})$. Useful additivity properties for the Euler characteristic are then spelled out and used to give explicit formulae for the Euler characteristics of various fat diagonals. Several examples and calculations are included.
Some generalized Lagrange-based Apostol-Bernoulli, Apostol-Euler and Apostol-Genocchi polynomials
Srivastava, H. M.; Özarslan, M. A.; Kaanoğlu, C.
2013-03-01
In this paper, we introduce a general family of Lagrange-based Apostol-type polynomials thereby unifying the Lagrange-based Apostol-Bernoulli and the Lagrange-based Apostol-Genocchi polynomials. We also define Lagrange-based Apostol-Euler polynomials via the generating function. In terms of these generalizations, we find new and useful relations between the unified family and the Apostol-Euler polynomials. We also derive their explicit representations and list some basic properties of each of them. Further relations between the above-mentioned polynomials, including a family of bilinear and bilateral generating functions, are given. Moreover, a generating relation involving the Stirling numbers of the second kind is derived.
A Missed Persistence Property for the Euler Equations, and its Effect on Inviscid Limits
da Veiga, H Beirao
2010-01-01
We consider the problem of the strong convergence, as the viscosity goes to zero, of the solutions to the three-dimensional evolutionary Navier-Stokes equations under a Navier slip-type boundary condition to the solution of the Euler equations under the zero flux boundary condition. In spite of the arbitrarily strong convergence results proved in the flat boundary case, see [4], it was shown in reference [5] that the result is false in general, by constructing an explicit family of smooth initial data in the sphere, for which the result fails. Our aim here is to present a more general, simpler and incisive proof. In particular, counterexamples can be displayed in arbitrary, smooth, domains. As in [5], the proof is reduced to the lack of a suitable persistence property for the Euler equations. This negative result is proved by a completely different approach.
THE EULER CHARACTERISTIC AS A MEASURE OF THE TOPOLOGY OF COSMIC REIONIZATION
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M. M. Friedrich
2011-01-01
Full Text Available Presentamos una introducción al uso de la Característica de Euler en simulaciones a gran escala de la época de la reionización cósmica. Para caracterizar la topología del campo de la fracción de ionización, hemos calculado la evolución de su Caracterstica de Euler. Nuestros resultados indican que la evolución de la topología durante la primera mitad de la reionización cosmica, es consistente con la reionización de dentro hacia afuera de un campo de densidad (log Gaussiano.
Global Well-Posedness of the Euler-Korteweg System for Small Irrotational Data
Audiard, Corentin; Haspot, Boris
2017-04-01
The Euler-Korteweg equations are a modification of the Euler equations that take into account capillary effects. In the general case they form a quasi-linear system that can be recast as a degenerate Schrödinger type equation. Local well-posedness (in subcritical Sobolev spaces) was obtained by Benzoni-Danchin-Descombes in any space dimension, however, except in some special case (semi-linear with particular pressure) no global well-posedness is known. We prove here that under a natural stability condition on the pressure, global well-posedness holds in dimension {d ≥ 3} for small irrotational initial data. The proof is based on a modified energy estimate, standard dispersive properties if {d ≥ 5}, and a careful study of the structure of quadratic nonlinearities in dimension 3 and 4, involving the method of space time resonances.
He, Lifeng; Chao, Yuyan
2015-09-01
Labeling connected components and calculating the Euler number in a binary image are two fundamental processes for computer vision and pattern recognition. This paper presents an ingenious method for identifying a hole in a binary image in the first scan of connected-component labeling. Our algorithm can perform connected component labeling and Euler number computing simultaneously, and it can also calculate the connected component (object) number and the hole number efficiently. The additional cost for calculating the hole number is only O(H) , where H is the hole number in the image. Our algorithm can be implemented almost in the same way as a conventional equivalent-label-set-based connected-component labeling algorithm. We prove the correctness of our algorithm and use experimental results for various kinds of images to demonstrate the power of our algorithm.
Wang, Xiao-Yen; Chow, Chuen-Yen; Chang, Sin-Chung
1996-01-01
The I-D, quasi I-D and 2-D Euler solvers based on the method of space-time conservation element and solution element are used to simulate various flow phenomena including shock waves, Mach stem, contact surface, expansion waves, and their intersections and reflections. Seven test problems are solved to demonstrate the capability of this method for handling unsteady compressible flows in various configurations. Numerical results so obtained are compared with exact solutions and/or numerical solutions obtained by schemes based on other established computational techniques. Comparisons show that the present Euler solvers can generate highly accurate numerical solutions to complex flow problems in a straightforward manner without using any ad hoc techniques in the scheme.
Restricted Euler dynamics along trajectories of small inertial particles in turbulence
Johnson, Perry L.; Meneveau, Charles
2017-04-01
The fate of small particles in turbulent flows depends strongly on the surrounding fluid's velocity gradient properties such as rotation and strain-rates. For non-inertial (fluid) particles, the Restricted Euler model provides a simple, low-dimensional dynamical system representation of Lagrangian evolution of velocity gradients in fluid turbulence, at least for short times. Here we derive a new restricted Euler dynamical system for the velocity gradient evolution of inertial particles such as solid particles in a gas or droplets and bubbles in turbulent liquid flows. The model is derived in the limit of small (sub Kolmogorov scale) particles and low Stokes number. The system exhibits interesting fixed points, stability and invariant properties. Comparisons with data from Direct Numerical Simulations show that the model predicts realistic trends such as the tendency of increased straining over rotation along heavy particle trajectories and, for light particles such as bubbles, the tendency of reduced self-stretching of strain-rate.
On reflection symmetry and its application to the Euler-Lagrange equations in fractional mechanics.
Klimek, Małgorzata
2013-05-13
We study the properties of fractional differentiation with respect to the reflection symmetry in a finite interval. The representation and integration formulae are derived for symmetric and anti-symmetric fractional derivatives, both of the Riemann-Liouville and Caputo type. The action dependent on the left-sided Caputo derivatives of orders in the range (1,2) is considered and we derive the Euler-Lagrange equations for the symmetric and anti-symmetric part of the trajectory. The procedure is illustrated with an example of the action dependent linearly on fractional velocities. For the obtained Euler-Lagrange system, we discuss its localization resulting from the subsequent symmetrization of the action.
Noether symmetries and exact solutions of an Euler-Bernoulli beam model
Fatima, Aeeman; Mahomed, Fazal M.; Khalique, Chaudry Masood
2016-07-01
In this paper, a Noether symmetry analysis is carried out for an Euler-Bernoulli beam equation via the standard Lagrangian of its reduced scalar second-order equation which arises from the standard Lagrangian of the fourth-order beam equation via its Noether integrals. The Noether symmetries corresponding to the reduced equation is shown to be the inherited Noether symmetries of the standard Lagrangian of the beam equation. The corresponding Noether integrals of the reduced Euler-Lagrange equations are deduced which remarkably allows for three families of new exact solutions of the static beam equation. These are shown to contain all the previous solutions obtained from the standard Lie analysis and more.
An Error Estimate for Symplectic Euler Approximation of Optimal Control Problems
Karlsson, Jesper
2015-01-01
This work focuses on numerical solutions of optimal control problems. A time discretization error representation is derived for the approximation of the associated value function. It concerns symplectic Euler solutions of the Hamiltonian system connected with the optimal control problem. The error representation has a leading-order term consisting of an error density that is computable from symplectic Euler solutions. Under an assumption of the pathwise convergence of the approximate dual function as the maximum time step goes to zero, we prove that the remainder is of higher order than the leading-error density part in the error representation. With the error representation, it is possible to perform adaptive time stepping. We apply an adaptive algorithm originally developed for ordinary differential equations. The performance is illustrated by numerical tests.
Burtscher, Annegret Y
2014-01-01
We study the evolution of a self-gravitating compressible fluid in spherical symmetry and we prove the existence of weak solutions with bounded variation for the Einstein-Euler equations of general relativity. We formulate the initial value problem in Eddington-Finkelstein coordinates and prescribe spherically symmetric data on a characteristic initial hypersurface. We introduce here a broad class of initial data which contain no trapped surfaces, and we then prove that their Cauchy development contains trapped surfaces. We therefore establish the formation of trapped surfaces in weak solutions to the Einstein equations. This result generalizes a theorem by Christodoulou for regular vacuum spacetimes (but without symmetry restriction). Our method of proof relies on a generalization of the "random choice" method for nonlinear hyperbolic systems and on a detailed analysis of the nonlinear coupling between the Einstein equations and the relativistic Euler equations in spherical symmetry.
A multi-dimensional kinetic-based upwind solver for the Euler equations
Eppard, W. M.; Grossman, B.
1993-01-01
A multidimensional kinetic fluctuation-splitting scheme has been developed for the Euler equations. The scheme is based on an N-scheme discretization of the Boltzmann equation at the kinetic level for triangulated Cartesian meshes with a diagonal-adaptive strategy. The resulting Euler scheme is a cell-vertex fluctuation-splitting scheme where fluctuations in the conserved-variable vector Q are obtained as moments of the fluctuation in the Maxwellian velocity distribution function at the kinetic level. Encouraging preliminary results have been obtained for perfect gases on Cartesian meshes with first-order spatial accuracy. The present approach represents an improvement to the well-established dimensionally-split upwind schemes.
An accuracy assessment of Cartesian-mesh approaches for the Euler equations
Coirier, William J.; Powell, Kenneth G.
1995-01-01
A critical assessment of the accuracy of Cartesian-mesh approaches for steady, transonic solutions of the Euler equations of gas dynamics is made. An exact solution of the Euler equations (Ringleb's flow) is used not only to infer the order of the truncation error of the Cartesian-mesh approaches, but also to compare the magnitude of the discrete error directly to that obtained with a structured mesh approach. Uniformly and adaptively refined solutions using a Cartesian-mesh approach are obtained and compared to each other and to uniformly refined structured mesh results. The effect of cell merging is investigated as well as the use of two different K-exact reconstruction procedures. The solution methodology of the schemes is explained and tabulated results are presented to compare the solution accuracies.
Shafiei, Navvab; Kazemi, Mohammad; Ghadiri, Majid
2016-09-01
The target of this paper is to present an exhaustive study on the small scale effect on vibrational behavior of a rotary tapered axially functionally graded (AFG) microbeam on the basis of Timoshenko and Euler-Bernoulli beam and modified couple stress theories. The variation of the material properties and cross section along the longitudinal direction of the microbeam are taken into consideration as a linear function. Hamilton's principle is used to derive the equations for cantilever and propped cantilever boundary conditions and the generalized differential quadrature method (GDQM) is employed to solve the equations. By parametric study, the effects of small-scale parameter, rates of cross section change of the microbeam and angular velocity on the fundamental and second frequencies of the microbeam are studied. Also, comparison between the frequencies of Timoshenko and Euler-Bernoulli microbeams are presented. The results can be used in many applications such as micro-robots and biomedical microsystems.
Restricted Euler dynamics along trajectories of small inertial particles in turbulence
Johnson, Perry L
2016-01-01
The fate of small particles in turbulent flows depends strongly on the surrounding fluid's velocity gradient properties such as rotation and strain-rates. For non-inertial (fluid) particles, the Restricted Euler model provides a simple, low-dimensional dynamical system representation of Lagrangian evolution of velocity gradients in fluid turbulence, at least for short times. Here we derive a new restricted Euler dynamical system for the velocity gradient evolution of inertial particles such as solid particles in a gas or droplets and bubbles in turbulent liquid flows. The model is derived in the limit of small (sub Kolmogorov scale) particles and low Stokes number. The system exhibits interesting fixed points, stability and invariant properties. Comparisons with data from Direct Numerical Simulations show that the model predicts realistic trends such as the tendency of increased straining over rotation along heavy particle trajectories and, for light particles such as bubbles, the tendency of reduced self-str...
An A Posteriori Error Estimate for Symplectic Euler Approximation of Optimal Control Problems
Karlsson, Jesper
2015-01-07
This work focuses on numerical solutions of optimal control problems. A time discretization error representation is derived for the approximation of the associated value function. It concerns Symplectic Euler solutions of the Hamiltonian system connected with the optimal control problem. The error representation has a leading order term consisting of an error density that is computable from Symplectic Euler solutions. Under an assumption of the pathwise convergence of the approximate dual function as the maximum time step goes to zero, we prove that the remainder is of higher order than the leading error density part in the error representation. With the error representation, it is possible to perform adaptive time stepping. We apply an adaptive algorithm originally developed for ordinary differential equations.
The Cauchy problem for the pressureless Euler/isentropic Navier-Stokes equations
Choi, Young-Pil; Kwon, Bongsuk
2016-07-01
We present a new hydrodynamic model consisting of the pressureless Euler equations and the isentropic compressible Navier-Stokes equations where the coupling of two systems is through the drag force. This coupled system can be derived, in the hydrodynamic limit, from the particle-fluid equations that are frequently used to study the medical sprays, aerosols and sedimentation problems. For the proposed system, we first construct the local-in-time classical solutions in an appropriate L2 Sobolev space. We also establish the a priori large-time behavior estimate by constructing a Lyapunov functional measuring the fluctuation of momentum and mass from the averaged quantities, and using this together with the bootstrapping argument, we obtain the global classical solution. The large-time behavior estimate asserts that the velocity functions of the pressureless Euler and the compressible Navier-Stokes equations are aligned exponentially fast as time tends to infinity.
The Euler-Poincaré Formula Through Contact Surfaces of Voxelized Objects
Directory of Open Access Journals (Sweden)
H. Sánchez-Cruz
2013-02-01
Full Text Available Two new versions of the Euler-Poincaré formula are proposed considering two new defined cuboids: the tetra-voxel and the octo-voxel, without losing information on the number of vertices and edges. The well-known relationship between contact and enclosing surface concepts, as well as the relationships between vertices, edges and enclosing surfaces, allowed us to compute an innovative algorithm for obtaining alternative versions of the Euler-Poincaré formula. This is a very important topological descriptor of 3D binary images. We considered not only topological but geometric aspects. Our method was compared to other proposals, obtaining that our proposed contact surface-based method offers more advantages.
Institute of Scientific and Technical Information of China (English)
Bao-Rong LU
2013-01-01
Effective conservation of crop wild relative (CWR) species is essential for the sustainable use and genetic improvement of crop varieties,which offers greater opportunities for world food security,particularly in modem agroecosystems where CWR diversity is under severe threat.Factors such as habitat fragmentation,human disturbances,global climate change,and invasion of harmful alien species have been identified to be responsible for losses and threats to CWR diversity.However,a neglected factor,gene introgression from domesticated species through repeated outcrossing,may have a significant impact on CWR diversity.Introgression can influence genetic diversity and evolutionary processes of CWR populations through effects such as demographic swarming,genetic assimilation,and selective sweep.When largely enhancing or reducing fitness of wild plants,the introgression of crop genes will impose more significant genetic and evolutionary impacts on CWR populations,leading to undesired consequences for conserved CWR populations and species.This situation is particularly true when genetically engineered (GE) crops are deployed for commercial cultivation.It is argued that a GE crop usually contains transgenes with strong natural selection advantages,and such transgenes introgressed into CWR populations may have strong impacts on their genetic diversity and evolutionary processes,threatening their conservation.This article reviews the challenge of crop-wild gene flow,and particularly transgene introgression from GE crops,for the in situ conservation of wild relative species.The design of effective management strategies for conserving CWR species under the scenario of extensive cultivation of GE crops is also discussed.
Automatic computation of Euler-marching and subsonic grids for wing-fuselage configurations
Barger, Raymond L.; Adams, Mary S.; Krishnan, Ramki R.
1994-01-01
Algebraic procedures are described for the automatic generation of structured, single-block flow computation grids for relatively simple configurations (wing, fuselage, and fin). For supersonic flows, a quasi two-dimensional grid for Euler-marching codes is developed, and some sample results in graphical form are included. A type of grid for subsonic flow calculation is also described. The techniques are algebraic and are based on a generalization of the method of transfinite interpolation.
Generalizations of Steffensen’s inequality via some Euler-type identities
Directory of Open Access Journals (Sweden)
Pečarić Josip
2016-08-01
Full Text Available Using Euler-type identities some new generalizations of Steffensen’s inequality for n–convex functions are obtained. Moreover, the Ostrowski-type inequalities related to obtained generalizations are given. Furthermore, using inequalities for the Čebyšev functional in terms of the first derivative some new bounds for the remainder in identities related to generalizations of Steffensen’s inequality are proven.
A Genuinely Two-Dimensional Scheme for the Compressible Euler Equations
Sidilkover, David
1996-01-01
We present a new genuinely multidimensional discretization for the compressible Euler equations. It is the only high-resolution scheme known to us where Gauss-Seidel relaxation is stable when applied as a smoother directly to the resulting high-resolution scheme. This allows us to construct a very simple and highly efficient multigrid steady-state solver. The scheme is formulated on triangular (possibly unstructured) meshes.
High-Order Spectral Volume Method for 2D Euler Equations
Wang, Z. J.; Zhang, Laiping; Liu, Yen; Kwak, Dochan (Technical Monitor)
2002-01-01
The Spectral Volume (SV) method is extended to the 2D Euler equations. The focus of this paper is to study the performance of the SV method on multidimensional non-linear systems. Implementation details including total variation diminishing (TVD) and total variation bounded (TVB) limiters are presented. Solutions with both smooth features and discontinuities are utilized to demonstrate the overall capability of the SV method.
The optimal upper bound of the number of generalized Euler configurations
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
Consider a generalized 3-body problem. The attraction force between any two bodies is proportional to the two "masses" and the b-th power of the mutual distance. Albouy and Fu have obtained the optimal upper bound of the number of generalized Euler configurations for the cases b 1 and b = 2, 3. This paper obtains the optimal upper bound for the remaining real values of b in a systematic way.
Euler-Lagrange CFD modelling of unconfined gas mixing in anaerobic digestion.
Dapelo, Davide; Alberini, Federico; Bridgeman, John
2015-11-15
A novel Euler-Lagrangian (EL) computational fluid dynamics (CFD) finite volume-based model to simulate the gas mixing of sludge for anaerobic digestion is developed and described. Fluid motion is driven by momentum transfer from bubbles to liquid. Model validation is undertaken by assessing the flow field in a labscale model with particle image velocimetry (PIV). Conclusions are drawn about the upscaling and applicability of the model to full-scale problems, and recommendations are given for optimum application.
Implicit Euler approximation of stochastic evolution equations with fractional Brownian motion
Kamrani, Minoo; Jamshidi, Nahid
2017-03-01
This work was intended as an attempt to motivate the approximation of quasi linear evolution equations driven by infinite-dimensional fractional Brownian motion with Hurst parameter H >1/2 . The spatial approximation method is based on Galerkin and the temporal approximation is based on implicit Euler scheme. An error bound and the convergence of the numerical method are given. The numerical results show usefulness and accuracy of the method.
On the Choquet-Bruhat-York-Friedrich formulation of the Einstein-Euler equations
Disconzi, Marcelo M
2013-01-01
Short-time existence for the Einstein-Euler and the vacuum Einstein equations is proven using a Friedrich inspired formulation due to Choquet-Bruhat and York, where the system is cast into a symmetric hyperbolic form and the Riemann tensor is treated as one of the fundamental unknowns of the problem. The reduced system of Choquet-Bruhat and York, along with the preservation of the gauge, is shown to imply the full Einstein equations.
THE REGULAR SOLUTIONS OF THE ISENTROPIC EULER EQUATIONS WITH DEGENERATE LINEAR DAMPING
Institute of Scientific and Technical Information of China (English)
ZHU XUSHENG; WANG WEIKE
2005-01-01
The regular solutions of the isentropic Euler equations with degenerate linear damping for a perfect gas are studied in this paper. And a critical degenerate linear damping coefficient is found, such that if the degenerate linear damping coefficient is larger than it and the gas lies in a compact domain initially, then the regular solution will blow up in finite time; if the degenerate linear damping coefficient is less than it, then undersome hypotheses on the initial data, the regular solution exists globally.
Regularity of Stagnation Point-form Solutions of the Two-dimensional Euler Equations
Sarria, Alejandro
2013-01-01
A class of semi-bounded solutions of the two-dimensional incompressible Euler equations, satisfying either periodic or Dirichlet boundary conditions, is examined. For smooth initial data, new blowup criteria in terms of the initial concavity profile is presented and the effects that the boundary conditions have on the global regularity of solutions is discussed. In particular, by deriving a formula for a general solution along Lagrangian trajectories, we describe how p...
THE VANISHING PRESSURE LIMIT OF SOLUTIONS TO THE SIMPLIFIED EULER EQUATIONS FOR ISENTROPIC FLUIDS
Institute of Scientific and Technical Information of China (English)
无
2012-01-01
In this paper,the Riemann problem of the 1-D reduced model for the 2-D Euler equations is considered and the Riemann solutions are obtained.It is proved that,as the pressure vanishes,they converge to two kinds of Riemann solutions to the 1D reduced model for the 2-D transport equations:one contains δ-shocks,the other contains vacuum.
Development and application of a 3D Cartesian grid Euler method
Melton, John E.; Aftosmis, Michael J.; Berger, Marsha J.; Wong, Michael D.
1995-01-01
This report describes recent progress in the development and application of 3D Cartesian grid generation and Euler flow solution techniques. Improvements to flow field grid generation algorithms, geometry representations, and geometry refinement criteria are presented, including details of a procedure for correctly identifying and resolving extremely thin surface features. An initial implementation of automatic flow field refinement is also presented. Results for several 3D multi-component configurations are provided and discussed.
Chen, Licui; Jia, Nana; Gao, Lianghui; Fang, Weihai; Golubovic, Leonardo
2013-04-11
We explore the effects of the peripheral and transmembrane antimicrobial peptides on the lipid bilayer membrane by using the coarse grained Dissipative Particle Dynamics simulations. We study peptide/lipid membrane complexes by considering peptides with various structure, hydrophobicity and peptide/lipid interaction strength. The role of lipid/water interaction is also discussed. We discuss a rich variety of membrane morphological changes induced by peptides, such as pore formation, membrane corrugation and Euler buckling.
Hamilton's Equations with Euler Parameters for Rigid Body Dynamics Modeling. Chapter 3
Shivarama, Ravishankar; Fahrenthold, Eric P.
2004-01-01
A combination of Euler parameter kinematics and Hamiltonian mechanics provides a rigid body dynamics model well suited for use in strongly nonlinear problems involving arbitrarily large rotations. The model is unconstrained, free of singularities, includes a general potential energy function and a minimum set of momentum variables, and takes an explicit state space form convenient for numerical implementation. The general formulation may be specialized to address particular applications, as illustrated in several three dimensional example problems.
Determination of volume fractions of texture components with standard distributions in Euler space
Cho, Jae-Hyung; Rollett, A. D.; Oh, K. H.
2004-03-01
The intensities of texture components are modeled by Gaussian distribution functions in Euler space. The multiplicities depend on the relation between the texture component and the crystal and sample symmetry elements. Higher multiplicities are associated with higher maximum values in the orientation distribution function (ODF). The ODF generated by Gaussian function shows that the S component has a multiplicity of 1, the brass and copper components, 2, and the Goss and cube components, 4 in the cubic crystal and orthorhombic sample symmetry. Typical texture components were modeled using standard distributions in Euler space to calculate a discrete ODF, and their volume fractions were collected and verified against the volume used to generate the ODF. The volume fraction of a texture component that has a standard spherical distribution can be collected using the misorientation approach. The misorientation approach means integrating the volume-weighted intensity that is located within a specified cut-off misorientation angle from the ideal orientation. The volume fraction of a sharply peaked texture component can be collected exactly with a small cut-off value, but textures with broad distributions (large full-width at half-maximum (FWHM)) need a larger cut-off value. Larger cut-off values require Euler space to be partitioned between texture components in order to avoid overlapping regions. The misorientation approach can be used for texture's volume in Euler space in a general manner. Fiber texture is also modeled with Gaussian distribution, and it is produced by rotation of a crystal located at g 0, around a sample axis. The volume of fiber texture in wire drawing or extrusion also can be calculated easily in the unit triangle with the angle distance approach.
Adali, Sarp
2009-05-01
Variational principles are derived for multiwalled carbon nanotubes undergoing vibrations. Derivations are based on the continuum modeling with the Euler-Bernoulli beam representing the nanotubes and small scale effects taken into account via the nonlocal elastic theory. Hamilton's principle for multiwalled nanotubes is given and Rayleigh's quotient for the frequencies is derived for nanotubes undergoing free vibrations. Natural and geometric boundary conditions are derived which lead to a set of coupled boundary conditions due to nonlocal effects.
Gaia16aas, Gaia16ade and Gaia16adz transients confirmed by Euler imaging
Blanco-Cuaresma, S.; Roelens, M.; Semaan, T.; Palaversa, L.; Mowlavi, N.; Eyer, L.
2016-02-01
We report confirmation of Gaia Science Alerts transients Gaia16aas, Gaia16ade and Gaia16adz. Images were obtained through modified Gunn R band filter of the ECAM instrument installed on the Swiss 1.2m Euler telescope at La Silla, on 2016 February 18 - 24 UT. These new sources are cataclysmic variable star candidates and they are not visible in archival 2MASS and DSS images: Gaia16aas, Gaia16ade and Gaia16adz.
Gaia16ali and Gaia16alj supernovae confirmed by Euler imaging
Roelens, M.; Blanco-Cuaresma, S.; Semaan, T.; Palaversa, L.; Mowlavi, N.; Eyer, L.
2016-04-01
We report confirmation of Gaia Science Alerts transients Gaia16ali and Gaia16alj. Images were obtained through modified Gunn R band filter of the ECAM instrument installed on the Swiss 1.2m Euler telescope at La Silla, on 2016 April 19 - 22 UT. These new sources are supernovae candidates and they are not visible in archival 2MASS and DSS images: Gaia16ali (near centre of galaxy GALEXASC J041551.89-621715.5) and Gaia16alj.
A note on Rubin's methods of the use of two Euler systems
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Here we show that Rubin's method of the use of two Euler systems to the proofs of Iwasawa main conjectures of the rational number field and of an imaginary quadratic field is only proper to these two kinds of number fields. We mainly use the properties of adéle ring and idéle group in class field theory to get the result.
On the First Digits of the Fibonacci Numbers and Their Euler Function
2014-01-01
there exist infinitely many Fibonacci numbers Fn whose base b representation starts with s1. In fact, the first digits of the Fibonacci sequence obey... Fibonacci sequence Fn in the above statements with some other sequence un for which it has been proved that φ(un)/un and un/σ(un), respectively, are...Uniform Distribution Theory 9 (2014), no.1, 21–25 uniform distribution theory ON THE FIRST DIGITS OF THE FIBONACCI NUMBERS AND THEIR EULER FUNCTION
Institute of Scientific and Technical Information of China (English)
Xu Shan-Shan; Li Shu-Min; Berakdax Jamal
2009-01-01
As a counterexample of the Euler condition for nonholonomic constraint problems [H.C.Shen,Acta Phys.Sin.54,2468 (2005)],we investigate the Apell-Hamel dynamical system on a horizontally moving plate.The inconsistency of the results with Newton mechanics suggests that the Euler condition is not a universal model for nonlinear nonholonomic systems.This is attributed to the fact that the virtual displacements so obtained are not normal to the constraint forces.
DEFF Research Database (Denmark)
Helmer, Martin
2016-01-01
Let V be a closed subscheme of a projective space Pn. We give an algorithm to compute the Chern-Schwartz-MacPherson class, and the Euler characteristic of V and an algorithm to compute the Segre class of V. The algorithms can be implemented using either symbolic or numerical methods. The algorithms...... to current algorithms for computing Chern-Schwartz-MacPherson classes, Segre classes and Euler characteristics....
Ravat, D.; Kirkham, K.; Hildenbrand, T.G.
2002-01-01
An overview is given on the benefits of applying the Euler method on derivatives of anomalies to enhance the location of shallow and deep sources. Used properly, the method is suitable for characterizing sources from all potential-field data and/or their derivative, as long as the data can be regarded mathematically as "continuous". Furthermore, the reasons why the use of the Euler method on derivatives of anomalies is particularly helpful in the analysis and interpretation of shallow features are explained.
M. Jahan; M.B Amiri; J Shabahang; Ahmadi, F; F. Soleymani
2014-01-01
Sustainable agriculture systems emphasized on the on-farm inputs likes use of biofertilizers, crop rotation and cover crops. This experiment was conducted in a split plots arrangement with two factors based on randomized complete block design with three replications during years 2009-2010, at Research Farm of Ferdowsi University of Mashhad. The main factor consisted of cultivation and no cultivation of cover crops in autumn. The sub factor was biofertilizer application with four levels, inclu...
The Cauchy-Lagrangian method for numerical analysis of Euler flow
Podvigina, O; Frisch, U
2015-01-01
A novel semi-Lagrangian method is introduced to solve numerically the Euler equation for ideal incompressible flow in arbitrary space dimension. It exploits the time-analyticity of fluid particle trajectories and requires, in principle, only limited spatial smoothness of the initial data. Efficient generation of high-order time-Taylor coefficients is made possible by simple recurrence relations that follow from the Cauchy invariants formulation of the Euler equations (Zheligovsky & Frisch, J. Fluid Mech. 2014, 749, 404-430). Truncated time-Taylor series of very high order allow the use of time steps vastly exceeding the Courant-Friedrichs-Lewy limit, without compromising the accuracy of the solution. Tests performed on the two-dimensional Euler equation indicate that the Cauchy-Lagrangian method is more --- and occasionally much more --- efficient and less prone to instability than Eulerian Runge-Kutta methods and less prone to rapid growth of rounding errors than the high-order Eulerian time-Taylor algor...
Institute of Scientific and Technical Information of China (English)
高超; 罗时钧; 刘锋
2003-01-01
This paper presents an efficient numerical method for solving the unsteady Euler equations on stationary rectilinear grids. Boundary conditions on the surface of an airfoil are implemented by using their first-order expansions on the mean chord line. The method is not restricted to flows with small disturbances since there are no restrictions on the mean angle of attack of the airfoil. The mathematical formulation and the numerical implementation of the wall boundary conditions in a fully implicit time-accurate finite-volume Euler scheme are described. Unsteady transonic flows about an oscillating NACA 0012 airfoil are calculated. Computational results compare well with Euler solutions by the full boundary conditions on a body-fitted curvilinear grid and published experimental data. This study establishes the feasibility for computing unsteady fluid-structure interaction problems, where the use of a stationary rectilinear grid offers substantial advantages in saving computer time and program design since it does not require the generation and implementation of time-dependent body-fitted grids.
Wing aeroelasticity analysis based on an integral boundary-layer method coupled with Euler solver
Institute of Scientific and Technical Information of China (English)
Ma Yanfeng; He Erming; Zeng Xianang; Li Junjie
2016-01-01
An interactive boundary-layer method, which solves the unsteady flow, is developed for aeroelastic computation in the time domain. The coupled method combines the Euler solver with the integral boundary-layer solver (Euler/BL) in a ‘‘semi-inverse” manner to compute flows with the inviscid and viscous interaction. Unsteady boundary conditions on moving surfaces are taken into account by utilizing the approximate small-perturbation method without moving the compu-tational grids. The steady and unsteady flow calculations for the LANN wing are presented. The wing tip displacement of high Reynolds number aero-structural dynamics (HIRENASD) Project is simulated under different angles of attack. The flutter-boundary predictions for the AGARD 445.6 wing are provided. The results of the interactive boundary-layer method are compared with those of the Euler method and experimental data. The study shows that viscous effects are signif-icant for these cases and the further data analysis confirms the validity and practicability of the cou-pled method.
Recursive adjustment approach for the inversion of the Euler-Liouville Equation
Kirschner, S.; Seitz, F.
2012-12-01
The pole tide Love number (k2) has a direct influence on the numerical forward modeling of the Earth orientation parameters (EOP), polar motion and length of day. This dependency is physically described by the Euler-Liouville equation, which is based on the balance of angular momentum in the Earth system. We use an inversion of Euler-Liouville equation to estimate the pole tide Love number. There are several possible approaches for the implementation of the inversion. Here we concentrate on a recursive adjustment approach. This approach allows the inversion of the Euler-Liouville equation in a computationally efficient way. It is alternative to a Kalman filter approach that will be discussed in the presentation by Seitz et al. in this session. The recursive adjustment approach and its results are analyzed and compared to the results from the Kalman approach. An improvement of the pole tide Love number is possible due to the use of highly precise observed EOP over many decades by geodetic methods. It is shown that the application of the improved pole tide Love number significantly enhances the performance of the forward model. The pole tide Love number effects directly the period and damping of the free rotation of the Earth (Chandler oscillation). The study is carried out in the frame of the German DFG research unit on Earth Rotation and Global Dynamic Processes.
Drawing area-proportional Euler diagrams representing up to three sets.
Rodgers, Peter; Stapleton, Gem; Flower, Jean; Howse, John
2014-01-01
Area-proportional Euler diagrams representing three sets are commonly used to visualize the results of medical experiments, business data, and information from other applications where statistical results are best shown using interlinking curves. Currently, there is no tool that will reliably visualize exact area-proportional diagrams for up to three sets. Limited success, in terms of diagram accuracy, has been achieved for a small number of cases, such as Venn-2 and Venn-3 where all intersections between the sets must be represented. Euler diagrams do not have to include all intersections and so permit the visualization of cases where some intersections have a zero value. This paper describes a general, implemented, method for visualizing all 40 Euler-3 diagrams in an area-proportional manner. We provide techniques for generating the curves with circles and convex polygons, analyze the drawability of data with these shapes, and give a mechanism for deciding whether such data can be drawn with circles. For the cases where nonconvex curves are necessary, our method draws an appropriate diagram using nonconvex polygons. Thus, we are now always able to automatically visualize data for up to three sets.
Self-truncation and scaling in Euler-Voigt-α and related fluid models.
Di Molfetta, Giuseppe; Krstlulovic, Giorgio; Brachet, Marc
2015-07-01
A generalization of the 3D Euler-Voigt-α model is obtained by introducing derivatives of arbitrary order β (instead of 2) in the Helmholtz operator. The β→∞ limit is shown to correspond to Galerkin truncation of the Euler equation. Direct numerical simulations (DNS) of the model are performed with resolutions up to 2048(3) and Taylor-Green initial data. DNS performed at large β demonstrate that this simple classical hydrodynamical model presents a self-truncation behavior, similar to that previously observed for the Gross-Pitaeveskii equation in Krstulovic and Brachet [Phys. Rev. Lett. 106, 115303 (2011)]. The self-truncation regime of the generalized model is shown to reproduce the behavior of the truncated Euler equation demonstrated in Cichowlas et al. [Phys. Rev. Lett. 95, 264502 (2005)]. The long-time growth of the self-truncation wave number k(st) appears to be self-similar. Two related α-Voigt versions of the eddy-damped quasinormal Markovian model and the Leith model are introduced. These simplified theoretical models are shown to reasonably reproduce intermediate time DNS results. The values of the self-similar exponents of these models are found analytically.
Reddy, T. S. R.; Srivastava, R.; Mehmed, Oral
2002-01-01
An aeroelastic analysis system for flutter and forced response analysis of turbomachines based on a two-dimensional linearized unsteady Euler solver has been developed. The ASTROP2 code, an aeroelastic stability analysis program for turbomachinery, was used as a basis for this development. The ASTROP2 code uses strip theory to couple a two dimensional aerodynamic model with a three dimensional structural model. The code was modified to include forced response capability. The formulation was also modified to include aeroelastic analysis with mistuning. A linearized unsteady Euler solver, LINFLX2D is added to model the unsteady aerodynamics in ASTROP2. By calculating the unsteady aerodynamic loads using LINFLX2D, it is possible to include the effects of transonic flow on flutter and forced response in the analysis. The stability is inferred from an eigenvalue analysis. The revised code, ASTROP2-LE for ASTROP2 code using Linearized Euler aerodynamics, is validated by comparing the predictions with those obtained using linear unsteady aerodynamic solutions.
Wing aeroelasticity analysis based on an integral boundary-layer method coupled with Euler solver
Directory of Open Access Journals (Sweden)
Ma Yanfeng
2016-10-01
Full Text Available An interactive boundary-layer method, which solves the unsteady flow, is developed for aeroelastic computation in the time domain. The coupled method combines the Euler solver with the integral boundary-layer solver (Euler/BL in a “semi-inverse” manner to compute flows with the inviscid and viscous interaction. Unsteady boundary conditions on moving surfaces are taken into account by utilizing the approximate small-perturbation method without moving the computational grids. The steady and unsteady flow calculations for the LANN wing are presented. The wing tip displacement of high Reynolds number aero-structural dynamics (HIRENASD Project is simulated under different angles of attack. The flutter-boundary predictions for the AGARD 445.6 wing are provided. The results of the interactive boundary-layer method are compared with those of the Euler method and experimental data. The study shows that viscous effects are significant for these cases and the further data analysis confirms the validity and practicability of the coupled method.
Correction to Euler's equations and elimination of the closure problem in turbulence
Directory of Open Access Journals (Sweden)
Michail Zak
2012-12-01
Full Text Available It has been demonstrated that the Euler equations of inviscid fluid are incomplete: according to the principle of release of constraints, absence of shear stresses must be compensated by additional degrees of freedom, and that leads to a Reynolds-type multivalued velocity field. However, unlike the Reynolds equations, the enlarged Euler's (EE model provides additional equations for fluctuations, and that eliminates the closure problem. Therefore the EE equations are applicable to fully developed turbulent motions where the physical viscosity is vanishingly small compare to the turbulent viscosity, as well as to superfluids and atomized fluids. Analysis of coupled mean/fluctuation EE equations shows that fluctuations stabilize the whole system generating elastic shear waves and increasing speed of sound. Those turbulent motions that originated from instability of underlying laminar motions can be described by the modified Euler's equation with the closure provided by the stabilization principle: driven by instability of laminar motion, fluctuations grow until the new state attains a neutral stability in the enlarged (multivalued class of functions, and these fluctuations can be taken as boundary conditions for the EE model. The approach is illustrated by an example.
Accuracy of an unstructured-grid upwind-Euler algorithm for the ONERA M6 wing
Batina, John T.
1991-01-01
Improved algorithms for the solution of the three-dimensional, time-dependent Euler equations are presented for aerodynamic analysis involving unstructured dynamic meshes. The improvements have been developed recently to the spatial and temporal discretizations used by unstructured-grid flow solvers. The spatial discretization involves a flux-split approach that is naturally dissipative and captures shock waves sharply with at most one grid point within the shock structure. The temporal discretization involves either an explicit time-integration scheme using a multistage Runge-Kutta procedure or an implicit time-integration scheme using a Gauss-Seidel relaxation procedure, which is computationally efficient for either steady or unsteady flow problems. With the implicit Gauss-Seidel procedure, very large time steps may be used for rapid convergence to steady state, and the step size for unsteady cases may be selected for temporal accuracy rather than for numerical stability. Steady flow results are presented for both the NACA 0012 airfoil and the Office National d'Etudes et de Recherches Aerospatiales M6 wing to demonstrate applications of the new Euler solvers. The paper presents a description of the Euler solvers along with results and comparisons that assess the capability.
Smilovic, Mikhail; Gleeson, Tom; Adamowski, Jan
2016-11-01
The crop-water production function quantitatively evaluates the relationship between seasonal water use and crop yield and is used to evaluate optimal irrigation depth and assess the potential of deficit and supplemental irrigation. A simple and easily applicable methodology to develop crop- and region-specific crop-water production functions using crop coefficients and sensitivity-indices is presented. Previous efforts to describe the crop-water production function have not accounted for the effects of the temporal distribution of water use and trivialize the associated variability in yields by assuming an optimized or arbitrary temporal distribution. The temporal distribution of water use throughout the growing season can significantly influence crop yield, and the ability of farmers to manage both the timing and amount of irrigation water may result in higher yields. We propose crop kites, a tool that explicitly acknowledges crop yield as a function of the temporal distribution of water use to both evaluate the complete space of water use and crop yield relationships, and extract from this space specific crop-water production functions. An example for winter wheat is presented using previously validated crop-specific sensitivity indices. Crop-water production functions are extracted from the crop kite related to specific irrigation schedules and temporal distributions of water use. Crop-water production functions associated with maximizing agricultural production agree with previous efforts characterizing the shape as a diminishing curvilinear function. Crop kites provide the tools for water managers and policy makers to evaluate crop- and region-specific agricultural production as it relates to water management and the associated economics, and to determine appropriate policies for developing and supporting the infrastructure to increase water productivity.
Genetically modified crops and food security.
Directory of Open Access Journals (Sweden)
Matin Qaim
Full Text Available The role of genetically modified (GM crops for food security is the subject of public controversy. GM crops could contribute to food production increases and higher food availability. There may also be impacts on food quality and nutrient composition. Finally, growing GM crops may influence farmers' income and thus their economic access to food. Smallholder farmers make up a large proportion of the undernourished people worldwide. Our study focuses on this latter aspect and provides the first ex post analysis of food security impacts of GM crops at the micro level. We use comprehensive panel data collected over several years from farm households in India, where insect-resistant GM cotton has been widely adopted. Controlling for other factors, the adoption of GM cotton has significantly improved calorie consumption and dietary quality, resulting from increased family incomes. This technology has reduced food insecurity by 15-20% among cotton-producing households. GM crops alone will not solve the hunger problem, but they can be an important component in a broader food security strategy.
Genetically modified crops and food security.
Qaim, Matin; Kouser, Shahzad
2013-01-01
The role of genetically modified (GM) crops for food security is the subject of public controversy. GM crops could contribute to food production increases and higher food availability. There may also be impacts on food quality and nutrient composition. Finally, growing GM crops may influence farmers' income and thus their economic access to food. Smallholder farmers make up a large proportion of the undernourished people worldwide. Our study focuses on this latter aspect and provides the first ex post analysis of food security impacts of GM crops at the micro level. We use comprehensive panel data collected over several years from farm households in India, where insect-resistant GM cotton has been widely adopted. Controlling for other factors, the adoption of GM cotton has significantly improved calorie consumption and dietary quality, resulting from increased family incomes. This technology has reduced food insecurity by 15-20% among cotton-producing households. GM crops alone will not solve the hunger problem, but they can be an important component in a broader food security strategy.
Sneessens, I; Veysset, P; Benoit, M; Lamadon, A; Brunschwig, G
2016-11-01
improving performances, crop-livestock organization influences the capacity of MC-L systems to benefit from crop-livestock interactions. As a consequence, we observed a decreasing performance trade-off between MC-L systems for farm income (-4%) and crop GHG emissions (-10%) whereas the gap increases for nitrogen balance (+23%), livestock production (+6%) - MJ consumption (+16%) - GHG emissions (+5%) and crop MJ consumption (+5%). However, the indirect impact of crop-livestock organization doesn't reverse the trend of trade-offs between objectives of sustainability determined by the direct impact of crop-livestock organization. As a conclusion, crop-livestock organization is a key factor that has to be taken into account when studying the sustainability of mixed crop-livestock systems.
Institute of Scientific and Technical Information of China (English)
Yeping LI
2013-01-01
In this paper,a one-dimensional bipolar Euler-Poisson system (a hydrodynamic model) from semiconductors or plasmas with boundary effects is considered.This system takes the form of Euler-Poisson with an electric field and frictional damping added to the momentum equations.The large-time behavior of uniformly bounded weak solutions to the initial-boundary value problem for the one-dimensional bipolar Euler-Poisson system is firstly presented.Next,two particle densities and the corresponding current momenta are verified to satisfy the porous medium equation and the classical Darcy's law time asymptotically.Finally,as a by-product,the quasineutral limit of the weak solutions to the initial-boundary value problem is investigated in the sense that the bounded L∞ entropy solution to the one-dimensional bipolar Euler-Poisson system converges to that of the corresponding one-dimensional compressible Euler equations with damping exponentially fast as t → +∞.As far as we know,this is the first result about the asymptotic behavior and the quasineutral limit for the one-dimensional bipolar Euler-Poisson system with boundary effects and a vacuum.
CROPS : high tech agricultural robots
Bontsema, J.; Hemming, J.; Pekkeriet, E.J.
2014-01-01
In the EU-funded CROPS (Clever Robots for Crops) project high tech robots are developed for site-specific spraying and selective harvesting of fruit and fruit vegetables. The harvesting robots are being designed to harvest high-value crops such as greenhouse vegetables, fruits in orchards and grapes
Crop coefficients for winter wheat in a sub-humid climate regime
DEFF Research Database (Denmark)
Kjaersgaard, J H; Plauborg, Finn; Mollerup, M
2008-01-01
and plant physiological factors influencing ET cause these estimations to be based on calculated values rather than the measured ones. The two-step approach where ET from a reference crop is calculated and multiplied by empirical crop coefficients to obtain ET from a crop has gained wide acceptance. Daily...... measurements were quality controlled and discarded from the analysis if flagged for errors. Daily values of ET from the reference crop and winter wheat calculated from hourly values were used to calculate the crop coefficients. Average daily crop coefficients were in the 1.1-1.15 range during mid...
Roy, Stuart J.
2014-04-01
Soil salinity is a major constraint to agriculture. To improve salinity tolerance of crops, various traits can be incorporated, including ion exclusion, osmotic tolerance and tissue tolerance. We review the roles of a range of genes involved in salt tolerance traits. Different tissues and cells are adapted for specific and often diverse function, so it is important to express the genes in specific cell-types and to pyramid a range of traits. Modern biotechnology (marker- assisted selection or genetic engineering) needs to be increasingly used to introduce the correct combination of genes into elite crop cultivars. Importantly, the effects of introduced genes need to be evaluated in the field to determine their effect on salinity tolerance and yield improvement.
Halophytes As Bioenergy Crops.
Sharma, Rita; Wungrampha, Silas; Singh, Vinay; Pareek, Ashwani; Sharma, Manoj K
2016-01-01
Shrinking arable land due to soil salinization and, depleting fresh water resources pose serious worldwide constraints to crop productivity. A vision of using plant feedstock for biofuel production can only be realized if we can identify alternate species that can be grown on saline soils and therefore, would not compete for the resources required for conventional agriculture. Halophytes have remarkable ability to grow under high salinity conditions. They can be irrigated with seawater without compromising their biomass and seed yields making them good alternate candidates as bioenergy crops. Both oil produced from the seeds and the lignocellulosic biomass of halophytes can be utilized for biofuel production. Several researchers across the globe have recognized this potential and assessed several halophytes for their tolerance to salt, seed oil contents and composition of their lignocellulosic biomass. Here, we review current advances and highlight the key species of halophytes analyzed for this purpose. We have critically assessed the challenges and opportunities associated with using halophytes as bioenergy crops.
Suppression of soilborne pathogens in mixed cropping systems
Hiddink, G.A.
2008-01-01
Since the green revolution, agricultural production has increased tremendously due to synthetic fertilizers, chemical crop protectants and high yielding plant varieties. However, soilborne pathogens remain yield-limiting factors in agricultural production. Hardly any sustainable solutions are availa
Areas within an agricultural field in the same season often differ in crop productivity despite having the same cropping history, crop genotype, and management practices. One hypothesis is that abiotic or biotic factors in the soils differ between areas resulting in these productivity differences. I...
Humic substances and its distribution in coffee crop under cover crops and weed control methods
Directory of Open Access Journals (Sweden)
Bruno Henrique Martins
2016-08-01
Full Text Available ABSTRACT Humic substances (HS comprise the passive element in soil organic matter (SOM, and represent one of the soil carbon pools which may be altered by different cover crops and weed control methods. This study aimed to assess HS distribution and characteristics in an experimental coffee crop area subjected to cover crops and cultural, mechanical, and chemical weed control. The study was carried out at Londrina, in the state of Paraná, southern Brazil (23°21’30” S; 51°10’17” W. In 2008, seven weed control/cover crops were established in a randomized block design between two coffee rows as the main-plot factor per plot and soil sampling depths (0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm as a split-plot. HS were extracted through alkaline and acid solutions and analyzed by chromic acid wet oxidation and UV-Vis spectroscopy. Chemical attributes presented variations in the topsoil between the field conditions analyzed. Cover crop cutting and coffee tree pruning residues left on the soil surface may have interfered in nutrient cycling and the humification process. Data showed that humic substances comprised about 50 % of SOM. Although different cover crops and weed control methods did not alter humic and fulvic acid carbon content, a possible incidence of condensed aromatic structures at depth increments in fulvic acids was observed, leading to an average decrease of 53 % in the E4/E6 ratio. Humin carbon content increased 25 % in the topsoil, particularly under crop weed-control methods, probably due to high incorporation of recalcitrant structures from coffee tree pruning residues and cover crops.
WEED POPULATION IN RELATION TO CROP ROTATION AND NITROGEN FERTILISATION.
Derycke, V; Latré, J; Van De Vijver, E; De Roo, B; De Cauwer, B; Haesaert, G
2014-01-01
In order to assess the impact of crop rotation and nitrogen fertilisation in an agro system, a long-term field experiment has been established in 2006 at the experimental farm of Ghent University and University College Ghent (Bottelare-Belgium). The trial comprises 11 different crop rotations in combination with four nitrogen fertilizer regimes. The different crop rotations are monoculture of grain- and silage maize, whether or not followed by Italian ryegrass, permanent and temporary grass-clover and six other rotations of maize in combination with potatoes, wheat, fodder beet and peas. Normal crop husbandry measures were taken for each crop. The experiment was set up on a sandy loam soil, according to a strip plot design with 3 replicates. In the course of the experiment, crop rotation was the horizontal factor and fertilizer nitrogen (N) the vertical factor. The effect of crop rotation on yield, disease pressure, soil structure and earthworm abundance were evaluated yearly. In autumn 2013 the weed seed bank was analysed for each plot using the seedling emergence method. The obtained results indicated differences between the different crop rotations.
Crop protection by seed coating.
Ehsanfar, S; Modarres-Sanavy, S A M
2005-01-01
Providence of sufficient and healthy food for increasing human population clears the importance of notice to increasing crop production in company with environmental loss reduction. Growth and yield of every plant with sexual reproduction, depends on germination & emergence of sown seeds. Seed is a small alive plant that its biological function is protection and nutrition of embryo. Biological, chemical and physiological characteristics of seed, affect on plant performance & its resistance to undesirable environmental conditions, and even on its total yield. So attention to seed and try to increase its performance is so important. One of the factors that cause reduction in germination percentage and seedling establishment, is seed disease. It's possible to control these diseases by treating the seed before planting it. Coating the seed with pesticides, is one of the ways to gain this goal. Seed coating is a technique in which several material as fertilizers, nutritional elements, moisture attractive or repulsive agents, plant growth regulators, rhizobium inocolum, chemical & pesticide etc, add to seed by adhesive agents and cause to increase seed performance and germination. Seed coating, leads to increase benefits in seed industry, because seeds can use all of their genetic vigor. This technique is used for seeds of many garden plants, valuable crops (such as corn, sunflower, canola, alfalfa,...) and some of the grasses. In this technique that was first used in coating cereal seeds in 1930, a thin and permeable layer of pesticide is stuck on seed surface and prevent damage of seedborn pathogens. This layer is melted or splited after absorption of moisture and suitable temperature by seed, and let the radical to exit the seed. In this approach materials are used accurately with seed, evaporation & leakage of pesticide and also adverse effects of some pesticides on seeds are diminished, and these factors cause to increase the accuracy and performance of pesticide
SMALLHOLDER FARMERS’ WILLINGNESS TO INCORPORATE BIOFUEL CROPS INTO CROPPING SYSTEMS IN MALAWI
Directory of Open Access Journals (Sweden)
Beston Bille Maonga
2015-01-01
Full Text Available Using cross-sectional data, this study analysed the critical and significant socioeconomic factors with high likelihood to determine smallholder farmers’ decision and willingness to adopt jatropha into cropping systems in Malawi. Employing desk study and multi-stage random sampling technique a sample of 592 households was drawn from across the country for analysis. A probit model was used for the analysis of determinants of jatropha adoption by smallholder farmers. Empirical findings show that education, access to loan, bicycle ownership and farmers’ expectation of raising socioeconomic status are major significant factors that would positively determine probability of smallholder farmers’ willingness to adopt jatropha as a biofuel crop on the farm. Furthermore, keeping of ruminant herds of livestock, long distance to market and fears of market unavailability have been revealed to have significant negative influence on farmers’ decision and willingness to adopt jatropha. Policy implications for sustainable crop diversification drive are drawn and discussed.
The Crop Journal Calls for Papers
Institute of Scientific and Technical Information of China (English)
2015-01-01
We would like to invite you to submit your latest research accomplishments to The Crop Journal,an international,peer‐reviewed research publication covering all aspects of crop sciences including crop genetics,breeding,agronomy,crop physiology,germplasm resources,grain chemistry,grain storage and processing,crop management practices,crop biotechnology,and biomathematics on a bimonthly basis.
The Crop Journal Calls for Papers
Institute of Scientific and Technical Information of China (English)
2015-01-01
We would like to invite you to submit your latest research accomplishments to The Crop Journal,an international,peer-reviewed research publication covering all aspects of crop sciences including crop genetics,breeding,agronomy,crop physiology,germplasm resources,grain chemistry,grain storage and processing,crop management practices,crop biotechnology,and biomathematics on a bimonthly basis.
The Crop Journal Calls for Papers
Institute of Scientific and Technical Information of China (English)
2016-01-01
We would like to invite you to submit your latest research accomplishments to The Crop Journal,an international,peer‐reviewed research publication covering all aspects of crop sciences including crop genetics,breeding,agronomy,crop physiology,germplasm resources,grain chemistry,grain storage and processing,crop management practices,crop biotechnology,and biomathematics on a bimonthly basis.
Energy Technology Data Exchange (ETDEWEB)
Cordier, S.
1995-05-01
In this work a 1-D model of electrons and ions plasma is considered. Electrons are supposed to be in Maxwell-Boltzmann thermodynamic equilibrium while ions are described with an isothermal flow model of charged particles submitted to a self-consistent electric field. A collision term between neutral particles and ions simulates the presence of neutral particles. This work demonstrates the existence of low entropy solutions for this simple model with arbitrary initial conditions. Most of the paper is devoted to the demonstration of this theorem and follows the successive steps: construction of a numerical scheme, recall of the classical properties of Riemann problem solutions using Glimm method, uniform estimations for the whole variation norm, and finally, convergence of the constructed solutions towards a low entropy solution for the non-linear Euler/Poisson system. Domains of application for this type of model are listed in the conclusion. (J.S.). 18 refs.
若干包含Euler函数φ(n)的方程%Some Equations Involving Euler Function φ( n )
Institute of Scientific and Technical Information of China (English)
孙翠芳; 程智
2012-01-01
For any positive integer n, let φ(n) be Euler function and Ω(n) denote the total number of prime factors of re, we studied the solutions of three kinds of equations n -φ(n) =2Ω(n) , n-φ(φ(n)) =2Ω(n) and φ(n -φ(n)) =2Ω(n) using the methods of number theory, obtaining all the positive integer solutions of these kinds of equations.%设n为任意正整数,φ(n)是Euler函数,Ω(n)表示n的素因数个数.利用数论中的理论和方法,研究三类方程n-φ(n)=2Ω(n),n-φ(φ(n))=2Ω(n)和φ(n-φ(n))=2Ω(n)的可解性问题,获得了这三类方程的所有正整数解.
Haruvy, Nava; Shalhevet, Sarit
2006-01-01
Regional planning should consider the impact of agricultural crops on housing value and leisure, as well as on the local environment. We designed an optimization model for allocating agricultural crops based on farmers profits as well as the impact on these three factors. Each crop creates a different landscape, as well as a different effect on shading and noise reduction. These in turn influence the value of nearby housing and the regional leisure opportunities. Each crop also has a positive...
Biotechnological Intervention for Biofortification in Crop Plants – A Brief Review
Patel, Y J; R. S. Ingalhalli
2013-01-01
Over half of the global population is estimated to be suffering from various food deficiency diseases. A large portion of the population in the developing countries relies mainly on one or more staple food crops for their nutrition. In this context, it has become imperative to supplement the staple crops with important necessary nutritional factors. Biotechnological approaches have played an important role in crop improvement and can be a helping tool in developing staple food crops with s...
Performance evaluation of selected crop yield-water use models for wheat crop
Directory of Open Access Journals (Sweden)
H. E. Igbadun
2001-10-01
Full Text Available Crop yield-water use models that provide useful information about the exact form of crop response to different amounts of water used by the crop throughout its growth stages and those that provide adequate information for decisions on optimal use of water in the farm were evaluated. Three crop yield models: Jensen (1968, Minhas et al., (1974 and Bras and Cordova (1981 additive type models were studied. Wheat (Triticum aestivum was planted at the Institute for Agricultural Research Farm during the 1995/96 and 1996/97 irrigation seasons of November to March. The data collected from the field experiments during the 1995/96 planting season were used to calibrate the models and their stress sensitivity factors estimated for four selected growth stages of the wheat crop. The ability of the model to predict grain yield of wheat with the estimated stress sensitivity factors was evaluated by comparing predicted grain yields by each model with those obtained in the field during the 1996/97 season. The three models performed fairly well in predicting grain yields, as the predicted results were not significantly different from the field measured grain yield at 5% level of significance.
GEOGLAM Crop Monitor Assessment Tool: Developing Monthly Crop Condition Assessments
McGaughey, K.; Becker Reshef, I.; Barker, B.; Humber, M. L.; Nordling, J.; Justice, C. O.; Deshayes, M.
2014-12-01
The Group on Earth Observations (GEO) developed the Global Agricultural Monitoring initiative (GEOGLAM) to improve existing agricultural information through a network of international partnerships, data sharing, and operational research. This presentation will discuss the Crop Monitor component of GEOGLAM, which provides the Agricultural Market Information System (AMIS) with an international, multi-source, and transparent consensus assessment of crop growing conditions, status, and agro-climatic conditions likely to impact global production. This activity covers the four primary crop types (wheat, maize, rice, and soybean) within the main agricultural producing regions of the AMIS countries. These assessments have been produced operationally since September 2013 and are published in the AMIS Market Monitor Bulletin. The Crop Monitor reports provide cartographic and textual summaries of crop conditions as of the 28th of each month, according to crop type. This presentation will focus on the building of international networks, data collection, and data dissemination.
IMPORTANCE OF CRITICAL PERIOD OF WEED COMPETITION FOR CROP GROWING
Directory of Open Access Journals (Sweden)
Marijana Ivanek-Martinčić
2010-06-01
Full Text Available A concept of critical period of weed competition has been introduced for more than 40 years ago. The concept is based on the assumption that weeds are not equally harmful to a crop during the whole season and that there is a period in crop development in which weeds impact on the yield is the biggest. This period is called critical period of weed competition (CPWC, critical period of weed interference, or critical period of weed control. There is a difference in CPWC between crops, but CPWC for a certain crop can vary a lot because it depends on many factors which can affect the crop or weeds competition ability. The critical period of weed competition identification is essential for integrated weed control and precise planning of a weed control strategy as well as for rationale use of herbicides and other weed control measures.
[Effects of agricultural activities and transgenic crops on agricultural biodiversity].
Zhang, Xi-Tao; Luo, Hong-Bing; Li, Jun-Sheng; Huang, Hai; Liu, Yong-Bo
2014-09-01
Agricultural biodiversity is a key part of the ecosystem biodiversity, but it receives little concern. The monoculture, environmental pollution and habitat fragmentation caused by agricultural activities have threatened agricultural biodiversity over the past 50 years. To optimize agricultural management measures for crop production and environmental protection, we reviewed the effects of agricultural activities, including cultivation patterns, plastic mulching, chemical additions and the cultivation of transgenic crops, on agricultural biodiversity. The results showed that chemical pesticides and fertilizers had the most serious influence and the effects of transgenic crops varied with other factors like the specific transgene inserted in crops. The environmental risk of transgenic crops should be assessed widely through case-by-case methods, particularly its potential impacts on agricultural biodiversity. It is important to consider the protection of agricultural biodiversity before taking certain agricultural practices, which could improve agricultural production and simultaneously reduce the environmental impacts.
Besse, Nicolas; Frisch, Uriel
2017-04-01
The 3D incompressible Euler equations are an important research topic in the mathematical study of fluid dynamics. Not only is the global regularity for smooth initial data an open issue, but the behaviour may also depend on the presence or absence of boundaries. For a good understanding, it is crucial to carry out, besides mathematical studies, high-accuracy and well-resolved numerical exploration. Such studies can be very demanding in computational resources, but recently it has been shown that very substantial gains can be achieved first, by using Cauchy's Lagrangian formulation of the Euler equations and second, by taking advantage of analyticity results of the Lagrangian trajectories for flows whose initial vorticity is Hölder-continuous. The latter has been known for about 20 years (Serfati in J Math Pures Appl 74:95-104, 1995), but the combination of the two, which makes use of recursion relations among time-Taylor coefficients to obtain constructively the time-Taylor series of the Lagrangian map, has been achieved only recently (Frisch and Zheligovsky in Commun Math Phys 326:499-505, 2014; Podvigina et al. in J Comput Phys 306:320-342, 2016 and references therein). Here we extend this methodology to incompressible Euler flow in an impermeable bounded domain whose boundary may be either analytic or have a regularity between indefinite differentiability and analyticity. Non-constructive regularity results for these cases have already been obtained by Glass et al. (Ann Sci Éc Norm Sup 45:1-51, 2012). Using the invariance of the boundary under the Lagrangian flow, we establish novel recursion relations that include contributions from the boundary. This leads to a constructive proof of time-analyticity of the Lagrangian trajectories with analytic boundaries, which can then be used subsequently for the design of a very high-order Cauchy-Lagrangian method.
Besse, Nicolas; Frisch, Uriel
2017-01-01
The 3D incompressible Euler equations are an important research topic in the mathematical study of fluid dynamics. Not only is the global regularity for smooth initial data an open issue, but the behaviour may also depend on the presence or absence of boundaries. For a good understanding, it is crucial to carry out, besides mathematical studies, high-accuracy and well-resolved numerical exploration. Such studies can be very demanding in computational resources, but recently it has been shown that very substantial gains can be achieved first, by using Cauchy's Lagrangian formulation of the Euler equations and second, by taking advantage of analyticity results of the Lagrangian trajectories for flows whose initial vorticity is Hölder-continuous. The latter has been known for about 20 years (Serfati in J Math Pures Appl 74:95-104, 1995), but the combination of the two, which makes use of recursion relations among time-Taylor coefficients to obtain constructively the time-Taylor series of the Lagrangian map, has been achieved only recently (Frisch and Zheligovsky in Commun Math Phys 326:499-505, 2014; Podvigina et al. in J Comput Phys 306:320-342, 2016 and references therein). Here we extend this methodology to incompressible Euler flow in an impermeable bounded domain whose boundary may be either analytic or have a regularity between indefinite differentiability and analyticity. Non-constructive regularity results for these cases have already been obtained by Glass et al. (Ann Sci Éc Norm Sup 45:1-51, 2012). Using the invariance of the boundary under the Lagrangian flow, we establish novel recursion relations that include contributions from the boundary. This leads to a constructive proof of time-analyticity of the Lagrangian trajectories with analytic boundaries, which can then be used subsequently for the design of a very high-order Cauchy-Lagrangian method.
Comparison of a Convected Helmholtz and Euler Model for Impedance Eduction in Flow
Watson, Willie R.; Jones, Michael G.
2006-01-01
Impedances educed from a well-tested convected Helmholtz model are compared to that of a recently developed linearized Euler model using two ceramic test liners under the assumed conditions or uniform flow and a plane wave source. The convected Helmholtz model is restricted to uniform mean flow whereas the linearized Euler model can account for the effect or the shear layer. Test data to educe the impedance is acquired from measurements obtained in the NASA Langley Research Center Grazing Incidence Tube for mean flow Mach numbers ranging from 0.0 to 0.5 and source frequencies ranging from 0.5 kHz to 3.0 kHz. The unknown impedance of the liner b educed by judiciously chooingth e impedance via an optimization method to match the measured acoustic pressure on the wall opposite the test liner. Results are presented on four spatial grids using three different optimization methods (contour deformation, Davidon-Fletcher Powell, and the Genetic Algorithm). All three optimization methods converge to the same impedance when used with the same model and to nearly identical impedances when used on different models. h anomaly was observed only at 0.5 kHz for high mean flow speeds. The anomaly is likely due to the use of measured data in a flow regime where shear layer effects are important but are neglected in the math models. Consistency between the impedances educed using the two models provides confidence that the linearized Euler model is ready For application to more realistic flows, such as those containing shear layers.