Quantitative comparison of foliage display in two plots of corn

1974 ◽  
Vol 52 (12) ◽  
pp. 2465-2471 ◽  
Author(s):  
W. J. Kyle ◽  
J. A. Davies
Keyword(s):  
Canopy Structure ◽  
Theoretical Models ◽  
Quantitative Comparison ◽  
Distribution Functions ◽  
Radiation Interception ◽  
Spherical Distribution ◽  
Solar Altitude ◽  
Leaf Distribution

A quantitative comparison of foliage display in two plots of corn, seeded differently, revealed that the plants in both have essentially the same architecture despite differences in planting procedure. No significant azimuth preferences were found. Investigations of leaf inclinations indicated that leaf distribution functions are very close to the theoretical spherical distribution, with the result that radiation interception calculations are independent of solar altitude. This greatly facilitates the incorporation of canopy structure variables into theoretical models of canopy radiation interception.

Corrigendum - Growth and productivity of irrigated Sorghum bicolor (L. Moench) in Northern Australia. II. Low solar altitude as a possible constraint to productivity in the tropical dry season

1984 ◽  
Vol 35 (2) ◽  
pp. 229
Author(s):  
MA Foale ◽  
GL Wilson ◽  
DB Coates ◽  
KP Haydock
Keyword(s):  
Solar Radiation ◽  
Canopy Structure ◽  
Dry Season ◽  
High Density ◽  
Light Penetration ◽  
Northern Australia ◽  
Growth Study ◽  
Altitude Effect ◽  
Solar Altitude ◽  
Sorghum Bicolor L

A growth study was carried out during the dry season on irrigated grain sorghum cultivar NK 300F at latitude 16�S. in northern Australia. The apparent efficiency of the canopy in the photosynthetic conversion of solar radiation increased progressively in high density stands between June and September, while low density stands showed no change. An hypothesis is advanced that the rise in canopy efficiency was due to increasing solar altitude combining with a suitable canopy structure at high density to give increased light penetration into the canopy. A parameter named weighted mean solar altitude (WMSA) is used in conjunction with noon solar altitude (NSA) to assist in the interpretation of published models of light penetration. This solar altitude effect, if verified by further work, would lower the expectations, based on mean daily solar radiation, for dry season yield of irrigated sorghum and possibly other cereals in the semi-arid tropics.

Some quantitative aspects of ionic melt microstructure

1972 ◽  
Vol 328 (1572) ◽  
pp. 83-95 ◽  
Keyword(s):  
Ionic Liquids ◽  
Ionic Radius ◽  
Theoretical Models ◽  
Liquid Argon ◽  
Distribution Functions ◽  
Ionic Melt ◽  
Ionic Melts ◽  
Equilibrium Microstructure ◽  
Pair Distribution Functions

Computer generated configurations of molten KCl are used to elucidate some aspects of the equilibrium microstructure of ionic liquids. Information obtained by analysis of the pre­viously reported pair distribution functions is expanded by considering corresponding fluctuation functions. The role of Coulombic forces in ionic melts is further illuminated by comparing the indiscriminate distributions of ions with those obtained for atoms in liquid argon. The V -T dependence of structure and ionic radius ratio effects are briefly considered. Current theoretical models are not conformal with the computed microstructure.

scholarly journals Seasonal Variation of the Canopy Structure Parameters and Its Correlation with Yield-Related Traits in Sugarcane

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Jun Luo ◽  
Youxiong Que ◽  
Hua Zhang ◽  
Liping Xu
Keyword(s):  
Transmission Coefficient ◽  
Canopy Structure ◽  
Diffuse Radiation ◽  
Growth Stages ◽  
Beam Radiation ◽  
Area Index ◽  
Sugarcane Varieties ◽  
Sugarcane Yield ◽  
Leaf Distribution ◽  
Different Growth Stages

Population structure determines sugarcane yield, of which canopy structure is a key component. To fully understand the relations between sugarcane yield and parameters of the canopy structure, 17 sugarcane varieties were investigated at five growth stages. The results indicated that there were significant differences between characterized parameters among sugarcane populations at different growth stages. During sugarcane growth after planting, leaf area index (LAI) and leaf distribution (LD) increased, while transmission coefficient for diffuse radiation (TD), mean foliage inclination angle (MFIA), transmission coefficient for solar beam radiation penetration (TR), and extinction coefficient (K) decreased. Significant negative correlations were found between sugarcane yield and MFIA, TD, TR, andKat the early elongation stage, while a significant positive correlation between sugarcane yield and LD was found at the same stage. A regression for sugarcane yield, with relative error of yield fitting less than 10%, was successfully established: sugarcane yield = 2380.12 + 46.25 × LD − 491.82 × LAI + 1.36 × MFIA + 614.91 × TD − 1908.05 × TR − 182.53 ×  K+ 1281.75 × LD − 1.35 × MFIA + 831.2 × TR − 407.8 ×  K+ 8.21 × MFIA − 834.50 × TD − 1695.49 ×  K  (R2=0.94**).

scholarly journals Cosmological parameter estimation via iterative emulation of likelihoods

2020 ◽  
Vol 499 (4) ◽  
pp. 5257-5268 ◽  
Author(s):  
Marcos Pellejero-Ibañez ◽  
Raul E Angulo ◽  
Giovanni Aricó ◽  
Matteo Zennaro ◽  
Sergio Contreras ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Parameter Estimation ◽  
Likelihood Function ◽  
Estimation Algorithm ◽  
Theoretical Models ◽  
Distribution Functions ◽  
Affine Invariant ◽  
New Approach ◽  
Comprehensive Exploitation ◽  
Parameter Estimation Algorithm

ABSTRACT The interpretation of cosmological observables requires the use of increasingly sophisticated theoretical models. Since these models are becoming computationally very expensive and display non-trivial uncertainties, the use of standard Bayesian algorithms for cosmological inferences, such as Markov chain Monte Carlo (MCMC), might become inadequate. Here, we propose a new approach to parameter estimation based on an iterative Gaussian emulation of the target likelihood function. This requires a minimal number of likelihood evaluations and naturally accommodates for stochasticity in theoretical models. We apply the algorithm to estimate 9 parameters from the monopole and quadrupole of a mock power spectrum in redshift space. We obtain accurate posterior distribution functions with approximately 100 times fewer likelihood evaluations than an affine invariant MCMC, roughly independently from the dimensionality of the problem. We anticipate that our parameter estimation algorithm will accelerate the adoption of more accurate theoretical models in data analysis, enabling more comprehensive exploitation of cosmological observables.

scholarly journals Efisiensi Penggunaan Radiasi Matahari dan Respon Tanaman Kedelai (Glycine max L.) terhadap Penggunaan Mulsa Reflektif

2019 ◽  
Vol 46 (3) ◽  
pp. 247-253 ◽  
Author(s):  
Syahrun Mubarak ◽  
Impron , ◽  
Dan Tania June
Keyword(s):  
Solar Radiation ◽  
Canopy Structure ◽  
Crop Productivity ◽  
Radiation Balance ◽  
Transmitted Radiation ◽  
Radiation Interception ◽  
Factors Affecting ◽  
Soybean Crop ◽  
Two Factors ◽  
Glycine Max L

One of factors affecting the productivity of soybean crop is the availability of solar radiation. Reduction of solar radiation reaching soybean crop by cloud cover especially during rainy season or by shade of trees could potentially decrease soybean production. The availability of radiation for the crop can be increased through the use of reflective mulch to reflect back transmitted radiation to the crop canopy. This study aimed to determine the effect of shade and reflective mulch on crop solar radiation balance and crop productivity responses. A field experiment in Bogor, Indonesia in July 2016 to January 2017, was conducted, applying a Nested Design-two factors model with three replications. The first factor was two levels of shading, i.e., without and with 50% shade; and the second factor was three levels, i.e., without mulch, black silver mulch, and metallic mulch. The results showed that the use of mulch influenced the radiation balance of plants, increasing distribution of radiation reception in plants, solar radiation interception and RUE. The use of mulch caused changes in canopy structure by increase LAI, so that the inhibited radiation was higher. The reflected radiation from the mulch increased production per plants and weight of 1,000 seeds in shaded plants.Keywords: black silver mulch, metallic mulch, radiation balance, radiation interception, shading

Unravelling the Internal Complexities of Molten Salts

1998 ◽  
Vol 53 (12) ◽  
pp. 1037-1048 ◽  
Author(s):  
Ashok K. Adya ◽  
Ryuzo Takagi ◽  
Marcelle Gaune-Escard
Keyword(s):  
Neutron Diffraction ◽  
Molten Salts ◽  
Theoretical Models ◽  
Short Review ◽  
Structural Features ◽  
Distribution Functions ◽  
Interatomic Potentials ◽  
X Rays ◽  
Dynamic Simulations ◽  
Simulation Techniques

Abstract Much experimental and theoretical effort has gone into revealing the internal complexities of molten salts for the past two decades. In this paper we shall show how neutron diffraction and computer simulation techniques have helped in gaining a better understanding of these systems at the microscopic level. Firstly, a short review on the structure of molten halide systems as revealed by these techniques will be presented. Complementarity of using X-rays with neutrons and, some recent results on the structure of molten DyCl3 obtained by combining neutron and X-ray diffraction with molecular dynamic simulations will be discussed. Neutron diffraction isotopic substitution techniques have played an important role in elucidating the interatomic structure of a diversity of molten salts. Pair distribution functions (PDFs), determined for a number of 1:1 and 2 :1 halide melts, provided theorists with a critical test of their model potentials. It is now clear that for 1:1 molten systems theoretical models based on Fumi-Tosi potentials can adequately describe many of the structural features. Nevertheless, the chal-lenge is two fold: (i) to determine real interatomic potentials for 2:1 and 3 :1 molten systems capable of reproducing not only the microscopic structural details obtained at the partial PDF, gαβ (r) level, but also their macroscopic behaviour and, (ii) to characterise the structure in binary molten salt mixtures.

scholarly journals Influence of Three-Dimensional Coral Structures on Hyperspectral Benthic Reflectance and Water-Leaving Reflectance

2018 ◽  
Vol 8 (12) ◽  
pp. 2688 ◽  
Author(s):  
John Hedley ◽  
Maryam Mirhakak ◽  
Adam Wentworth ◽  
Heidi Dierssen
Keyword(s):  
Remote Sensing ◽  
Canopy Structure ◽  
Three Dimensional ◽  
Distribution Functions ◽  
Shallow Waters ◽  
Reasonable Assumption ◽  
Sensing Applications ◽  
Remote Sensing Applications ◽  
Canopy Model ◽  
Reflectance Measurements

Shading and inter-reflections created by the three-dimensional coral canopy structure play an important role on benthic reflectance and its propagation above the water. Here, a plane parallel model was coupled with a three-dimensional radiative transfer canopy model, incorporating measured coral shapes and hyperspectral benthic reflectances, to investigate this question under different illumination and water column conditions. Results indicated that a Lambertian treatment of the bottom reflectance can be a reasonable assumption if a variable shading factor is included. Without flexibility in the shading treatment, nadir view bottom reflectances can vary by as much as ±20% (or ±9% in above-water remote sensing reflectance) under solar zenith angles (SZAs) up to 50°. Spectrally-independent shading factors are developed for benthic coral reflectance measurements based on the rugosity of the coral. In remote sensing applications, where the rugosity is unknown, a shading factor could be incorporated as an endmember for retrieval in the inversion scheme. In dense coral canopies in clear shallow waters, the benthos cannot always be treated as Lambertian, and for large solar-view angles the bi-directional reflectance distribution functions (BRDF) hotspot propagated to above water reflectances can create up to a 50% or more difference in water-leaving reflectances, and discrepancies of 20% even for nadir-view geometries.

scholarly journals Canopy structure and radiation interception of Salix matsudana: Stand density dependent relationships

2017 ◽  
Vol 41 (6) ◽  
pp. 661-669
Author(s):  
CHEN Jing ◽  
◽  
ZHAO Cheng-Zhang ◽  
WANG Ji-Wei ◽  
and ZHAO Lian-Chun
Keyword(s):  
Canopy Structure ◽  
Stand Density ◽  
Radiation Interception ◽  
Density Dependent ◽  
Salix Matsudana

A study of luminous environment with prism daylight redirecting fenestrations in classrooms

2020 ◽  
pp. 1420326X1989556 ◽  
Author(s):  
Zhen Tian ◽  
Peng Lin ◽  
Ying He ◽  
Jacob C Jonsson
Keyword(s):  
Dynamic Range ◽  
High Dynamic Range ◽  
Distribution Functions ◽  
International Commission ◽  
Range Image ◽  
Solar Altitude ◽  
Discomfort Glare ◽  
High Dynamic ◽  
Evaluation Metric ◽  
Illuminance Uniformity

This study explored the classroom luminous environment with prism daylight redirecting fenestrations. The differences between the International Commission on Illumination standard sky and the Perez all-weather sky models were analysed. The study described the method of generating a valid bi-directional scattering distribution functions .xml data for the prism daylight redirecting fenestrations. A new evaluation metric, daylight evenness, was proposed to describe indoor illuminance dispersion. Radiance simulation results indicate that at various solar altitude angles, compared with conventional glazing, the micro-prism film and micro-prism with an added diffuse layer on clerestories can improve the space average illuminance levels 23.2% and 18.7% under the International Commission on Illumination sky, as well as 15.4% and 10.6% under the Perez sky, respectively. The analysis results indicate that prism daylight redirecting fenestrations clerestories can improve indoor illuminance uniformity and daylight evenness when the solar altitudes range from 23.8° to 75°. A method combined field questionnaire and high dynamic range image analysis were conducted for discomfort glare study. Adding a diffused layer to the prism film clerestory is expected to alleviate discomfort glare for east- and west-facing prism daylight redirecting fenestrations clerestory with the daylight glare probability reduction of 3.8% to 21.7% at various solar altitudes. The research results present promising advantages of applying prism daylight redirecting fenestrations at classroom clerestories to improve the daylight luminous environment.

Sign in / Sign up

Export Citation Format

Share Document